- Published on
Emergency and Acute Medicine – Cauda Equina Syndrome
Core Concept
Cauda equina syndrome results from compression of the lumbar and sacral nerve roots within the cauda equina, which consists of nerve fibers below the conus medullaris, typically ending at the L1–L2 interspace. This condition represents a neurologic emergency because delayed diagnosis and treatment can lead to permanent deficits.
Predisposing Factors
Patients at increased risk include those with neoplastic disease, intravenous drug use, immunocompromised states, and a history of trauma.
Underlying Causes
Lumbar disc herniation is the most common etiology, most frequently involving the L4–L5 level, followed by L5–S1 and L3–L4, and is most often seen in the fourth and fifth decades of life. Other causes include mass lesions such as myeloma, lymphoma, sarcoma, meningioma, neurofibroma, hematoma, and metastatic disease from breast, lung, prostate, thyroid, or renal malignancies. Infectious causes include spinal epidural abscess, particularly in IV drug users. Additional etiologies include blunt or penetrating trauma, complications of spinal anesthesia, and postoperative or spontaneous hematoma.
Clinical Manifestations
Patients commonly report low back pain with unilateral or bilateral radicular symptoms, lower-extremity numbness or weakness, and difficulty ambulating due to pain or motor deficits. Bladder or bowel dysfunction is a key feature and may present as urinary retention, overflow incontinence, or fecal incontinence. On examination, lumbosacral tenderness may be present along with asymmetric lower-extremity sensory or motor deficits, reduced dorsiflexion strength, quadriceps weakness, diminished deep tendon reflexes, saddle hypalgesia or anesthesia, and decreased anal sphincter tone.
Essential Bedside Assessment
A thorough neurologic examination is critical and includes straight-leg raise testing and the Lasègue maneuver, where hip flexion with foot dorsiflexion reproduces posterior thigh pain. Evaluation of perineal sensation, rectal tone, and the anal wink reflex is essential. Measurement of postvoid residual volume by bladder catheterization or ultrasound is strongly recommended, with volumes greater than 50–100 mL considered abnormal, recognizing that residual volume increases with age; a normal residual makes the diagnosis less likely.
Diagnostic Evaluation
Laboratory testing is guided by the suspected differential and may include CBC, urinalysis, ESR, and CRP, particularly when infection or malignancy is a concern. MRI of the spine is the definitive diagnostic study and should be obtained urgently. If MRI is unavailable or contraindicated, CT myelography is an acceptable alternative. Plain radiographs of the lumbosacral spine may be obtained but are insufficient to exclude the diagnosis.
Key Alternative Diagnoses
Conditions that may mimic cauda equina syndrome include lumbosacral strain, osteoarthritis, sciatica, vertebral fractures, osteomyelitis, spinal epidural abscess, conus medullaris or higher spinal cord compression, ankylosing spondylitis, spinal stenosis, abdominal aortic aneurysm or dissection, vascular claudication, hip pathology, and acute transverse myelitis.
Initial Management Priorities
Airway and other traumatic injuries should be managed as indicated. In trauma patients, full spinal immobilization is mandatory, and even in nontrauma presentations, immobilization should be considered because of the possibility of an unstable spinal lesion. Provide adequate analgesia and keep the patient NPO pending neurosurgical evaluation.
Emergency Department Management
Serial neurologic examinations are required to identify progression. Immediate neurosurgical consultation is mandatory in all suspected cases. For acute spinal cord trauma within 8 hours of onset, initiate high-dose methylprednisolone per protocol. If an epidural abscess is suspected, start empiric antibiotics in consultation with neurosurgery. Although there is debate regarding the exact timing of surgical decompression, recommendations generally range from within 6 hours to within 24 hours of symptom onset, with earlier intervention associated with better outcomes.
Pharmacologic Therapy
High-dose methylprednisolone may be administered for acute spinal cord injury using a protocol of a 30 mg/kg IV bolus followed by a continuous infusion of 5.4 mg/kg/hr over 23 hours, provided therapy is initiated within 8 hours of injury.
Disposition and Follow-Up
All patients with acute cauda equina syndrome require hospital admission under neurosurgical care, and treatment should not be delayed. Rapid surgical decompression is associated with improved neurologic recovery, although patients presenting later than 48 hours may still derive benefit. Discharge is appropriate only for patients with a prior complete evaluation, established diagnosis, no new neurologic deficits, and close follow-up arranged with their neurosurgeon.
Clinical Insights and Cautions
Early recognition before irreversible neurologic injury is crucial. Red flags include back pain disproportionate to exam findings, back pain with fever, and back pain in high-risk populations. When infection is suspected, ESR and CRP should be used as screening tools to avoid missed diagnoses.
Core Concept
Cauda equina syndrome results from compression of the lumbar and sacral nerve roots within the cauda equina, which consists of nerve fibers below the conus medullaris, typically ending at the L1–L2 interspace. This condition represents a neurologic emergency because delayed diagnosis and treatment can lead to permanent deficits.
Predisposing Factors
Patients at increased risk include those with neoplastic disease, intravenous drug use, immunocompromised states, and a history of trauma.
Underlying Causes
Lumbar disc herniation is the most common etiology, most frequently involving the L4–L5 level, followed by L5–S1 and L3–L4, and is most often seen in the fourth and fifth decades of life. Other causes include mass lesions such as myeloma, lymphoma, sarcoma, meningioma, neurofibroma, hematoma, and metastatic disease from breast, lung, prostate, thyroid, or renal malignancies. Infectious causes include spinal epidural abscess, particularly in IV drug users. Additional etiologies include blunt or penetrating trauma, complications of spinal anesthesia, and postoperative or spontaneous hematoma.
Clinical Manifestations
Patients commonly report low back pain with unilateral or bilateral radicular symptoms, lower-extremity numbness or weakness, and difficulty ambulating due to pain or motor deficits. Bladder or bowel dysfunction is a key feature and may present as urinary retention, overflow incontinence, or fecal incontinence. On examination, lumbosacral tenderness may be present along with asymmetric lower-extremity sensory or motor deficits, reduced dorsiflexion strength, quadriceps weakness, diminished deep tendon reflexes, saddle hypalgesia or anesthesia, and decreased anal sphincter tone.
Essential Bedside Assessment
A thorough neurologic examination is critical and includes straight-leg raise testing and the Lasègue maneuver, where hip flexion with foot dorsiflexion reproduces posterior thigh pain. Evaluation of perineal sensation, rectal tone, and the anal wink reflex is essential. Measurement of postvoid residual volume by bladder catheterization or ultrasound is strongly recommended, with volumes greater than 50–100 mL considered abnormal, recognizing that residual volume increases with age; a normal residual makes the diagnosis less likely.
Diagnostic Evaluation
Laboratory testing is guided by the suspected differential and may include CBC, urinalysis, ESR, and CRP, particularly when infection or malignancy is a concern. MRI of the spine is the definitive diagnostic study and should be obtained urgently. If MRI is unavailable or contraindicated, CT myelography is an acceptable alternative. Plain radiographs of the lumbosacral spine may be obtained but are insufficient to exclude the diagnosis.
Key Alternative Diagnoses
Conditions that may mimic cauda equina syndrome include lumbosacral strain, osteoarthritis, sciatica, vertebral fractures, osteomyelitis, spinal epidural abscess, conus medullaris or higher spinal cord compression, ankylosing spondylitis, spinal stenosis, abdominal aortic aneurysm or dissection, vascular claudication, hip pathology, and acute transverse myelitis.
Initial Management Priorities
Airway and other traumatic injuries should be managed as indicated. In trauma patients, full spinal immobilization is mandatory, and even in nontrauma presentations, immobilization should be considered because of the possibility of an unstable spinal lesion. Provide adequate analgesia and keep the patient NPO pending neurosurgical evaluation.
Emergency Department Management
Serial neurologic examinations are required to identify progression. Immediate neurosurgical consultation is mandatory in all suspected cases. For acute spinal cord trauma within 8 hours of onset, initiate high-dose methylprednisolone per protocol. If an epidural abscess is suspected, start empiric antibiotics in consultation with neurosurgery. Although there is debate regarding the exact timing of surgical decompression, recommendations generally range from within 6 hours to within 24 hours of symptom onset, with earlier intervention associated with better outcomes.
Pharmacologic Therapy
High-dose methylprednisolone may be administered for acute spinal cord injury using a protocol of a 30 mg/kg IV bolus followed by a continuous infusion of 5.4 mg/kg/hr over 23 hours, provided therapy is initiated within 8 hours of injury.
Disposition and Follow-Up
All patients with acute cauda equina syndrome require hospital admission under neurosurgical care, and treatment should not be delayed. Rapid surgical decompression is associated with improved neurologic recovery, although patients presenting later than 48 hours may still derive benefit. Discharge is appropriate only for patients with a prior complete evaluation, established diagnosis, no new neurologic deficits, and close follow-up arranged with their neurosurgeon.
Clinical Insights and Cautions
Early recognition before irreversible neurologic injury is crucial. Red flags include back pain disproportionate to exam findings, back pain with fever, and back pain in high-risk populations. When infection is suspected, ESR and CRP should be used as screening tools to avoid missed diagnoses.
- Published on
Emergency and Acute Medicine – Cavernous Sinus Thrombosis
Overview
Cavernous sinus thrombosis is thrombosis within a major intracranial venous drainage pathway and is most often infectious in origin. Infection commonly spreads from facial, odontogenic, or paranasal sinus sources, with hematogenous or contiguous extension. Less frequently, thrombosis occurs in the setting of hypercoagulable states. The cavernous sinus lies superolateral to the sphenoid sinus and surrounds the sella; cranial nerves III, IV, V1, and V2 course within its lateral wall, while cranial nerve VI and the internal carotid artery run medially. Although the cavernous sinus is most often involved, the transverse and superior sagittal sinuses may also be affected.
Pathophysiologic Mechanisms
Infection spreads hematogenously from facial, otic, or neck sources or directly from infected sinus cavities, most commonly sphenoid and ethmoid sinuses. Bacterial proliferation triggers inflammation and coagulation, leading to venous thrombosis. Resulting venous congestion affects adjacent neurovascular structures, producing ophthalmoplegia from involvement of cranial nerves III, IV, or VI, pupillary abnormalities from cranial nerve III dysfunction, and sensory deficits of the forehead or cheek from cranial nerves V1 and V2.
Causative Factors
Septic thrombosis is most common, with Staphylococcus aureus responsible for approximately 70% of cases; Streptococcus pneumoniae, gram-negative organisms, and anaerobes are also implicated. Fungal causes such as Aspergillus and Rhizopus are less frequent. Aseptic causes include granulomatous disease such as tuberculosis, inflammatory disorders, mass effect from skull-base tumors or aneurysms, and hypercoagulable states.
Clinical Presentation
Headache is present in the majority of patients, often accompanied by fever, ocular or retrobulbar pain, facial swelling, visual disturbances, facial dysesthesia, and lethargy or altered mental status. Early physical findings include periorbital edema and chemosis with retinal venous congestion, followed by ptosis, proptosis, and ophthalmoplegia. Cranial nerve deficits are common, particularly lateral gaze palsy from cranial nerve VI involvement and sensory changes in V1 or V2 distributions. Advanced disease may present with meningismus, seizures, coma, or septic shock.
Risk-Oriented History
High-risk features include recent facial trauma, ENT or neurosurgical procedures, manipulation of central facial furuncles, diabetes, or immunocompromised states such as HIV infection, chronic steroid use, or malignancy. Pediatric patients may present with nonspecific symptoms including fever, vomiting, lethargy, or signs of increased intracranial pressure, particularly following otitis or pharyngitis; neonatal cases are especially challenging to diagnose.
Initial Clinical Assessment
Diagnosis is primarily clinical, suggested by venous congestion, ocular findings, unilateral symptoms that rapidly progress to bilateral involvement, and overall toxic appearance. Laboratory studies are supportive but nonspecific, and early imaging findings may be subtle.
Diagnostic Evaluation
Laboratory testing may show leukocytosis, bandemia, and elevated ESR or D-dimer, but lacks sensitivity and specificity. Cerebrospinal fluid analysis may demonstrate parameningeal inflammation or meningitis. Noncontrast CT imaging can be normal early but may later show increased density, filling defects with contrast, dilation of the superior ophthalmic vein, intracranial hemorrhage, or signs of raised intracranial pressure. MRI with MR venography is the diagnostic modality of choice, allowing direct visualization of thrombus and venous structures at all stages of disease.
Alternative Diagnoses
Consider meningitis or encephalitis, intracranial abscess, orbital or periorbital cellulitis, carotid artery aneurysm or fistula, pseudotumor cerebri, acute angle-closure glaucoma, intracranial hemorrhage, and Tolosa–Hunt syndrome.
Emergency Stabilization
Patients may be critically ill and unstable. Immediate assessment and stabilization of airway, breathing, and circulation are essential, with early intubation for airway protection when mental status is impaired and aggressive fluid resuscitation for hemodynamic instability.
Definitive Emergency Management
Initiate broad-spectrum intravenous antibiotics promptly to cover gram-positive organisms including MRSA, gram-negative organisms, and anaerobes, typically using vancomycin or nafcillin combined with a third-generation cephalosporin and metronidazole or clindamycin when indicated. Anticoagulation with heparin may limit clot propagation and improve outcomes, though its use remains controversial and requires exclusion of intracranial hemorrhage prior to initiation. Endovascular thrombolysis may be considered in refractory, severe cases. Systemic corticosteroids may be beneficial in selected patients, particularly with pituitary involvement or inflammatory etiologies. Surgical consultation is required for drainage of the primary infectious source, such as sinus or dental abscesses, and intracranial pressure should be managed aggressively when elevated.
Disposition and Follow-Up
All patients with cavernous sinus thrombosis require hospital admission to a monitored setting, often the intensive care unit. Neurology and neurosurgical consultation are mandatory, and discharge from the emergency department is not appropriate.
Complications and Clinical Cautions
Potential complications include permanent visual impairment, persistent cranial nerve palsies, meningitis, intracranial abscess, seizures, pituitary necrosis with endocrine insufficiency, septic emboli, sepsis, and shock. Mortality remains significant. Maintain a high index of suspicion in patients with recent ENT infections, refractory headache, ocular findings, or hypercoagulable risk factors, as early CT imaging may be misleadingly normal and MRI/MRV should be pursued promptly.
Overview
Cavernous sinus thrombosis is thrombosis within a major intracranial venous drainage pathway and is most often infectious in origin. Infection commonly spreads from facial, odontogenic, or paranasal sinus sources, with hematogenous or contiguous extension. Less frequently, thrombosis occurs in the setting of hypercoagulable states. The cavernous sinus lies superolateral to the sphenoid sinus and surrounds the sella; cranial nerves III, IV, V1, and V2 course within its lateral wall, while cranial nerve VI and the internal carotid artery run medially. Although the cavernous sinus is most often involved, the transverse and superior sagittal sinuses may also be affected.
Pathophysiologic Mechanisms
Infection spreads hematogenously from facial, otic, or neck sources or directly from infected sinus cavities, most commonly sphenoid and ethmoid sinuses. Bacterial proliferation triggers inflammation and coagulation, leading to venous thrombosis. Resulting venous congestion affects adjacent neurovascular structures, producing ophthalmoplegia from involvement of cranial nerves III, IV, or VI, pupillary abnormalities from cranial nerve III dysfunction, and sensory deficits of the forehead or cheek from cranial nerves V1 and V2.
Causative Factors
Septic thrombosis is most common, with Staphylococcus aureus responsible for approximately 70% of cases; Streptococcus pneumoniae, gram-negative organisms, and anaerobes are also implicated. Fungal causes such as Aspergillus and Rhizopus are less frequent. Aseptic causes include granulomatous disease such as tuberculosis, inflammatory disorders, mass effect from skull-base tumors or aneurysms, and hypercoagulable states.
Clinical Presentation
Headache is present in the majority of patients, often accompanied by fever, ocular or retrobulbar pain, facial swelling, visual disturbances, facial dysesthesia, and lethargy or altered mental status. Early physical findings include periorbital edema and chemosis with retinal venous congestion, followed by ptosis, proptosis, and ophthalmoplegia. Cranial nerve deficits are common, particularly lateral gaze palsy from cranial nerve VI involvement and sensory changes in V1 or V2 distributions. Advanced disease may present with meningismus, seizures, coma, or septic shock.
Risk-Oriented History
High-risk features include recent facial trauma, ENT or neurosurgical procedures, manipulation of central facial furuncles, diabetes, or immunocompromised states such as HIV infection, chronic steroid use, or malignancy. Pediatric patients may present with nonspecific symptoms including fever, vomiting, lethargy, or signs of increased intracranial pressure, particularly following otitis or pharyngitis; neonatal cases are especially challenging to diagnose.
Initial Clinical Assessment
Diagnosis is primarily clinical, suggested by venous congestion, ocular findings, unilateral symptoms that rapidly progress to bilateral involvement, and overall toxic appearance. Laboratory studies are supportive but nonspecific, and early imaging findings may be subtle.
Diagnostic Evaluation
Laboratory testing may show leukocytosis, bandemia, and elevated ESR or D-dimer, but lacks sensitivity and specificity. Cerebrospinal fluid analysis may demonstrate parameningeal inflammation or meningitis. Noncontrast CT imaging can be normal early but may later show increased density, filling defects with contrast, dilation of the superior ophthalmic vein, intracranial hemorrhage, or signs of raised intracranial pressure. MRI with MR venography is the diagnostic modality of choice, allowing direct visualization of thrombus and venous structures at all stages of disease.
Alternative Diagnoses
Consider meningitis or encephalitis, intracranial abscess, orbital or periorbital cellulitis, carotid artery aneurysm or fistula, pseudotumor cerebri, acute angle-closure glaucoma, intracranial hemorrhage, and Tolosa–Hunt syndrome.
Emergency Stabilization
Patients may be critically ill and unstable. Immediate assessment and stabilization of airway, breathing, and circulation are essential, with early intubation for airway protection when mental status is impaired and aggressive fluid resuscitation for hemodynamic instability.
Definitive Emergency Management
Initiate broad-spectrum intravenous antibiotics promptly to cover gram-positive organisms including MRSA, gram-negative organisms, and anaerobes, typically using vancomycin or nafcillin combined with a third-generation cephalosporin and metronidazole or clindamycin when indicated. Anticoagulation with heparin may limit clot propagation and improve outcomes, though its use remains controversial and requires exclusion of intracranial hemorrhage prior to initiation. Endovascular thrombolysis may be considered in refractory, severe cases. Systemic corticosteroids may be beneficial in selected patients, particularly with pituitary involvement or inflammatory etiologies. Surgical consultation is required for drainage of the primary infectious source, such as sinus or dental abscesses, and intracranial pressure should be managed aggressively when elevated.
Disposition and Follow-Up
All patients with cavernous sinus thrombosis require hospital admission to a monitored setting, often the intensive care unit. Neurology and neurosurgical consultation are mandatory, and discharge from the emergency department is not appropriate.
Complications and Clinical Cautions
Potential complications include permanent visual impairment, persistent cranial nerve palsies, meningitis, intracranial abscess, seizures, pituitary necrosis with endocrine insufficiency, septic emboli, sepsis, and shock. Mortality remains significant. Maintain a high index of suspicion in patients with recent ENT infections, refractory headache, ocular findings, or hypercoagulable risk factors, as early CT imaging may be misleadingly normal and MRI/MRV should be pursued promptly.
- Published on
Emergency and Acute Medicine – Cellulitis
Core Concepts
Cellulitis is an acute, spreading infection of the skin and subcutaneous tissues with erythema, warmth, pain, tenderness, and progressive expansion. Extension into deeper layers may evolve into necrotizing soft-tissue infection. Predisposing factors include lymphedema, tinea pedis, open wounds, pre-existing lesions such as furuncles, prior trauma or surgery, retained foreign body, vascular or immune compromise, and injection drug use.
Likely Causes
Uncomplicated cellulitis is most often due to group A streptococci or Staphylococcus aureus, including community-associated MRSA (CA-MRSA). CA-MRSA risk is higher with prior MRSA infection, close contact with MRSA cases, daycare exposure, children, soldiers, incarcerated persons, contact-sport athletes, IV drug users, and men who have sex with men; CA-MRSA prevalence is high enough that empiric coverage is often appropriate, especially in nonresponding cases. Hospital-acquired MRSA is associated with recent hospitalization or long-term care, surgery, vascular devices, dialysis, recent antibiotic exposure, and injection drug use and is resistant to many antibiotics. After lymphatic disruption, nongroup A β-hemolytic streptococci (groups C, B, G) are more common. Diabetic cellulitis may be polymicrobial with streptococci, S. aureus, gram-negatives, and anaerobes, especially with ulcers. Special patterns include periorbital cellulitis (staph and strep), buccal cellulitis (historically Hib, plus anaerobic oral flora with intraoral lacerations or dental abscess), and less common exposures such as Pasteurella (cat/dog bites), Eikenella (human bites), Pseudomonas (hot-tub folliculitis; puncture wounds), Aeromonas (freshwater), Vibrio (seawater/raw seafood), Erysipelothrix (raw fish/meat handlers), clostridia, and anthrax. Pediatric patterns include facial cellulitis (strep pneumo and Hib—declining with vaccination), perianal cellulitis (group A strep), and neonatal cases (group B strep).
Clinical Features
Typical findings include pain, warmth, erythema, edema/induration, fever/chills, tender regional nodes, lymphangitis, and sometimes superficial vesicles. A concurrent subcutaneous abscess can coexist, and a deep abscess should be suspected if there is treatment failure. Buccal/odontogenic cellulitis may progress with fever, neck swelling, dysphagia, and deep-space spread. Pediatric facial cellulitis can be rapidly progressive, usually unilateral with URTI symptoms, and carries risk of cavernous sinus thrombosis and optic nerve injury. Perianal cellulitis presents with pruritic erythema extending outward from the anus, pain with defecation, and sometimes blood-streaked stools. Bedside clues: staphylococcal infection tends to have focal pustule/abscess with fluctuance or drainage and a slower course, while streptococcal infection often has sharper borders, lymphangitis, lymphedema association, and may include nausea from toxin effects.
Key Assessment
Cellulitis is primarily a clinical diagnosis; the exam should look for a portal of entry or deeper infection and assess for airway risk in deep facial/neck involvement.
Testing Strategy
Routine WBC is usually unnecessary. Aspirate/punch biopsy for Gram stain and culture is most useful in treatment failures and in admitted patients to identify resistant organisms such as MRSA. Blood cultures are typically negative in uncomplicated disease but may help in lymphedema-associated infections, buccal or periorbital cellulitis, water-exposure cases, or systemic symptoms with fever/chills. Plain radiographs can detect foreign bodies, subcutaneous gas, or suggest abscess; early osteomyelitis is not reliably seen. Ultrasound helps identify abscess when exam is equivocal and may show “cobblestoning” of the subcutaneous tissue in cellulitis. CT/MRI can help evaluate for necrotizing fasciitis.
Conditions to Differentiate
Important alternatives include necrotizing fasciitis, lymphangitis/lymphadenitis, thrombophlebitis or DVT, insect bite/allergy, gout/pseudogout, ruptured Baker cyst, herpetic whitlow, neoplasm, phytophotodermatitis, erythema migrans, and for facial disease, angioedema, conjunctivitis, or contusion. Pediatric perianal differentials include Candida intertrigo, psoriasis, pinworms, abuse, behavioral causes, and inflammatory bowel disease.
Emergency Management
Airway compromise is a concern with deep facial or neck extension. General approach: account for local resistance patterns and include CA-MRSA coverage when appropriate (notably uncomplicated cellulitis in many settings, periorbital disease, and diabetics). Typical outpatient duration is 7–10 days, with cool compresses, analgesia, elevation, and treatment of tinea pedis when present.
Antibiotic Approach by Scenario
Simple cellulitis outpatient: oral cephalexin plus TMP-SMX for CA-MRSA coverage; alternatives for β-lactam include dicloxacillin, macrolide, or levofloxacin; alternatives to TMP-SMX include clindamycin or doxycycline. Inpatient: IV nafcillin (or equivalent) plus IV vancomycin. Post-lymphatic disruption cellulitis: treat like simple cellulitis. Diabetic cellulitis outpatient: amoxicillin/clavulanate plus TMP-SMX or clindamycin; inpatient: IV ampicillin/sulbactam or imipenem-cilastatin plus IV vancomycin. Adult periorbital cellulitis outpatient: dicloxacillin or azithromycin plus TMP-SMX; inpatient: IV vancomycin. Adult buccal cellulitis outpatient: amoxicillin/clavulanate; inpatient: IV ceftriaxone; odontogenic cases require drainage and anaerobe coverage such as clindamycin. Pediatric facial cellulitis: IV ceftriaxone. Perianal cellulitis: oral penicillin VK outpatient or IV penicillin G inpatient. Bite wounds: amoxicillin/clavulanate. Foot puncture wounds: ciprofloxacin or IV ceftazidime. MRSA: hospital-acquired—IV vancomycin or linezolid; CA-MRSA—TMP-SMX, clindamycin, or doxycycline orally, and vancomycin or clindamycin IV.
Medication Options
Common regimens include amoxicillin/clavulanate, ampicillin/sulbactam, azithromycin, ceftazidime, ceftriaxone, cephalexin, ciprofloxacin, clindamycin, dicloxacillin, doxycycline, imipenem-cilastatin, levofloxacin, linezolid, nafcillin, penicillin VK, aqueous penicillin G, TMP-SMX, and vancomycin with pediatric adjustments and therapeutic monitoring where appropriate.
Disposition Criteria
Admit patients who appear toxic, have tissue necrosis, immunosuppression, significant comorbid illness, inability to tolerate oral meds, unreliable follow-up, or high-risk anatomy. Discharge is reasonable for mild infection in a nontoxic patient who can take oral therapy, has no immunosuppression or major comorbidities, no hand/face involvement, and has reliable follow-up within 24–48 hours.
Follow-Up Guidance
Reassess within 24–48 hours, sooner if fever worsens, lymphangitis develops, or erythema expands. Mark the edge of erythema prior to discharge to track progression.
Clinical Traps
Strep and staph remain the most common causes, and CA-MRSA is common enough that empiric coverage is often required. Clinicians are not reliably accurate at identifying MRSA by appearance alone. Deep abscess can be mistaken for cellulitis; use clinical suspicion and ultrasound to avoid missed abscess.
Core Concepts
Cellulitis is an acute, spreading infection of the skin and subcutaneous tissues with erythema, warmth, pain, tenderness, and progressive expansion. Extension into deeper layers may evolve into necrotizing soft-tissue infection. Predisposing factors include lymphedema, tinea pedis, open wounds, pre-existing lesions such as furuncles, prior trauma or surgery, retained foreign body, vascular or immune compromise, and injection drug use.
Likely Causes
Uncomplicated cellulitis is most often due to group A streptococci or Staphylococcus aureus, including community-associated MRSA (CA-MRSA). CA-MRSA risk is higher with prior MRSA infection, close contact with MRSA cases, daycare exposure, children, soldiers, incarcerated persons, contact-sport athletes, IV drug users, and men who have sex with men; CA-MRSA prevalence is high enough that empiric coverage is often appropriate, especially in nonresponding cases. Hospital-acquired MRSA is associated with recent hospitalization or long-term care, surgery, vascular devices, dialysis, recent antibiotic exposure, and injection drug use and is resistant to many antibiotics. After lymphatic disruption, nongroup A β-hemolytic streptococci (groups C, B, G) are more common. Diabetic cellulitis may be polymicrobial with streptococci, S. aureus, gram-negatives, and anaerobes, especially with ulcers. Special patterns include periorbital cellulitis (staph and strep), buccal cellulitis (historically Hib, plus anaerobic oral flora with intraoral lacerations or dental abscess), and less common exposures such as Pasteurella (cat/dog bites), Eikenella (human bites), Pseudomonas (hot-tub folliculitis; puncture wounds), Aeromonas (freshwater), Vibrio (seawater/raw seafood), Erysipelothrix (raw fish/meat handlers), clostridia, and anthrax. Pediatric patterns include facial cellulitis (strep pneumo and Hib—declining with vaccination), perianal cellulitis (group A strep), and neonatal cases (group B strep).
Clinical Features
Typical findings include pain, warmth, erythema, edema/induration, fever/chills, tender regional nodes, lymphangitis, and sometimes superficial vesicles. A concurrent subcutaneous abscess can coexist, and a deep abscess should be suspected if there is treatment failure. Buccal/odontogenic cellulitis may progress with fever, neck swelling, dysphagia, and deep-space spread. Pediatric facial cellulitis can be rapidly progressive, usually unilateral with URTI symptoms, and carries risk of cavernous sinus thrombosis and optic nerve injury. Perianal cellulitis presents with pruritic erythema extending outward from the anus, pain with defecation, and sometimes blood-streaked stools. Bedside clues: staphylococcal infection tends to have focal pustule/abscess with fluctuance or drainage and a slower course, while streptococcal infection often has sharper borders, lymphangitis, lymphedema association, and may include nausea from toxin effects.
Key Assessment
Cellulitis is primarily a clinical diagnosis; the exam should look for a portal of entry or deeper infection and assess for airway risk in deep facial/neck involvement.
Testing Strategy
Routine WBC is usually unnecessary. Aspirate/punch biopsy for Gram stain and culture is most useful in treatment failures and in admitted patients to identify resistant organisms such as MRSA. Blood cultures are typically negative in uncomplicated disease but may help in lymphedema-associated infections, buccal or periorbital cellulitis, water-exposure cases, or systemic symptoms with fever/chills. Plain radiographs can detect foreign bodies, subcutaneous gas, or suggest abscess; early osteomyelitis is not reliably seen. Ultrasound helps identify abscess when exam is equivocal and may show “cobblestoning” of the subcutaneous tissue in cellulitis. CT/MRI can help evaluate for necrotizing fasciitis.
Conditions to Differentiate
Important alternatives include necrotizing fasciitis, lymphangitis/lymphadenitis, thrombophlebitis or DVT, insect bite/allergy, gout/pseudogout, ruptured Baker cyst, herpetic whitlow, neoplasm, phytophotodermatitis, erythema migrans, and for facial disease, angioedema, conjunctivitis, or contusion. Pediatric perianal differentials include Candida intertrigo, psoriasis, pinworms, abuse, behavioral causes, and inflammatory bowel disease.
Emergency Management
Airway compromise is a concern with deep facial or neck extension. General approach: account for local resistance patterns and include CA-MRSA coverage when appropriate (notably uncomplicated cellulitis in many settings, periorbital disease, and diabetics). Typical outpatient duration is 7–10 days, with cool compresses, analgesia, elevation, and treatment of tinea pedis when present.
Antibiotic Approach by Scenario
Simple cellulitis outpatient: oral cephalexin plus TMP-SMX for CA-MRSA coverage; alternatives for β-lactam include dicloxacillin, macrolide, or levofloxacin; alternatives to TMP-SMX include clindamycin or doxycycline. Inpatient: IV nafcillin (or equivalent) plus IV vancomycin. Post-lymphatic disruption cellulitis: treat like simple cellulitis. Diabetic cellulitis outpatient: amoxicillin/clavulanate plus TMP-SMX or clindamycin; inpatient: IV ampicillin/sulbactam or imipenem-cilastatin plus IV vancomycin. Adult periorbital cellulitis outpatient: dicloxacillin or azithromycin plus TMP-SMX; inpatient: IV vancomycin. Adult buccal cellulitis outpatient: amoxicillin/clavulanate; inpatient: IV ceftriaxone; odontogenic cases require drainage and anaerobe coverage such as clindamycin. Pediatric facial cellulitis: IV ceftriaxone. Perianal cellulitis: oral penicillin VK outpatient or IV penicillin G inpatient. Bite wounds: amoxicillin/clavulanate. Foot puncture wounds: ciprofloxacin or IV ceftazidime. MRSA: hospital-acquired—IV vancomycin or linezolid; CA-MRSA—TMP-SMX, clindamycin, or doxycycline orally, and vancomycin or clindamycin IV.
Medication Options
Common regimens include amoxicillin/clavulanate, ampicillin/sulbactam, azithromycin, ceftazidime, ceftriaxone, cephalexin, ciprofloxacin, clindamycin, dicloxacillin, doxycycline, imipenem-cilastatin, levofloxacin, linezolid, nafcillin, penicillin VK, aqueous penicillin G, TMP-SMX, and vancomycin with pediatric adjustments and therapeutic monitoring where appropriate.
Disposition Criteria
Admit patients who appear toxic, have tissue necrosis, immunosuppression, significant comorbid illness, inability to tolerate oral meds, unreliable follow-up, or high-risk anatomy. Discharge is reasonable for mild infection in a nontoxic patient who can take oral therapy, has no immunosuppression or major comorbidities, no hand/face involvement, and has reliable follow-up within 24–48 hours.
Follow-Up Guidance
Reassess within 24–48 hours, sooner if fever worsens, lymphangitis develops, or erythema expands. Mark the edge of erythema prior to discharge to track progression.
Clinical Traps
Strep and staph remain the most common causes, and CA-MRSA is common enough that empiric coverage is often required. Clinicians are not reliably accurate at identifying MRSA by appearance alone. Deep abscess can be mistaken for cellulitis; use clinical suspicion and ultrasound to avoid missed abscess.
- Published on
Emergency and Acute Medicine – Central Retinal Artery Occlusion
Overview
Central retinal artery occlusion (CRAO) is an obstruction of the central retinal artery resulting in sudden, painless, monocular vision loss. It typically affects adults aged 50–70 years and is often described as a “stroke of the eye.” The ophthalmic artery is the first branch of the carotid artery. Risk factors include hypertension, atherosclerosis, carotid artery disease, valvular heart disease, coronary artery disease, vasculitis, lupus, sickle cell disease, and trauma. Incidence is approximately 1–10 per 100,000. Irreversible retinal injury can occur within 90 minutes.
Causative Mechanisms
Embolic causes are most common and include cholesterol or platelet emboli from carotid atherosclerosis, carotid stenosis, valvular heart disease, atrial myxoma, or arterial dissection. Thrombotic causes result from rupture of an atherosclerotic plaque or hypercoagulable states such as sickle cell disease. Inflammatory causes include giant cell arteritis, lupus, and systemic vasculitis. Arterial spasm may be migraine-related. Reduced ocular perfusion may occur with severe hypotension, acute angle-closure glaucoma, or retrobulbar hemorrhage.
Clinical Presentation
Patients present with sudden, painless, unilateral vision loss. Some report prior transient episodes of visual loss lasting seconds to minutes (amaurosis fugax). Visual acuity is markedly reduced. An afferent pupillary defect is usually present. Fundoscopy may reveal emboli within retinal vessels appearing as yellow-white glistening plaques, ischemic retinal edema within 15–20 minutes, and a classic cherry-red spot at the fovea. Retinal arteries may appear empty or show segmented “box-carring.” Within 1–2 hours, the infarcted retina becomes opaque. Partial visual field deficits suggest branch retinal artery involvement.
Essential Evaluation
Immediate assessment includes visual acuity, visual fields, fundoscopic examination, intraocular pressure measurement, and urgent ophthalmology consultation.
Diagnostic Studies
Laboratory evaluation targets underlying causes and includes CBC with platelets, PT/PTT, electrolytes, renal function, glucose, ESR and CRP (especially in patients >55 years for giant cell arteritis), ANA, RF, RPR, hemoglobin electrophoresis, and serum protein electrophoresis. Imaging focuses on embolic sources and includes carotid Doppler ultrasound and echocardiography. Fluorescein angiography or electroretinography may confirm diagnosis.
Differential Considerations
Acute angle-closure glaucoma, central retinal vein occlusion, giant cell arteritis, optic neuritis, and retinal detachment.
Emergency Management Principles
This is a true ophthalmologic emergency. Treatment must begin immediately to attempt retinal salvage. Goals include embolus displacement or dissolution, vasodilation to improve retinal perfusion, and reduction of intraocular pressure to enhance the perfusion gradient.
Emergency Department Interventions
Initiate immediate ocular (global) massage with the patient supine: apply firm pressure on the closed eyelid for 15 seconds, release for 15 seconds, and repeat for five cycles. Administer 100% oxygen via nonrebreather mask and consider hyperbaric oxygen if within 24 hours of onset. Carbogen inhalation may be used if available. Reduce intraocular pressure with IV acetazolamide and topical timolol. Administer aspirin and IV heparin to prevent clot propagation. Obtain emergent ophthalmology consultation for possible anterior chamber paracentesis and consideration of intra-arterial fibrinolysis. If inflammatory arteritis is suspected, begin high-dose systemic corticosteroids immediately.
Medications
First-line options include acetazolamide 500 mg IV or PO, timolol maleate 0.5% ophthalmic drops, IV heparin (80 U/kg bolus then 18 U/kg/hr infusion), and carbogen inhalation. Second-line or adjunctive therapies include aspirin 325 mg PO, methylprednisolone 250 mg IV for suspected arteritis, mannitol, and sublingual nitroglycerin.
Disposition and Follow-Up
Most acute cases require admission for urgent evaluation of embolic, thrombotic, or inflammatory sources. Chronic or remote occlusions without active disease may be evaluated outpatient. All suspected cases require immediate ophthalmology involvement. Carotid imaging is recommended in most patients.
Clinical Insights and Pitfalls
Transient monocular vision loss (amaurosis fugax) is a warning sign for CRAO and systemic stroke and requires urgent evaluation. CRAO is a medical and ophthalmologic emergency with a very narrow therapeutic window. Thorough documentation of visual acuity and fundoscopic findings is essential.
Overview
Central retinal artery occlusion (CRAO) is an obstruction of the central retinal artery resulting in sudden, painless, monocular vision loss. It typically affects adults aged 50–70 years and is often described as a “stroke of the eye.” The ophthalmic artery is the first branch of the carotid artery. Risk factors include hypertension, atherosclerosis, carotid artery disease, valvular heart disease, coronary artery disease, vasculitis, lupus, sickle cell disease, and trauma. Incidence is approximately 1–10 per 100,000. Irreversible retinal injury can occur within 90 minutes.
Causative Mechanisms
Embolic causes are most common and include cholesterol or platelet emboli from carotid atherosclerosis, carotid stenosis, valvular heart disease, atrial myxoma, or arterial dissection. Thrombotic causes result from rupture of an atherosclerotic plaque or hypercoagulable states such as sickle cell disease. Inflammatory causes include giant cell arteritis, lupus, and systemic vasculitis. Arterial spasm may be migraine-related. Reduced ocular perfusion may occur with severe hypotension, acute angle-closure glaucoma, or retrobulbar hemorrhage.
Clinical Presentation
Patients present with sudden, painless, unilateral vision loss. Some report prior transient episodes of visual loss lasting seconds to minutes (amaurosis fugax). Visual acuity is markedly reduced. An afferent pupillary defect is usually present. Fundoscopy may reveal emboli within retinal vessels appearing as yellow-white glistening plaques, ischemic retinal edema within 15–20 minutes, and a classic cherry-red spot at the fovea. Retinal arteries may appear empty or show segmented “box-carring.” Within 1–2 hours, the infarcted retina becomes opaque. Partial visual field deficits suggest branch retinal artery involvement.
Essential Evaluation
Immediate assessment includes visual acuity, visual fields, fundoscopic examination, intraocular pressure measurement, and urgent ophthalmology consultation.
Diagnostic Studies
Laboratory evaluation targets underlying causes and includes CBC with platelets, PT/PTT, electrolytes, renal function, glucose, ESR and CRP (especially in patients >55 years for giant cell arteritis), ANA, RF, RPR, hemoglobin electrophoresis, and serum protein electrophoresis. Imaging focuses on embolic sources and includes carotid Doppler ultrasound and echocardiography. Fluorescein angiography or electroretinography may confirm diagnosis.
Differential Considerations
Acute angle-closure glaucoma, central retinal vein occlusion, giant cell arteritis, optic neuritis, and retinal detachment.
Emergency Management Principles
This is a true ophthalmologic emergency. Treatment must begin immediately to attempt retinal salvage. Goals include embolus displacement or dissolution, vasodilation to improve retinal perfusion, and reduction of intraocular pressure to enhance the perfusion gradient.
Emergency Department Interventions
Initiate immediate ocular (global) massage with the patient supine: apply firm pressure on the closed eyelid for 15 seconds, release for 15 seconds, and repeat for five cycles. Administer 100% oxygen via nonrebreather mask and consider hyperbaric oxygen if within 24 hours of onset. Carbogen inhalation may be used if available. Reduce intraocular pressure with IV acetazolamide and topical timolol. Administer aspirin and IV heparin to prevent clot propagation. Obtain emergent ophthalmology consultation for possible anterior chamber paracentesis and consideration of intra-arterial fibrinolysis. If inflammatory arteritis is suspected, begin high-dose systemic corticosteroids immediately.
Medications
First-line options include acetazolamide 500 mg IV or PO, timolol maleate 0.5% ophthalmic drops, IV heparin (80 U/kg bolus then 18 U/kg/hr infusion), and carbogen inhalation. Second-line or adjunctive therapies include aspirin 325 mg PO, methylprednisolone 250 mg IV for suspected arteritis, mannitol, and sublingual nitroglycerin.
Disposition and Follow-Up
Most acute cases require admission for urgent evaluation of embolic, thrombotic, or inflammatory sources. Chronic or remote occlusions without active disease may be evaluated outpatient. All suspected cases require immediate ophthalmology involvement. Carotid imaging is recommended in most patients.
Clinical Insights and Pitfalls
Transient monocular vision loss (amaurosis fugax) is a warning sign for CRAO and systemic stroke and requires urgent evaluation. CRAO is a medical and ophthalmologic emergency with a very narrow therapeutic window. Thorough documentation of visual acuity and fundoscopic findings is essential.
- Published on
Emergency and Acute Medicine – Central Retinal Vein Occlusion
Overview
Central retinal vein occlusion (CRVO) is characterized by decreased visual acuity due to venous outflow obstruction of the retina. Vision loss is typically acute, unilateral, and painless. The condition results from impaired venous drainage leading to retinal hemorrhage, edema, and ischemia.
Pathophysiologic Types
Ischemic CRVO accounts for approximately 20–25% of cases and represents complete venous obstruction. Blocked venous return causes capillary backflow, extensive hemorrhage, macular edema, and retinal ischemia. Thrombosis is promoted by limited space at the lamina cribrosa, slow blood flow, vessel wall changes, adjacent arteriosclerotic arterial compression, and increased blood viscosity.
Nonischemic CRVO represents partial or incomplete occlusion and is generally milder with better visual prognosis.
Clinical Features
Patients present with acute, painless, unilateral loss of vision. In nonischemic CRVO, vision loss may be intermittent or incomplete. Visual acuity is often severely reduced, commonly worse than 20/200. An afferent pupillary defect may be present. Fundoscopic examination reveals dilated and tortuous retinal veins, widespread retinal hemorrhages involving all four quadrants in central involvement, optic disc edema, and cotton wool spots. Extensive hemorrhage produces the classic “blood and thunder” appearance.
Essential Assessment
Measure blood pressure. Perform visual acuity testing, visual field assessment, fundoscopy, and tonometry. Normal intraocular pressure ranges from 10–21 mm Hg.
Diagnostic Evaluation
Laboratory studies include CBC, PT/PTT, ESR, ANA, and serum protein electrophoresis to assess for systemic or hyperviscosity conditions. Fluorescein angiography, performed by ophthalmology, differentiates ischemic from nonischemic CRVO by identifying areas of capillary nonperfusion. Gonioscopy is used to evaluate for iris or angle neovascularization.
Differential Considerations
Amaurosis fugax or TIA, cavernous sinus thrombosis, diabetic or hypertensive retinopathy, hyperviscosity syndromes (sickle cell disease, polycythemia, leukemia, multiple myeloma), ocular ischemia syndrome, papilledema, retinal artery occlusion, retinal detachment, temporal arteritis, vitreous hemorrhage, severe anemia with thrombocytopenia, and functional vision loss.
Initial Management Principles
There are no prehospital eye-specific interventions. In the ED, address elevated intraocular pressure if present and manage underlying systemic conditions. The cornerstone of management is early recognition and urgent ophthalmologic referral.
Emergency Department Management
No therapy has proven definitive benefit in the ED setting. In consultation with ophthalmology, attempted therapies may include aspirin, anti-inflammatory agents, systemic corticosteroids, systemic anticoagulation, fibrinolytics (controversial), or laser chorioretinal anastomosis.
Definitive and Ophthalmologic Therapies
Ophthalmologists may use intravitreal corticosteroids such as triamcinolone or antivascular endothelial growth factor agents such as bevacizumab. Panretinal photocoagulation is often performed if neovascularization develops.
Disposition and Follow-Up
Admission depends on ophthalmologic assessment and need for intervention. Patients may be discharged if immediate ophthalmology follow-up is ensured. If ophthalmologic care is unavailable, initiate management of associated conditions and transfer to a facility with specialty services. Long-term follow-up is essential, particularly for ischemic CRVO, to detect neovascularization and secondary glaucoma. Patients require full medical evaluation for underlying vascular disease and comorbidity management.
Clinical Insights and Pitfalls
Elevated intraocular pressure from edema or neovascularization can worsen ischemia and lead to permanent vision loss if untreated. Bilateral CRVO or CRVO in young patients should prompt evaluation for hyperviscosity syndromes and systemic disease.
Overview
Central retinal vein occlusion (CRVO) is characterized by decreased visual acuity due to venous outflow obstruction of the retina. Vision loss is typically acute, unilateral, and painless. The condition results from impaired venous drainage leading to retinal hemorrhage, edema, and ischemia.
Pathophysiologic Types
Ischemic CRVO accounts for approximately 20–25% of cases and represents complete venous obstruction. Blocked venous return causes capillary backflow, extensive hemorrhage, macular edema, and retinal ischemia. Thrombosis is promoted by limited space at the lamina cribrosa, slow blood flow, vessel wall changes, adjacent arteriosclerotic arterial compression, and increased blood viscosity.
Nonischemic CRVO represents partial or incomplete occlusion and is generally milder with better visual prognosis.
Clinical Features
Patients present with acute, painless, unilateral loss of vision. In nonischemic CRVO, vision loss may be intermittent or incomplete. Visual acuity is often severely reduced, commonly worse than 20/200. An afferent pupillary defect may be present. Fundoscopic examination reveals dilated and tortuous retinal veins, widespread retinal hemorrhages involving all four quadrants in central involvement, optic disc edema, and cotton wool spots. Extensive hemorrhage produces the classic “blood and thunder” appearance.
Essential Assessment
Measure blood pressure. Perform visual acuity testing, visual field assessment, fundoscopy, and tonometry. Normal intraocular pressure ranges from 10–21 mm Hg.
Diagnostic Evaluation
Laboratory studies include CBC, PT/PTT, ESR, ANA, and serum protein electrophoresis to assess for systemic or hyperviscosity conditions. Fluorescein angiography, performed by ophthalmology, differentiates ischemic from nonischemic CRVO by identifying areas of capillary nonperfusion. Gonioscopy is used to evaluate for iris or angle neovascularization.
Differential Considerations
Amaurosis fugax or TIA, cavernous sinus thrombosis, diabetic or hypertensive retinopathy, hyperviscosity syndromes (sickle cell disease, polycythemia, leukemia, multiple myeloma), ocular ischemia syndrome, papilledema, retinal artery occlusion, retinal detachment, temporal arteritis, vitreous hemorrhage, severe anemia with thrombocytopenia, and functional vision loss.
Initial Management Principles
There are no prehospital eye-specific interventions. In the ED, address elevated intraocular pressure if present and manage underlying systemic conditions. The cornerstone of management is early recognition and urgent ophthalmologic referral.
Emergency Department Management
No therapy has proven definitive benefit in the ED setting. In consultation with ophthalmology, attempted therapies may include aspirin, anti-inflammatory agents, systemic corticosteroids, systemic anticoagulation, fibrinolytics (controversial), or laser chorioretinal anastomosis.
Definitive and Ophthalmologic Therapies
Ophthalmologists may use intravitreal corticosteroids such as triamcinolone or antivascular endothelial growth factor agents such as bevacizumab. Panretinal photocoagulation is often performed if neovascularization develops.
Disposition and Follow-Up
Admission depends on ophthalmologic assessment and need for intervention. Patients may be discharged if immediate ophthalmology follow-up is ensured. If ophthalmologic care is unavailable, initiate management of associated conditions and transfer to a facility with specialty services. Long-term follow-up is essential, particularly for ischemic CRVO, to detect neovascularization and secondary glaucoma. Patients require full medical evaluation for underlying vascular disease and comorbidity management.
Clinical Insights and Pitfalls
Elevated intraocular pressure from edema or neovascularization can worsen ischemia and lead to permanent vision loss if untreated. Bilateral CRVO or CRVO in young patients should prompt evaluation for hyperviscosity syndromes and systemic disease.
- Published on
Emergency and Acute Medicine - Cerebrovascular Accident (Stroke)
Overview
A cerebrovascular accident (CVA) results from interruption of blood flow to a specific brain region. Clinical deficits correspond to the vascular territory involved. Onset may be abrupt and complete or stepwise and fluctuating. Stroke accounts for ~1 in 18 deaths in the United States, with ~610,000 new cases annually.
Predisposing Factors
Hypertension, diabetes mellitus, smoking, coronary artery disease, cardiac dysrhythmias, peripheral vascular disease, oral contraceptive use, polycythemia vera, sickle cell disease, antithrombin III deficiency, protein C or S deficiency.
Pathologic Mechanisms
Ischemic stroke includes thrombotic, embolic, dissection-related, or hypoperfusion etiologies. Thrombotic stroke most often results from clot formation at an ulcerated atherosclerotic plaque or from sludging states (sickle cell disease, polycythemia vera, protein C deficiency). Embolic stroke arises from cardiac mural thrombi (atrial fibrillation, mitral stenosis, cardiomyopathy, CHF, MI), prosthetic or abnormal valves, carotid or aortic arch plaques, atrial myxoma, or ventricular aneurysm thrombi. Arterial dissection may involve carotid arteries or be associated with arteritis (giant cell, Takayasu) or fibromuscular dysplasia. Global ischemic stroke results from systemic hypotension due to sepsis, hemorrhage, or shock. Hemorrhagic stroke includes intracerebral and subarachnoid hemorrhage.
Pediatrics: Usually secondary to underlying disease (sickle cell disease, leukemia, infection, blood dyscrasia); younger children often present with seizures or altered mental status.
Clinical Features
History focuses on exact time of onset or last known normal, trauma or surgery, medications, confusion, headache, vertigo, and focal neurologic deficits.
General exam may show Cheyne–Stokes respirations, apnea, hypertension, dysrhythmias, or murmurs.
Anterior cerebral artery involvement causes contralateral leg-predominant weakness and sensory loss, apraxia, confusion, and impaired judgment.
Middle cerebral artery involvement causes contralateral face and arm weakness, hemisensory loss, homonymous hemianopsia, aphasia or dysarthria, and agnosia.
Posterior cerebral artery involvement causes cortical blindness, visual agnosia, memory impairment, altered mental status, third-nerve palsy, or hemiballismus.
Vertebrobasilar strokes cause vertigo, diplopia, nystagmus, visual field defects, and crossed cranial nerve and motor deficits; basilar artery occlusion may lead to quadriplegia, locked-in syndrome, or coma.
Watershed infarcts produce proximal limb weakness with sparing of face, hands, and feet.
Initial Evaluation Priorities
Perform a focused neurologic examination and calculate the NIH Stroke Scale when possible. Obtain emergent noncontrast head CT to differentiate ischemic from hemorrhagic stroke; early CT may be normal within 24–48 hours. Goals include CT completion within 25 minutes, interpretation within 45 minutes, and thrombolytic administration within 60 minutes if indicated. If CT is negative but subarachnoid hemorrhage is suspected, perform lumbar puncture. Obtain ECG, oxygen saturation, and rapid blood glucose.
Diagnostic Studies
Laboratory tests include CBC, electrolytes, renal and liver function, PT/PTT, urinalysis, and ESR when indicated. Additional studies may include cardiac enzymes, pregnancy test, toxicology screen, alcohol level, ABG, and blood cultures. Imaging may include MRI for early ischemia, chest radiograph, and carotid ultrasound. ECG evaluates for arrhythmia; lumbar puncture is required if CT is nondiagnostic and SAH remains suspected.
Key Differentials
Intracranial hemorrhage, hypoglycemia, seizure with Todd paralysis, conversion disorder, transient global amnesia, encephalitis or meningitis, peripheral neuropathy, intracranial abscess, migraine, air embolism, TIA, metabolic encephalopathy, neoplasm, vasculitis, multiple sclerosis, compressive myelopathy, vestibulitis, medication or toxin effects.
Prehospital Considerations
Patients may have impaired movement or communication. Field neurologic assessment should include level of consciousness, GCS, speech, facial symmetry, gait, and motor deficits. Fingerstick glucose is essential.
Stabilization Measures
Ensure airway protection; provide supplemental oxygen at 2–4 L/min. Intubation may be required for airway control or ICP management. For altered mental status, administer naloxone and thiamine and correct hypoglycemia.
Emergency Department Management
Treat severe hypertension only if SBP >220 mm Hg or DBP >120 mm Hg, or if required for comorbid conditions; initial target is <180 />10 mm Hg. Control seizures with benzodiazepines followed by fosphenytoin or phenytoin. Maintain euvolemia and normothermia.
Thrombolysis: For ischemic stroke only, administer IV alteplase within 4.5 hours of symptom onset if criteria are met. Avoid antiplatelet and anticoagulant therapy for 24 hours post-tPA.
Contraindications: Prior intracranial hemorrhage, recent stroke or head trauma (<3 months), major surgery (<14 days), uncontrolled hypertension, bleeding diathesis, recent mi, inr>1.7, platelets <100,000, intracranial neoplasm, seizure at onset, rapidly improving symptoms, pregnancy, recent internal bleeding, glucose <50 mg />L, age <18 years.< />pan>
3-4.5 hour exclusions: Age >80, oral anticoagulant use, NIHSS >25 or >1/3 MCA involvement, prior stroke plus diabetes.
Manage cerebral edema with head elevation, controlled ventilation (PaCO₂ 35–40 mm Hg), mannitol, and neurosurgical consultation when indicated. Selected patients may undergo intra-arterial thrombolysis or mechanical thrombectomy.
Medications
First line: Alteplase 0.9 mg/kg IV (max 90 mg), aspirin 81–325 mg PO/PR, labetalol IV bolus and infusion.
Second line: Clopidogrel, diazepam, enalapril, hydralazine, mannitol, nicardipine, nitroprusside, trimethaphan.
Pediatrics: Heparin or LMWH often used; pediatric stroke consultation available via 1-800-NOCLOTS.
Disposition
All acute strokes require hospital admission. ICU admission is indicated for depressed consciousness, hemodynamic instability, serious arrhythmias, elevated ICP, or tPA administration.
Discharge may be considered for completed strokes days to weeks old in patients who are functionally independent or have reliable support.
Follow-Up Care
Neurology consultation, primary care follow-up, and rehabilitation services including speech and occupational therapy.
Clinical Pearls
Document prehospital observations carefully. Accurate symptom onset time is critical for thrombolysis eligibility. Avoid rapid BP reduction to prevent cerebral hypoperfusion. Door-to-needle time goal is under 60 minutes.
Overview
A cerebrovascular accident (CVA) results from interruption of blood flow to a specific brain region. Clinical deficits correspond to the vascular territory involved. Onset may be abrupt and complete or stepwise and fluctuating. Stroke accounts for ~1 in 18 deaths in the United States, with ~610,000 new cases annually.
Predisposing Factors
Hypertension, diabetes mellitus, smoking, coronary artery disease, cardiac dysrhythmias, peripheral vascular disease, oral contraceptive use, polycythemia vera, sickle cell disease, antithrombin III deficiency, protein C or S deficiency.
Pathologic Mechanisms
Ischemic stroke includes thrombotic, embolic, dissection-related, or hypoperfusion etiologies. Thrombotic stroke most often results from clot formation at an ulcerated atherosclerotic plaque or from sludging states (sickle cell disease, polycythemia vera, protein C deficiency). Embolic stroke arises from cardiac mural thrombi (atrial fibrillation, mitral stenosis, cardiomyopathy, CHF, MI), prosthetic or abnormal valves, carotid or aortic arch plaques, atrial myxoma, or ventricular aneurysm thrombi. Arterial dissection may involve carotid arteries or be associated with arteritis (giant cell, Takayasu) or fibromuscular dysplasia. Global ischemic stroke results from systemic hypotension due to sepsis, hemorrhage, or shock. Hemorrhagic stroke includes intracerebral and subarachnoid hemorrhage.
Pediatrics: Usually secondary to underlying disease (sickle cell disease, leukemia, infection, blood dyscrasia); younger children often present with seizures or altered mental status.
Clinical Features
History focuses on exact time of onset or last known normal, trauma or surgery, medications, confusion, headache, vertigo, and focal neurologic deficits.
General exam may show Cheyne–Stokes respirations, apnea, hypertension, dysrhythmias, or murmurs.
Anterior cerebral artery involvement causes contralateral leg-predominant weakness and sensory loss, apraxia, confusion, and impaired judgment.
Middle cerebral artery involvement causes contralateral face and arm weakness, hemisensory loss, homonymous hemianopsia, aphasia or dysarthria, and agnosia.
Posterior cerebral artery involvement causes cortical blindness, visual agnosia, memory impairment, altered mental status, third-nerve palsy, or hemiballismus.
Vertebrobasilar strokes cause vertigo, diplopia, nystagmus, visual field defects, and crossed cranial nerve and motor deficits; basilar artery occlusion may lead to quadriplegia, locked-in syndrome, or coma.
Watershed infarcts produce proximal limb weakness with sparing of face, hands, and feet.
Initial Evaluation Priorities
Perform a focused neurologic examination and calculate the NIH Stroke Scale when possible. Obtain emergent noncontrast head CT to differentiate ischemic from hemorrhagic stroke; early CT may be normal within 24–48 hours. Goals include CT completion within 25 minutes, interpretation within 45 minutes, and thrombolytic administration within 60 minutes if indicated. If CT is negative but subarachnoid hemorrhage is suspected, perform lumbar puncture. Obtain ECG, oxygen saturation, and rapid blood glucose.
Diagnostic Studies
Laboratory tests include CBC, electrolytes, renal and liver function, PT/PTT, urinalysis, and ESR when indicated. Additional studies may include cardiac enzymes, pregnancy test, toxicology screen, alcohol level, ABG, and blood cultures. Imaging may include MRI for early ischemia, chest radiograph, and carotid ultrasound. ECG evaluates for arrhythmia; lumbar puncture is required if CT is nondiagnostic and SAH remains suspected.
Key Differentials
Intracranial hemorrhage, hypoglycemia, seizure with Todd paralysis, conversion disorder, transient global amnesia, encephalitis or meningitis, peripheral neuropathy, intracranial abscess, migraine, air embolism, TIA, metabolic encephalopathy, neoplasm, vasculitis, multiple sclerosis, compressive myelopathy, vestibulitis, medication or toxin effects.
Prehospital Considerations
Patients may have impaired movement or communication. Field neurologic assessment should include level of consciousness, GCS, speech, facial symmetry, gait, and motor deficits. Fingerstick glucose is essential.
Stabilization Measures
Ensure airway protection; provide supplemental oxygen at 2–4 L/min. Intubation may be required for airway control or ICP management. For altered mental status, administer naloxone and thiamine and correct hypoglycemia.
Emergency Department Management
Treat severe hypertension only if SBP >220 mm Hg or DBP >120 mm Hg, or if required for comorbid conditions; initial target is <180 />10 mm Hg. Control seizures with benzodiazepines followed by fosphenytoin or phenytoin. Maintain euvolemia and normothermia.
Thrombolysis: For ischemic stroke only, administer IV alteplase within 4.5 hours of symptom onset if criteria are met. Avoid antiplatelet and anticoagulant therapy for 24 hours post-tPA.
Contraindications: Prior intracranial hemorrhage, recent stroke or head trauma (<3 months), major surgery (<14 days), uncontrolled hypertension, bleeding diathesis, recent mi, inr>1.7, platelets <100,000, intracranial neoplasm, seizure at onset, rapidly improving symptoms, pregnancy, recent internal bleeding, glucose <50 mg />L, age <18 years.< />pan>
3-4.5 hour exclusions: Age >80, oral anticoagulant use, NIHSS >25 or >1/3 MCA involvement, prior stroke plus diabetes.
Manage cerebral edema with head elevation, controlled ventilation (PaCO₂ 35–40 mm Hg), mannitol, and neurosurgical consultation when indicated. Selected patients may undergo intra-arterial thrombolysis or mechanical thrombectomy.
Medications
First line: Alteplase 0.9 mg/kg IV (max 90 mg), aspirin 81–325 mg PO/PR, labetalol IV bolus and infusion.
Second line: Clopidogrel, diazepam, enalapril, hydralazine, mannitol, nicardipine, nitroprusside, trimethaphan.
Pediatrics: Heparin or LMWH often used; pediatric stroke consultation available via 1-800-NOCLOTS.
Disposition
All acute strokes require hospital admission. ICU admission is indicated for depressed consciousness, hemodynamic instability, serious arrhythmias, elevated ICP, or tPA administration.
Discharge may be considered for completed strokes days to weeks old in patients who are functionally independent or have reliable support.
Follow-Up Care
Neurology consultation, primary care follow-up, and rehabilitation services including speech and occupational therapy.
Clinical Pearls
Document prehospital observations carefully. Accurate symptom onset time is critical for thrombolysis eligibility. Avoid rapid BP reduction to prevent cerebral hypoperfusion. Door-to-needle time goal is under 60 minutes.
- Published on
Emergency and Acute Medicine – Cardiac Pacemakers
Core Concept
A cardiac pacemaker is an electronic device that delivers electrical impulses to stimulate myocardial contraction and maintain an adequate heart rate and cardiac output when intrinsic conduction is inadequate.
Pacing Modalities
Transcutaneous pacing uses external pads placed in anterior–lateral or anterior–posterior positions. Current is increased until electrical and mechanical capture is achieved. This is a temporary emergency measure until definitive therapy is available.
Temporary transvenous pacing involves insertion of a pacing wire via central venous access into the right atrium or ventricle, connected to an external generator. It is typically used as a bridge to permanent pacing or until pacing is no longer required.
Permanent implanted pacemakers consist of a lithium-powered battery (lifespan approximately 7–10 years), a programmable generator, and one or more leads positioned in the right atrium and/or ventricle to sense intrinsic activity and pace as needed.
A pacemaker magnet placed over the generator converts the device to asynchronous pacing. This is useful when pacer spikes are absent on ECG; a reduced magnet rate (≈10% decrease) suggests battery depletion.
Key Terminology
Fixed-rate pacing fires at a preset rate regardless of intrinsic rhythm and is now rarely used.
Demand pacing senses native cardiac activity and delivers impulses only when intrinsic rates fall below a programmed threshold.
Sensing refers to the device’s ability to detect intrinsic cardiac depolarization.
Pacemakers are described using a standardized code; in emergency care, the first three letters are most relevant: the chamber sensed, the chamber paced, and the response to sensing. Common configurations include VVI (single-chamber ventricular pacing) and DDD (dual-chamber pacing).
Common Causes of Pacemaker Complications
Infection of pacemaker components is most often due to Staphylococcus epidermidis or Staphylococcus aureus and may be associated with endocarditis; transesophageal echocardiography is preferred for diagnosis.
Venous thrombosis related to pacing leads is common but usually asymptomatic; pulmonary embolism is rare.
Failure to pace may result from lead fracture or disconnection, oversensing of muscle activity or electrical interference, or gradual battery depletion.
Failure to capture is commonly due to lead dislodgment, including Twiddler’s syndrome, or elevated myocardial pacing thresholds caused by hyperkalemia or ischemia.
Pacemaker-mediated tachycardia occurs in dual-chamber devices via re-entry involving the generator and intrinsic conduction system, typically limited to about 140 bpm.
Runaway pacemaker is rare and characterized by extremely rapid pacing (>200 bpm) due to component failure or battery depletion, often causing hemodynamic instability.
Clinical Presentation
Pacemaker failure may manifest as bradycardia, syncope, hypotension progressing to shock, fatigue, dyspnea from heart failure, ischemic chest pain, or altered mental status.
Pacemaker-induced tachycardia presents with dyspnea, chest pain, lightheadedness, or syncope.
Pacemaker syndrome, usually seen with ventricular-only pacing, results from atrioventricular dyssynchrony and causes palpitations, weakness, exercise intolerance, dyspnea, or syncope.
Focused History and Examination
Key history includes date of implantation, device type, and adherence to routine follow-up and battery checks. Examination should include cardiovascular and pulmonary assessment and inspection of the generator site for signs of infection.
Essential Emergency Evaluation
A 12-lead ECG is critical to identify pacing spikes, capture, sensing abnormalities, or dysrhythmias.
Metabolic evaluation should assess for reversible causes of elevated pacing thresholds.
ECG evaluation with a pacemaker magnet helps assess device function: normal magnet rate suggests intact function, a rate slowed by more than 10% indicates battery depletion, and absence of spikes suggests significant malfunction.
Diagnostic Studies
Laboratory testing includes serum potassium, arterial blood gas, and serum levels of antiarrhythmic drugs when relevant.
Chest radiography evaluates lead integrity and position, identifying fractures, dislodgment, or perforation.
Prehospital Considerations
Obtain and preserve rhythm strips for later analysis.
Initial Stabilization
Administer supplemental oxygen, secure the airway if needed, establish IV access, and treat bradycardia per ACLS protocols. Avoid placing defibrillation pads directly over the pacemaker generator. Initiate transcutaneous pacing in unstable patients.
Definitive Emergency Management
For pacemaker failure with instability, initiate transcutaneous pacing and arrange for temporary transvenous pacing via central venous access, preferably the right internal jugular vein. Confirm capture electrically and mechanically, determine capture threshold, and set output at two to three times this threshold.
Correct reversible causes such as hyperkalemia.
Pacemaker-mediated or runaway tachycardia may require AV nodal blockade, device reprogramming, or, in extreme cases, surgical disconnection of the lead.
Medications
Adenosine 6 mg IV bolus may be used in select tachyarrhythmias, with cardiology guidance.
Disposition Planning
Admission is required for permanent pacemaker malfunction or suspected device-related infection.
Patients may be discharged only if asymptomatic and after formal device interrogation by cardiology.
Follow-Up Strategy
All patients require referral to cardiology or a specialized pacemaker clinic for definitive evaluation and management.
Clinical Pearls and Pitfalls
Always consider pacemaker malfunction in patients presenting with unexplained bradycardia, syncope, or decompensated heart failure. Early use of a pacemaker magnet is a simple and valuable diagnostic tool in the emergency setting.
Core Concept
A cardiac pacemaker is an electronic device that delivers electrical impulses to stimulate myocardial contraction and maintain an adequate heart rate and cardiac output when intrinsic conduction is inadequate.
Pacing Modalities
Transcutaneous pacing uses external pads placed in anterior–lateral or anterior–posterior positions. Current is increased until electrical and mechanical capture is achieved. This is a temporary emergency measure until definitive therapy is available.
Temporary transvenous pacing involves insertion of a pacing wire via central venous access into the right atrium or ventricle, connected to an external generator. It is typically used as a bridge to permanent pacing or until pacing is no longer required.
Permanent implanted pacemakers consist of a lithium-powered battery (lifespan approximately 7–10 years), a programmable generator, and one or more leads positioned in the right atrium and/or ventricle to sense intrinsic activity and pace as needed.
A pacemaker magnet placed over the generator converts the device to asynchronous pacing. This is useful when pacer spikes are absent on ECG; a reduced magnet rate (≈10% decrease) suggests battery depletion.
Key Terminology
Fixed-rate pacing fires at a preset rate regardless of intrinsic rhythm and is now rarely used.
Demand pacing senses native cardiac activity and delivers impulses only when intrinsic rates fall below a programmed threshold.
Sensing refers to the device’s ability to detect intrinsic cardiac depolarization.
Pacemakers are described using a standardized code; in emergency care, the first three letters are most relevant: the chamber sensed, the chamber paced, and the response to sensing. Common configurations include VVI (single-chamber ventricular pacing) and DDD (dual-chamber pacing).
Common Causes of Pacemaker Complications
Infection of pacemaker components is most often due to Staphylococcus epidermidis or Staphylococcus aureus and may be associated with endocarditis; transesophageal echocardiography is preferred for diagnosis.
Venous thrombosis related to pacing leads is common but usually asymptomatic; pulmonary embolism is rare.
Failure to pace may result from lead fracture or disconnection, oversensing of muscle activity or electrical interference, or gradual battery depletion.
Failure to capture is commonly due to lead dislodgment, including Twiddler’s syndrome, or elevated myocardial pacing thresholds caused by hyperkalemia or ischemia.
Pacemaker-mediated tachycardia occurs in dual-chamber devices via re-entry involving the generator and intrinsic conduction system, typically limited to about 140 bpm.
Runaway pacemaker is rare and characterized by extremely rapid pacing (>200 bpm) due to component failure or battery depletion, often causing hemodynamic instability.
Clinical Presentation
Pacemaker failure may manifest as bradycardia, syncope, hypotension progressing to shock, fatigue, dyspnea from heart failure, ischemic chest pain, or altered mental status.
Pacemaker-induced tachycardia presents with dyspnea, chest pain, lightheadedness, or syncope.
Pacemaker syndrome, usually seen with ventricular-only pacing, results from atrioventricular dyssynchrony and causes palpitations, weakness, exercise intolerance, dyspnea, or syncope.
Focused History and Examination
Key history includes date of implantation, device type, and adherence to routine follow-up and battery checks. Examination should include cardiovascular and pulmonary assessment and inspection of the generator site for signs of infection.
Essential Emergency Evaluation
A 12-lead ECG is critical to identify pacing spikes, capture, sensing abnormalities, or dysrhythmias.
Metabolic evaluation should assess for reversible causes of elevated pacing thresholds.
ECG evaluation with a pacemaker magnet helps assess device function: normal magnet rate suggests intact function, a rate slowed by more than 10% indicates battery depletion, and absence of spikes suggests significant malfunction.
Diagnostic Studies
Laboratory testing includes serum potassium, arterial blood gas, and serum levels of antiarrhythmic drugs when relevant.
Chest radiography evaluates lead integrity and position, identifying fractures, dislodgment, or perforation.
Prehospital Considerations
Obtain and preserve rhythm strips for later analysis.
Initial Stabilization
Administer supplemental oxygen, secure the airway if needed, establish IV access, and treat bradycardia per ACLS protocols. Avoid placing defibrillation pads directly over the pacemaker generator. Initiate transcutaneous pacing in unstable patients.
Definitive Emergency Management
For pacemaker failure with instability, initiate transcutaneous pacing and arrange for temporary transvenous pacing via central venous access, preferably the right internal jugular vein. Confirm capture electrically and mechanically, determine capture threshold, and set output at two to three times this threshold.
Correct reversible causes such as hyperkalemia.
Pacemaker-mediated or runaway tachycardia may require AV nodal blockade, device reprogramming, or, in extreme cases, surgical disconnection of the lead.
Medications
Adenosine 6 mg IV bolus may be used in select tachyarrhythmias, with cardiology guidance.
Disposition Planning
Admission is required for permanent pacemaker malfunction or suspected device-related infection.
Patients may be discharged only if asymptomatic and after formal device interrogation by cardiology.
Follow-Up Strategy
All patients require referral to cardiology or a specialized pacemaker clinic for definitive evaluation and management.
Clinical Pearls and Pitfalls
Always consider pacemaker malfunction in patients presenting with unexplained bradycardia, syncope, or decompensated heart failure. Early use of a pacemaker magnet is a simple and valuable diagnostic tool in the emergency setting.
- Published on
Emergency and Acute Medicine – Cardiac Testing
Overview
Cardiac testing is essential in emergency patients with concern for acute coronary syndrome (ACS) or heart failure (HF). These entities exist on a continuum, where unstable angina may progress to myocardial infarction and subsequently to heart failure. Missed ACS remains a major source of emergency department malpractice, with a small but significant percentage of ACS patients discharged inappropriately. History, physical examination, and ECG are the foundation of evaluation but fail to detect a minority of myocardial infarctions, necessitating adjunctive testing such as biomarkers and imaging.
Underlying Causes
ACS most commonly results from atherosclerotic coronary artery disease or coronary vasospasm. In pregnancy, spontaneous coronary artery dissection should be considered when ischemic ECG changes accompany chest pain.
Clinical Presentation
Anginal discomfort is typically provoked by exertion or emotional stress and relieved by rest. Chest pain described as sharp, stabbing, pleuritic, or reproducible by palpation is less suggestive of ACS, though ischemia can still be present in a minority of these cases. Symptom relief with nitroglycerin or gastrointestinal treatments does not reliably distinguish cardiac from noncardiac causes. Anginal episodes often last more than 5 minutes but less than 20 minutes; symptoms persisting beyond 20 minutes raise concern for unstable angina or infarction. Physical examination is frequently normal.
Core Emergency Evaluation
A 12-lead ECG should be obtained within 10 minutes of arrival for patients with chest pain. A single ECG may miss up to half of acute myocardial infarctions, as changes can evolve over time. Hyperacute T waves may represent the earliest ischemic sign. Continuous ECG monitoring or repeat ECGs within 15–60 minutes improves detection. ST-segment depression of 1 mm suggests ischemia, while ST elevation greater than 1–2 mm in contiguous leads defines STEMI. New left bundle branch block complicates diagnosis; concordant ST changes using Sgarbossa criteria increase suspicion. Additional ECG leads may identify infarctions not seen on standard views, including right ventricular and posterior wall involvement.
Laboratory Assessment
Cardiac biomarkers are indicated when ACS is suspected. Troponin I and T rise within 2–3 hours, peak by 8–12 hours, and remain elevated for days. A single negative troponin has limited sensitivity unless drawn 8–12 hours after symptom onset. Mild elevations may occur in nonischemic conditions such as renal failure, sepsis, pulmonary embolism, or heart failure. CK-MB is less sensitive and generally adds little unless renal failure or recent infarction limits troponin interpretation. BNP assists in diagnosing heart failure, with levels above 100 pg/mL supporting the diagnosis.
Imaging Modalities
Chest radiography is often normal but may reveal cardiomegaly, pulmonary edema, pneumonia, or mediastinal widening. Rest echocardiography can identify wall motion abnormalities and pump failure, providing moderate sensitivity for ACS and higher sensitivity for myocardial infarction. Myocardial perfusion imaging using technetium-99m sestamibi detects regions of reduced perfusion and is reserved for intermediate- to high-risk patients. CT coronary angiography offers a high negative predictive value but may increase downstream testing without reducing cost. Exercise stress testing provides diagnostic and prognostic information, with enhanced accuracy when combined with echocardiography or nuclear imaging. Cardiac catheterization remains the gold standard for coronary assessment but does not exclude vasospasm-related events.
Prehospital and Initial ED Management
Prehospital ECG monitoring improves early detection of ACS. In the emergency department, continuous cardiac monitoring and pulse oximetry are standard. Further management depends on risk stratification and test results.
Diagnostic Strategy in the ED
Patients with concerning history should undergo ECG and initial troponin testing. Abnormal findings warrant admission and cardiology consultation. Persistent symptoms or evolving ECG changes necessitate repeat testing or advanced imaging. Low- to moderate-risk patients may undergo stress testing, either during observation or as an outpatient within 72 hours if reliable follow-up exists. Abnormal ancillary testing requires admission or specialty consultation.
Disposition Planning
Admission is indicated for patients with abnormal ECGs, positive biomarkers, concerning imaging, or unavailable observation resources. Observation units may be used for serial testing when diagnosis is uncertain. Discharge is appropriate for patients with noncardiac histories, normal ECGs, and negative cardiac testing.
Follow-Up Considerations
Abnormal stress tests require close cardiology follow-up. Patients discharged with undifferentiated chest pain should have timely outpatient evaluation if inpatient testing is deferred.
Clinical Insights and Cautions
A normal ECG or troponin does not exclude coronary artery disease. Serial ECGs and additional leads increase diagnostic sensitivity. Most emergency patients with undifferentiated chest pain require some form of additional cardiac testing to safely exclude ACS.
Overview
Cardiac testing is essential in emergency patients with concern for acute coronary syndrome (ACS) or heart failure (HF). These entities exist on a continuum, where unstable angina may progress to myocardial infarction and subsequently to heart failure. Missed ACS remains a major source of emergency department malpractice, with a small but significant percentage of ACS patients discharged inappropriately. History, physical examination, and ECG are the foundation of evaluation but fail to detect a minority of myocardial infarctions, necessitating adjunctive testing such as biomarkers and imaging.
Underlying Causes
ACS most commonly results from atherosclerotic coronary artery disease or coronary vasospasm. In pregnancy, spontaneous coronary artery dissection should be considered when ischemic ECG changes accompany chest pain.
Clinical Presentation
Anginal discomfort is typically provoked by exertion or emotional stress and relieved by rest. Chest pain described as sharp, stabbing, pleuritic, or reproducible by palpation is less suggestive of ACS, though ischemia can still be present in a minority of these cases. Symptom relief with nitroglycerin or gastrointestinal treatments does not reliably distinguish cardiac from noncardiac causes. Anginal episodes often last more than 5 minutes but less than 20 minutes; symptoms persisting beyond 20 minutes raise concern for unstable angina or infarction. Physical examination is frequently normal.
Core Emergency Evaluation
A 12-lead ECG should be obtained within 10 minutes of arrival for patients with chest pain. A single ECG may miss up to half of acute myocardial infarctions, as changes can evolve over time. Hyperacute T waves may represent the earliest ischemic sign. Continuous ECG monitoring or repeat ECGs within 15–60 minutes improves detection. ST-segment depression of 1 mm suggests ischemia, while ST elevation greater than 1–2 mm in contiguous leads defines STEMI. New left bundle branch block complicates diagnosis; concordant ST changes using Sgarbossa criteria increase suspicion. Additional ECG leads may identify infarctions not seen on standard views, including right ventricular and posterior wall involvement.
Laboratory Assessment
Cardiac biomarkers are indicated when ACS is suspected. Troponin I and T rise within 2–3 hours, peak by 8–12 hours, and remain elevated for days. A single negative troponin has limited sensitivity unless drawn 8–12 hours after symptom onset. Mild elevations may occur in nonischemic conditions such as renal failure, sepsis, pulmonary embolism, or heart failure. CK-MB is less sensitive and generally adds little unless renal failure or recent infarction limits troponin interpretation. BNP assists in diagnosing heart failure, with levels above 100 pg/mL supporting the diagnosis.
Imaging Modalities
Chest radiography is often normal but may reveal cardiomegaly, pulmonary edema, pneumonia, or mediastinal widening. Rest echocardiography can identify wall motion abnormalities and pump failure, providing moderate sensitivity for ACS and higher sensitivity for myocardial infarction. Myocardial perfusion imaging using technetium-99m sestamibi detects regions of reduced perfusion and is reserved for intermediate- to high-risk patients. CT coronary angiography offers a high negative predictive value but may increase downstream testing without reducing cost. Exercise stress testing provides diagnostic and prognostic information, with enhanced accuracy when combined with echocardiography or nuclear imaging. Cardiac catheterization remains the gold standard for coronary assessment but does not exclude vasospasm-related events.
Prehospital and Initial ED Management
Prehospital ECG monitoring improves early detection of ACS. In the emergency department, continuous cardiac monitoring and pulse oximetry are standard. Further management depends on risk stratification and test results.
Diagnostic Strategy in the ED
Patients with concerning history should undergo ECG and initial troponin testing. Abnormal findings warrant admission and cardiology consultation. Persistent symptoms or evolving ECG changes necessitate repeat testing or advanced imaging. Low- to moderate-risk patients may undergo stress testing, either during observation or as an outpatient within 72 hours if reliable follow-up exists. Abnormal ancillary testing requires admission or specialty consultation.
Disposition Planning
Admission is indicated for patients with abnormal ECGs, positive biomarkers, concerning imaging, or unavailable observation resources. Observation units may be used for serial testing when diagnosis is uncertain. Discharge is appropriate for patients with noncardiac histories, normal ECGs, and negative cardiac testing.
Follow-Up Considerations
Abnormal stress tests require close cardiology follow-up. Patients discharged with undifferentiated chest pain should have timely outpatient evaluation if inpatient testing is deferred.
Clinical Insights and Cautions
A normal ECG or troponin does not exclude coronary artery disease. Serial ECGs and additional leads increase diagnostic sensitivity. Most emergency patients with undifferentiated chest pain require some form of additional cardiac testing to safely exclude ACS.
- Published on
Emergency and Acute Medicine – Cardiac Transplantation Complications
Overview
Heart transplant recipients represent a high-risk emergency population because of denervated graft physiology and chronic immunosuppression. They are vulnerable to ischemia, heart failure, infection, and medication toxicity. Approximately 1,900–2,300 cardiac transplants are performed annually in the United States, with survival rates of 85–90% at 1 year and about 75% at 5 years. Most patients receive triple-drug immunosuppressive regimens, commonly including corticosteroids. The highest complication rate occurs within the first 6 weeks post-transplant, though late complications are common.
Special Populations
Older transplant recipients have increased susceptibility to severe infection and acute rejection due to age-related immune changes. Pregnancy after cardiac transplantation is increasingly reported and usually results in live births, though hypertension, preeclampsia, and rejection are common. Physiologic changes of pregnancy do not significantly increase heart failure risk, but vigilance for infection and rejection is essential.
Mechanisms of Complications
Rejection may be hyperacute, acute, or chronic. Hyperacute rejection occurs within minutes due to ABO or major incompatibility and is immediately graft-fatal. Acute rejection, characterized by lymphocytic infiltration and myocyte injury, is most common in the first 6 weeks but can occur at any time. Chronic rejection manifests as fibrosis and graft vascular disease and has no effective therapy. Cardiac allograft vasculopathy represents immune-mediated accelerated coronary disease and is the leading cause of late mortality beyond the first year.
Infectious complications dominate early outcomes. During the first month, bacterial infections such as pneumonia, mediastinitis, wound infections, and UTIs are common. Within the first year, opportunistic infections including CMV, HSV, Legionella, fungi, and Pneumocystis become prominent. Medication toxicities are frequent, particularly nephrotoxicity, neurotoxicity, metabolic derangements, and bone marrow suppression from immunosuppressants. Long-term immunosuppression markedly increases malignancy risk, especially skin cancers, lymphomas, Kaposi sarcoma, and solid tumors.
Clinical Manifestations
Acute rejection presents with nonspecific symptoms due to cardiac denervation, including fatigue, dyspnea, low-grade fever, nausea, and vomiting. Heart failure may manifest as tachypnea, rales, hypoxia, S3 gallop, murmurs, and edema. Allograft vasculopathy often presents insidiously with fatigue, cough, or dyspnea; acute presentations include heart failure, infarction, or sudden death, often without angina. Infection may present with fever, skin lesions, or organ-specific symptoms. CMV infection ranges from mild flu-like illness to pneumonitis, hepatitis, gastroenteritis, and severe leukopenia with high mortality. Pediatric patients have higher risk of post-transplant lymphoproliferative disease and pneumonia.
Essential Emergency Assessment
Evaluation focuses on identifying rejection, graft dysfunction, ischemia, and infection. Initial studies include ECG, cardiac enzymes, chest radiograph, and echocardiography. Suspected rejection requires urgent consultation with the transplant team and often endomyocardial biopsy. In children, standard fever evaluation with chest radiograph and ECG is required, and lumbar puncture should be considered if the patient is on steroids.
Diagnostic Findings
Laboratory abnormalities may include renal dysfunction, electrolyte disturbances, metabolic acidosis, and hyperkalemia related to calcineurin inhibitors. Relative eosinophilia may favor rejection over infection. BNP is often chronically elevated. CMV testing and immunosuppressant trough levels are frequently necessary. ECG typically shows sinus tachycardia (90–110 bpm) in denervated hearts; voltage reduction may be seen. Chest radiography may reveal cardiomegaly, pulmonary edema, or effusions. Echocardiography may show diastolic dysfunction, biventricular dilation, valvular regurgitation, or reduced filling parameters.
Key Differentials
Rejection, infection, ischemia, CMV disease, malignancy, and medication toxicity should always be considered.
Prehospital Considerations
Adenosine should be avoided due to prolonged and unpredictable effects in denervated hearts.
Initial Stabilization
Management follows airway, breathing, and circulation priorities with oxygen, IV access, monitoring, and ventilatory or hemodynamic support as needed. Bradycardia does not respond to atropine; isoproterenol is preferred. ACLS protocols apply, with awareness of altered pharmacologic responses.
Emergency Department Management
Hemodynamically significant rejection requires high-dose IV corticosteroids and possible anti–T-cell antibody therapy in coordination with the transplant team. Ischemia or vasculopathy is treated with antiplatelet therapy, anticoagulation, and possible revascularization, though retransplantation may ultimately be required. Suspected CMV infection warrants empiric IV ganciclovir. HSV infections are treated with acyclovir. Fever without source mandates early infectious disease or transplant consultation. Headache or neurologic symptoms require low threshold for neuroimaging and lumbar puncture. Stress-dose steroids may be required during severe illness or trauma, and NSAIDs should be minimized due to nephrotoxicity risk.
Disposition Planning
Admission is indicated for hemodynamically significant rejection, ischemia, new dysrhythmias, heart failure, hypoxia, syncope, poorly controlled hypertension, suspected CMV infection, inability to tolerate oral medications, or fever in immunosuppressed patients. Discharge for mild rejection or select pediatric fever cases should occur only after direct consultation with the transplant team.
Clinical Insights
Symptoms of rejection and infection overlap and are often subtle. Denervated hearts mask classic ischemic pain. Bradycardia will not respond to atropine. Early consultation with the transplant center is essential for optimal outcomes.
Overview
Heart transplant recipients represent a high-risk emergency population because of denervated graft physiology and chronic immunosuppression. They are vulnerable to ischemia, heart failure, infection, and medication toxicity. Approximately 1,900–2,300 cardiac transplants are performed annually in the United States, with survival rates of 85–90% at 1 year and about 75% at 5 years. Most patients receive triple-drug immunosuppressive regimens, commonly including corticosteroids. The highest complication rate occurs within the first 6 weeks post-transplant, though late complications are common.
Special Populations
Older transplant recipients have increased susceptibility to severe infection and acute rejection due to age-related immune changes. Pregnancy after cardiac transplantation is increasingly reported and usually results in live births, though hypertension, preeclampsia, and rejection are common. Physiologic changes of pregnancy do not significantly increase heart failure risk, but vigilance for infection and rejection is essential.
Mechanisms of Complications
Rejection may be hyperacute, acute, or chronic. Hyperacute rejection occurs within minutes due to ABO or major incompatibility and is immediately graft-fatal. Acute rejection, characterized by lymphocytic infiltration and myocyte injury, is most common in the first 6 weeks but can occur at any time. Chronic rejection manifests as fibrosis and graft vascular disease and has no effective therapy. Cardiac allograft vasculopathy represents immune-mediated accelerated coronary disease and is the leading cause of late mortality beyond the first year.
Infectious complications dominate early outcomes. During the first month, bacterial infections such as pneumonia, mediastinitis, wound infections, and UTIs are common. Within the first year, opportunistic infections including CMV, HSV, Legionella, fungi, and Pneumocystis become prominent. Medication toxicities are frequent, particularly nephrotoxicity, neurotoxicity, metabolic derangements, and bone marrow suppression from immunosuppressants. Long-term immunosuppression markedly increases malignancy risk, especially skin cancers, lymphomas, Kaposi sarcoma, and solid tumors.
Clinical Manifestations
Acute rejection presents with nonspecific symptoms due to cardiac denervation, including fatigue, dyspnea, low-grade fever, nausea, and vomiting. Heart failure may manifest as tachypnea, rales, hypoxia, S3 gallop, murmurs, and edema. Allograft vasculopathy often presents insidiously with fatigue, cough, or dyspnea; acute presentations include heart failure, infarction, or sudden death, often without angina. Infection may present with fever, skin lesions, or organ-specific symptoms. CMV infection ranges from mild flu-like illness to pneumonitis, hepatitis, gastroenteritis, and severe leukopenia with high mortality. Pediatric patients have higher risk of post-transplant lymphoproliferative disease and pneumonia.
Essential Emergency Assessment
Evaluation focuses on identifying rejection, graft dysfunction, ischemia, and infection. Initial studies include ECG, cardiac enzymes, chest radiograph, and echocardiography. Suspected rejection requires urgent consultation with the transplant team and often endomyocardial biopsy. In children, standard fever evaluation with chest radiograph and ECG is required, and lumbar puncture should be considered if the patient is on steroids.
Diagnostic Findings
Laboratory abnormalities may include renal dysfunction, electrolyte disturbances, metabolic acidosis, and hyperkalemia related to calcineurin inhibitors. Relative eosinophilia may favor rejection over infection. BNP is often chronically elevated. CMV testing and immunosuppressant trough levels are frequently necessary. ECG typically shows sinus tachycardia (90–110 bpm) in denervated hearts; voltage reduction may be seen. Chest radiography may reveal cardiomegaly, pulmonary edema, or effusions. Echocardiography may show diastolic dysfunction, biventricular dilation, valvular regurgitation, or reduced filling parameters.
Key Differentials
Rejection, infection, ischemia, CMV disease, malignancy, and medication toxicity should always be considered.
Prehospital Considerations
Adenosine should be avoided due to prolonged and unpredictable effects in denervated hearts.
Initial Stabilization
Management follows airway, breathing, and circulation priorities with oxygen, IV access, monitoring, and ventilatory or hemodynamic support as needed. Bradycardia does not respond to atropine; isoproterenol is preferred. ACLS protocols apply, with awareness of altered pharmacologic responses.
Emergency Department Management
Hemodynamically significant rejection requires high-dose IV corticosteroids and possible anti–T-cell antibody therapy in coordination with the transplant team. Ischemia or vasculopathy is treated with antiplatelet therapy, anticoagulation, and possible revascularization, though retransplantation may ultimately be required. Suspected CMV infection warrants empiric IV ganciclovir. HSV infections are treated with acyclovir. Fever without source mandates early infectious disease or transplant consultation. Headache or neurologic symptoms require low threshold for neuroimaging and lumbar puncture. Stress-dose steroids may be required during severe illness or trauma, and NSAIDs should be minimized due to nephrotoxicity risk.
Disposition Planning
Admission is indicated for hemodynamically significant rejection, ischemia, new dysrhythmias, heart failure, hypoxia, syncope, poorly controlled hypertension, suspected CMV infection, inability to tolerate oral medications, or fever in immunosuppressed patients. Discharge for mild rejection or select pediatric fever cases should occur only after direct consultation with the transplant team.
Clinical Insights
Symptoms of rejection and infection overlap and are often subtle. Denervated hearts mask classic ischemic pain. Bradycardia will not respond to atropine. Early consultation with the transplant center is essential for optimal outcomes.
- Published on
Emergency and Acute Medicine – Hypertrophic Cardiomyopathy
Core Overview
Hypertrophic cardiomyopathy (HCM) is a genetic disorder of the cardiac sarcomere caused by numerous mutations, resulting in a hypertrophied, nondilated left ventricle (and rarely right ventricle) without another cause such as hypertension or aortic stenosis. Phenotypic expression is highly variable. Two major forms exist: nonobstructive HCM, accounting for approximately 75% of patients with an estimated annual mortality of ~1%, and obstructive hypertrophic cardiomyopathy (HOCM), accounting for ~25% with more severe disease and an estimated annual mortality of ~2%.
HCM can present at any age, from neonates to the elderly, but most cases manifest during childhood or adolescence, often coinciding with the pubertal growth spurt. Disease diagnosed at younger ages is typically more severe. A small subset progresses to reduced left ventricular systolic function later in life. Adult-onset presentations are not uncommon and are frequently misdiagnosed as asthma, COPD, deconditioning, or sleep apnea. Lethal ventricular arrhythmias are more common in younger patients, while supraventricular arrhythmias increase with age. Atrial fibrillation is common and often poorly tolerated. HCM is the most common cause of atraumatic sudden death in young athletes under 35 years of age. Prevalence is approximately 1 in 500 adults based on echocardiographic screening.
Structural and Pathophysiologic Features
Pathology is characterized by marked and irregular ventricular wall thickening with myofibrillar disarray and fibrin deposition, predominantly affecting the high-pressure left ventricle. Septal hypertrophy is usually more pronounced than free wall thickening. In obstructive disease, hypertrophy may regress if outflow obstruction is relieved. Some phenotypes demonstrate progressive wall thinning with age, typically following marked hypertrophy earlier in life. Diastolic stiffness leads to atrial dilation. Microvascular dysfunction occurs due to impaired vasodilation, intimal thickening, and perivascular collagen deposition.
Long-Term Outpatient Management Principles
Management focuses on avoiding volume depletion and excessive cardiac demand, with therapy tailored to hypertrophy severity and distribution. Pharmacologic treatment includes beta-blockers or verapamil to slow heart rate and prolong diastole. Implantable cardioverter-defibrillators are indicated in patients with prior syncope, cardiac arrest, family history of sudden death, nonsustained ventricular tachycardia, abnormal blood pressure response to exercise, or massive hypertrophy. Septal reduction strategies include alcohol septal ablation and surgical septal myectomy, with improving outcomes at experienced centers.
Genetic Risk Profile
HCM was the first cardiac disease with an identified genetic basis (1989). It follows an autosomal-dominant inheritance pattern with more than 10 associated genes, most encoding sarcomeric proteins. Over 700 distinct mutations have been identified, with high penetrance and marked phenotypic variability. Some genotypes carry significantly higher risk of sudden death. Routine genotype-based risk stratification remains impractical due to complexity and incomplete understanding of modifier genes and environmental factors. Certain mutations involving cell membrane pumps are associated with increased arrhythmogenic risk.
Clinical Presentation
Symptoms often correlate with exertion or sudden upright posture, both of which reduce venous return and ventricular filling. Severity depends on hypertrophy location and extent. Common symptoms include exertional dyspnea, shortness of breath, postprandial or exertional angina, presyncope, syncope, congestive heart failure, cardiovascular collapse, and dysrhythmias. Paroxysmal atrial fibrillation may precipitate rapid deterioration, particularly in heart failure, and increases thromboembolic risk. Ventricular tachycardia or fibrillation may cause sudden death, while bradyarrhythmias are rare.
Patients may have a history of septal myectomy or alcohol ablation, with associated risks of conduction abnormalities or septal rupture. High-risk individuals may have implanted defibrillators. A family history of unexplained sudden death or known HCM is a critical diagnostic clue.
Pediatric Considerations
Disease severity may increase during adolescence. Any child with unexplained syncope, especially during exertion, warrants detailed family history (standard three-generation pedigree) and specialist referral.
Physical Examination Findings
Findings may be absent or subtle in nonobstructive disease. In obstructive HCM, findings may include a loud left-sided S4, a double apical impulse, and a crescendo–decrescendo midsystolic murmur best heard at the left sternal border. The murmur increases with standing or Valsalva and decreases with squatting, recumbency, or handgrip. Mitral regurgitation is common; radiation to the axilla suggests associated mitral insufficiency.
Electrocardiographic Features
ECG is abnormal in over 90% of patients. Findings include T-wave inversion >1 mm in multiple leads, ST-segment depression >0.5 mm, deep Q waves (>3 mm or >40 ms) excluding leads III and aVR, prolonged P waves with negative terminal forces in V1, and nonspecific intraventricular conduction delay >140 ms. Athletic ECG variants require careful interpretation, especially in non–African-Caribbean athletes over 16 years.
Laboratory and Imaging Evaluation
Routine laboratory testing has no diagnostic value in the emergency setting. Genetic testing is outpatient-focused. Chest radiography is usually normal but may show left ventricular free wall bulging, atrial enlargement, or pulmonary vascular redistribution. Transthoracic echocardiography with Doppler is the diagnostic cornerstone, demonstrating LV wall thickness >15 mm in adults (or ≥13–14 mm with supportive features), small or normal LV cavity, systolic outflow obstruction, and diastolic dysfunction. In children, wall thickness ≥2 standard deviations above the mean is diagnostic. Cardiac MRI supplements echocardiography, offering detailed assessment of hypertrophy distribution and fibrosis. Stress thallium and PET imaging may identify ischemia.
Differential Diagnosis
Consider vasovagal syncope, heat illness, aortic or pulmonic stenosis, ventricular septal defect, mitral regurgitation or prolapse, and coronary artery disease. Angina or heart failure in HCM carries higher risk than in non-HCM populations.
Emergency Management Principles
Suspect HCM in patients who deteriorate with standard heart failure, ischemia, or supraventricular tachycardia treatment, and in young athletes collapsing during exertion. Patients are highly sensitive to preload reduction and impaired diastolic filling. Initial management includes airway stabilization, oxygen, IV access, cardiac monitoring, and pulse oximetry. Patients may need to remain supine.
Avoid routine vasodilators for CHF or angina, as they may precipitate collapse. If hypotension occurs, administer cautious fluid boluses. Even mild hypovolemia can significantly reduce cardiac output. Rate control and improved diastolic filling are central goals. Beta-blockers are first-line therapy; verapamil is useful but nifedipine is relatively contraindicated due to vasodilation.
Supraventricular dysrhythmias are treated initially with beta-blockers or calcium channel blockers. Amiodarone is the drug of choice for ventricular dysrhythmias or refractory cases. Early electrical cardioversion is recommended for new-onset atrial fibrillation with heart failure.
Key Medications
Amiodarone, propranolol, verapamil, phenylephrine (for refractory hypotension without inotropic effect), and diltiazem (contraindicated in children under 12) may be used with careful hemodynamic assessment. All medications must be evaluated for their impact on outflow tract obstruction.
Disposition Decisions
Admission is required for unexplained syncope, heart failure, angina, or hemodynamically significant tachydysrhythmias, often to ICU level care. Discharge may be considered only when hypertrophy is an incidental finding without personal or family history of syncope or sudden death, with urgent cardiology follow-up arranged. Patients must be counseled to avoid exertion or situations that reduce preload until evaluated.
Clinical Pitfalls and Key Insights
Genetic and phenotypic diversity complicates diagnosis and risk stratification. Some advocate routine echocardiographic screening for youth sports participation or ICD placement at diagnosis. Any patient with syncope in whom HCM is suspected must be fully evaluated, as recurrence carries a high risk of sudden death.
Core Overview
Hypertrophic cardiomyopathy (HCM) is a genetic disorder of the cardiac sarcomere caused by numerous mutations, resulting in a hypertrophied, nondilated left ventricle (and rarely right ventricle) without another cause such as hypertension or aortic stenosis. Phenotypic expression is highly variable. Two major forms exist: nonobstructive HCM, accounting for approximately 75% of patients with an estimated annual mortality of ~1%, and obstructive hypertrophic cardiomyopathy (HOCM), accounting for ~25% with more severe disease and an estimated annual mortality of ~2%.
HCM can present at any age, from neonates to the elderly, but most cases manifest during childhood or adolescence, often coinciding with the pubertal growth spurt. Disease diagnosed at younger ages is typically more severe. A small subset progresses to reduced left ventricular systolic function later in life. Adult-onset presentations are not uncommon and are frequently misdiagnosed as asthma, COPD, deconditioning, or sleep apnea. Lethal ventricular arrhythmias are more common in younger patients, while supraventricular arrhythmias increase with age. Atrial fibrillation is common and often poorly tolerated. HCM is the most common cause of atraumatic sudden death in young athletes under 35 years of age. Prevalence is approximately 1 in 500 adults based on echocardiographic screening.
Structural and Pathophysiologic Features
Pathology is characterized by marked and irregular ventricular wall thickening with myofibrillar disarray and fibrin deposition, predominantly affecting the high-pressure left ventricle. Septal hypertrophy is usually more pronounced than free wall thickening. In obstructive disease, hypertrophy may regress if outflow obstruction is relieved. Some phenotypes demonstrate progressive wall thinning with age, typically following marked hypertrophy earlier in life. Diastolic stiffness leads to atrial dilation. Microvascular dysfunction occurs due to impaired vasodilation, intimal thickening, and perivascular collagen deposition.
Long-Term Outpatient Management Principles
Management focuses on avoiding volume depletion and excessive cardiac demand, with therapy tailored to hypertrophy severity and distribution. Pharmacologic treatment includes beta-blockers or verapamil to slow heart rate and prolong diastole. Implantable cardioverter-defibrillators are indicated in patients with prior syncope, cardiac arrest, family history of sudden death, nonsustained ventricular tachycardia, abnormal blood pressure response to exercise, or massive hypertrophy. Septal reduction strategies include alcohol septal ablation and surgical septal myectomy, with improving outcomes at experienced centers.
Genetic Risk Profile
HCM was the first cardiac disease with an identified genetic basis (1989). It follows an autosomal-dominant inheritance pattern with more than 10 associated genes, most encoding sarcomeric proteins. Over 700 distinct mutations have been identified, with high penetrance and marked phenotypic variability. Some genotypes carry significantly higher risk of sudden death. Routine genotype-based risk stratification remains impractical due to complexity and incomplete understanding of modifier genes and environmental factors. Certain mutations involving cell membrane pumps are associated with increased arrhythmogenic risk.
Clinical Presentation
Symptoms often correlate with exertion or sudden upright posture, both of which reduce venous return and ventricular filling. Severity depends on hypertrophy location and extent. Common symptoms include exertional dyspnea, shortness of breath, postprandial or exertional angina, presyncope, syncope, congestive heart failure, cardiovascular collapse, and dysrhythmias. Paroxysmal atrial fibrillation may precipitate rapid deterioration, particularly in heart failure, and increases thromboembolic risk. Ventricular tachycardia or fibrillation may cause sudden death, while bradyarrhythmias are rare.
Patients may have a history of septal myectomy or alcohol ablation, with associated risks of conduction abnormalities or septal rupture. High-risk individuals may have implanted defibrillators. A family history of unexplained sudden death or known HCM is a critical diagnostic clue.
Pediatric Considerations
Disease severity may increase during adolescence. Any child with unexplained syncope, especially during exertion, warrants detailed family history (standard three-generation pedigree) and specialist referral.
Physical Examination Findings
Findings may be absent or subtle in nonobstructive disease. In obstructive HCM, findings may include a loud left-sided S4, a double apical impulse, and a crescendo–decrescendo midsystolic murmur best heard at the left sternal border. The murmur increases with standing or Valsalva and decreases with squatting, recumbency, or handgrip. Mitral regurgitation is common; radiation to the axilla suggests associated mitral insufficiency.
Electrocardiographic Features
ECG is abnormal in over 90% of patients. Findings include T-wave inversion >1 mm in multiple leads, ST-segment depression >0.5 mm, deep Q waves (>3 mm or >40 ms) excluding leads III and aVR, prolonged P waves with negative terminal forces in V1, and nonspecific intraventricular conduction delay >140 ms. Athletic ECG variants require careful interpretation, especially in non–African-Caribbean athletes over 16 years.
Laboratory and Imaging Evaluation
Routine laboratory testing has no diagnostic value in the emergency setting. Genetic testing is outpatient-focused. Chest radiography is usually normal but may show left ventricular free wall bulging, atrial enlargement, or pulmonary vascular redistribution. Transthoracic echocardiography with Doppler is the diagnostic cornerstone, demonstrating LV wall thickness >15 mm in adults (or ≥13–14 mm with supportive features), small or normal LV cavity, systolic outflow obstruction, and diastolic dysfunction. In children, wall thickness ≥2 standard deviations above the mean is diagnostic. Cardiac MRI supplements echocardiography, offering detailed assessment of hypertrophy distribution and fibrosis. Stress thallium and PET imaging may identify ischemia.
Differential Diagnosis
Consider vasovagal syncope, heat illness, aortic or pulmonic stenosis, ventricular septal defect, mitral regurgitation or prolapse, and coronary artery disease. Angina or heart failure in HCM carries higher risk than in non-HCM populations.
Emergency Management Principles
Suspect HCM in patients who deteriorate with standard heart failure, ischemia, or supraventricular tachycardia treatment, and in young athletes collapsing during exertion. Patients are highly sensitive to preload reduction and impaired diastolic filling. Initial management includes airway stabilization, oxygen, IV access, cardiac monitoring, and pulse oximetry. Patients may need to remain supine.
Avoid routine vasodilators for CHF or angina, as they may precipitate collapse. If hypotension occurs, administer cautious fluid boluses. Even mild hypovolemia can significantly reduce cardiac output. Rate control and improved diastolic filling are central goals. Beta-blockers are first-line therapy; verapamil is useful but nifedipine is relatively contraindicated due to vasodilation.
Supraventricular dysrhythmias are treated initially with beta-blockers or calcium channel blockers. Amiodarone is the drug of choice for ventricular dysrhythmias or refractory cases. Early electrical cardioversion is recommended for new-onset atrial fibrillation with heart failure.
Key Medications
Amiodarone, propranolol, verapamil, phenylephrine (for refractory hypotension without inotropic effect), and diltiazem (contraindicated in children under 12) may be used with careful hemodynamic assessment. All medications must be evaluated for their impact on outflow tract obstruction.
Disposition Decisions
Admission is required for unexplained syncope, heart failure, angina, or hemodynamically significant tachydysrhythmias, often to ICU level care. Discharge may be considered only when hypertrophy is an incidental finding without personal or family history of syncope or sudden death, with urgent cardiology follow-up arranged. Patients must be counseled to avoid exertion or situations that reduce preload until evaluated.
Clinical Pitfalls and Key Insights
Genetic and phenotypic diversity complicates diagnosis and risk stratification. Some advocate routine echocardiographic screening for youth sports participation or ICD placement at diagnosis. Any patient with syncope in whom HCM is suspected must be fully evaluated, as recurrence carries a high risk of sudden death.
