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Emergency and Acute Medicine – Joint Pain and Fever
Overview and Definitions
Joint pain accompanied by fever suggests an inflammatory or infectious process and requires prompt evaluation. Joint involvement may be monoarticular, oligoarticular, or polyarticular and may be symmetric or asymmetric. Arthritis refers to inflammation of a joint and is a clinical finding rather than a diagnosis, whereas arthralgia denotes joint pain without objective inflammation. Acute joint disorders last less than six weeks, while chronic disorders persist beyond this duration.
Clinical Approach
The presence of fever narrows the differential diagnosis toward infectious, crystal-induced, immune-mediated, or reactive etiologies. Noninflammatory disorders such as osteoarthritis or fibromyalgia are rarely associated with fever. History should focus on onset and tempo of symptoms, recent infections, travel, trauma, sexual exposure, immunosuppression, and prior joint disease. Physical examination should assess for warmth, erythema, swelling, effusion, and limitation of motion, as well as extra-articular features such as rash, cardiac murmurs, or enthesitis. Synovial fluid aspiration and analysis are mandatory in acute monoarthritis or when infection or crystal disease is suspected.
Epidemiology
Septic arthritis is usually monoarticular, with polyarticular involvement occurring in 10–20% of adults. Risk factors include diabetes mellitus, chronic kidney disease, malignancy, immunosuppression, intravenous drug use, trauma, prosthetic joints, and underlying joint disease. Musculoskeletal manifestations occur in up to 45% of patients with infective endocarditis. Viral outbreaks, particularly chikungunya, have caused large numbers of cases of acute febrile polyarthritis, especially among travelers.
Etiology and Pathophysiology
Septic arthritis is the most important diagnosis to exclude and is most commonly caused by Staphylococcus aureus. Other infectious causes include disseminated gonococcal infection, endocarditis, Lyme disease, Whipple’s disease, secondary syphilis, and mycobacterial or fungal infections. Viral etiologies include parvovirus B19, acute HIV infection, hepatitis B, dengue virus, and chikungunya. Noninfectious causes include gout, pseudogout, acute rheumatic fever, adult-onset Still’s disease, systemic lupus erythematosus, vasculitis, and rarely malignancy.
Diagnostic Evaluation
Synovial fluid analysis is central to diagnosis. Bacterial arthritis is suggested by leukocyte counts greater than 50,000 cells/µL with polymorphonuclear predominance, turbid appearance, and low viscosity. Gram stain and culture should always be performed, and blood cultures obtained in acute presentations. Gonococcal arthritis frequently yields negative synovial cultures, requiring sampling of mucosal sites. Elevated ESR and CRP favor bacterial infection, while markedly elevated ferritin levels suggest adult-onset Still’s disease.
Management
Suspected septic arthritis requires immediate empiric antimicrobial therapy after appropriate cultures are obtained. Most cases of nongonococcal septic arthritis require surgical drainage or joint washout. Gonococcal arthritis is usually managed medically with ceftriaxone. NSAIDs provide symptomatic relief in viral and reactive arthritis. Early joint immobilization followed by gradual mobilization is recommended once infection is controlled.
Complications
Delayed or inadequate treatment of septic arthritis may result in irreversible joint destruction, osteomyelitis, bacteremia, and systemic sepsis.
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Emergency and Acute Medicine – Lymphocytosis
Overview and Definition
Lymphocytosis is defined as an absolute lymphocyte count greater than 4,000 cells/mm³ in peripheral blood. It may be reactive or neoplastic in origin. Reactive lymphocytosis is caused by infectious or noninfectious conditions, whereas neoplastic lymphocytosis reflects underlying hematologic malignancy. Infectious causes include viral, bacterial, protozoal, and parasitic diseases, while noninfectious causes include drugs, autoimmune disorders, and certain endocrinopathies. Atypical lymphocytes are non-neoplastic, activated lymphocytes that appear in response to immunologic stimulation; they are typically large, with nucleoli, irregular cytoplasm, and may appear to “indent” surrounding red blood cells on smear.
Clinical Approach
History and physical examination are essential to distinguish reactive from neoplastic lymphocytosis. Age is an important clue: acute EBV infection is common in children and young adults, while chronic lymphocytic leukemia is more common after the fifth decade. Assess symptom duration, vaccination history, prior illnesses, and medication use. Evaluate risk factors for HIV and tuberculosis, including sexual exposure, intravenous drug use, close contacts, travel, homelessness, and institutionalization. A detailed travel history should assess risk for food-, water-, and arthropod-borne infections. Physical examination should focus on lymphadenopathy and organ involvement such as hepatomegaly or splenomegaly. Many clinically stable patients without systemic toxicity can be evaluated as outpatients. Peripheral blood smears should be reviewed by experienced personnel, as atypical lymphocytes may be subtle.
Epidemiology
Lymphocytosis is common across many clinical conditions. Evidence of prior EBV infection is present in over 90% of adults. Primary EBV infection is frequent and often asymptomatic in children. CMV seroprevalence increases with age, exceeding 90% in adults over 80 years. Acute HIV infection may present with atypical lymphocytosis and a mononucleosis-like illness. Tuberculosis remains highly prevalent worldwide, with a large reservoir of latent infection.
Etiology
Common infectious causes include EBV, CMV, HIV, adenovirus, influenza, hepatitis A and B, measles, mumps, rubella, dengue, rickettsial infections, pertussis, tuberculosis, Bartonella, Brucella, syphilis, Q fever, Mycoplasma pneumoniae, toxoplasmosis, malaria, and babesiosis. Noninfectious causes include drug and toxic reactions, post-perfusion syndrome, immunizations, radiation exposure, endocrine disorders such as thyrotoxicosis or adrenal insufficiency, autoimmune diseases, smoking, and stress-related catecholamine release. Malignant causes include acute and chronic lymphocytic leukemia, lymphomas, hairy cell leukemia, and paraneoplastic syndromes. Other causes include sarcoidosis, thymoma, myasthenia gravis, Guillain–Barré syndrome, serum sickness, graft rejection, and inherited immune disorders.
Clinical Features
Acute EBV, CMV, or HIV infection may present with fever, lymphadenopathy, pharyngitis, fatigue, and anorexia. EBV typically causes exudative pharyngitis and hepatosplenomegaly, while CMV more often presents with prolonged fever and less prominent organomegaly. Cat-scratch disease presents with localized lymphadenopathy near the inoculation site. Cycling (Pel–Ebstein) fevers raise concern for Hodgkin lymphoma. Generalized lymphadenopathy is seen in many infections, leukemias, lymphomas, and sarcoidosis. Massive splenomegaly suggests myeloproliferative disorders, lymphomas, malaria, visceral leishmaniasis, or storage diseases. Viral hepatitis may present with jaundice and right upper quadrant tenderness.
Diagnostic Evaluation
Peripheral blood smear review is essential, and prior blood counts should be reviewed to assess chronicity. EBV infection is characterized by atypical lymphocytosis, positive heterophile antibody testing, and mild transaminitis. The Monospot test is highly specific and moderately sensitive. EBV serology distinguishes acute from past infection. CMV diagnosis relies on IgM and IgG serology, with PCR reserved for immunocompromised patients. HIV testing includes antigen–antibody screening with confirmatory testing; PCR is required in suspected acute infection. Toxoplasmosis is diagnosed by serology. Respiratory viruses such as influenza are detected by nasopharyngeal swab, with PCR offering the highest sensitivity. If malignancy is suspected, further evaluation may include flow cytometry, bone marrow biopsy, and cytogenetic studies. Imaging is reserved for clinical indications such as suspected pneumonia, organomegaly, or focal neurologic findings.
Management
Treatment is directed at the underlying cause. Uncomplicated EBV infection requires supportive care only. Patients with hepatosplenomegaly should avoid contact sports for up to two months due to risk of splenic rupture. Antibiotics such as ampicillin may cause rash in EBV infection and should be avoided. CMV treatment is generally reserved for immunocompromised patients. HIV infection requires antiretroviral therapy under specialist care.
Medications
Supportive therapy with acetaminophen or NSAIDs is appropriate for uncomplicated viral infections. Corticosteroids may be used for airway compromise in EBV. Antiviral therapy for CMV includes ganciclovir or valganciclovir in selected patients. Herpesvirus infections may be treated with acyclovir or valacyclovir. Influenza is treated with neuraminidase inhibitors when indicated.
Follow-Up and Prognosis
Patients should be counseled regarding warning signs and complications, particularly in EBV infection. Liver enzymes should be monitored until normalization. Persistent or unexplained lymphocytosis warrants hematology consultation to exclude malignancy.
Overview and Definition
Lymphocytosis is defined as an absolute lymphocyte count greater than 4,000 cells/mm³ in peripheral blood. It may be reactive or neoplastic in origin. Reactive lymphocytosis is caused by infectious or noninfectious conditions, whereas neoplastic lymphocytosis reflects underlying hematologic malignancy. Infectious causes include viral, bacterial, protozoal, and parasitic diseases, while noninfectious causes include drugs, autoimmune disorders, and certain endocrinopathies. Atypical lymphocytes are non-neoplastic, activated lymphocytes that appear in response to immunologic stimulation; they are typically large, with nucleoli, irregular cytoplasm, and may appear to “indent” surrounding red blood cells on smear.
Clinical Approach
History and physical examination are essential to distinguish reactive from neoplastic lymphocytosis. Age is an important clue: acute EBV infection is common in children and young adults, while chronic lymphocytic leukemia is more common after the fifth decade. Assess symptom duration, vaccination history, prior illnesses, and medication use. Evaluate risk factors for HIV and tuberculosis, including sexual exposure, intravenous drug use, close contacts, travel, homelessness, and institutionalization. A detailed travel history should assess risk for food-, water-, and arthropod-borne infections. Physical examination should focus on lymphadenopathy and organ involvement such as hepatomegaly or splenomegaly. Many clinically stable patients without systemic toxicity can be evaluated as outpatients. Peripheral blood smears should be reviewed by experienced personnel, as atypical lymphocytes may be subtle.
Epidemiology
Lymphocytosis is common across many clinical conditions. Evidence of prior EBV infection is present in over 90% of adults. Primary EBV infection is frequent and often asymptomatic in children. CMV seroprevalence increases with age, exceeding 90% in adults over 80 years. Acute HIV infection may present with atypical lymphocytosis and a mononucleosis-like illness. Tuberculosis remains highly prevalent worldwide, with a large reservoir of latent infection.
Etiology
Common infectious causes include EBV, CMV, HIV, adenovirus, influenza, hepatitis A and B, measles, mumps, rubella, dengue, rickettsial infections, pertussis, tuberculosis, Bartonella, Brucella, syphilis, Q fever, Mycoplasma pneumoniae, toxoplasmosis, malaria, and babesiosis. Noninfectious causes include drug and toxic reactions, post-perfusion syndrome, immunizations, radiation exposure, endocrine disorders such as thyrotoxicosis or adrenal insufficiency, autoimmune diseases, smoking, and stress-related catecholamine release. Malignant causes include acute and chronic lymphocytic leukemia, lymphomas, hairy cell leukemia, and paraneoplastic syndromes. Other causes include sarcoidosis, thymoma, myasthenia gravis, Guillain–Barré syndrome, serum sickness, graft rejection, and inherited immune disorders.
Clinical Features
Acute EBV, CMV, or HIV infection may present with fever, lymphadenopathy, pharyngitis, fatigue, and anorexia. EBV typically causes exudative pharyngitis and hepatosplenomegaly, while CMV more often presents with prolonged fever and less prominent organomegaly. Cat-scratch disease presents with localized lymphadenopathy near the inoculation site. Cycling (Pel–Ebstein) fevers raise concern for Hodgkin lymphoma. Generalized lymphadenopathy is seen in many infections, leukemias, lymphomas, and sarcoidosis. Massive splenomegaly suggests myeloproliferative disorders, lymphomas, malaria, visceral leishmaniasis, or storage diseases. Viral hepatitis may present with jaundice and right upper quadrant tenderness.
Diagnostic Evaluation
Peripheral blood smear review is essential, and prior blood counts should be reviewed to assess chronicity. EBV infection is characterized by atypical lymphocytosis, positive heterophile antibody testing, and mild transaminitis. The Monospot test is highly specific and moderately sensitive. EBV serology distinguishes acute from past infection. CMV diagnosis relies on IgM and IgG serology, with PCR reserved for immunocompromised patients. HIV testing includes antigen–antibody screening with confirmatory testing; PCR is required in suspected acute infection. Toxoplasmosis is diagnosed by serology. Respiratory viruses such as influenza are detected by nasopharyngeal swab, with PCR offering the highest sensitivity. If malignancy is suspected, further evaluation may include flow cytometry, bone marrow biopsy, and cytogenetic studies. Imaging is reserved for clinical indications such as suspected pneumonia, organomegaly, or focal neurologic findings.
Management
Treatment is directed at the underlying cause. Uncomplicated EBV infection requires supportive care only. Patients with hepatosplenomegaly should avoid contact sports for up to two months due to risk of splenic rupture. Antibiotics such as ampicillin may cause rash in EBV infection and should be avoided. CMV treatment is generally reserved for immunocompromised patients. HIV infection requires antiretroviral therapy under specialist care.
Medications
Supportive therapy with acetaminophen or NSAIDs is appropriate for uncomplicated viral infections. Corticosteroids may be used for airway compromise in EBV. Antiviral therapy for CMV includes ganciclovir or valganciclovir in selected patients. Herpesvirus infections may be treated with acyclovir or valacyclovir. Influenza is treated with neuraminidase inhibitors when indicated.
Follow-Up and Prognosis
Patients should be counseled regarding warning signs and complications, particularly in EBV infection. Liver enzymes should be monitored until normalization. Persistent or unexplained lymphocytosis warrants hematology consultation to exclude malignancy.
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Infectious Disease and Microbiology – Neurological Symptoms and Signs with Fever
Overview and Definitions
Clouding of consciousness refers to mild inattentiveness and slightly reduced wakefulness. Obtundation describes slowed responses to external stimuli with decreased alertness and increased sleepiness. Coma is a state of unarousable unconsciousness with no purposeful response to pain. Encephalitis is inflammation of the brain associated with neurologic or mental status changes. Meningitis is inflammation of the meninges surrounding the central nervous system and may be acute, presenting over hours, or chronic, lasting longer than four weeks.
Clinical Approach
Fever with neurologic symptoms requires urgent evaluation for central nervous system infection, systemic infection, or noninfectious neurologic pathology. History should include onset and progression of neurologic symptoms, medication and substance use, trauma, travel, animal exposures, immunocompromised states, and past medical history, with collateral history when available. A complete physical examination should be performed with emphasis on dermatologic, head and neck, cardiopulmonary, and a comprehensive neurologic assessment including mental status, cranial nerves, funduscopy, gait, tone, power, reflexes, sensation, and cerebellar function. Level of consciousness should be documented using the Glasgow Coma Scale. Examination for meningitis includes assessment of neck stiffness, Kernig and Brudzinski signs, and jolt accentuation of headache. Funduscopic examination is important to detect papilledema, subarachnoid hemorrhage, or hypertensive encephalopathy.
Epidemiology
Herpes simplex virus type 1 accounts for approximately 10% of encephalitis cases. In regions where tuberculosis is endemic, tuberculomas are a frequent cause of intracranial mass lesions. The annual incidence of bacterial meningitis in the United States is approximately 1.5 per 100,000 population. In adults, the most common pathogens are Streptococcus pneumoniae, Neisseria meningitidis, and Listeria monocytogenes, with Staphylococcus aureus, including methicillin-resistant strains, increasingly recognized.
Etiology
Acute fever with neurologic signs suggests bacterial meningitis, encephalitis, or infectious intracranial lesions, all of which are medical emergencies. CNS granulomas may be caused by syphilis, cysticercosis, tuberculoma, fungal infections, or sarcoidosis. Enteroviruses are the most common cause of aseptic meningitis. Opportunistic infections are common in advanced HIV infection. Listeria rhombencephalitis presents with brainstem and cranial nerve involvement and is best identified on MRI. Parasitic causes include Echinococcus granulosus, schistosomiasis, amebiasis, and paragonimiasis. Fungal causes include Cryptococcus neoformans, Histoplasma, Coccidioides, Blastomyces, Aspergillus, mucormycosis, and Pseudallescheria. Viral cerebellar encephalitis may follow measles, varicella, Lyme disease, rabies, or legionellosis. Free-living amoebae such as Naegleria fowleri cause acute fulminant meningitis, while Acanthamoeba and Balamuthia cause chronic meningoencephalitis. Noninfectious causes include drug intoxication or withdrawal, malignancy, and subarachnoid hemorrhage.
Clinical Features
Bacterial meningitis typically presents with acute onset of fever, headache, neck stiffness, photophobia, nausea, and vomiting. Absence of headache and jolt accentuation makes bacterial meningitis unlikely, although individual clinical features lack sensitivity. Central nervous system tuberculosis is commonly associated with fever. Brucellosis may cause chronic granulomatous meningitis with constitutional symptoms and relevant animal exposure.
Diagnostic Evaluation
Initial investigations include complete blood count, electrolytes, renal and liver function tests, and blood cultures. Lumbar puncture is essential unless contraindicated by raised intracranial pressure or coagulopathy and should include opening pressure, cell count with differential, protein, glucose, Gram stain, culture, mycobacterial and fungal studies, cryptococcal antigen, syphilis testing, and PCR for herpes simplex or varicella zoster virus. Neuroimaging with CT or MRI is required to exclude space-occupying lesions, with MRI offering superior sensitivity for encephalitis and brainstem disease. In bacterial meningitis, cerebrospinal fluid typically shows elevated opening pressure, neutrophilic pleocytosis, high protein, and low or normal glucose. Viral meningitis usually demonstrates lower white cell counts with lymphocytic predominance and moderately elevated protein.
Management
Empiric treatment for suspected bacterial meningitis includes a third- or fourth-generation cephalosporin combined with vancomycin, with ampicillin added in patients over 50 years of age or immunocompromised to cover Listeria. Dexamethasone should be administered early when pneumococcal meningitis is suspected. Acyclovir should be initiated if herpes simplex encephalitis is a consideration. Antimicrobial therapy must not be delayed for imaging or lumbar puncture when meningitis is suspected.
Additional Care
Management often requires a multidisciplinary approach, with involvement of physiotherapy, occupational therapy, and speech and language pathology during recovery.
Follow-Up and Prognosis
Early recognition and prompt treatment are critical to reducing morbidity and mortality associated with infectious neurologic syndromes.
Complications
Complications include death, deafness, visual impairment, seizures, stroke, cognitive impairment, and increased intracranial pressure.
Overview and Definitions
Clouding of consciousness refers to mild inattentiveness and slightly reduced wakefulness. Obtundation describes slowed responses to external stimuli with decreased alertness and increased sleepiness. Coma is a state of unarousable unconsciousness with no purposeful response to pain. Encephalitis is inflammation of the brain associated with neurologic or mental status changes. Meningitis is inflammation of the meninges surrounding the central nervous system and may be acute, presenting over hours, or chronic, lasting longer than four weeks.
Clinical Approach
Fever with neurologic symptoms requires urgent evaluation for central nervous system infection, systemic infection, or noninfectious neurologic pathology. History should include onset and progression of neurologic symptoms, medication and substance use, trauma, travel, animal exposures, immunocompromised states, and past medical history, with collateral history when available. A complete physical examination should be performed with emphasis on dermatologic, head and neck, cardiopulmonary, and a comprehensive neurologic assessment including mental status, cranial nerves, funduscopy, gait, tone, power, reflexes, sensation, and cerebellar function. Level of consciousness should be documented using the Glasgow Coma Scale. Examination for meningitis includes assessment of neck stiffness, Kernig and Brudzinski signs, and jolt accentuation of headache. Funduscopic examination is important to detect papilledema, subarachnoid hemorrhage, or hypertensive encephalopathy.
Epidemiology
Herpes simplex virus type 1 accounts for approximately 10% of encephalitis cases. In regions where tuberculosis is endemic, tuberculomas are a frequent cause of intracranial mass lesions. The annual incidence of bacterial meningitis in the United States is approximately 1.5 per 100,000 population. In adults, the most common pathogens are Streptococcus pneumoniae, Neisseria meningitidis, and Listeria monocytogenes, with Staphylococcus aureus, including methicillin-resistant strains, increasingly recognized.
Etiology
Acute fever with neurologic signs suggests bacterial meningitis, encephalitis, or infectious intracranial lesions, all of which are medical emergencies. CNS granulomas may be caused by syphilis, cysticercosis, tuberculoma, fungal infections, or sarcoidosis. Enteroviruses are the most common cause of aseptic meningitis. Opportunistic infections are common in advanced HIV infection. Listeria rhombencephalitis presents with brainstem and cranial nerve involvement and is best identified on MRI. Parasitic causes include Echinococcus granulosus, schistosomiasis, amebiasis, and paragonimiasis. Fungal causes include Cryptococcus neoformans, Histoplasma, Coccidioides, Blastomyces, Aspergillus, mucormycosis, and Pseudallescheria. Viral cerebellar encephalitis may follow measles, varicella, Lyme disease, rabies, or legionellosis. Free-living amoebae such as Naegleria fowleri cause acute fulminant meningitis, while Acanthamoeba and Balamuthia cause chronic meningoencephalitis. Noninfectious causes include drug intoxication or withdrawal, malignancy, and subarachnoid hemorrhage.
Clinical Features
Bacterial meningitis typically presents with acute onset of fever, headache, neck stiffness, photophobia, nausea, and vomiting. Absence of headache and jolt accentuation makes bacterial meningitis unlikely, although individual clinical features lack sensitivity. Central nervous system tuberculosis is commonly associated with fever. Brucellosis may cause chronic granulomatous meningitis with constitutional symptoms and relevant animal exposure.
Diagnostic Evaluation
Initial investigations include complete blood count, electrolytes, renal and liver function tests, and blood cultures. Lumbar puncture is essential unless contraindicated by raised intracranial pressure or coagulopathy and should include opening pressure, cell count with differential, protein, glucose, Gram stain, culture, mycobacterial and fungal studies, cryptococcal antigen, syphilis testing, and PCR for herpes simplex or varicella zoster virus. Neuroimaging with CT or MRI is required to exclude space-occupying lesions, with MRI offering superior sensitivity for encephalitis and brainstem disease. In bacterial meningitis, cerebrospinal fluid typically shows elevated opening pressure, neutrophilic pleocytosis, high protein, and low or normal glucose. Viral meningitis usually demonstrates lower white cell counts with lymphocytic predominance and moderately elevated protein.
Management
Empiric treatment for suspected bacterial meningitis includes a third- or fourth-generation cephalosporin combined with vancomycin, with ampicillin added in patients over 50 years of age or immunocompromised to cover Listeria. Dexamethasone should be administered early when pneumococcal meningitis is suspected. Acyclovir should be initiated if herpes simplex encephalitis is a consideration. Antimicrobial therapy must not be delayed for imaging or lumbar puncture when meningitis is suspected.
Additional Care
Management often requires a multidisciplinary approach, with involvement of physiotherapy, occupational therapy, and speech and language pathology during recovery.
Follow-Up and Prognosis
Early recognition and prompt treatment are critical to reducing morbidity and mortality associated with infectious neurologic syndromes.
Complications
Complications include death, deafness, visual impairment, seizures, stroke, cognitive impairment, and increased intracranial pressure.
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KembaraXtra-Medicine: Abdominal Aortic Aneurysm
An abdominal aortic aneurysm (AAA) is a segmental, full-thickness dilation of the abdominal aorta that measures at least 50% larger than the normal vessel diameter. Because the average infrarenal aortic diameter in adults is about 2 cm, an aortic diameter of 3.0 cm or greater is commonly used as the threshold for defining an AAA. The relevant ICD-10-CM codes include I71.4 for abdominal aortic aneurysm without rupture and I71.3 for abdominal aortic aneurysm with rupture.
AAA is primarily a disease of older adults and occurs far more often in men than women, with men affected about four times as frequently. In the United States, roughly 13,000 deaths per year are attributed to AAA. Among men older than 60 years, the prevalence is estimated at about 1.2% to 3.3%, which is lower than older reports, likely reflecting reductions in smoking rates. Importantly, men with a subaneurysmal aorta (about 2.6-2.9 cm) have a meaningful risk of progression, with more than half developing an AAA (>3.0 cm) within 5 years, and a notable proportion eventually reaching larger sizes over longer follow-up.
Most AAAs develop in the infrarenal aorta and tend to enlarge progressively over time, with faster expansion as diameter increases. Aneurysm size is the strongest predictor of rupture, and because larger aneurysms grow more quickly, surveillance intervals shorten as size increases. Typical monitoring intervals include imaging every 3 years for AAAs 3.0–3.9 cm, every 12 months for 4.0–4.9 cm, and every 6 months for 5.0–5.4 cm. Rupture is often catastrophic, especially outside the hospital setting, where mortality is commonly 80–90%. Female sex, older age, and especially current smoking are associated with higher rupture risk, and rupture risk rises steeply as aneurysm diameter increases, particularly once the AAA exceeds 5.5 cm.
Screening is designed to detect AAAs before rupture. The USPSTF recommends one-time screening ultrasound for men aged 65–75 who have ever smoked and suggests selective screening for older men who never smoked but have risk factors such as a first-degree family history. Repeat screening after a negative scan is generally not considered beneficial, and men older than 75 are unlikely to benefit. Evidence is currently insufficient to clearly define the balance of benefits and harms of screening women aged 65–75 who have smoked or have a family history. The Society for Vascular Surgery recommends one-time ultrasound screening for men and women aged 65–75 with tobacco history, for men and women aged 65–75 with a first-degree relative with AAA, and for selected patients older than 75 who are otherwise in good health and have smoking history or a first-degree relative with AAA.
Most AAAs are asymptomatic and discovered incidentally on imaging. Physical examination may reveal a pulsatile abdominal mass, but exam sensitivity is only moderate and becomes less reliable with larger abdominal girth; importantly, palpation does not increase rupture risk. When symptoms occur, they may include abdominal, back, flank, or groin pain, or symptoms caused by compression of nearby structures such as early satiety, nausea, vomiting, venous thrombosis from venous compression, ureteral obstruction with hydronephrosis, or distal thromboembolization causing leg pain and discoloration. A ruptured AAA can present with the classic triad of abdominal/back pain, hypotension, and a pulsatile mass, though this full triad is seen in only about half of cases, and rupture rapidly progresses to hemorrhagic shock requiring emergent repair.
AAA formation is driven by degenerative and inflammatory processes within the aortic wall, including smooth muscle cell loss, thinning of the media, infiltration by inflammatory cells, and breakdown of extracellular matrix components such as elastin, leading to progressive dilation and risk of rupture. Age is a major nonmodifiable risk factor, with markedly increased risk after 65 years. Smoking is the strongest modifiable risk factor, strongly linked to aneurysm formation, enlargement, and rupture. Family history also increases risk and may reflect inherited connective tissue susceptibility. Other associated conditions include hyperlipidemia, obesity, peripheral arterial disease, cerebrovascular disease, coronary artery disease, hypertension, and the presence of aneurysms elsewhere. Healthier dietary patterns and regular moderate exercise are associated with lower AAA risk, and moderate exercise does not appear to increase expansion or rupture risk.
Diagnosis is most often made by imaging rather than labs. AAA should be considered in the differential for patients with abdominal, back, or flank pain—especially older adults and smokers—and in those with a pulsatile abdominal mass. Important alternative diagnoses include aortic dissection, ulcerated aortic plaque, renal colic, mesenteric ischemia, pancreatitis, diverticulitis, peptic ulcer disease, and biliary disease. Laboratory testing is not routinely needed, but inflammatory markers and blood cultures may be considered if an inflammatory or infected aneurysm is suspected.
Ultrasound is the preferred screening and surveillance tool because it is noninvasive, widely available, and highly accurate. CT is typically used for preoperative planning and is the imaging modality of choice for symptomatic AAA or suspected rupture because it better defines anatomy, involvement near renal arteries, and signs of wall instability or rupture. MRA may also be used and can be highly accurate. Traditional diagnostic angiography has largely been replaced by noninvasive imaging, though angiographic techniques remain relevant in procedural planning and intraoperative decision-making.
Management depends on aneurysm size, symptoms, and overall surgical risk. Smoking cessation is essential because it reduces AAA expansion and rupture risk, and patients should be offered structured cessation support. Blood pressure and lipid control should follow standard cardiovascular prevention guidance, though medications such as statins or beta blockers are not used solely to prevent AAA expansion. Definitive treatment is aneurysm repair, performed either as open surgical repair (OSR) or endovascular aneurysm repair (EVAR). EVAR is generally favored when anatomy is suitable because it reduces short-term morbidity, but it requires lifelong surveillance for complications such as endoleaks, graft migration, fractures, infection, and aneurysm sac enlargement. CTA is commonly used early in follow-up, with ultrasound increasingly used for ongoing surveillance to reduce radiation and contrast exposure.
Elective repair is generally recommended for infrarenal or juxtarenal AAAs at about 5.5 cm or larger, for AAAs growing more than 0.5 cm in 6 months, and for any AAA that is symptomatic, regardless of size. For women, repair may be considered at slightly smaller diameters (often around 5.0 cm) depending on guideline and risk context. Ruptured AAA requires emergent repair, and symptomatic AAA usually requires urgent intervention. For small asymptomatic AAAs, studies show no clear advantage to early repair compared with careful imaging surveillance.
Referral to vascular surgery is recommended at the time an AAA is diagnosed so that surveillance, risk reduction, and timing of repair can be individualized. At the same time, it is important to optimize comorbidities—particularly coronary artery disease, pulmonary disease, and renal dysfunction—because these conditions increase operative risk and influence whether EVAR or open repair is appropriate.
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Infectious Disease and Microbiology – Pleural Effusion and Fever
Basics and Definitions
A pleural effusion is the accumulation of fluid in the pleural space due to increased production or decreased absorption. Light’s criteria distinguish transudates from exudates with high sensitivity and specificity. An exudative effusion meets at least one of the following: pleural fluid protein/serum protein >0.5, pleural fluid LDH/serum LDH >0.6, or pleural fluid LDH greater than two-thirds the upper limit of normal serum LDH. Parapneumonic effusions occur secondary to bacterial pneumonia and are classified as uncomplicated (free-flowing, sterile, resolve with antibiotics), complicated (low pH, low glucose, loculated), or empyema (gross pus in the pleural space). Empyema may be simple (single locule) or complex (multiloculated), most commonly caused by Streptococcus pneumoniae.
Clinical Approach
Symptoms depend on etiology and include dyspnea, pleuritic chest pain, fever, weight loss, edema, and hemoptysis. Evaluation requires careful history, physical examination, and diagnostic thoracentesis. Initial pleural fluid analysis includes protein, LDH, glucose, amylase, cytology, and cell count. In febrile patients or when fluid is turbid or malodorous, Gram stain, aerobic and anaerobic cultures are essential, with consideration of pH, acid-fast bacilli smear and culture, and fungal studies. Pleural biopsy and bronchoscopy are indicated when tuberculosis or malignancy is suspected. Thoracoscopy or open pleural biopsy is reserved for unresolved diagnostic cases.
Epidemiology
Pleural effusions account for approximately 1.5 million cases annually in the United States. Tuberculosis is the leading cause of exudative effusions worldwide but is less common in the US. In intensive care units, about 10% of pleural effusions are parapneumonic.
Etiology
Transudative effusions result from systemic factors and are rarely associated with fever; causes include heart failure, nephrotic syndrome, cirrhosis, constrictive pericarditis, pulmonary embolism, and myxedema. Exudative effusions arise from local pleural disease and commonly present with fever; causes include infections (bacterial, mycobacterial, fungal, viral, parasitic), malignancy, pulmonary embolism, and connective tissue diseases. Other causes include pancreatitis, esophageal rupture, chylothorax, hemothorax, drug reactions, asbestos-related disease, post-cardiac injury syndromes, radiation, sarcoidosis, uremia, and yellow nail syndrome. In patients with AIDS, noninfectious causes predominate, though bacterial pneumonia, Pneumocystis jirovecii, tuberculosis, and disseminated fungal infections remain important. Tuberculous pleurisy is typically an exudate with low pH, normal-to-low glucose, and lymphocytic predominance. Vertebral osteomyelitis, hantavirus pulmonary syndrome, parasitic infections, and Chagas disease should also be considered in appropriate settings.
Diagnosis
Acute febrile illness with chest pain and leukocytosis suggests aerobic bacterial pneumonia with parapneumonic effusion. Subacute presentations with weight loss and aspiration risk suggest anaerobic infection. Tuberculous pleuritis presents with fever, dyspnea, pleuritic pain, and weight loss, though pleural pain may be absent.
Diagnostic Tests and Interpretation
Neutrophil-predominant effusions suggest parapneumonic effusion, pulmonary embolism, or pancreatitis, while lymphocyte predominance favors tuberculosis, malignancy, or rheumatologic disease. Eosinophilic effusions occur in hemothorax, parasitic disease, asbestos exposure, pulmonary embolism, and Churg–Strauss syndrome. Low pleural glucose (<60 mg />L) and low pH (<7.3) indicate complicated infection, malignancy, or rheumatoid pleuritis. acid-fast stains and cultures have low sensitivity in tuberculous pleurisy; pleural biopsy significantly improves diagnostic yield. ada levels>70 U/L and elevated interferon-γ support tuberculosis, with reduced utility in low-prevalence regions. Elevated pleural amylase suggests pancreatic disease, lung adenocarcinoma, or esophageal rupture. Imaging includes chest radiography, ultrasound for septations, CT for parenchymal disease or embolism, and PET scanning for suspected malignancy.
Management
Uncomplicated parapneumonic effusions require antibiotics alone. Complicated effusions require tube thoracostomy, often with intrapleural fibrinolytics. Persistent loculated effusions or empyema require thoracoscopy or decortication. Simple empyema is managed with large-bore chest tubes; complex empyema often necessitates surgical intervention.
Follow-Up and Prognosis
Persistently unexplained effusions require reevaluation for tuberculosis and pulmonary embolism. Untreated tuberculous pleurisy frequently progresses to active tuberculosis within several years, mandating full antituberculous therapy. Tuberculous empyema may lead to severe pleural fibrosis and restrictive lung disease.
Basics and Definitions
A pleural effusion is the accumulation of fluid in the pleural space due to increased production or decreased absorption. Light’s criteria distinguish transudates from exudates with high sensitivity and specificity. An exudative effusion meets at least one of the following: pleural fluid protein/serum protein >0.5, pleural fluid LDH/serum LDH >0.6, or pleural fluid LDH greater than two-thirds the upper limit of normal serum LDH. Parapneumonic effusions occur secondary to bacterial pneumonia and are classified as uncomplicated (free-flowing, sterile, resolve with antibiotics), complicated (low pH, low glucose, loculated), or empyema (gross pus in the pleural space). Empyema may be simple (single locule) or complex (multiloculated), most commonly caused by Streptococcus pneumoniae.
Clinical Approach
Symptoms depend on etiology and include dyspnea, pleuritic chest pain, fever, weight loss, edema, and hemoptysis. Evaluation requires careful history, physical examination, and diagnostic thoracentesis. Initial pleural fluid analysis includes protein, LDH, glucose, amylase, cytology, and cell count. In febrile patients or when fluid is turbid or malodorous, Gram stain, aerobic and anaerobic cultures are essential, with consideration of pH, acid-fast bacilli smear and culture, and fungal studies. Pleural biopsy and bronchoscopy are indicated when tuberculosis or malignancy is suspected. Thoracoscopy or open pleural biopsy is reserved for unresolved diagnostic cases.
Epidemiology
Pleural effusions account for approximately 1.5 million cases annually in the United States. Tuberculosis is the leading cause of exudative effusions worldwide but is less common in the US. In intensive care units, about 10% of pleural effusions are parapneumonic.
Etiology
Transudative effusions result from systemic factors and are rarely associated with fever; causes include heart failure, nephrotic syndrome, cirrhosis, constrictive pericarditis, pulmonary embolism, and myxedema. Exudative effusions arise from local pleural disease and commonly present with fever; causes include infections (bacterial, mycobacterial, fungal, viral, parasitic), malignancy, pulmonary embolism, and connective tissue diseases. Other causes include pancreatitis, esophageal rupture, chylothorax, hemothorax, drug reactions, asbestos-related disease, post-cardiac injury syndromes, radiation, sarcoidosis, uremia, and yellow nail syndrome. In patients with AIDS, noninfectious causes predominate, though bacterial pneumonia, Pneumocystis jirovecii, tuberculosis, and disseminated fungal infections remain important. Tuberculous pleurisy is typically an exudate with low pH, normal-to-low glucose, and lymphocytic predominance. Vertebral osteomyelitis, hantavirus pulmonary syndrome, parasitic infections, and Chagas disease should also be considered in appropriate settings.
Diagnosis
Acute febrile illness with chest pain and leukocytosis suggests aerobic bacterial pneumonia with parapneumonic effusion. Subacute presentations with weight loss and aspiration risk suggest anaerobic infection. Tuberculous pleuritis presents with fever, dyspnea, pleuritic pain, and weight loss, though pleural pain may be absent.
Diagnostic Tests and Interpretation
Neutrophil-predominant effusions suggest parapneumonic effusion, pulmonary embolism, or pancreatitis, while lymphocyte predominance favors tuberculosis, malignancy, or rheumatologic disease. Eosinophilic effusions occur in hemothorax, parasitic disease, asbestos exposure, pulmonary embolism, and Churg–Strauss syndrome. Low pleural glucose (<60 mg />L) and low pH (<7.3) indicate complicated infection, malignancy, or rheumatoid pleuritis. acid-fast stains and cultures have low sensitivity in tuberculous pleurisy; pleural biopsy significantly improves diagnostic yield. ada levels>70 U/L and elevated interferon-γ support tuberculosis, with reduced utility in low-prevalence regions. Elevated pleural amylase suggests pancreatic disease, lung adenocarcinoma, or esophageal rupture. Imaging includes chest radiography, ultrasound for septations, CT for parenchymal disease or embolism, and PET scanning for suspected malignancy.
Management
Uncomplicated parapneumonic effusions require antibiotics alone. Complicated effusions require tube thoracostomy, often with intrapleural fibrinolytics. Persistent loculated effusions or empyema require thoracoscopy or decortication. Simple empyema is managed with large-bore chest tubes; complex empyema often necessitates surgical intervention.
Follow-Up and Prognosis
Persistently unexplained effusions require reevaluation for tuberculosis and pulmonary embolism. Untreated tuberculous pleurisy frequently progresses to active tuberculosis within several years, mandating full antituberculous therapy. Tuberculous empyema may lead to severe pleural fibrosis and restrictive lung disease.
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KembaraXtra-Medicine: 22q11.2 Deletion Syndrome
22q11.2 deletion syndrome (22q11.2 DS) is a contiguous gene deletion syndrome caused by a heterozygous deletion on the long arm of chromosome 22 at position q11.2. This deletion typically involves approximately 50 genes, including TBX1, a critical developmental gene involved in cardiac and thymic formation. The syndrome is characterized by a broad and highly variable phenotype, most commonly including congenital heart disease, hypocalcemia, immune dysfunction, palatal abnormalities, renal and skeletal anomalies, gastrointestinal issues, learning difficulties, and psychiatric disorders. It is the most common microdeletion syndrome and most often arises as a de novo event, though it may also be inherited in an autosomal dominant pattern.
The condition has been described under several synonymous diagnoses, including DiGeorge syndrome, velocardiofacial syndrome (VCFS), conotruncal anomaly face syndrome, Cayler cardiofacial syndrome, and autosomal dominant Opitz G/BBB syndrome. From a coding perspective, it is classified under ICD-10-CM codes Q93.59, Q93.81, Q93.88, and Q93.89, reflecting various chromosomal deletion categories.
Epidemiologically, 22q11.2 deletion syndrome has an estimated incidence and prevalence of approximately 1 in 2,148 individuals. It affects males and females equally and is present at birth, although diagnosis may be delayed or missed in individuals with milder manifestations. Diagnosis tends to occur earlier in patients with congenital heart disease. While it appears more prevalent among individuals of European descent, it occurs across all populations.
Genetically, approximately 85% of affected individuals have the classic 3 Mb deletion at 22q11.2, while around 10% have a smaller nested 1.5 Mb deletion. Because smaller deletions may be missed by fluorescence in situ hybridization (FISH), chromosomal microarray or MLPA is the preferred diagnostic method. About 94% of cases occur de novo due to nonallelic homologous recombination, but when a parent is affected, there is a 50% recurrence risk in each pregnancy. The condition is not associated with advanced maternal age.
Clinically, congenital heart disease is one of the most common and serious manifestations, occurring in approximately 69% of individuals, with about one-third requiring surgical repair. Endocrine abnormalities are present in over half of patients, most notably hypocalcemia due to hypoparathyroidism, as well as thyroid dysfunction, vitamin D deficiency, hypoglycemia, and occasional growth hormone deficiency. Immune dysfunction is seen in the majority of individuals and may include T-cell lymphopenia from thymic hypoplasia, humoral immune deficiencies, recurrent infections, allergies, asthma, and autoimmune conditions.
Otolaryngologic and craniofacial manifestations are frequent and include velopharyngeal insufficiency, submucous cleft palate, bifid uvula, and, less commonly, overt cleft palate or cleft lip. Chronic otitis media, hearing loss, airway abnormalities, obstructive sleep apnea, and characteristic facial features such as hooded eyelids, bulbous nasal tip, and micrognathia are commonly observed. Gastrointestinal involvement often presents as feeding difficulties, dysphagia, gastroesophageal reflux, constipation, and the need for tube feeding in infancy, with occasional structural anomalies such as malrotation or imperforate anus.
Skeletal anomalies occur in roughly half of affected individuals and most commonly involve the cervical spine, sometimes with instability, as well as scoliosis, clubfoot, craniosynostosis, and limb anomalies. Genitourinary findings include renal anomalies, hypospadias, cryptorchidism, and absent or malformed reproductive organs in some patients. Neurologic and developmental manifestations are prominent, with most individuals experiencing learning difficulties, speech and language delay, and mild motor delay. Psychiatric conditions such as ADHD, anxiety, autism spectrum disorder, mood disorders, psychosis, and sleep disturbances are common, particularly in adolescence and adulthood.
Hematologic abnormalities may occur due to deletion of the GP1BB gene, leading to platelet dysfunction and bleeding tendencies. Although malignancy remains uncommon overall, individuals with 22q11.2 deletion syndrome have an increased risk compared with the general population, including leukemias and solid tumors such as Wilms tumor and thyroid carcinoma.
Diagnosis is confirmed by chromosomal microarray or MLPA, with additional baseline evaluation guided by age and clinical findings. Recommended assessments include echocardiography, renal ultrasound, immune studies, calcium and thyroid monitoring, developmental evaluations, and neuropsychological testing. Brain imaging and spinal imaging are reserved for specific clinical indications.
Management is multidisciplinary and lifelong, focusing on early intervention and surveillance. Nonpharmacologic therapy includes early speech therapy beginning in infancy, as well as physical, occupational, educational, and behavioral supports. Medical management may involve calcium and vitamin D supplementation, cardiac medications, endocrine replacement therapy, treatment of immune dysfunction with antibiotics or IVIG, gastrointestinal support, and psychiatric medications when indicated. Surgical interventions may be required for cardiac defects, airway anomalies, gastrointestinal malformations, or palatal abnormalities.
Prognosis varies widely depending on the severity of organ involvement. Most individuals attend mainstream school with additional support, and many achieve varying degrees of independence in adulthood. Morbidity and mortality are increased compared with the general population, with congenital heart disease being the leading cause of death. Long-term follow-up at a specialized 22q center, genetic counseling, and comprehensive family education are essential components of care.
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KembaraXtra-Medicine: Absence Seizures
Absence seizures are a form of generalized seizure characterized by brief episodes of impaired consciousness, typically presenting as sudden staring spells. These events usually last 20 to 30 seconds or less, begin and end abruptly, and are not followed by post-ictal confusion. Patients are usually unaware that a seizure has occurred and immediately resume their prior activity. The classic electroencephalographic (EEG) hallmark is a generalized 3-Hz spike-and-wave discharge, often provoked by hyperventilation.
Absence seizures are also referred to as childhood absence epilepsy or simply absence seizures and are classified under ICD-10-CM code G40.309 (generalized idiopathic epilepsy, not intractable, without status epilepticus). They represent up to 18% of pediatric epilepsy syndromes, with an incidence of approximately 1 to 10 cases per 100,000 population. The condition is more common in girls than boys. Onset typically occurs between 4 and 10 years of age, with a peak incidence around 6 to 7 years, and seizures often remit spontaneously by early adulthood.
On physical and neurologic examination, patients with absence seizures are usually entirely normal. During seizures, patients are briefly unresponsive and may exhibit subtle motor features such as eye blinking, lip smacking, or small hand movements (automatisms). Unlike focal seizures, absence seizures are not associated with an aura, post-ictal confusion, or prolonged recovery. They may occur many times per day and are commonly triggered by hyperventilation, such as during exercise or intentional over-breathing during EEG testing. Tonic-clonic seizures are not typical of classic childhood absence epilepsy; if present, alternative epilepsy syndromes should be considered.
The etiology of absence seizures is considered genetic, with dysfunction in thalamocortical circuits leading to abnormal synchronous neuronal firing. Because of this generalized mechanism, seizures involve both hemispheres simultaneously, which explains the abrupt onset, brief duration, and lack of post-ictal symptoms.
Diagnosis relies heavily on EEG, which is essential and often diagnostic. EEG performed with hyperventilation and photic stimulation typically provokes the characteristic generalized 3-Hz spike-and-wave pattern. Ambulatory EEG or video EEG monitoring may be used when diagnostic uncertainty exists, particularly to distinguish absence seizures from focal seizures with impaired awareness or nonepileptic staring spells. In patients with a classic clinical presentation and EEG findings, neuroimaging is often unnecessary; however, brain MRI should be performed if the EEG is atypical or if focal features are suspected. CT scans should generally be avoided in children due to radiation exposure and low diagnostic yield.
The differential diagnosis includes juvenile absence epilepsy, juvenile myoclonic epilepsy, focal seizures with impaired awareness (complex partial seizures), and nonepileptic staring episodes. Key distinguishing features include seizure duration (seconds in absence seizures vs minutes in focal seizures), lack of post-ictal confusion, frequent daily occurrence, and the characteristic EEG findings. Correct differentiation is critical, as some antiseizure medications used for focal epilepsy can worsen absence seizures.
Treatment outcomes are generally excellent. Ethosuximide is considered the first-line therapy based on the best available evidence, followed by valproic acid and lamotrigine as alternatives. Ethosuximide is particularly favored because of its effectiveness and relatively narrow side-effect profile for absence seizures. Valproic acid should be used cautiously, especially in girls and women of childbearing potential, due to teratogenic risks. Carbamazepine and phenytoin are contraindicated, as they may exacerbate absence seizures or provoke absence status epilepticus.
Children with recurrent absence seizures require chronic antiseizure therapy, but prognosis is favorable. Many children become seizure-free and can be considered for medication withdrawal after 1 to 2 years without seizures. Absence seizures commonly remit during adolescence, and epilepsy may be considered resolved after 10 years without seizures, including at least 5 years off medication.
Patients with absence seizures should be referred to a child neurologist, ideally one with expertise in epilepsy, for diagnosis confirmation and long-term management. Families should be educated about seizure recognition, medication adherence, and safety considerations. Driving restrictions apply to patients with ongoing seizures, and regulations vary by jurisdiction. Preventive strategies include avoiding sleep deprivation and alcohol, both of which may lower seizure threshold.
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KembaraXtra-Medicine: Abusive Head Trauma
Abusive head trauma (AHT) refers to traumatic brain injury resulting from the deliberate application of force to an infant or young child, most commonly under 4 years of age. Formerly termed shaken baby syndrome, AHT may result from shaking, blunt impact, or a combination of both, and the injury patterns do not reliably distinguish between these mechanisms. AHT is a life-threatening condition, and survivors frequently experience severe, lifelong neurologic sequelae. The most characteristic injury pattern includes subdural hemorrhage, often accompanied by extensive retinal hemorrhages and encephalopathy, although children may present with or without additional cutaneous, musculoskeletal, or visceral injuries. Diagnosis is often challenging because symptoms may be vague, caregivers may provide no history or an inconsistent history of trauma, and external signs of injury may be absent.
AHT is also known as shaken baby syndrome, infant whiplash syndrome, inflicted pediatric neurotrauma, or nonaccidental head injury. Relevant ICD-10-CM codes include T74.4 (shaken infant syndrome), T74.12 (child physical abuse, confirmed), and T76.12 (child physical abuse, suspected).
Epidemiologically, the incidence of AHT is estimated at 32–38 cases per 100,000 children under 1 year of age. It is the most common cause of fatal head injury in children under 2 years, accounting for more than half of serious or fatal traumatic injuries in this age group, and it is the leading cause of death from physical abuse overall. Mortality approaches 25%, and among survivors, long-term neurologic disability occurs in approximately 70%, including visual impairment, cognitive deficits, seizures, cerebral palsy, and intellectual disability. Males are affected more frequently than females, with reported ratios as high as 2:1.
Victims of AHT are typically younger than 1 year, with a median age of about 4 months. The peak incidence of fatal AHT occurs even earlier, between 1 and 2 months of age, which coincides with the normal developmental peak in infant crying. Infants are particularly vulnerable due to their relatively large head size, weak neck musculature, neural immaturity, and unique neuroanatomy, all of which increase susceptibility to acceleration–deceleration and rotational forces.
Risk factors for AHT include prematurity, perinatal illness, multiple gestations, male sex, excessive crying, and a range of caregiver and social factors such as young parental age, low educational attainment, substance use, mental illness, intimate partner violence, family disruption, social isolation, low socioeconomic status, and lack of affordable child care. Perpetrators are most often male caregivers, frequently the child’s father or the mother’s partner, although AHT occurs across all socioeconomic groups and may be inflicted by caregivers of any gender.
Clinically, infants with AHT often present with nonspecific symptoms such as lethargy, irritability, vomiting, poor feeding, seizures, apnea, or abnormal breathing. Caregivers may report no trauma or describe a minor fall inconsistent with the severity of injury. Presentations range from subtle symptoms to coma or cardiopulmonary arrest. Physical examination may reveal bruising, intraoral injuries such as a torn frenulum, macrocephaly, or a bulging fontanelle, but many infants have no external signs of injury.
Subdural hemorrhage is the most common neuroimaging finding in AHT and is one of the leading causes of subdural bleeding in infancy. Additional findings may include cerebral edema, loss of gray–white matter differentiation, parenchymal injury, torn or thrombosed bridging veins, cervical spine ligamentous injury, and spinal subdural hematomas. Skeletal surveys may reveal posterior rib fractures or classic metaphyseal lesions, and dilated ophthalmologic examination often shows retinal hemorrhages that are bilateral, multilayered, too numerous to count, and extending to the ora serrata, though some affected children may have no retinal hemorrhages. Retinoschisis may also be present. AHT is missed on initial presentation in roughly 30% of cases, often leading to repeated and escalating injury before diagnosis. Bias contributes to missed diagnoses, particularly among children from intact or socioeconomically advantaged families, underscoring that diagnosis must be based on clinical findings, not demographics.
The pathophysiology of AHT is thought to involve rotational deceleration forces, such as those generated during shaking, which damage bridging veins and result in subdural hemorrhage. Blunt impact can produce similar injury patterns. Severe cases may involve traumatic axonal injury, and vitreoretinal traction explains the characteristic retinal hemorrhages and retinoschisis. Many victims experience recurrent episodes of abuse, highlighting the importance of early recognition to prevent further harm.
The differential diagnosis includes accidental head trauma, severe infection, bleeding disorders, metabolic disorders, birth trauma, and brief resolved unexplained events (BRUE). Evaluation requires a thorough history and physical examination, including head circumference measurement, along with head CT for acute symptoms, followed by MRI of the brain and spine, ideally obtained several days after presentation. A skeletal survey is required, with repeat imaging after 2–3 weeks to identify healing fractures. A dilated ophthalmologic examination is essential. Laboratory testing is used to assess for coagulopathies, metabolic disorders, abdominal injury, and bone health, and social work evaluation is mandatory.
Management focuses on treating the child’s acute injuries and ensuring future safety. Most infants require hospital admission, often to an intensive care unit, for neurologic monitoring and supportive care. Long-term management includes consistent primary care, developmental surveillance, social services involvement, parenting support, and specialty referrals as indicated, including child abuse pediatrics, ophthalmology, neurology, neurosurgery, rehabilitation medicine, and early intervention services.
All health care providers are mandatory reporters of suspected child abuse. Every case of suspected AHT must be reported to child protective services, and many involve law enforcement. Other children in the household should undergo medical evaluation, as abuse is frequently recurrent. The role of the medical team is to objectively diagnose injury, not to determine legal responsibility.
Prevention efforts focus on parent and caregiver education, particularly around normal infant crying and the dangers of shaking. Programs such as the Period of Purple Crying, along with similar initiatives, aim to reduce AHT through anticipatory guidance, though results have been mixed. Broader public health strategies that reduce family stress—such as access to food assistance, health care, paid family leave, and affordable child care—are also important components of AHT prevention.
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KembaraXtra-Medicine: Abdominal Compartment Syndrome
Abdominal compartment syndrome (ACS) is defined as organ dysfunction caused by increased intraabdominal pressure, also referred to as intraabdominal hypertension. When pressure within the abdomen rises, blood flow to vital organs falls, which can rapidly progress to multisystem organ failure and death if not recognized and treated promptly. The ICD-10-CM code is M79.A3 (Nontraumatic compartment syndrome of abdomen).
The true incidence of ACS outside trauma populations is not well defined, but among trauma patients it has been reported in roughly 1% to 14%, depending on the patient population and type of injury. ACS is most commonly seen in critically ill patients, and critical illness itself is the largest overarching risk factor. A particularly important trigger is large-volume intravenous fluid resuscitation, because “third-spacing” and tissue edema can increase intraabdominal pressure. As a result, ACS is often associated with severe burns, major trauma, postoperative states, and sepsis. It is also linked to intraabdominal or retroperitoneal conditions that increase abdominal contents or reduce abdominal wall compliance, including bowel distention/obstruction or ileus, pancreatitis with retroperitoneal edema, massive ascites, hemoperitoneum (such as after ruptured abdominal aortic aneurysm), liver transplantation, and large intraabdominal or retroperitoneal hematomas.
Clinically, the most striking physical finding is typically marked abdominal distention. Patients often develop difficulty with ventilation and decreased urine output, which are common early clues to organ compromise. Additional findings may reflect poor perfusion and shock physiology, including hypotension, cool extremities, skin mottling, and altered mental status. Many patients have abdominal tenderness and signs of volume overload such as edema and elevated jugular venous pressure, and they may deteriorate quickly with acute respiratory decompensation.
ACS can impair nearly every organ system because elevated intraabdominal pressure disrupts both perfusion and mechanics. Rising abdominal pressure can increase intracranial pressure, potentially worsening cerebral perfusion. Cardiovascular compromise can occur through reduced venous return from inferior vena cava compression and reduced ventricular compliance, leading to higher central venous and pulmonary pressures and reduced cardiac output. Respiratory failure is common because elevated abdominal pressure pushes the diaphragm upward, reducing chest wall compliance and tidal volumes, which contributes to atelectasis, hypoxemia, hypercarbia, and pneumonia. Mechanically ventilated patients may require higher airway pressures, increasing the risk of barotrauma. Renal dysfunction occurs as renal vein compression and renal arterial vasoconstriction reduce renal blood flow, producing oliguria or anuria. Reduced mesenteric perfusion may cause bowel ischemia and lactic acidosis.
A definitive diagnosis requires direct measurement of intraabdominal pressure, most commonly estimated using bladder pressure measured through a urinary catheter. For accuracy, measurements are ideally obtained with the patient supine, at end-expiration, and without active abdominal muscle contractions. While many research definitions use a threshold of >20 mm Hg with associated organ dysfunction, ACS may occur at lower pressures in susceptible patients. Oliguria commonly appears around 15 mm Hg, and anuria may occur near 30 mm Hg. Other measurement approaches (such as intragastric or intracolonic pressure estimation) exist but are used less commonly. Laboratory studies are generally not diagnostic, although lactic acidosis can suggest bowel ischemia and signals a worse prognosis. Imaging does not establish ACS, but chest imaging may show diaphragmatic elevation or pulmonary complications, and abdominal CT may sometimes demonstrate findings such as vena cava compression or bowel ischemia-related injury—these should be considered supportive rather than diagnostic.
Treatment focuses on supportive care and rapid reduction of intraabdominal pressure, with surgical decompression as the only definitive therapy when conservative measures fail or when pressures and organ dysfunction are severe. Supportive management includes aggressive hemodynamic and ventilatory support, along with measures to improve abdominal wall compliance. Patients should be kept supine when possible, since head-of-bed elevation can raise intraabdominal pressure. Nasogastric and rectal decompression may be required when bowel distention is contributing. Adequate sedation and analgesia help reduce abdominal wall muscle tone, and some patients need chemical paralysis to maximize relaxation. If tense ascites is a major contributor, large-volume paracentesis can substantially lower pressures. In patients with severe abdominal burns, escharotomy may be necessary to restore abdominal wall compliance. Mechanical ventilation is often challenging and may require low tidal volumes, permissive hypercapnia, high PEEP, and paralytics to maintain adequate gas exchange.
Although vasopressors, fluids, sedatives, analgesics, and paralytics are used to stabilize the patient, there are no medications that directly treat ACS, and diuretics do not play a therapeutic role even when patients appear volume overloaded. If intraabdominal pressure remains high with ongoing organ dysfunction, surgical decompression is performed, typically by opening the abdomen via a midline incision through the linea alba. In emergent situations this can be done at the bedside, followed by temporary abdominal closure (often vacuum-assisted systems) to prevent evisceration, manage fluid loss, and allow delayed closure once swelling resolves. Many consensus recommendations support decompression when pressures exceed 25 mm Hg, though some clinicians will intervene earlier in the right clinical context, recognizing that earlier decompression may improve outcomes.
Because mortality with ACS can be very high, often greater than 40%, patients require close inpatient monitoring—preferably in an intensive care unit—and early surgical consultation. The key clinical principle is that ACS is both a pressure problem and an organ failure syndrome: diagnosis requires evidence of intraabdominal hypertension plus end-organ dysfunction, and definitive management depends on timely decompression when supportive measures are insufficient.
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KembaraXtra-Medicine: Achalasia
Achalasia is a chronic esophageal motility disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absence of normal peristalsis in the smooth muscle portion of the esophagus. Together, these abnormalities create a functional obstruction at the esophagogastric junction, leading to progressive difficulty with esophageal emptying. Achalasia is treatable but not curable, and therapy focuses on relieving obstruction rather than restoring peristalsis. The condition is coded under ICD-10-CM K22.0 (achalasia of cardia) and is also referred to as cardiospasm, esophageal achalasia, aperistalsis of the esophagus, or megaesophagus.
The incidence of achalasia has increased with the widespread use of high-resolution esophageal manometry (HRM) and is currently estimated at 0.03–1.63 cases per 100,000 persons per year, with a prevalence of approximately 10 per 100,000. Although symptoms may begin at any age, achalasia demonstrates a bimodal age distribution, most commonly presenting between 20–40 years and again after 60 years of age. Men and women are affected equally, with a slightly higher incidence observed in older adults.
Patients most commonly present with progressive dysphagia to both solids and liquids, a key feature distinguishing achalasia from mechanical obstruction. Other frequent symptoms include regurgitation of undigested food, difficulty belching, chest pain or heartburn, globus sensation, frequent hiccups, nocturnal cough, aspiration symptoms, weight loss, and recurrent pneumonia. Disease severity and treatment response are often assessed using the Eckardt score, which evaluates dysphagia, regurgitation, chest pain, and weight loss. The Brief Esophageal Dysphagia Questionnaire (BEDQ) is a sensitive screening tool for dysphagia and may outperform symptom-based GERD scales. Physical examination is often benign, though lung findings such as wheezing or crackles may be present due to aspiration.
The precise etiology of achalasia remains incompletely understood. The disease is characterized by degeneration of inhibitory neurons in the esophageal myenteric plexus, leading to loss of nitric oxide and vasoactive intestinal polypeptide (VIP) signaling. This results in unopposed cholinergic excitation, incomplete LES relaxation, and aperistalsis. Histopathologic findings include inflammatory infiltrates, fibrosis, nerve hypertrophy, and capillaritis. Increasing evidence supports an autoimmune mechanism, with associations to specific HLA class II alleles, antineural antibodies, and a higher prevalence of other autoimmune diseases. Viral triggers, including herpes simplex virus and varicella zoster virus, have also been implicated. Secondary forms of achalasia may occur in Chagas disease, following vagal nerve injury, or after foregut surgery. Type III achalasia has been associated with chronic opioid use.
The differential diagnosis is broad and includes pseudoachalasia caused by esophageal or gastric malignancy, as well as other motility disorders such as diffuse esophageal spasm, scleroderma, gastroesophageal reflux disease, esophageal strictures, webs, rings, Barrett esophagus, and opioid-induced dysmotility. Non-esophageal causes such as angina, eating disorders, and gastric bezoars should also be considered.
Diagnostic evaluation typically includes endoscopy, barium esophagram, and esophageal manometry, which are complementary. Endoscopy is essential to exclude malignancy, strictures, and secondary causes of obstruction before manometry is performed. A timed barium esophagram may show classic findings such as esophageal dilation, retained food and secretions, poor emptying, and the characteristic “bird’s beak” tapering at the LES. In advanced disease, the esophagus may become tortuous and sigmoid-shaped.
High-resolution manometry is the gold standard for diagnosis and allows classification according to the Chicago Classification v4.0, which defines three achalasia subtypes. Type I (classic achalasia) shows complete aperistalsis with impaired LES relaxation. Type II includes aperistalsis with panesophageal pressurization and generally responds best to therapy. Type III (spastic achalasia) is characterized by premature or spastic distal esophageal contractions and often requires longer myotomy. HRM also identifies esophagogastric junction outflow obstruction (EGJOO), a related but distinct condition that requires correlation with symptoms and additional testing.
Treatment is aimed at lowering LES pressure to relieve obstruction and prevent progression to megaesophagus. Pneumatic dilation disrupts LES muscle fibers and provides symptom relief in many patients, though repeat dilations may be required and there is a small risk of perforation. Laparoscopic Heller myotomy, often combined with partial fundoplication, offers durable symptom control and is highly effective, though postoperative reflux is common. Peroral endoscopic myotomy (POEM) has emerged as an effective minimally invasive alternative, particularly for type III achalasia, but carries a higher risk of postprocedural reflux due to the absence of an antireflux barrier.
Medical therapy plays a limited role and is generally reserved for patients who are poor procedural candidates or require temporary symptom relief. Options include nitrates, calcium channel blockers, and botulinum toxin injections, the latter of which is particularly useful in elderly or medically frail patients but has limited durability. End-stage disease with severe dilation and failed prior therapy may require esophagectomy, though this is uncommon.
Key clinical considerations include recognizing that medications offer only transient benefit, while pneumatic dilation, surgical myotomy, and POEM provide more durable symptom control. Patients with long-standing achalasia have an increased risk of esophageal squamous cell carcinoma, and treated patients may develop reflux-related complications, including Barrett esophagus. Routine surveillance endoscopy is not universally recommended, but long-term clinical follow-up is essential.
