​Emergency And Acute Medicine – Cluster Headache
Overview And Key Features
Cluster headache is an excruciating primary headache disorder and represents an infrequent cause of emergency department visits, affecting approximately 0.1% of the population. Attacks often resolve before ED presentation. Individual headache episodes last 15–180 minutes, with about 75% resolving within 60 minutes. The disorder is more common in men at a ratio of approximately 3:1, with typical onset between 30 and 50 years of age. Headaches occur in clusters lasting weeks to months, followed by remission periods longer than one month. During a cluster period, attacks commonly occur 1–3 times per day over 2–3 months, often at the same time of day and during the same season, most frequently in spring and fall. A chronic form exists in about 10% of patients, characterized by remission periods shorter than one month or no remission at all. Cluster headache shares clinical and pathophysiologic similarities with migraine variants and often follows a trigeminal nerve dermatome.

​Pathophysiology
The condition is mediated by activation of the trigeminovascular reflex. This reflex arc amplifies trigeminal nociceptive input and cranial autonomic symptoms through positive feedback mechanisms, resulting in severe unilateral pain and associated autonomic features.

Clinical Presentation
History typically reveals strictly unilateral pain that usually does not alternate sides between attacks. The pain is described as sharp, stabbing, or boring, with abrupt onset and rapid escalation to peak intensity within 5–15 minutes. Attacks end suddenly, and patients are often exhausted afterward. Pain is most commonly located in the eye or temple and may radiate to the ear, cheek, jaw, teeth, nose, or ipsilateral neck. Episodes frequently occur at night. Attacks are often triggered by alcohol ingestion, nitroglycerin, or histamine-containing substances and are more likely during periods of stress, prolonged strain, overwork, or emotional distress. There is no prodrome or aura.

Physical Examination Findings
Patients appear agitated and restless, often pacing or standing rather than lying quietly, which contrasts with migraine behavior. Prominent ipsilateral cranial autonomic symptoms accompany the headache, including nasal congestion or rhinorrhea, conjunctival injection or lacrimation, facial flushing, eyelid edema, partial Horner syndrome (ptosis and/or miosis), and sweating of the face or forehead.

Initial Evaluation
Diagnosis is primarily clinical and based on a characteristic history and physical examination. Life-threatening secondary causes of headache must be excluded, particularly when presentation is atypical.

Diagnostic Testing
Laboratory studies are generally unnecessary unless alternative diagnoses are suspected. Lumbar puncture is indicated if meningitis or subarachnoid hemorrhage is a concern. ESR should be obtained when temporal arteritis is suspected. Neuroimaging with CT or MRI is warranted if there is concern for intracranial hemorrhage, mass lesion, or other secondary pathology.

Differential Diagnosis
Important considerations include migraine headache, trigeminal neuralgia, meningitis, temporal arteritis, intracranial mass lesions, herpes zoster, intracerebral hemorrhage, dental pathology, orbital or ocular disease such as acute angle-closure glaucoma, and temporomandibular joint disorders.

Prehospital Care
Prehospital priorities include recognizing and excluding life-threatening causes of headache. Administration of high-flow oxygen by face mask may provide symptom relief during transport.

Emergency Department Management
Initial management focuses on ruling out secondary causes and administering supplemental oxygen. High-flow 100% oxygen via nonrebreather mask is the preferred first-line therapy.

Pharmacologic Treatment
First-line acute therapies include 100% oxygen at 12 L/min via nonrebreather mask for 15 minutes, increasing to 15 L/min if symptoms persist. Subcutaneous sumatriptan and intravenous dihydroergotamine are also effective.
Second-line options include narcotic analgesics and corticosteroids. Additional medications that may be used include ketorolac, prochlorperazine, somatostatin, fentanyl, or morphine for refractory cases. Verapamil (immediate-release, starting at 80 mg three times daily) is the preventive agent of choice.

Disposition And Follow-Up
Admission is indicated for persistent headaches unresponsive to standard therapy or when the diagnosis remains uncertain. Patients with moderate to complete pain relief, a normal neurologic examination, and a confident diagnosis may be discharged. Consider prescribing home oxygen and/or subcutaneous sumatriptan for outpatient management. Neurology follow-up should be arranged for ongoing preventive therapy and cluster management.

​Clinical Pearls And Pitfalls
A careful history is essential, as pain may have improved by the time of ED evaluation. High-flow 100% oxygen should be initiated immediately as first-line therapy. Cluster headaches can be so severe that they are associated with suicidal ideation; appropriate counseling and follow-up are critical. Ongoing follow-up is essential because cluster periods may persist for months.

​Emergency And Acute Medicine – Migraine Headache
Overview And Pathophysiology
Migraine is a chronic, episodic primary headache disorder and accounts for the majority of headache-related emergency department visits, with approximately one million visits annually. It is three times more common in women, and prevalence peaks in the fourth decade of life. Migraine is no longer considered a primarily vascular disorder. Instead, it reflects a neurovascular process characterized by abnormal trigeminal nerve activation, stimulation of nociceptive pathways within the brainstem, disordered sensory processing, and autonomic dysfunction. Vascular dilation is reactive rather than causative. Cortical spreading depression is believed to underlie migraine aura.

Diagnostic Criteria And Subtypes
Migraine without aura is defined by established clinical criteria requiring at least five attacks lasting 4–72 hours, with headaches demonstrating at least two of the following features: unilateral location, pulsating quality, moderate to severe intensity that interferes with daily activity, and worsening with or avoidance of routine physical activity. During attacks, patients experience nausea and/or vomiting and photophobia with phonophobia, and symptoms are not attributable to another disorder.
Migraine with aura is less common and consists of reversible neurologic symptoms that typically precede headache but may occur simultaneously or afterward. Aura most often involves visual or sensory disturbances. Less common subtypes include basilar-type migraine, which may present with dysarthria, vertigo, ataxia, diplopia, or decreased level of consciousness; hemiplegic migraine, characterized by fully reversible motor weakness; and retinal migraine, involving recurrent monocular visual disturbances.

Special Population Considerations
In children, migraines more often present with bilateral pain and shorter duration. Associated symptoms may be difficult to verbalize and are often inferred from behavior. Cyclical vomiting syndrome is associated with pediatric migraine, and placebo response rates are high. Migraine has a strong genetic basis with variable penetrance and is influenced by environmental factors.

Clinical Presentation
History often reveals triggers such as chocolate, cheese, nuts, alcohol, sulfites, monosodium glutamate, stress, or menstruation. A prodrome may precede the headache by several days and can include yawning, drowsiness, or cognitive and emotional changes. Aura typically precedes headache by up to one hour and most commonly consists of visual phenomena such as scintillating scotoma or fortification spectra, as well as sensory symptoms like numbness or tingling.

The headache itself is usually unilateral and throbbing, although it may be bilateral, and is sufficiently severe to impair function. Symptoms typically develop gradually and are accompanied by nausea, vomiting, photophobia, phonophobia, and sometimes osmophobia. Patients frequently report similar headaches in the past.

Physical Examination Findings
Physical examination is generally normal. Allodynia, or pain from normally nonpainful stimuli, may be present and suggests a more refractory migraine. Funduscopic examination and assessment of visual fields should be performed. Elevated blood pressure or sinus tenderness does not exclude migraine as the diagnosis.

Initial Evaluation Strategy
Migraine is a clinical diagnosis based on history and examination. Patients presenting with a new headache syndrome or atypical features may require further evaluation, including neuroimaging or cerebrospinal fluid analysis, to exclude secondary causes.

Diagnostic Testing Considerations
No routine laboratory studies, imaging, or procedures are required for patients with a typical migraine presentation. Testing is reserved for cases with red flags or diagnostic uncertainty.

Differential Diagnosis
Conditions to consider include cluster headache, medication overuse headache, tension-type headache, allergic or viral rhinosinusitis, idiopathic intracranial hypertension, and reversible cerebral vasoconstriction syndrome.

Prehospital And Early Emergency Care
Patients benefit from a calm, dark environment. Supplemental oxygen may provide symptomatic relief. Early goals include exclusion of secondary headache causes and rapid, effective analgesia.

Emergency Department Management
A detailed history usually excludes secondary pathology. Treatment should prioritize nonopioid analgesia. Intravenous saline hydration is often beneficial. Clear communication of the diagnosis and education regarding trigger avoidance are important aspects of care. In pregnancy, metoclopramide and prochlorperazine are preferred treatment options.
Pharmacologic Therapy

First-line abortive therapy in the emergency department includes dopamine antagonists such as prochlorperazine or droperidol administered with diphenhydramine to prevent akathisia, as well as metoclopramide or trimethobenzamide. Triptans, such as subcutaneous sumatriptan, are effective but should be avoided in patients with significant cardiac risk factors. Ergot derivatives, including dihydroergotamine, may be used with antiemetics in appropriate patients. Nonsteroidal anti-inflammatory drugs such as ketorolac are commonly effective. Corticosteroids, including dexamethasone, may be used to reduce post-discharge headache recurrence. Opioids should be reserved only for refractory cases when other therapies have failed.

Disposition And Follow-Up Planning
Admission is indicated for patients with persistent severe headache, focal neurologic deficits, intractable vomiting, electrolyte abnormalities, inability to tolerate oral intake, or coexisting medication overuse headache. Patients may be discharged once pain relief is achieved and secondary causes have been excluded. Individuals with chronic or frequent episodic migraine should be referred for specialist care.

Outpatient Care And Prevention
Patients should be encouraged to maintain a headache diary to identify triggers and patterns. Ongoing primary care or specialty follow-up is essential to establish effective outpatient abortive and preventive therapies.
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Clinical Pearls And Common Pitfalls
Opioids should not be used as first-line therapy for migraine in the emergency department. Migraine commonly recurs after ED discharge, so patients should leave with an appropriate prescription and management plan. It is critical to distinguish migraine, a chronic recurrent disorder, from new-onset or progressively worsening headaches that may signal serious underlying disease.

Emergency And Acute Medicine – Heart Murmur


Basics And Description
Heart murmurs are sounds produced by normal physiologic flow or by functional and structural abnormalities of the heart. Stenotic lesions result in pressure overload of the chamber proximal to the valve, leading to compensatory hypertrophy. Regurgitant lesions cause volume overload of the preceding chamber, resulting in chamber dilatation. Genetic abnormalities and congenital defects may also produce abnormal cardiac blood flow and murmurs.


Etiology
Aortic stenosis may result from rheumatic heart disease, congenital bicuspid valve, calcification, or prosthetic valves. Aortic regurgitation is associated with rheumatic disease, endocarditis, aortic dissection, and prosthetic valves. Mitral stenosis is commonly caused by rheumatic heart disease, rheumatologic disorders such as systemic lupus erythematosus, calcification, atrial myxoma, congenital abnormalities, or prosthetic valves.
Acute mitral regurgitation may occur due to endocarditis, papillary muscle rupture or dysfunction, rupture of chordae tendineae, or prosthetic valve failure, while chronic mitral regurgitation is associated with rheumatic disease, mitral valve prolapse, and connective tissue disorders such as Marfan syndrome. Mitral valve prolapse itself may be congenital or related to connective tissue disease.
Tricuspid stenosis is usually rheumatic in origin, whereas tricuspid regurgitation may result from rheumatic disease, endocarditis, or pulmonary hypertension. Pericardial friction rubs arise from pericarditis or pericardial effusion. Ventricular septal defects may be congenital, traumatic, or postinfarction. Ventricular assist devices produce mechanical flow sounds due to implantable pumps supporting ventricular function.


Pediatric And Congenital Causes
Pulmonic stenosis is often congenital and may be associated with maternal–fetal rubella exposure or rheumatic disease. Pulmonic regurgitation may be congenital or related to pulmonary hypertension. Atrial septal defects and patent ductus arteriosus are congenital, with PDA also associated with prematurity and maternal rubella exposure. Coarctation of the aorta is congenital and linked to Turner syndrome. Hypertrophic cardiomyopathy, also known as idiopathic hypertrophic subaortic stenosis, is a congenital condition with a genetic predisposition.


Clinical Features And Murmur Characteristics
Aortic stenosis presents with a systolic crescendo–decrescendo murmur radiating to the carotids, diminished and delayed carotid upstroke (parvus et tardus), angina, exertional dyspnea, and syncope. Aortic regurgitation produces a diastolic blowing murmur along the left sternal border with findings such as widened pulse pressure, pulmonary edema, tachycardia, chest pain, Austin Flint murmur, Corrigan pulse, Quincke pulse, and de Musset sign.
Mitral stenosis causes a diastolic rumbling murmur at the apex with a loud S1 and opening snap, accompanied by dyspnea, orthopnea, hemoptysis, pulmonary edema, atrial fibrillation, and systemic emboli. Acute mitral regurgitation presents with a harsh systolic murmur at the apex and pulmonary edema, while chronic mitral regurgitation produces a holosystolic murmur radiating to the axilla with dyspnea, fatigue, and atrial fibrillation.
Mitral valve prolapse is characterized by an early- to mid-systolic click followed by a systolic murmur and may cause palpitations and chest pain. Tricuspid stenosis causes a diastolic murmur with peripheral edema, hepatosplenomegaly, ascites, atrial fibrillation, and prominent jugular venous A waves. Tricuspid regurgitation presents with a holosystolic murmur along the left sternal border and large V waves in the jugular venous pulse.
Patent ductus arteriosus produces a continuous machinery murmur and may lead to heart failure. Pericardial friction rubs are intermittent with systolic and/or diastolic components. Ventricular septal defects cause a harsh holosystolic murmur at the lower left sternal border. Ventricular assist devices generate a continuous or pulsatile mechanical hum, often with adequate perfusion despite absent palpable pulses.


Pediatric Murmur Features
Pulmonic stenosis presents with a systolic ejection murmur at the left upper sternal border, possible thrill, widely split S2, exertional dyspnea, and signs of right heart failure in severe cases. Pulmonic regurgitation causes a high-pitched early diastolic murmur with a widely split S2 and may be associated with pulmonary hypertension. Atrial septal defects often present with a systolic ejection murmur and wide fixed S2, while patent foramen ovale produces no murmur. Coarctation of the aorta may cause a continuous or late systolic murmur with differential upper and lower extremity pulses. Hypertrophic cardiomyopathy presents with a harsh systolic murmur that increases with Valsalva and may cause dyspnea, chest pain, syncope, or sudden death.


Physical Examination Focus
Evaluation includes careful auscultation of the heart and lungs, assessment of peripheral pulses, perfusion, edema, and jugular venous findings.


Essential Evaluation
Further assessment is guided by suspected pathology, with reference to specific valvular or congenital heart disease entities when appropriate.


Diagnostic Testing And Interpretation
Electrocardiography and chest radiography are commonly obtained. Echocardiography is essential for evaluating valves, chamber size, and flow patterns. CT imaging may be required to exclude aortic dissection. Acute regurgitant lesions may require cardiac catheterization.


Differential Diagnosis
Differential considerations mirror the underlying etiologies of murmurs and associated cardiac conditions.


Initial And Emergency Management
Prehospital care includes cautious IV fluid administration, especially in critical aortic stenosis, and oxygen as needed. In the emergency department, management focuses on oxygen, IV access, cardiac monitoring, and treatment of associated conditions such as heart failure or arrhythmias. Fluids and medications must be used cautiously in patients with aortic stenosis.


Medications
Therapy may include digoxin for rate control, calcium channel blockers or beta blockers for arrhythmias, diuretics for volume overload, anticoagulation when indicated, and vasodilators such as nitroglycerin or nitroprusside with careful monitoring. Medication choice depends on the underlying lesion and hemodynamic status.


Disposition And Follow-Up
Admission is required for patients with ischemia, syncope, pulmonary edema, hemodynamic instability, endocarditis, or significant arrhythmias. Asymptomatic and hemodynamically stable patients may be discharged with follow-up. New murmurs warrant referral to a primary provider or cardiologist.


Follow-Up Advice
Patients should inform all medical and dental providers of their heart murmur. Antibiotic prophylaxis may be necessary before certain procedures to prevent endocarditis.


Clinical Insights And Pitfalls
New heart murmurs accompanied by fever must prompt evaluation for infective endocarditis.

Emergency And Acute Medicine – Hellp Syndrome


Basics And Description
HELLP syndrome is defined by hemolysis, elevated liver enzymes, and low platelet count. It exists on a continuum with severe preeclampsia, as most affected patients are hypertensive, although a subset may have normal blood pressure. Hepatic involvement is the hallmark feature, but other organs such as the brain, kidneys, and lungs may also be affected.
The condition is categorized into three severity classes based on the platelet nadir. Class 1 represents the most severe form with platelet counts below 50,000/μL and accounts for most maternal deaths. Class 2 involves platelet counts between 50,000 and 100,000/μL, while Class 3 is the least severe with platelet counts between 100,000 and 150,000/μL. Increased mortality is associated with hepatic hemorrhage and central nervous system or cardiopulmonary complications. HELLP syndrome occurs in approximately 0.2% of all pregnancies, affects 20% of pregnancies with severe preeclampsia or eclampsia, and may present antepartum, intrapartum, or postpartum.


Risk Factors And Epidemiology
Patients are often white, multiparous, and of older maternal age. Infant mortality is higher in pregnancies complicated by HELLP syndrome.


Etiology And Pathophysiology
The exact cause is unclear, but widespread vasospasm is central to disease development. Fetal–placental debris enters the maternal circulation, triggering a systemic inflammatory response. Vasoconstriction increases vascular resistance and contributes to hypertension. Endothelial injury leads to intercellular leakage, platelet activation, fibrin deposition, and microvascular thrombosis. These processes result in tissue hypoxia, hemorrhage, necrosis, and end-organ damage.


Clinical Presentation And Symptoms
Patients may present with nonspecific flulike symptoms including fatigue and malaise. Common complaints include nausea, vomiting, right upper quadrant or epigastric pain that worsens with disease severity, and headache often accompanied by visual changes.
High-risk symptoms include dyspnea or signs of fluid overload suggesting pulmonary edema, chest pain concerning for myocardial ischemia, altered mental status, seizures, focal neurologic deficits, peripheral edema, ascites, hematuria, and reduced urine output. Determining gestational age and fetal viability is critical.


Physical Examination Findings
Vital signs require close attention to blood pressure, which may be normal or elevated. Right upper quadrant tenderness may suggest hepatic involvement or subcapsular hematoma. Signs of fluid overload, neurologic abnormalities, and fetal heart tones should be carefully assessed.


Essential Initial Evaluation
Immediate laboratory evaluation includes a complete blood count with platelet count and smear, liver function tests, blood urea nitrogen, creatinine, coagulation profile, magnesium level, and urinalysis for protein. Patient weight should be recorded to assess recent fluid shifts.


Diagnostic Tests And Interpretation
Laboratory findings typically reveal anemia, thrombocytopenia, and evidence of microangiopathic hemolytic anemia on peripheral smear. Elevated lactate dehydrogenase, bilirubin, and reticulocyte count indicate hemolysis. Liver enzymes are elevated, commonly with AST and ALT above 40 IU/L, LDH above 600 IU/L, and bilirubin above 1.2 mg/dL.
Imaging may include chest radiography for suspected pulmonary edema, head CT for altered mental status or focal deficits, and pelvic ultrasound to assess fetal and placental status.


Differential Diagnosis
Gastrointestinal conditions include cholecystitis, pancreatitis, hepatitis, acute fatty liver of pregnancy, and severe reflux disease. Hematologic considerations include gestational thrombocytopenia, idiopathic thrombocytopenic purpura, thrombotic thrombocytopenic purpura, and hemolytic uremic syndrome. Neurologic causes include epilepsy, meningitis, encephalopathy, brain tumor, or intracranial hemorrhage. Other considerations include sepsis, pyelonephritis, and substance use.


Prehospital And Early Management Considerations
Patients should be transported in the left lateral decubitus position to avoid inferior vena cava compression. IV access should be established, and seizures managed preferentially with magnesium sulfate. Transport to a facility capable of high-risk obstetric care is essential.


Initial Stabilization And Monitoring
Management begins with airway, breathing, and circulation support. High-flow oxygen is administered, and maternal cardiac and oxygen monitoring initiated. Continuous fetal monitoring and uterine activity assessment are required.


Emergency Department Management
Hypertension is controlled with appropriate antihypertensives while avoiding ACE inhibitors. Magnesium sulfate is administered for seizure prophylaxis or treatment, not for blood pressure control. Obstetric consultation is mandatory, with consideration of neonatology involvement and emergent delivery when indicated.
IV fluids are restricted to prevent worsening capillary leak, typically limited to 60 mL/hr unless dehydration is present. Platelet transfusion is indicated for counts below 20,000/μL or higher thresholds if delivery or surgery is planned. Blood products are administered as needed for anemia or coagulopathy.


Medications
First-line antihypertensives include IV hydralazine or labetalol, titrated to maintain diastolic blood pressure below 110 mm Hg. Magnesium sulfate is given as a loading dose followed by continuous infusion, with monitoring for toxicity. Nitroprusside is reserved for refractory hypertension. Calcium gluconate is available as an antidote for magnesium toxicity.


Disposition And Follow-Up
All patients with HELLP syndrome require admission to an obstetric service for continuous maternal and fetal monitoring. ICU admission is indicated for severe complications such as pulmonary edema, respiratory failure, cerebral edema, or hemodynamic instability. Discharge decisions are made exclusively by obstetric specialists.


Clinical Pearls And Common Errors
Pregnant patients with abdominal pain, elevated liver enzymes, and thrombocytopenia require immediate evaluation for HELLP syndrome, even in the absence of hypertension. Normal blood pressure does not exclude the diagnosis. Prompt stabilization and transfer to a high-risk obstetric facility are critical to reducing maternal and fetal morbidity and mortality.

Emergency And Acute Medicine – Hematuria/Proteinuria


Basics And Description
Microscopic hematuria is defined as the presence of three or more red blood cells per high-power field in at least two of three properly collected urine specimens. Gross hematuria refers to visible blood in a properly collected urine sample. Proteinuria is defined as urinary protein excretion greater than 150 mg per day.
Risk factors for significant disease in asymptomatic proteinuria include diabetes mellitus, hypertension, NSAID abuse, and heroin use. Risk factors for significant disease in asymptomatic hematuria include tobacco use, occupational exposure to benzenes or aromatic amines, prior gross hematuria, age over 40 years, history of urologic disease, painful voiding, recurrent UTIs, analgesic abuse, and prior pelvic irradiation.


Etiology
Proteinuria may be glomerular, tubular, or overflow in origin. Glomerular causes include nephritic processes such as postinfectious glomerulonephritis, IgA nephropathy, lupus nephritis, and vasculitis, as well as nephrotic conditions such as minimal change disease, diabetes, and preeclampsia. Tubular proteinuria results from impaired reabsorption, while overflow proteinuria occurs with excess filtered proteins as seen in hemolysis, rhabdomyolysis, or multiple myeloma.
Hematuria may arise from urinary tract infection, nephrolithiasis, benign prostatic hypertrophy, malignancy of the bladder, kidney, or prostate, transient idiopathic causes, or acute glomerulonephritis.


Clinical Presentation And Symptoms
Patients may report dysuria, visible blood in urine, fever, flank pain, or flank ecchymosis. Initial hematuria suggests an anterior urethral source, terminal hematuria suggests pathology of the posterior urethra or bladder neck, and cyclic hematuria may indicate endometriosis. A history of recent upper respiratory or skin infection raises concern for postinfectious glomerulonephritis. Associated findings may include peripheral edema, congestive heart failure, hemoptysis as seen in Goodpasture disease, hypertension, headache, right upper quadrant pain, or signs of pregnancy-related disease.
History should focus on onset, duration, associated symptoms, prior renal or urologic disease, medication use including nephrotoxic agents or anticoagulants, and systemic illnesses.
Physical examination should be comprehensive with special attention to periorbital or peripheral edema, rashes, flank tenderness or ecchymosis, and a detailed genitourinary examination including prostate assessment.


Essential Workup
Initial evaluation includes urine dipstick testing followed by urinalysis with microscopic examination. Urine culture should be considered. Blood urea nitrogen, serum creatinine, complete blood count, platelet count, and pregnancy testing when appropriate are essential. Liver function tests and coagulation studies may be indicated based on clinical context.


Diagnostic Tests And Interpretation
Urine studies may include culture, cytology, 24-hour urine protein and creatinine measurement, spot urine protein-to-creatinine ratio, spot protein-to-osmolality ratio, and urine protein electrophoresis. Serum testing may include coagulation studies and serum protein electrophoresis.
Imaging options include renal ultrasound and noncontrast helical CT scan. Diagnostic procedures may involve cystourethroscopy, urethrogram, cystogram, retrograde pyelogram, or intravenous pyelogram when indicated.


Differential Diagnosis
Glomerular causes include IgA nephropathy, postinfectious glomerulonephritis, membranoproliferative glomerulonephritis, focal segmental glomerulosclerosis, lupus nephritis, vasculitis, Henoch–Schönlein purpura, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, Alport syndrome, and Goodpasture disease.
Nonglomerular causes include infections, inflammatory conditions, urothelial malignancy, renal and extrarenal tumors, interstitial nephritis, papillary necrosis, polycystic kidney disease, renal vascular thrombosis or embolism, sickle cell disease, malignant hypertension, metabolic disorders, urolithiasis, strictures, endometriosis, foreign bodies, benign prostatic hypertrophy, coagulopathies, trauma, recent instrumentation, and factitious causes.
Proteinuria differentials include glomerular diseases, tubular disorders, overflow states such as monoclonal gammopathies or leukemia, and transient causes such as dehydration, fever, stress, heat injury, or orthostatic proteinuria.


Prehospital And Initial Stabilization
Management begins with airway, breathing, and circulation assessment and stabilization. Life-threatening traumatic injuries are treated first. Initial laboratory evaluation should be obtained promptly.
In pregnancy, suspected preeclampsia requires aggressive blood pressure control, magnesium therapy when indicated, and immediate obstetric consultation.


Emergency Department Management
Uncomplicated urinary tract infections and pyelonephritis are treated with appropriate antibiotics. Analgesics and antipyretics are provided as needed. Rapidly progressive glomerulonephritis warrants steroid therapy and nephrology consultation. Acute renal failure may require renal ultrasound, urine electrolyte analysis, nephrology consultation, and initiation of hemodialysis.
Renal colic is managed with IV fluids, analgesia, and noncontrast CT imaging if this is the initial presentation. Gross hematuria with clot retention requires placement of a three-way Foley catheter and continuous bladder irrigation.


Disposition And Follow-Up
Admission is indicated for acute renal failure, hemodynamic instability, traumatic hematuria, obstructing ureteral stones with infection or renal failure, hypertensive emergencies, oliguria or anuria, pregnancy with preeclampsia or complicated infection, intractable pain, or inability to tolerate oral intake.
Patients may be discharged if hemodynamically stable without life-threatening pathology. Gross hematuria generally requires urology follow-up, except in young women with confirmed uncomplicated UTIs. Microscopic hematuria requires repeat urinalysis and primary care follow-up, with urology or nephrology referral as needed. Mild proteinuria may be evaluated outpatient, while nephrotic-range proteinuria or proteinuria with renal failure warrants urgent nephrology referral.


Clinical Pearls And Common Errors
Failure to recognize acute glomerulonephritis in children is a common pitfall. Spot urine protein-to-creatinine ratio correlates well with 24-hour urine protein excretion. Periorbital edema may indicate nephritic syndrome rather than allergy. Inadequate follow-up for asymptomatic hematuria, particularly in patients older than 40 years, is a frequent and significant error.

Emergency And Acute Medicine – Hemophilia


Basics And Description
Hemophilia is a hereditary bleeding disorder caused by deficiency of functional clotting factor VIII or factor IX, resulting in impaired activation of the coagulation cascade and defective hemostasis. Hemophilia A is due to factor VIII deficiency, while hemophilia B (Christmas disease) is due to factor IX deficiency. Clinical severity depends on residual factor activity. Mild disease (5–30% activity) presents with bleeding after major trauma or surgery. Moderate disease (1–5% activity) causes bleeding with trauma or surgery and occasional spontaneous hemarthroses. Severe disease (<1% activity) leads to spontaneous bleeding beginning in infancy, often occurring weekly and frequently requiring factor replacement. major complications include fatal hemorrhage, progressive joint destruction from recurrent hemarthroses, transfusion-transmitted infections (now rare with purified products), development of inhibitors—igg antibodies that neutralize clotting factors.< />pan>


Etiology
Hemophilia is inherited in an X-linked recessive pattern, although approximately one-third of cases arise from spontaneous mutations. Hemophilia A occurs in approximately 1 in 5,000–7,000 males, while hemophilia B occurs in about 1 in 30,000 males. Inhibitors develop in roughly 20% of patients with severe hemophilia A and fewer than 5% of those with severe hemophilia B.


Clinical Presentation And Symptoms
Bleeding manifestations include hemarthrosis, most commonly affecting the knee, followed by elbow, ankle, shoulder, and wrist. Other presentations include muscle hemorrhage, prolonged bleeding from soft tissue lacerations, post–dental extraction or oral mucosal bleeding, epistaxis in severe disease, hematuria, gastrointestinal bleeding, intracranial hemorrhage, and pseudotumors formed by encapsulated blood collections.


Essential Workup
Evaluation begins with a thorough history and physical examination, including bleeding pattern, known factor deficiency, baseline factor levels, inhibitor status, and prior treatments.


Diagnostic Tests And Interpretation
Laboratory findings typically show a normal platelet count, normal bleeding time, normal prothrombin time, and prolonged partial thromboplastin time. Urinalysis may reveal asymptomatic hematuria. Specific factor assays demonstrate decreased factor VIII or IX activity. Von Willebrand factor levels are normal, helping distinguish hemophilia from von Willebrand disease. Imaging is guided by clinical presentation and may include CT of the head for suspected intracranial hemorrhage, renal ultrasound or cystoscopy for persistent hematuria, or abdominal CT for suspected retroperitoneal bleeding.


Differential Diagnosis
Consider von Willebrand disease, anticoagulant or antiplatelet medication use, thrombocytopenia, and hepatic dysfunction.


Initial Stabilization And Therapy
Bleeding control begins immediately with proximal pressure when appropriate. Establish IV access and obtain type and screen. Packed red blood cells may be required for significant blood loss. Early factor replacement is critical and should not be delayed for imaging or consultation.


Emergency Department Management
Patients often know their diagnosis, factor type, dose, and inhibitor status. Emergency care should be coordinated with the patient’s hematologist whenever possible. Factor replacement should be initiated immediately for any suspected bleed.
Desired factor activity depends on bleeding severity. For low to moderate bleeding, target 30–50% activity. For moderate to severe bleeding, including gastrointestinal or genitourinary hemorrhage, target 50–100%. For life-threatening bleeding such as intracranial hemorrhage, major trauma, or airway compromise, target 100% activity.
Factor VIII dosing is calculated as body weight (kg) × 0.5 × desired percent activity, with dosing every 12 hours. Factor IX dosing is calculated as body weight (kg) × desired percent activity, with dosing every 24 hours.
Hemarthrosis is managed with splinting, compression, and ice; arthrocentesis is rarely indicated. Muscle hemorrhage requires monitoring for compartment syndrome, particularly in the forearm, calf, or iliopsoas. Oral and dental bleeding may benefit from local hemostatic agents and antifibrinolytics. Hematuria is usually mild and managed with hydration; antifibrinolytics and cryoprecipitate should be avoided. All head injuries are treated as significant, and therapy must precede imaging. Gastrointestinal bleeding requires factor replacement before endoscopic procedures.


Medications And Factor Therapy
First-line treatment for patients without inhibitors is recombinant factor VIII or IX concentrates. Plasma-derived factor concentrates are second-line options. Cryoprecipitate is reserved for hemophilia A only when factor concentrates are unavailable. Fresh frozen plasma may be used temporarily in life-threatening bleeding if specific factors are delayed.
Adjunctive therapies include desmopressin for mild hemophilia A, antifibrinolytics for mucosal bleeding, and topical thrombin for superficial wounds.
For patients with inhibitors, recombinant factor VIIa is first-line therapy, with activated prothrombin complex concentrates as second-line options. High-dose factor concentrates may be considered in low-titer inhibitor patients. Intramuscular injections and aspirin-containing products must be avoided.


Disposition And Follow-Up
There should be a low threshold for hospital admission. Indications include joint or muscle bleeds, internal hemorrhage, severe bleeding, need for repeated transfusions, complications, or any head trauma. Minor superficial bleeding with complete control may be discharged with close follow-up. All patients require hematology consultation and outpatient follow-up, with instructions to return immediately for recurrent or worsening bleeding.


Clinical Pearls And Common Errors
Never delay factor replacement while awaiting imaging in suspected serious bleeding, especially head trauma. In unknown factor levels, assume zero activity and treat as severe disease. Be familiar with management differences in patients with and without inhibitors. Replace factor before transfers, procedures, or consultations. Maintain a low threshold for admission and hematology involvement.

Emergency And Acute Medicine – Hemorrhagic Fevers


Basics And Description
Hemorrhagic fever refers to a multisystem syndrome characterized by vasocapillary permeability, hemorrhage, and organ dysfunction. Viral hemorrhagic fevers (VHF) are caused by a distinct group of viruses and often begin with a nonspecific influenza-like illness. Hemorrhagic manifestations occur in a minority of patients and typically appear in later stages of disease.


Risk Factors
Travel to endemic regions
Exposure related to biologic warfare
Close contact with animals
Insect bites or ingestion


Pathophysiology
Viral hemorrhagic fevers cause endothelial injury leading to increased vascular permeability, hemorrhage, and progression to shock. The shock state is both hypovolemic and distributive and is often difficult to reverse. Rapid progression to hypotension indicates a very high mortality risk. Disseminated intravascular coagulation is commonly seen in Marburg and Crimean-Congo hemorrhagic fever but is less frequent in arenavirus infections. Dengue hemorrhagic fever is immune mediated and often results from secondary infection and is among the most common causes of VHF.


Etiology
Viral hemorrhagic fevers are caused by RNA viruses with zoonotic life cycles and short incubation periods of less than 10–21 days.
Filoviruses include Ebola and Marburg, with fruit bat reservoirs and transmission primarily in sub-Saharan Africa.
Arenaviruses include Lassa fever and South American hemorrhagic fevers, transmitted via aerosolized rodent excreta.
Flaviviruses include Dengue and Yellow fever, transmitted by mosquitoes, primarily in tropical regions.
Bunyaviridae include Rift Valley fever and Crimean-Congo hemorrhagic fever, transmitted by ticks or mosquitoes.
Hantaviridae include hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome, transmitted via aerosolized rodent excreta.


Alert
Viral hemorrhagic fevers represent a potential biowarfare threat. With the exception of dengue, most are transmissible via aerosols and body fluids. Some have very high morbidity and mortality, and many replicate efficiently in cell culture, allowing weaponization.


Diagnosis – Signs And Symptoms
Common symptoms include acute fever, malaise, headache, nausea, vomiting, flushing, diarrhea, abdominal pain, and myalgias.
Less common manifestations include gingival bleeding, conjunctival hemorrhage, petechiae, hematemesis, melena, epistaxis, and ecchymoses.
Hemorrhagic features usually appear after day three and may involve skin, IV sites, gums, lungs, gastrointestinal tract, or uterus. Diffuse alveolar hemorrhage and ARDS may occur, particularly in Ebola, Marburg, Lassa, Crimean-Congo hemorrhagic fever, and hantavirus infections.
Characteristic rashes include nonpruritic centripetal maculopapular eruptions in Ebola and Marburg, jaundice in Yellow fever, and blanching maculopapular truncal rash in Dengue.
Late-stage disease may progress to shock, seizures, coma, and death.


History And Physical Examination
History should assess recent travel, exposure to sick contacts, animal or insect exposure, and clustering of cases.
Strict protection of healthcare workers is essential, using universal blood and body fluid precautions.
Vital signs should be monitored closely, as narrowed pulse pressure may signal impending cardiovascular collapse.
Physical examination may reveal hemorrhage, rash, hepatomegaly, right upper quadrant tenderness, and abnormal lung findings.


Essential Workup
The primary goal is to distinguish VHF from other acute febrile illnesses, especially malaria, in returning travelers. Lung involvement suggests systemic disease and poorer prognosis. Consider the possibility of a biologic attack if multiple patients present with similar unusual findings.


Diagnostic Tests And Interpretation
Laboratory studies may show leukocytosis, leukopenia, thrombocytopenia, pancytopenia, or hemoconcentration. Elevated hematocrit suggests third spacing and impending shock. Renal and hepatic dysfunction are common. Coagulation studies may reveal DIC, particularly in Ebola, Marburg, and Crimean-Congo hemorrhagic fever.
Definitive diagnosis requires specialized biosafety level 4 laboratories using RT-PCR, viral isolation, or immunohistochemistry, coordinated through the CDC.
Imaging such as chest radiograph or CT may identify ARDS, pneumonia, or internal hemorrhage.


Differential Diagnosis
Malaria
Dengue fever
Rickettsial infections
Typhoid fever
Meningococcemia
Sepsis
Hemolytic uremic syndrome
Thrombotic thrombocytopenic purpura
Leukemia
Pit viper envenomation


Treatment – Prehospital And Initial Stabilization
Early recognition is critical due to increased globalization and imported cases. Suspected cases must be reported to the CDC immediately.
Patients should be isolated, and healthcare workers must use full protective equipment, including HEPA-filtered respirators during aerosol-generating procedures.


Emergency Department Management
Treatment is primarily supportive. Empiric antimalarial therapy should be initiated until malaria is excluded. Secondary infections should be treated aggressively.
Bleeding is usually mild; if severe, manage with blood products and clotting factors.
Fluid resuscitation must be cautious due to third spacing and risk of flash pulmonary edema. Colloids or blood products should be reserved for impending shock.
Ribavirin is effective against Lassa fever, South American hemorrhagic fever, Crimean-Congo hemorrhagic fever, and hantavirus infections but is ineffective against filoviruses.
Convalescent plasma may benefit South American hemorrhagic fever if administered early.


Medications
Ribavirin intravenous loading dose of 33 mg/kg, followed by 16 mg/kg every 6 hours for 4 days, then 8 mg/kg every 8 hours for 3 days.
Oral prophylaxis consists of 500 mg every 6 hours for 7 days.
Vaccines are available for Yellow fever, while others remain under development.


Disposition And Follow-Up
All suspected cases require admission with isolation precautions. ICU care is indicated for shock or multiorgan failure. Discharge is not appropriate when VHF is suspected.
Coordination with the CDC is mandatory for patient management and postexposure prophylaxis of contacts.


Clinical Pearls And Pitfalls
Use extreme caution with fluid resuscitation.
Hemoconcentration and pulmonary involvement are critical warning signs.
Always consider viral hemorrhagic fever in febrile patients returning from endemic regions.
Strict isolation and universal precautions are essential to prevent transmission.
Notify the CDC immediately for all suspected cases.

Emergency And Acute Medicine – Hemorrhoid


Basics And Description
Hemorrhoids are normal venous sinusoids of the distal rectum and proximal anal canal that function as vascular cushions contributing to anal continence. These cushions consist of thick submucosa containing blood vessels, smooth muscle, and elastic connective tissue. An arteriovenous shunt system at the level of the internal hemorrhoids explains the typical presentation of bright red blood per rectum. Hemorrhoid disease develops when these normal structures become symptomatic. Hemorrhoids are generally painless unless thrombosed or strangulated. Pathologically, disease occurs when portions of the anal canal lining slide downward.


External hemorrhoids are located below the dentate line, covered by skin or anoderm, and drain into the internal iliac venous system. Internal hemorrhoids arise from submucosal vessels above the dentate line, drain into the portal venous system, and are typically found at the left lateral, right posterolateral, and right anterolateral positions. Internal hemorrhoids are classified by degree of prolapse: grade 1 causes painless bleeding without prolapse; grade 2 prolapses with bowel movements but reduces spontaneously; grade 3 prolapses with bowel movements and requires manual reduction; grade 4 is chronically prolapsed and not reducible.


Etiology
The exact cause of hemorrhoid disease is unclear. Gravitational forces and increased abdominal pressure contribute to distention of venous sinusoids. It is commonly associated with straining and irregular bowel habits, including hard, bulky stools or diarrhea, which cause tenesmus and excessive straining. These forces weaken submucosal support tissue, promoting prolapse of anal cushions. Additional contributing factors include higher resting anal pressures related to erect posture, hereditary absence of venous valves, and chronically elevated intra-abdominal pressure from conditions such as pregnancy, ascites, and portal hypertension.


Diagnosis – Signs And Symptoms
Patients most commonly present with painless rectal bleeding during or after defecation. Blood is typically bright red and may appear on toilet paper, coat the stool, or drip into the toilet bowl. Rectal discomfort or a sensation of pressure may occur. Severe pain suggests thrombosed external hemorrhoids or prolapsed internal hemorrhoids that have become strangulated. Pruritus ani is common, and anal fissures may coexist.


History
Key historical features include duration and severity of bleeding, association with pain, presence of new perianal masses, stool consistency, prior anorectal disease, changes in stool caliber, and use of anticoagulants.


Physical Examination
Examination begins with inspection of the perianal area by gently separating the buttocks. A discrete, dark blue, tender mass covered by skin is consistent with a thrombosed external hemorrhoid and may coexist with an internal component. A purplish, tender, mucosa-covered mass suggests a prolapsed and strangulated internal hemorrhoid, often accompanied by thrombosed external hemorrhoids. Asking the patient to bear down may reveal prolapse. Digital rectal examination is mandatory to exclude malignancy. Anoscopy allows direct visualization of the anal canal and identification of bleeding internal hemorrhoids.


Essential Workup
Diagnosis is primarily clinical and based on a detailed history and thorough anorectal examination.


Diagnostic Tests And Interpretation
Laboratory testing is not routinely required. A complete blood count is indicated if there is significant bleeding to assess hemoglobin and hematocrit. Platelet count and coagulation studies (PT, PTT, INR) should be obtained in patients on anticoagulation or with significant comorbid disease.


Differential Diagnosis
Rectal prolapse, anal fissure, perirectal abscess or fistula, condyloma acuminata, anorectal carcinoma, and melanoma.


Treatment – Prehospital Care
Establish intravenous access in cases of severe bleeding.


Initial Stabilization And Therapy
Apply direct digital pressure to control active bleeding when present.


Emergency Department Treatment And Procedures
Conservative therapy is the foundation of treatment for all patients. This includes warm sitz baths for 15 minutes three times daily and after bowel movements, a high-fiber diet targeting approximately 30 g/day, increased oral hydration, stool softeners, bulk-forming laxatives, and analgesia with NSAIDs or acetaminophen.


Thrombosed external hemorrhoids causing severe pain may be excised if symptoms are present for fewer than five days and the clot has not begun to resolve. The procedure is performed with the patient in the prone jackknife or left lateral decubitus position. After local anesthesia with lidocaine containing epinephrine, an elliptical incision is made to excise the clot and overlying skin. Hemostasis may require silver nitrate. A small piece of Gelfoam or gauze is applied, and the dressing is removed at the first sitz bath approximately six hours later.


Nonthrombosed prolapsed internal hemorrhoids may be manually reduced, sometimes requiring topical anesthesia or an anal sphincter block. Bleeding internal hemorrhoids may be treated with sclerotherapy using agents such as sodium morrhuate or hypertonic saline, or with rubber band ligation of one or two hemorrhoids, which should be avoided in immunocompromised patients. Nonstrangulated, nonreducible hemorrhoids are managed conservatively with surgical referral, whereas strangulated internal hemorrhoids require immediate surgical consultation.


Pregnancy-associated hemorrhoids are common in the third trimester and are managed conservatively. Certain topical agents should be avoided due to fetal risk.


Medications
Analgesics include acetaminophen with or without codeine and NSAIDs such as ibuprofen. Stool regulation is achieved with fiber supplements, psyllium, and docusate sodium. Topical therapies include lidocaine-based anorectal creams, hydrocortisone-containing preparations, and 0.2% nitroglycerin ointment applied locally to reduce sphincter spasm and pain. Caution is required with topical anesthetics due to systemic absorption.


Follow-Up And Disposition
Admission is indicated for strangulated grade 4 hemorrhoids requiring urgent surgery, severe anemia due to bleeding, or significant bleeding in patients on anticoagulation or with portal hypertension. Most patients can be discharged with outpatient management.


Issues For Referral
Surgical referral is indicated for grade 3 or 4 internal hemorrhoids, suspected malignancy, inflammatory bowel disease, coagulopathy, pregnancy, or immunocompromised status.


Follow-Up Recommendations
Patients with advanced hemorrhoids or concern for neoplasia should have colorectal surgery follow-up. Uncomplicated cases should follow up with primary care. All patients with bright red blood per rectum should be referred for gastrointestinal or colorectal evaluation to exclude malignancy.


Key Clinical Insights And Common Pitfalls
Hemorrhoids are a common but not exclusive cause of anorectal bleeding and pain. Failure to evaluate for alternative diagnoses, including malignancy, is a frequent pitfall.

Emergency And Acute Medicine – Hemothorax


Basics And Description
Hemothorax is the accumulation of blood within the intrapleural space, most commonly following blunt or penetrating chest trauma, though nontraumatic causes exist. Bleeding usually results from disruption of chest wall tissues, pleura, or intrathoracic vessels, leading to decreased vital capacity, hypoxia, and respiratory compromise. Significant intravascular blood loss may cause hemodynamic instability and hemorrhagic shock. Massive hemothorax can increase intrathoracic pressure, impair venous return, and reduce cardiac output. In blunt trauma, hemothorax is rarely isolated and is frequently associated with pneumothorax, extrathoracic injuries, and pulmonary contusion. Large collections may release anticoagulant substances, promoting continued bleeding. Untreated hemothorax can progress to empyema or fibrothorax due to pleural adhesions and lung trapping.


Etiology
Traumatic causes include injury to major thoracic vessels such as intercostal arteries, internal mammary arteries, pulmonary vessels, the aorta, vena cava, and the heart. Lung parenchymal injuries may also cause bleeding, which often stops spontaneously because of low pulmonary pressures and high thromboplastin levels, and are frequently associated with pneumothorax. Nontraumatic or spontaneous hemothorax is rare and should prompt evaluation for coagulation disorders, malignancy, vascular catastrophes such as aortic dissection or ruptured aneurysm, pulmonary embolism with infarction, tuberculosis, bullous emphysema, pulmonary arteriovenous malformations, or lobar sequestration. Hemothorax may also occur from torn pleural adhesions during spontaneous pneumothorax or following tube thoracostomy.


Diagnosis – Signs And Symptoms
Small hemothoraces, generally less than 400 mL, may cause minimal or no changes in vital signs or physical examination. Large hemothoraces, typically exceeding 1,000 mL, present with restlessness, anxiety, pallor, pleuritic chest pain, hemoptysis, dyspnea, and air hunger. Signs of hemorrhagic shock appear when blood loss reaches or exceeds 30% of circulating volume, including tachycardia, tachypnea, and hypotension. In cases with slow or insidious onset, such as malignancy-related hemothorax, dyspnea is often the predominant symptom without acute hemodynamic compromise.


History
Important historical features include recent blunt or penetrating chest trauma, rib fractures, flail chest, or delayed onset of symptoms hours to days after injury. Delayed hemothorax may result from rupture of chest wall hematomas or intercostal vessel injury from rib fracture movement. Additional history includes known malignancy, metastatic disease, or recent thoracic procedures such as thoracentesis or chest tube placement.


Physical Examination
Vital signs may reveal hypoxia, tachypnea, tachycardia, or hypotension depending on severity. Jugular venous distention may be present with increased intrathoracic pressure, and tracheal deviation can occur in massive collections. Chest inspection may show asymmetric expansion, deformity, contusions, abrasions, or paradoxical movement. Palpation may elicit rib tenderness, crepitus, or subcutaneous emphysema, while percussion typically reveals dullness over the affected hemithorax. Auscultation demonstrates decreased or absent breath sounds, best appreciated in the upright patient.


Essential Workup
Chest radiography is the primary diagnostic study. In stable patients, an upright posteroanterior film is ideal and can detect pleural fluid volumes greater than 200–300 mL, seen as meniscus formation or blunting of the costophrenic angle. In supine trauma patients, up to 1,000 mL of blood may be missed, appearing only as diffuse haziness of the hemithorax. Associated injuries such as pneumothorax, rib fractures, pulmonary contusions, or mediastinal widening should be assessed.


Diagnostic Tests And Interpretation
Laboratory evaluation includes hematocrit monitoring for trends, type and cross-match, pulse oximetry, and arterial blood gas analysis when indicated. Pleural fluid hematocrit exceeding 50% of peripheral blood hematocrit confirms hemothorax. Ultrasound, particularly extended FAST, is highly sensitive for detecting intrapleural fluid in trained hands. Computed tomography is useful for identifying small hemothoraces not visible on chest radiographs and for evaluating associated injuries.


Differential Diagnosis
Hemopneumothorax, pneumothorax, pulmonary contusion, pleural effusion, and empyema or pneumonia.


Treatment – Prehospital Care
Initial management includes assessment of vital signs and oxygen saturation, supplemental oxygen, intravenous access, and fluid resuscitation for hypotension. Clinical differentiation between hemothorax and pneumothorax may be difficult; subcutaneous emphysema suggests pneumothorax, while dullness to percussion favors hemothorax. In unstable patients with suspected tension pneumothorax, needle thoracostomy should be performed immediately.


Initial Stabilization And Therapy
Airway, breathing, and circulation are prioritized. Endotracheal intubation is indicated for impending respiratory failure. High-flow oxygen, two large-bore intravenous lines, and rapid fluid resuscitation are initiated. If chest tube equipment is not immediately available in an unstable patient, needle thoracostomy should not be delayed. Patients should be positioned upright when possible.


Emergency Department Treatment And Procedures
Definitive management involves evacuation of blood from the pleural space via tube thoracostomy. A large-bore chest tube, typically 36–40 French, is inserted in the 4th or 5th intercostal space at the mid-axillary line, directed posteriorly and superiorly, and connected to underwater seal drainage with suction. Post-procedure chest radiography confirms placement and lung re-expansion. Autotransfusion should be considered when available. Indications for operative thoracotomy include initial chest tube output greater than 20 mL/kg in children or approximately 1,000 mL in adults, persistent bleeding exceeding 7 mL/kg/hr or 200 mL/hr for four hours, enlarging hemothorax, refractory hypotension, or clinical deterioration after initial response. Emergency department thoracotomy may be indicated in select cases of penetrating trauma with recent arrest or profound shock, and rarely in blunt trauma under specialized circumstances.


Medications
Local anesthetics are used for chest tube placement in awake patients. Procedural sedation and analgesia with agents such as fentanyl and midazolam may be administered in stable patients. Additional sedatives may be used as clinically appropriate.


Follow-Up And Disposition
Patients requiring tube thoracostomy should be admitted to a trauma, cardiothoracic, or surgical service experienced in chest tube management. Small, isolated hemothoraces detected incidentally may be observed for 4–6 hours and discharged if asymptomatic, normoxic, and without evidence of ongoing bleeding. Asymptomatic blunt chest trauma patients with normal initial radiographs do not require repeat imaging prior to discharge.


Key Clinical Insights And Common Pitfalls
The pleural cavity can hold more than 4 liters of blood, allowing massive hemorrhage without external bleeding. In supine patients, physical findings may be subtle due to posterior blood distribution. Hemothorax may be misread as pneumonia in the absence of trauma history. Concurrent diaphragmatic injury raises concern for intra-abdominal bleeding. Early preparation for autotransfusion is important, as the greatest blood loss often occurs at initial chest tube placement. Improper chest tube positioning, especially too anterior or superior, can impair drainage; all fenestrations must lie within the thoracic cavity. Prophylactic antibiotics with chest tube placement do not reduce pneumonia or empyema risk.

Emergency And Acute Medicine – Hepatic Encephalopathy


Basics And Description
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome characterized by alterations in behavior, level of consciousness, and motor function resulting from hepatic insufficiency and the accumulation of substances normally detoxified by the liver. The condition arises from a multifactorial process, most notably the accumulation of ammonia produced from protein degradation by colonic bacteria and deamination of glutamine in the small bowel, kidneys, and muscle. Ammonia crosses the blood–brain barrier and is metabolized by astrocytes into glutamine, leading to astrocytic swelling, cerebral edema, and mitochondrial dysfunction. Additional neurotoxins such as short-chain fatty acids, manganese, neurosteroids, phenols, mercaptans, and amino acids including tryptophan also contribute. Neurotransmitter imbalance plays a role, with increased inhibitory neurotransmitters such as benzodiazepines, γ-aminobutyric acid, and serotonin, and decreased excitatory neurotransmitters including glutamate, dopamine, aspartate, and catecholamines. Other contributing factors include reduced cerebral blood flow and oxygen delivery, increased cerebral glucose utilization with potential hypoglycemia, zinc deficiency affecting urea cycle enzymes, and rare inherited urea cycle disorders.


Etiology
Hepatic encephalopathy is classified according to the 11th World Congress of Gastroenterology. Type A is associated with acute liver injury and fulminant hepatic failure. Type B is related to portosystemic shunting without intrinsic liver disease. Type C is associated with cirrhosis and portal hypertension. Common precipitating factors include gastrointestinal bleeding, electrolyte abnormalities such as hypokalemia and hyponatremia, metabolic alkalosis reducing renal ammonium excretion, sepsis including spontaneous bacterial peritonitis, constipation, noncompliance with treatment in chronic liver disease, high-protein diet, hypoglycemia, hypovolemia following large-volume paracentesis, azotemia from diuretics or diarrhea, sedatives or narcotics including alcohol, zinc deficiency, hepatocellular injury from viral or drug-induced hepatitis, and post portosystemic shunt placement. Recurrent episodes may occur even without identifiable triggers.


Diagnosis – Signs And Symptoms
Type A HE progresses rapidly and may lead to seizures, decerebrate rigidity, coma, and death from cerebral edema. Type B and C HE are typically chronic and may present as minimal or overt encephalopathy. Minimal HE manifests as impaired psychomotor speed, attention, concentration, visual perception, memory deficits, and slowed mental processing, detectable only with psychometric testing. Overt HE includes slow and monotonous speech, impaired fine motor skills, hyperreflexia, clonus, hyperventilation, extrapyramidal movements, seizures, confusion, coma, and abnormal posturing. Episodic HE is characterized by transient changes in consciousness over hours to days with return to baseline after treatment, whereas persistent HE does not fully resolve.


Clinical Grading (West Haven Criteria)
Stage 0 shows no overt clinical changes but abnormal neuropsychological testing and no asterixis. Stage I includes personality changes, irritability, depression or euphoria, sleep–wake reversal, impaired writing or calculations, and possible asterixis. Stage II is marked by inappropriate behavior, lethargy, slowed responses, asterixis, slurred speech, and ataxia. Stage III presents with disorientation, amnesia, paranoia, nystagmus, hypoactive reflexes, positive Babinski sign, and stupor. Stage IV is characterized by coma and dilated pupils.


Essential Workup
Evaluation should include a detailed history of liver disease and prior HE episodes, identification of precipitating factors, and assessment for electrolyte disturbances, as even mild abnormalities may cause significant clinical deterioration.


Diagnostic Tests And Interpretation
Ammonia levels correlate poorly with disease severity but may assist in evaluating unexplained altered mental status. Samples must be handled correctly and processed promptly. A normal ammonia level should prompt investigation for alternative diagnoses. Additional studies include fecal occult blood testing and nasogastric lavage to assess for gastrointestinal bleeding, complete blood count for anemia or infection, electrolytes, renal function, glucose, coagulation studies, and liver enzymes. Urinalysis and cultures of urine and ascitic fluid help identify infection. Toxicology screening may be required to exclude other causes of altered consciousness. Additional testing may include thyroid function, arterial blood gases, magnesium, and viral serologies. Imaging includes chest radiography for pneumonia or heart failure and head CT for new-onset altered mental status, focal deficits, trauma, or suspected cerebral edema. Brain MRI may aid diagnosis in patients with portosystemic shunts without intrinsic liver disease. ECG assesses arrhythmias and electrolyte effects. Lumbar puncture is indicated for unexplained or worsening symptoms, and paracentesis is required when spontaneous bacterial peritonitis is suspected. EEG typically shows generalized slowing.


Differential Diagnosis
Consider alcohol withdrawal, cerebrovascular accident, congestive heart failure, carbon dioxide narcosis, head trauma, electrolyte disturbances, hypoglycemia, meningitis, encephalitis, metabolic encephalopathies, psychiatric illness, drug or alcohol intoxication, uremia, and in children, Reye syndrome or fatty acid oxidation disorders.


Initial Stabilization And Therapy
Management includes supplemental oxygen, cardiac monitoring, and airway protection, with intubation required for grade III or IV encephalopathy. Propofol is preferred for sedation if needed. Standard initial altered mental status treatment includes naloxone, glucose administration, and thiamine.


Emergency Department Treatment And Procedures
Identification and correction of precipitating factors is central to management. Frequent glucose monitoring is essential due to the risk of hypoglycemia. Complications such as gastrointestinal bleeding, sepsis, electrolyte abnormalities, coagulopathy, and renal dysfunction must be treated promptly. Sedatives and narcotics should be avoided when possible; if required, agents with minimal hepatic metabolism are preferred. Ammonia reduction is achieved with nonabsorbable disaccharides such as lactulose, administered orally, via nasogastric tube, or as retention enemas in severe cases. Intestinal flora reduction may include rifaximin, neomycin, metronidazole, or vancomycin, often in combination with lactulose. Rifaximin is preferred for lactulose-resistant HE due to its efficacy and favorable safety profile. Cerebral edema should be treated promptly if present. Zinc deficiency should be corrected, and short-term protein restriction may be considered. Flumazenil may provide transient improvement in select patients but should be avoided in chronic benzodiazepine or alcohol users. Liver transplantation is the definitive therapy for severe or recurrent HE. Additional therapies under investigation include L-carnitine, albumin dialysis, N-acetylcysteine, probiotics, branched-chain amino acids, and manganese chelation.


Medications
Therapy may include intravenous dextrose for hypoglycemia, lactulose titrated to achieve two to three soft stools daily, rifaximin 550 mg twice daily, neomycin or metronidazole when indicated, naloxone for suspected opioid effect, thiamine supplementation, zinc acetate or sulfate, and mannitol for cerebral edema.


Follow-Up And Disposition
Patients with grade II to IV HE, type A HE of any grade, type B or C HE grade II or higher, associated complications such as sepsis or gastrointestinal bleeding, or diagnostic uncertainty require admission, often to the intensive care unit with gastroenterology consultation. Discharge may be considered for patients with known chronic HE presenting with grade 0 or I symptoms, a reversible cause, and reliable supervision. Discharged patients should receive lactulose therapy and dietary guidance.


Follow-Up Recommendations
Patients should realize the importance of dietary counseling, medication adherence, and alcohol cessation when appropriate. Referral to gastroenterology is recommended for recurrent episodes, and patients with type A HE should be evaluated for liver transplantation.


Clinical Insights And Common Errors
Rifaximin is effective for lactulose-resistant hepatic encephalopathy. Hypoglycemia is common and easily overlooked. Sedatives and narcotics can worsen encephalopathy and should be avoided whenever possible or replaced with agents not metabolized by the liver.