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Emergency and Acute Medicine – Lymphadenitis
Basics description
Lymphadenitis refers to inflammation and enlargement of lymph nodes, most commonly as part of a systemic response to infection. Nodes become engorged with lymphocytes and macrophages and may be secondarily involved from infection in a distal extremity, producing painful, tender adenopathy proximally. Acute suppurative lymphadenitis may follow pharyngeal or skin infections and can progress to abscess formation.
Etiology
Lymphadenitis is most frequently caused by bacterial infection. The most common organisms in pyogenic lymphadenitis are Staphylococcus aureus, including community-associated methicillin-resistant S. aureus (CA-MRSA), and group A β-hemolytic Streptococcus. CA-MRSA risk factors include prior MRSA infection, household exposure, military service, incarceration, contact sports, injection drug use, and men who have sex with men. Cervical lymphadenitis usually originates from pharyngeal or periodontal infections and commonly involves streptococci and anaerobes. Axillary lymphadenitis is often caused by group A streptococcus. Nosocomial MRSA should be suspected in patients with recent hospitalization, surgery, dialysis, vascular catheters, recent antibiotic use, or unresponsive infection. In children, acute unilateral cervical suppurative lymphadenitis is most common in those younger than six years and is typically caused by S. aureus, group A streptococcus, or anaerobes.
Diagnosis signs and symptoms
Patients typically present with painful swelling and inflammation of affected lymph nodes, often in association with cellulitis or abscess if the cause is pyogenic. Axillary lymphadenitis may present with fever, axillary pain, and acute lymphedema of the arm or chest and may be associated with ipsilateral pleural effusion. History should include duration of lymphadenopathy, pain, fever, night sweats, weight loss, fatigue, sore throat, cough, occupational and animal exposures, sexual history, drug use, and travel. Physical examination should assess whether lymphadenopathy is localized or generalized, node size, tenderness, overlying skin changes, presence of skin lesions, splenomegaly, and involvement of supraclavicular or scalene nodes, which is always abnormal.
Essential workup
Acute regional lymphadenitis is usually a clinical diagnosis and often part of a broader infectious syndrome such as cellulitis. History and physical examination should focus on identifying an infectious source.
Diagnosis tests and interpretation
Laboratory testing is not always required. A CBC may show leukocytosis with left shift or be normal. Serologic testing for EBV, CMV, HIV, or other pathogens should be guided by clinical suspicion. Ultrasound or CT imaging is indicated when patients fail to improve with therapy or when suppuration is suspected. Percutaneous needle aspiration or surgical drainage should be considered if abscess formation occurs or if there is poor clinical response.
Differential diagnosis
The differential diagnosis includes common infections such as adenovirus, scarlet fever, cat scratch disease, fungal infections, and herpes zoster, as well as unusual infections including sporotrichosis, diphtheria, plague, anthrax, typhoid, rubella, and West Nile virus. Sexually transmitted infections, systemic infections such as HIV, infectious mononucleosis, toxoplasmosis, tuberculosis, hepatitis, and dengue should be considered. Noninfectious causes include drug reactions, malignancy, rheumatologic disorders, and pediatric-specific conditions such as Kawasaki disease and PFAPA syndrome.
Treatment
Initial management includes ensuring airway, breathing, and circulation stability. Treatment is directed at the underlying cause and should account for local resistance patterns, including CA-MRSA prevalence. Outpatient therapy typically lasts 7–10 days and includes limb elevation, moist heat, analgesics, and antibiotics. Abscesses require drainage with culture when possible. Skin-source infections are commonly treated with oral cephalexin plus trimethoprim–sulfamethoxazole or alternatives such as clindamycin or doxycycline. Pharyngeal or periodontal sources are treated with penicillin VK or alternatives such as clindamycin or amoxicillin–clavulanate. Inpatient therapy may require IV penicillin-based regimens with MRSA coverage using vancomycin or clindamycin when indicated.
Disposition and follow-up
Admission is indicated for toxic-appearing patients, those with immunosuppression or significant comorbidities, inability to tolerate oral therapy, or unreliable follow-up. Patients with mild infection who are nontoxic, can take oral antibiotics, and have reliable follow-up within 24–48 hours may be discharged. Failure to resolve promptly with antibiotics should prompt evaluation for malignancy or other serious causes, and lymph node biopsy may be indicated for persistent, large, or supraclavicular nodes.
Pearls and pitfalls
Staphylococcus species are the most common cause of acute regional pyogenic lymphadenitis. Empiric antibiotic therapy should include coverage for CA-MRSA in addition to streptococci, particularly in unresponsive or high-risk infections.
Basics description
Lymphadenitis refers to inflammation and enlargement of lymph nodes, most commonly as part of a systemic response to infection. Nodes become engorged with lymphocytes and macrophages and may be secondarily involved from infection in a distal extremity, producing painful, tender adenopathy proximally. Acute suppurative lymphadenitis may follow pharyngeal or skin infections and can progress to abscess formation.
Etiology
Lymphadenitis is most frequently caused by bacterial infection. The most common organisms in pyogenic lymphadenitis are Staphylococcus aureus, including community-associated methicillin-resistant S. aureus (CA-MRSA), and group A β-hemolytic Streptococcus. CA-MRSA risk factors include prior MRSA infection, household exposure, military service, incarceration, contact sports, injection drug use, and men who have sex with men. Cervical lymphadenitis usually originates from pharyngeal or periodontal infections and commonly involves streptococci and anaerobes. Axillary lymphadenitis is often caused by group A streptococcus. Nosocomial MRSA should be suspected in patients with recent hospitalization, surgery, dialysis, vascular catheters, recent antibiotic use, or unresponsive infection. In children, acute unilateral cervical suppurative lymphadenitis is most common in those younger than six years and is typically caused by S. aureus, group A streptococcus, or anaerobes.
Diagnosis signs and symptoms
Patients typically present with painful swelling and inflammation of affected lymph nodes, often in association with cellulitis or abscess if the cause is pyogenic. Axillary lymphadenitis may present with fever, axillary pain, and acute lymphedema of the arm or chest and may be associated with ipsilateral pleural effusion. History should include duration of lymphadenopathy, pain, fever, night sweats, weight loss, fatigue, sore throat, cough, occupational and animal exposures, sexual history, drug use, and travel. Physical examination should assess whether lymphadenopathy is localized or generalized, node size, tenderness, overlying skin changes, presence of skin lesions, splenomegaly, and involvement of supraclavicular or scalene nodes, which is always abnormal.
Essential workup
Acute regional lymphadenitis is usually a clinical diagnosis and often part of a broader infectious syndrome such as cellulitis. History and physical examination should focus on identifying an infectious source.
Diagnosis tests and interpretation
Laboratory testing is not always required. A CBC may show leukocytosis with left shift or be normal. Serologic testing for EBV, CMV, HIV, or other pathogens should be guided by clinical suspicion. Ultrasound or CT imaging is indicated when patients fail to improve with therapy or when suppuration is suspected. Percutaneous needle aspiration or surgical drainage should be considered if abscess formation occurs or if there is poor clinical response.
Differential diagnosis
The differential diagnosis includes common infections such as adenovirus, scarlet fever, cat scratch disease, fungal infections, and herpes zoster, as well as unusual infections including sporotrichosis, diphtheria, plague, anthrax, typhoid, rubella, and West Nile virus. Sexually transmitted infections, systemic infections such as HIV, infectious mononucleosis, toxoplasmosis, tuberculosis, hepatitis, and dengue should be considered. Noninfectious causes include drug reactions, malignancy, rheumatologic disorders, and pediatric-specific conditions such as Kawasaki disease and PFAPA syndrome.
Treatment
Initial management includes ensuring airway, breathing, and circulation stability. Treatment is directed at the underlying cause and should account for local resistance patterns, including CA-MRSA prevalence. Outpatient therapy typically lasts 7–10 days and includes limb elevation, moist heat, analgesics, and antibiotics. Abscesses require drainage with culture when possible. Skin-source infections are commonly treated with oral cephalexin plus trimethoprim–sulfamethoxazole or alternatives such as clindamycin or doxycycline. Pharyngeal or periodontal sources are treated with penicillin VK or alternatives such as clindamycin or amoxicillin–clavulanate. Inpatient therapy may require IV penicillin-based regimens with MRSA coverage using vancomycin or clindamycin when indicated.
Disposition and follow-up
Admission is indicated for toxic-appearing patients, those with immunosuppression or significant comorbidities, inability to tolerate oral therapy, or unreliable follow-up. Patients with mild infection who are nontoxic, can take oral antibiotics, and have reliable follow-up within 24–48 hours may be discharged. Failure to resolve promptly with antibiotics should prompt evaluation for malignancy or other serious causes, and lymph node biopsy may be indicated for persistent, large, or supraclavicular nodes.
Pearls and pitfalls
Staphylococcus species are the most common cause of acute regional pyogenic lymphadenitis. Empiric antibiotic therapy should include coverage for CA-MRSA in addition to streptococci, particularly in unresponsive or high-risk infections.
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Emergency and Acute Medicine – Lyme Disease
Basics description
Lyme disease is the most common tick-borne illness in North America. It is endemic in the northeastern United States, the upper Midwest, and parts of northwestern California. The disease follows a multisystem course and may present with dermatologic, neurologic, cardiac, and musculoskeletal manifestations.
Etiology and pathophysiology
Lyme disease is caused by the spirochete Borrelia burgdorferi, which is transmitted through the bite of an Ixodes tick, most commonly Ixodes dammini (the deer tick). Transmission occurs primarily between April and November, with 80–90% of cases in the summer months. Fewer than half of patients recall a tick bite. Disease pathogenesis involves organism-induced local inflammation, cytokine release, and autoimmune mechanisms. There is no person-to-person transmission. A related spirochete, Borrelia miyamotoi, has also been identified as a cause of a Lyme-like illness.
Clinical presentation and stages
Lyme disease progresses through three clinical stages, although not all patients experience every stage.
Stage I, or early localized disease, begins days to weeks after a tick bite. The hallmark finding is erythema chronicum migrans, a pathognomonic expanding annular rash greater than 5 cm in diameter, often with central clearing and a red outer border (“bull’s-eye” rash). Associated symptoms include regional lymphadenopathy, low-grade fever, headache, myalgias, arthralgias, fatigue, and malaise.
Stage II, or early disseminated disease, occurs days to weeks after infection and is characterized by intermittent, fluctuating symptoms. Neurologic involvement includes the triad of aseptic meningitis, cranial neuritis, and radiculoneuritis, with facial (Bell) palsy being the most common cranial nerve deficit. Cardiac manifestations may include tachycardia, bradycardia, atrioventricular block, and myopericarditis. Rash may be absent at this stage. Prognosis is generally good with appropriate treatment.
Stage III, or late disease, develops months to years after initial infection. Musculoskeletal involvement is most common, typically presenting as recurrent monoarticular or oligoarticular arthritis, most often affecting the knee. Dermatologic findings may include acrodermatitis chronica atrophicans on the extensor surfaces of the extremities. Less commonly, late neurologic complications such as chronic polyneuropathy or encephalopathy may occur. A Jarisch–Herxheimer reaction, consisting of transient symptom worsening shortly after treatment initiation, may be seen.
Special populations
Children are more likely than adults to present with fever and may lack a history of erythema migrans. Facial palsy in pediatric patients is frequently associated with aseptic meningitis. Cardiac involvement may be asymptomatic but detectable on ECG. With appropriate treatment, children generally have excellent long-term outcomes. There is no clear evidence that Lyme disease during pregnancy causes fetal harm.
Diagnosis and evaluation
Lyme disease is primarily a clinical diagnosis. The presence of erythema migrans eliminates the need for serologic testing. In patients without the classic rash, serologic testing with ELISA followed by confirmatory Western blot is indicated. Lumbar puncture is reserved for patients with meningeal signs, arthrocentesis for acute arthritis, and ECG for suspected cardiac involvement.
Laboratory findings are nonspecific and may include elevated erythrocyte sedimentation rate, mild cytopenias, or elevated liver enzymes. Cerebrospinal fluid analysis may show pleocytosis and elevated protein in neuroborreliosis.
Differential diagnosis
The differential diagnosis includes other tick-borne illnesses, viral meningitis, septic arthritis, rheumatic fever, syphilis, parvovirus B19 infection, infectious endocarditis, juvenile idiopathic arthritis, fibromyalgia, and chronic fatigue syndrome.
Treatment
Initial stabilization focuses on hydration, IV access for neurologic or cardiac involvement, and cardiac monitoring when indicated. Tick removal should be performed promptly using blunt forceps applied close to the skin.
Antibiotic therapy depends on disease stage and severity. Early localized disease is treated with oral antibiotics such as amoxicillin, doxycycline (for patients ≥8 years old and nonpregnant), or cefuroxime. Disseminated disease with mild neurologic involvement may be treated orally, while meningitis, significant carditis, or severe arthritis requires parenteral therapy, typically with ceftriaxone, cefotaxime, or penicillin G. Late disease usually requires prolonged parenteral therapy. NSAIDs are used for arthralgias and arthritis, and aspirin may be used adjunctively in cardiac involvement.
Disposition and follow-up
Hospital admission is required for patients with meningoencephalitis or significant cardiac involvement requiring telemetry or ICU monitoring. Patients with uncomplicated disease treated with oral antibiotics may be discharged with close outpatient follow-up.
Key points
Early recognition and treatment of Lyme disease prevent late complications. The presence of erythema migrans is diagnostic and should prompt immediate treatment without waiting for serology. Clinicians should remain vigilant for coinfections such as anaplasmosis and babesiosis in endemic regions, and prolonged treatment is required for later-stage organ involvement.
Basics description
Lyme disease is the most common tick-borne illness in North America. It is endemic in the northeastern United States, the upper Midwest, and parts of northwestern California. The disease follows a multisystem course and may present with dermatologic, neurologic, cardiac, and musculoskeletal manifestations.
Etiology and pathophysiology
Lyme disease is caused by the spirochete Borrelia burgdorferi, which is transmitted through the bite of an Ixodes tick, most commonly Ixodes dammini (the deer tick). Transmission occurs primarily between April and November, with 80–90% of cases in the summer months. Fewer than half of patients recall a tick bite. Disease pathogenesis involves organism-induced local inflammation, cytokine release, and autoimmune mechanisms. There is no person-to-person transmission. A related spirochete, Borrelia miyamotoi, has also been identified as a cause of a Lyme-like illness.
Clinical presentation and stages
Lyme disease progresses through three clinical stages, although not all patients experience every stage.
Stage I, or early localized disease, begins days to weeks after a tick bite. The hallmark finding is erythema chronicum migrans, a pathognomonic expanding annular rash greater than 5 cm in diameter, often with central clearing and a red outer border (“bull’s-eye” rash). Associated symptoms include regional lymphadenopathy, low-grade fever, headache, myalgias, arthralgias, fatigue, and malaise.
Stage II, or early disseminated disease, occurs days to weeks after infection and is characterized by intermittent, fluctuating symptoms. Neurologic involvement includes the triad of aseptic meningitis, cranial neuritis, and radiculoneuritis, with facial (Bell) palsy being the most common cranial nerve deficit. Cardiac manifestations may include tachycardia, bradycardia, atrioventricular block, and myopericarditis. Rash may be absent at this stage. Prognosis is generally good with appropriate treatment.
Stage III, or late disease, develops months to years after initial infection. Musculoskeletal involvement is most common, typically presenting as recurrent monoarticular or oligoarticular arthritis, most often affecting the knee. Dermatologic findings may include acrodermatitis chronica atrophicans on the extensor surfaces of the extremities. Less commonly, late neurologic complications such as chronic polyneuropathy or encephalopathy may occur. A Jarisch–Herxheimer reaction, consisting of transient symptom worsening shortly after treatment initiation, may be seen.
Special populations
Children are more likely than adults to present with fever and may lack a history of erythema migrans. Facial palsy in pediatric patients is frequently associated with aseptic meningitis. Cardiac involvement may be asymptomatic but detectable on ECG. With appropriate treatment, children generally have excellent long-term outcomes. There is no clear evidence that Lyme disease during pregnancy causes fetal harm.
Diagnosis and evaluation
Lyme disease is primarily a clinical diagnosis. The presence of erythema migrans eliminates the need for serologic testing. In patients without the classic rash, serologic testing with ELISA followed by confirmatory Western blot is indicated. Lumbar puncture is reserved for patients with meningeal signs, arthrocentesis for acute arthritis, and ECG for suspected cardiac involvement.
Laboratory findings are nonspecific and may include elevated erythrocyte sedimentation rate, mild cytopenias, or elevated liver enzymes. Cerebrospinal fluid analysis may show pleocytosis and elevated protein in neuroborreliosis.
Differential diagnosis
The differential diagnosis includes other tick-borne illnesses, viral meningitis, septic arthritis, rheumatic fever, syphilis, parvovirus B19 infection, infectious endocarditis, juvenile idiopathic arthritis, fibromyalgia, and chronic fatigue syndrome.
Treatment
Initial stabilization focuses on hydration, IV access for neurologic or cardiac involvement, and cardiac monitoring when indicated. Tick removal should be performed promptly using blunt forceps applied close to the skin.
Antibiotic therapy depends on disease stage and severity. Early localized disease is treated with oral antibiotics such as amoxicillin, doxycycline (for patients ≥8 years old and nonpregnant), or cefuroxime. Disseminated disease with mild neurologic involvement may be treated orally, while meningitis, significant carditis, or severe arthritis requires parenteral therapy, typically with ceftriaxone, cefotaxime, or penicillin G. Late disease usually requires prolonged parenteral therapy. NSAIDs are used for arthralgias and arthritis, and aspirin may be used adjunctively in cardiac involvement.
Disposition and follow-up
Hospital admission is required for patients with meningoencephalitis or significant cardiac involvement requiring telemetry or ICU monitoring. Patients with uncomplicated disease treated with oral antibiotics may be discharged with close outpatient follow-up.
Key points
Early recognition and treatment of Lyme disease prevent late complications. The presence of erythema migrans is diagnostic and should prompt immediate treatment without waiting for serology. Clinicians should remain vigilant for coinfections such as anaplasmosis and babesiosis in endemic regions, and prolonged treatment is required for later-stage organ involvement.
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Emergency and Acute Medicine – Lymphadenitis
Basics description
Lymphadenitis refers to inflammation and enlargement of lymph nodes, most commonly as part of a systemic response to infection. Nodes become engorged with lymphocytes and macrophages and may be secondarily involved from infection in a distal extremity, producing painful, tender adenopathy proximally. Acute suppurative lymphadenitis may follow pharyngeal or skin infections and can progress to abscess formation.
Etiology
Lymphadenitis is most frequently caused by bacterial infection. The most common organisms in pyogenic lymphadenitis are Staphylococcus aureus, including community-associated methicillin-resistant S. aureus (CA-MRSA), and group A β-hemolytic Streptococcus. CA-MRSA risk factors include prior MRSA infection, household exposure, military service, incarceration, contact sports, injection drug use, and men who have sex with men. Cervical lymphadenitis usually originates from pharyngeal or periodontal infections and commonly involves streptococci and anaerobes. Axillary lymphadenitis is often caused by group A streptococcus. Nosocomial MRSA should be suspected in patients with recent hospitalization, surgery, dialysis, vascular catheters, recent antibiotic use, or unresponsive infection. In children, acute unilateral cervical suppurative lymphadenitis is most common in those younger than six years and is typically caused by S. aureus, group A streptococcus, or anaerobes.
Diagnosis signs and symptoms
Patients typically present with painful swelling and inflammation of affected lymph nodes, often in association with cellulitis or abscess if the cause is pyogenic. Axillary lymphadenitis may present with fever, axillary pain, and acute lymphedema of the arm or chest and may be associated with ipsilateral pleural effusion. History should include duration of lymphadenopathy, pain, fever, night sweats, weight loss, fatigue, sore throat, cough, occupational and animal exposures, sexual history, drug use, and travel. Physical examination should assess whether lymphadenopathy is localized or generalized, node size, tenderness, overlying skin changes, presence of skin lesions, splenomegaly, and involvement of supraclavicular or scalene nodes, which is always abnormal.
Essential workup
Acute regional lymphadenitis is usually a clinical diagnosis and often part of a broader infectious syndrome such as cellulitis. History and physical examination should focus on identifying an infectious source.
Diagnosis tests and interpretation
Laboratory testing is not always required. A CBC may show leukocytosis with left shift or be normal. Serologic testing for EBV, CMV, HIV, or other pathogens should be guided by clinical suspicion. Ultrasound or CT imaging is indicated when patients fail to improve with therapy or when suppuration is suspected. Percutaneous needle aspiration or surgical drainage should be considered if abscess formation occurs or if there is poor clinical response.
Differential diagnosis
The differential diagnosis includes common infections such as adenovirus, scarlet fever, cat scratch disease, fungal infections, and herpes zoster, as well as unusual infections including sporotrichosis, diphtheria, plague, anthrax, typhoid, rubella, and West Nile virus. Sexually transmitted infections, systemic infections such as HIV, infectious mononucleosis, toxoplasmosis, tuberculosis, hepatitis, and dengue should be considered. Noninfectious causes include drug reactions, malignancy, rheumatologic disorders, and pediatric-specific conditions such as Kawasaki disease and PFAPA syndrome.
Treatment
Initial management includes ensuring airway, breathing, and circulation stability. Treatment is directed at the underlying cause and should account for local resistance patterns, including CA-MRSA prevalence. Outpatient therapy typically lasts 7–10 days and includes limb elevation, moist heat, analgesics, and antibiotics. Abscesses require drainage with culture when possible. Skin-source infections are commonly treated with oral cephalexin plus trimethoprim–sulfamethoxazole or alternatives such as clindamycin or doxycycline. Pharyngeal or periodontal sources are treated with penicillin VK or alternatives such as clindamycin or amoxicillin–clavulanate. Inpatient therapy may require IV penicillin-based regimens with MRSA coverage using vancomycin or clindamycin when indicated.
Disposition and follow-up
Admission is indicated for toxic-appearing patients, those with immunosuppression or significant comorbidities, inability to tolerate oral therapy, or unreliable follow-up. Patients with mild infection who are nontoxic, can take oral antibiotics, and have reliable follow-up within 24–48 hours may be discharged. Failure to resolve promptly with antibiotics should prompt evaluation for malignancy or other serious causes, and lymph node biopsy may be indicated for persistent, large, or supraclavicular nodes.
Pearls and pitfalls
Staphylococcus species are the most common cause of acute regional pyogenic lymphadenitis. Empiric antibiotic therapy should include coverage for CA-MRSA in addition to streptococci, particularly in unresponsive or high-risk infections.
Basics description
Lymphadenitis refers to inflammation and enlargement of lymph nodes, most commonly as part of a systemic response to infection. Nodes become engorged with lymphocytes and macrophages and may be secondarily involved from infection in a distal extremity, producing painful, tender adenopathy proximally. Acute suppurative lymphadenitis may follow pharyngeal or skin infections and can progress to abscess formation.
Etiology
Lymphadenitis is most frequently caused by bacterial infection. The most common organisms in pyogenic lymphadenitis are Staphylococcus aureus, including community-associated methicillin-resistant S. aureus (CA-MRSA), and group A β-hemolytic Streptococcus. CA-MRSA risk factors include prior MRSA infection, household exposure, military service, incarceration, contact sports, injection drug use, and men who have sex with men. Cervical lymphadenitis usually originates from pharyngeal or periodontal infections and commonly involves streptococci and anaerobes. Axillary lymphadenitis is often caused by group A streptococcus. Nosocomial MRSA should be suspected in patients with recent hospitalization, surgery, dialysis, vascular catheters, recent antibiotic use, or unresponsive infection. In children, acute unilateral cervical suppurative lymphadenitis is most common in those younger than six years and is typically caused by S. aureus, group A streptococcus, or anaerobes.
Diagnosis signs and symptoms
Patients typically present with painful swelling and inflammation of affected lymph nodes, often in association with cellulitis or abscess if the cause is pyogenic. Axillary lymphadenitis may present with fever, axillary pain, and acute lymphedema of the arm or chest and may be associated with ipsilateral pleural effusion. History should include duration of lymphadenopathy, pain, fever, night sweats, weight loss, fatigue, sore throat, cough, occupational and animal exposures, sexual history, drug use, and travel. Physical examination should assess whether lymphadenopathy is localized or generalized, node size, tenderness, overlying skin changes, presence of skin lesions, splenomegaly, and involvement of supraclavicular or scalene nodes, which is always abnormal.
Essential workup
Acute regional lymphadenitis is usually a clinical diagnosis and often part of a broader infectious syndrome such as cellulitis. History and physical examination should focus on identifying an infectious source.
Diagnosis tests and interpretation
Laboratory testing is not always required. A CBC may show leukocytosis with left shift or be normal. Serologic testing for EBV, CMV, HIV, or other pathogens should be guided by clinical suspicion. Ultrasound or CT imaging is indicated when patients fail to improve with therapy or when suppuration is suspected. Percutaneous needle aspiration or surgical drainage should be considered if abscess formation occurs or if there is poor clinical response.
Differential diagnosis
The differential diagnosis includes common infections such as adenovirus, scarlet fever, cat scratch disease, fungal infections, and herpes zoster, as well as unusual infections including sporotrichosis, diphtheria, plague, anthrax, typhoid, rubella, and West Nile virus. Sexually transmitted infections, systemic infections such as HIV, infectious mononucleosis, toxoplasmosis, tuberculosis, hepatitis, and dengue should be considered. Noninfectious causes include drug reactions, malignancy, rheumatologic disorders, and pediatric-specific conditions such as Kawasaki disease and PFAPA syndrome.
Treatment
Initial management includes ensuring airway, breathing, and circulation stability. Treatment is directed at the underlying cause and should account for local resistance patterns, including CA-MRSA prevalence. Outpatient therapy typically lasts 7–10 days and includes limb elevation, moist heat, analgesics, and antibiotics. Abscesses require drainage with culture when possible. Skin-source infections are commonly treated with oral cephalexin plus trimethoprim–sulfamethoxazole or alternatives such as clindamycin or doxycycline. Pharyngeal or periodontal sources are treated with penicillin VK or alternatives such as clindamycin or amoxicillin–clavulanate. Inpatient therapy may require IV penicillin-based regimens with MRSA coverage using vancomycin or clindamycin when indicated.
Disposition and follow-up
Admission is indicated for toxic-appearing patients, those with immunosuppression or significant comorbidities, inability to tolerate oral therapy, or unreliable follow-up. Patients with mild infection who are nontoxic, can take oral antibiotics, and have reliable follow-up within 24–48 hours may be discharged. Failure to resolve promptly with antibiotics should prompt evaluation for malignancy or other serious causes, and lymph node biopsy may be indicated for persistent, large, or supraclavicular nodes.
Pearls and pitfalls
Staphylococcus species are the most common cause of acute regional pyogenic lymphadenitis. Empiric antibiotic therapy should include coverage for CA-MRSA in addition to streptococci, particularly in unresponsive or high-risk infections.
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Emergency and Acute Medicine – Lymphangitis
Basics description
Lymphangitis is an infection of the lymphatic vessels that drain an area of inflammation or infection. Histologically, lymphatic channels become dilated and filled with lymphocytes and histiocytes. Inflammation often extends into surrounding perilymphatic tissues and may progress to cellulitis or abscess formation if untreated.
Etiology
Acute lymphangitis is most commonly caused by bacterial infection, particularly group A β-hemolytic Streptococcus. Less common causes include other streptococcal species and Staphylococcus aureus, including community-associated methicillin-resistant S. aureus (CA-MRSA). CA-MRSA risk factors include prior MRSA infection, close household contact, military service, incarceration, contact sports, injection drug use, and men who have sex with men. CA-MRSA is now prevalent enough to warrant empiric coverage in many settings, especially in unresponsive or recurrent infections. Other causes include Pasteurella multocida from animal bites, Spirillum minus in rat-bite fever, and Wuchereria bancrofti in filariasis, particularly in immigrants from endemic regions. Chronic lymphangitis is usually due to fungal, mycobacterial, or parasitic infections, most commonly Sporothrix schenckii, acquired through gardening or farming injuries, and Mycobacterium marinum, associated with fish tanks and swimming pools.
Diagnosis signs and symptoms
Acute lymphangitis presents with warm, tender, erythematous streaks extending proximally from a primary site of infection toward regional lymph nodes. Associated findings include painful lymphadenopathy, peripheral edema of the involved extremity, and systemic symptoms such as fever, rigors, tachycardia, and headache. Chronic nodular lymphangitis typically presents with painless erythematous nodules, chancriform ulcers, or wart-like lesions at the inoculation site, with possible progression along lymphatic channels and minimal systemic symptoms.
Essential workup
Lymphangitis is primarily a clinical diagnosis based on history and physical examination, with attention directed toward identifying the source of infection.
Diagnosis tests and interpretation
Laboratory testing is often unnecessary, though leukocytosis may be present. Gram stain and culture of aspirate or biopsy from the most inflamed area are recommended in cases of treatment failure or when resistant organisms such as MRSA are suspected. Culture confirmation is essential when sporotrichosis or M. marinum infection is considered. Blood cultures may be positive in severe cases. Imaging is rarely required but plain radiographs may help identify abscesses, subcutaneous gas, or foreign bodies, and Doppler ultrasound may be useful to exclude deep venous thrombosis.
Differential diagnosis
The differential diagnosis includes superficial or deep thrombophlebitis, which typically lacks an initial infectious focus or regional lymphadenopathy, IV line infiltration, vaccine-related reactions, and phytophotodermatitis, which can cause linear inflammatory skin changes mimicking lymphangitis.
Treatment
Initial management focuses on stabilizing septic patients with airway support and resuscitation as needed. Antimicrobial therapy should be initiated promptly, with the first dose given in the emergency department. Treatment typically lasts 7–10 days and includes limb elevation, moist heat, and antibiotics guided by local resistance patterns. Empiric outpatient therapy often includes oral cephalexin plus trimethoprim–sulfamethoxazole to cover CA-MRSA, with alternatives such as clindamycin or doxycycline. Inpatient therapy may require IV nafcillin or equivalent agents. Animal bite–associated lymphangitis is treated with IV ampicillin–sulbactam. Chronic infections require organism-specific therapy, such as itraconazole or potassium iodide for sporotrichosis and combination antimycobacterial therapy for M. marinum.
Disposition and follow-up
Admission is indicated for toxic-appearing patients, those with immunosuppression, significant comorbidities, inability to tolerate oral therapy, or unreliable follow-up. Patients with mild disease who are clinically stable and able to take oral antibiotics may be discharged with close follow-up within 24–48 hours. Marking the borders of erythema before discharge helps assess treatment response.
Pearls and pitfalls
Empiric antibiotic therapy should include coverage for CA-MRSA in addition to streptococcal species. Failure to recognize resistant organisms or chronic infectious causes can lead to treatment failure and progression of disease.
Basics description
Lymphangitis is an infection of the lymphatic vessels that drain an area of inflammation or infection. Histologically, lymphatic channels become dilated and filled with lymphocytes and histiocytes. Inflammation often extends into surrounding perilymphatic tissues and may progress to cellulitis or abscess formation if untreated.
Etiology
Acute lymphangitis is most commonly caused by bacterial infection, particularly group A β-hemolytic Streptococcus. Less common causes include other streptococcal species and Staphylococcus aureus, including community-associated methicillin-resistant S. aureus (CA-MRSA). CA-MRSA risk factors include prior MRSA infection, close household contact, military service, incarceration, contact sports, injection drug use, and men who have sex with men. CA-MRSA is now prevalent enough to warrant empiric coverage in many settings, especially in unresponsive or recurrent infections. Other causes include Pasteurella multocida from animal bites, Spirillum minus in rat-bite fever, and Wuchereria bancrofti in filariasis, particularly in immigrants from endemic regions. Chronic lymphangitis is usually due to fungal, mycobacterial, or parasitic infections, most commonly Sporothrix schenckii, acquired through gardening or farming injuries, and Mycobacterium marinum, associated with fish tanks and swimming pools.
Diagnosis signs and symptoms
Acute lymphangitis presents with warm, tender, erythematous streaks extending proximally from a primary site of infection toward regional lymph nodes. Associated findings include painful lymphadenopathy, peripheral edema of the involved extremity, and systemic symptoms such as fever, rigors, tachycardia, and headache. Chronic nodular lymphangitis typically presents with painless erythematous nodules, chancriform ulcers, or wart-like lesions at the inoculation site, with possible progression along lymphatic channels and minimal systemic symptoms.
Essential workup
Lymphangitis is primarily a clinical diagnosis based on history and physical examination, with attention directed toward identifying the source of infection.
Diagnosis tests and interpretation
Laboratory testing is often unnecessary, though leukocytosis may be present. Gram stain and culture of aspirate or biopsy from the most inflamed area are recommended in cases of treatment failure or when resistant organisms such as MRSA are suspected. Culture confirmation is essential when sporotrichosis or M. marinum infection is considered. Blood cultures may be positive in severe cases. Imaging is rarely required but plain radiographs may help identify abscesses, subcutaneous gas, or foreign bodies, and Doppler ultrasound may be useful to exclude deep venous thrombosis.
Differential diagnosis
The differential diagnosis includes superficial or deep thrombophlebitis, which typically lacks an initial infectious focus or regional lymphadenopathy, IV line infiltration, vaccine-related reactions, and phytophotodermatitis, which can cause linear inflammatory skin changes mimicking lymphangitis.
Treatment
Initial management focuses on stabilizing septic patients with airway support and resuscitation as needed. Antimicrobial therapy should be initiated promptly, with the first dose given in the emergency department. Treatment typically lasts 7–10 days and includes limb elevation, moist heat, and antibiotics guided by local resistance patterns. Empiric outpatient therapy often includes oral cephalexin plus trimethoprim–sulfamethoxazole to cover CA-MRSA, with alternatives such as clindamycin or doxycycline. Inpatient therapy may require IV nafcillin or equivalent agents. Animal bite–associated lymphangitis is treated with IV ampicillin–sulbactam. Chronic infections require organism-specific therapy, such as itraconazole or potassium iodide for sporotrichosis and combination antimycobacterial therapy for M. marinum.
Disposition and follow-up
Admission is indicated for toxic-appearing patients, those with immunosuppression, significant comorbidities, inability to tolerate oral therapy, or unreliable follow-up. Patients with mild disease who are clinically stable and able to take oral antibiotics may be discharged with close follow-up within 24–48 hours. Marking the borders of erythema before discharge helps assess treatment response.
Pearls and pitfalls
Empiric antibiotic therapy should include coverage for CA-MRSA in addition to streptococcal species. Failure to recognize resistant organisms or chronic infectious causes can lead to treatment failure and progression of disease.
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Emergency and Acute Medicine – Malaria
Basics description
Malaria is a protozoan infection transmitted through the bite of an infected female Anopheles mosquito. The incubation period is typically 8–16 days, although symptoms may be delayed for months depending on the species. The periodic nature of malaria symptoms reflects the parasite life cycle, which includes an exoerythrocytic phase in the liver followed by an erythrocytic phase in red blood cells. Fever corresponds to synchronous red blood cell lysis and release of merozoites into the circulation.
Pathophysiology and species differences
In the exoerythrocytic phase, sporozoites migrate to the liver and multiply into merozoites. These then enter the bloodstream and invade red blood cells, where replication leads to cell rupture every 48–72 hours. Plasmodium falciparum causes most severe disease and nearly all malaria-related deaths. It infects red blood cells of all ages, leading to profound hemolysis, anemia, and capillary obstruction with resultant end-organ hypoxia. Plasmodium vivax and Plasmodium ovale may cause relapsing disease due to dormant liver forms (hypnozoites), while Plasmodium malariae can persist at low levels in the bloodstream for decades.
Etiology and transmission
Transmission usually occurs via mosquito bite but may also result from blood transfusions or shared needles. Rare autochthonous transmission has been reported in North America due to the presence of Anopheles mosquitoes. Post-traumatic immunosuppression may precipitate relapse in individuals previously exposed in endemic regions. Children with sickle cell trait have partial protection, while pregnant patients—especially primigravidas—are at higher risk for severe disease.
Diagnosis signs and symptoms
Most patients become symptomatic within one year of exposure. Common symptoms include malaise, chills, fever greater than 38°C, myalgias, arthralgias, and orthostatic hypotension. The classic malaria paroxysm consists of chills followed by high fever and subsequent diaphoresis, although this pattern is uncommon in clinical practice. Hemolysis may lead to jaundice, dark urine (blackwater fever), anemia, and splenomegaly. Severe manifestations include cerebral malaria with headache, altered mental status, seizures, or coma; pulmonary edema; renal failure; abnormal bleeding; and circulatory collapse.
Essential workup and diagnostic testing
Diagnosis relies on oil immersion light microscopy of thick and thin Giemsa-stained blood smears, which demonstrate intraerythrocytic parasites. At least three negative smears over 48 hours are required to exclude malaria. Laboratory findings commonly include anemia, thrombocytopenia, leukocytopenia, elevated bilirubin and lactate dehydrogenase, electrolyte abnormalities, and evidence of renal or hepatic dysfunction. Chest radiography may reveal pulmonary edema. Advanced testing such as antigen detection assays or PCR can identify Plasmodium species and mixed infections. Lumbar puncture may be necessary to distinguish cerebral malaria from meningitis.
Differential diagnosis
The differential includes meningitis, encephalitis, sepsis, acute renal failure, viral hepatitis, acute hemolytic anemia, hypoglycemic coma, and heat stroke. In travelers or immigrants from endemic areas, malaria must be considered in any febrile illness.
Treatment and emergency management
Initial stabilization includes airway, breathing, and circulation management, isotonic fluid resuscitation for hypotension, active cooling for hyperthermia, and treatment of hypoglycemia or seizures as indicated. Antimalarial therapy depends on species, severity, and geographic resistance patterns, with artemisinin-based combination therapies recommended as first-line treatment worldwide. Severe P. falciparum infection requires intravenous artesunate. Supportive care for complications such as anemia, renal failure, and cerebral edema is critical.
Disposition and follow-up
ICU admission is indicated for severe P. falciparum malaria, high parasitemia, neurologic involvement, or inability to tolerate oral therapy. Patients with non–P. falciparum malaria who are clinically stable and able to take oral medications may be treated as outpatients with close follow-up.
Pearls and pitfalls
Malaria should always be considered in patients with fever and compatible exposure history, even months after travel. Fever patterns are unreliable, and early recognition is essential, as delays in treatment—especially with P. falciparum—are associated with high mortality.
Basics description
Malaria is a protozoan infection transmitted through the bite of an infected female Anopheles mosquito. The incubation period is typically 8–16 days, although symptoms may be delayed for months depending on the species. The periodic nature of malaria symptoms reflects the parasite life cycle, which includes an exoerythrocytic phase in the liver followed by an erythrocytic phase in red blood cells. Fever corresponds to synchronous red blood cell lysis and release of merozoites into the circulation.
Pathophysiology and species differences
In the exoerythrocytic phase, sporozoites migrate to the liver and multiply into merozoites. These then enter the bloodstream and invade red blood cells, where replication leads to cell rupture every 48–72 hours. Plasmodium falciparum causes most severe disease and nearly all malaria-related deaths. It infects red blood cells of all ages, leading to profound hemolysis, anemia, and capillary obstruction with resultant end-organ hypoxia. Plasmodium vivax and Plasmodium ovale may cause relapsing disease due to dormant liver forms (hypnozoites), while Plasmodium malariae can persist at low levels in the bloodstream for decades.
Etiology and transmission
Transmission usually occurs via mosquito bite but may also result from blood transfusions or shared needles. Rare autochthonous transmission has been reported in North America due to the presence of Anopheles mosquitoes. Post-traumatic immunosuppression may precipitate relapse in individuals previously exposed in endemic regions. Children with sickle cell trait have partial protection, while pregnant patients—especially primigravidas—are at higher risk for severe disease.
Diagnosis signs and symptoms
Most patients become symptomatic within one year of exposure. Common symptoms include malaise, chills, fever greater than 38°C, myalgias, arthralgias, and orthostatic hypotension. The classic malaria paroxysm consists of chills followed by high fever and subsequent diaphoresis, although this pattern is uncommon in clinical practice. Hemolysis may lead to jaundice, dark urine (blackwater fever), anemia, and splenomegaly. Severe manifestations include cerebral malaria with headache, altered mental status, seizures, or coma; pulmonary edema; renal failure; abnormal bleeding; and circulatory collapse.
Essential workup and diagnostic testing
Diagnosis relies on oil immersion light microscopy of thick and thin Giemsa-stained blood smears, which demonstrate intraerythrocytic parasites. At least three negative smears over 48 hours are required to exclude malaria. Laboratory findings commonly include anemia, thrombocytopenia, leukocytopenia, elevated bilirubin and lactate dehydrogenase, electrolyte abnormalities, and evidence of renal or hepatic dysfunction. Chest radiography may reveal pulmonary edema. Advanced testing such as antigen detection assays or PCR can identify Plasmodium species and mixed infections. Lumbar puncture may be necessary to distinguish cerebral malaria from meningitis.
Differential diagnosis
The differential includes meningitis, encephalitis, sepsis, acute renal failure, viral hepatitis, acute hemolytic anemia, hypoglycemic coma, and heat stroke. In travelers or immigrants from endemic areas, malaria must be considered in any febrile illness.
Treatment and emergency management
Initial stabilization includes airway, breathing, and circulation management, isotonic fluid resuscitation for hypotension, active cooling for hyperthermia, and treatment of hypoglycemia or seizures as indicated. Antimalarial therapy depends on species, severity, and geographic resistance patterns, with artemisinin-based combination therapies recommended as first-line treatment worldwide. Severe P. falciparum infection requires intravenous artesunate. Supportive care for complications such as anemia, renal failure, and cerebral edema is critical.
Disposition and follow-up
ICU admission is indicated for severe P. falciparum malaria, high parasitemia, neurologic involvement, or inability to tolerate oral therapy. Patients with non–P. falciparum malaria who are clinically stable and able to take oral medications may be treated as outpatients with close follow-up.
Pearls and pitfalls
Malaria should always be considered in patients with fever and compatible exposure history, even months after travel. Fever patterns are unreliable, and early recognition is essential, as delays in treatment—especially with P. falciparum—are associated with high mortality.
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Emergency and Acute Medicine – Mallory–Weiss Syndrome
Basics description
Mallory–Weiss syndrome is a partial-thickness, longitudinal mucosal tear of the distal esophagus or proximal stomach. It results from a sudden increase in intra-abdominal or transgastric pressure, leading to mild to moderate submucosal arterial or venous bleeding. Endoscopic observations suggest that transient “mushrooming” of the stomach into the esophagus during forceful retching contributes to tear formation. It accounts for approximately 5% of all cases of upper gastrointestinal bleeding.
Etiology and risk factors
The condition is most commonly associated with forceful vomiting or retching but may also occur with coughing, laughing, lifting, straining, blunt abdominal trauma, seizures, childbirth, or cardiopulmonary resuscitation. Alcohol use, particularly following binge drinking, and the presence of a hiatal hernia are significant risk factors. More severe bleeding is seen in patients with portal hypertension, esophageal varices, or underlying coagulopathy.
Diagnosis signs and symptoms
Patients typically report multiple episodes of nonbloody vomiting or retching followed by hematemesis. Most bleeding is self-limited, though severe or life-threatening hemorrhage can occur. Associated symptoms include epigastric or back pain and signs of volume depletion such as dizziness, light-headedness, or syncope. Physical examination may reveal hematemesis, melena, postural hypotension, or shock in severe cases.
Essential workup and diagnostic testing
Initial evaluation includes a complete blood count and rectal examination for occult blood. Additional laboratory studies include coagulation parameters, electrolytes, renal function tests, liver function tests, and type and cross-match if bleeding is significant. Upright chest radiography may be obtained to exclude esophageal or gastric perforation. Upper endoscopy is the diagnostic and therapeutic modality of choice, allowing direct visualization and management of the bleeding source.
Differential diagnosis
Conditions to consider include nasopharyngeal bleeding, hemoptysis, esophageal rupture (Boerhaave syndrome), esophagitis, gastritis, peptic ulcer disease, variceal bleeding, malignancy, and vascular-enteric fistula.
Treatment and emergency management
Initial management focuses on airway protection, oxygenation, and hemodynamic stabilization with large-bore intravenous access and fluid resuscitation. Blood transfusion is indicated for ongoing bleeding or hemodynamic instability. Most cases resolve with conservative therapy. Persistent or active bleeding requires urgent endoscopic intervention, which may include injection therapy, thermal coagulation, clipping, or band ligation. Proton pump inhibitors and antiemetics are used adjunctively. Surgical or angiographic intervention is reserved for refractory cases.
Disposition and follow-up
Patients with ongoing or massive hemorrhage, hemodynamic instability, significant comorbidities, or advanced age require ICU admission. Stable patients with minimal bleeding that has resolved and stable hematocrit may be admitted for observation or, in select cases, discharged with close follow-up and outpatient endoscopy.
Key points and cautions
Early placement of large-bore intravenous access and prompt resuscitation are critical in upper gastrointestinal bleeding. Early gastroenterology consultation is essential when bleeding is significant. Rebleeding most often occurs within the first 24 hours and is more likely in patients with coagulopathy or portal hypertension.
Basics description
Mallory–Weiss syndrome is a partial-thickness, longitudinal mucosal tear of the distal esophagus or proximal stomach. It results from a sudden increase in intra-abdominal or transgastric pressure, leading to mild to moderate submucosal arterial or venous bleeding. Endoscopic observations suggest that transient “mushrooming” of the stomach into the esophagus during forceful retching contributes to tear formation. It accounts for approximately 5% of all cases of upper gastrointestinal bleeding.
Etiology and risk factors
The condition is most commonly associated with forceful vomiting or retching but may also occur with coughing, laughing, lifting, straining, blunt abdominal trauma, seizures, childbirth, or cardiopulmonary resuscitation. Alcohol use, particularly following binge drinking, and the presence of a hiatal hernia are significant risk factors. More severe bleeding is seen in patients with portal hypertension, esophageal varices, or underlying coagulopathy.
Diagnosis signs and symptoms
Patients typically report multiple episodes of nonbloody vomiting or retching followed by hematemesis. Most bleeding is self-limited, though severe or life-threatening hemorrhage can occur. Associated symptoms include epigastric or back pain and signs of volume depletion such as dizziness, light-headedness, or syncope. Physical examination may reveal hematemesis, melena, postural hypotension, or shock in severe cases.
Essential workup and diagnostic testing
Initial evaluation includes a complete blood count and rectal examination for occult blood. Additional laboratory studies include coagulation parameters, electrolytes, renal function tests, liver function tests, and type and cross-match if bleeding is significant. Upright chest radiography may be obtained to exclude esophageal or gastric perforation. Upper endoscopy is the diagnostic and therapeutic modality of choice, allowing direct visualization and management of the bleeding source.
Differential diagnosis
Conditions to consider include nasopharyngeal bleeding, hemoptysis, esophageal rupture (Boerhaave syndrome), esophagitis, gastritis, peptic ulcer disease, variceal bleeding, malignancy, and vascular-enteric fistula.
Treatment and emergency management
Initial management focuses on airway protection, oxygenation, and hemodynamic stabilization with large-bore intravenous access and fluid resuscitation. Blood transfusion is indicated for ongoing bleeding or hemodynamic instability. Most cases resolve with conservative therapy. Persistent or active bleeding requires urgent endoscopic intervention, which may include injection therapy, thermal coagulation, clipping, or band ligation. Proton pump inhibitors and antiemetics are used adjunctively. Surgical or angiographic intervention is reserved for refractory cases.
Disposition and follow-up
Patients with ongoing or massive hemorrhage, hemodynamic instability, significant comorbidities, or advanced age require ICU admission. Stable patients with minimal bleeding that has resolved and stable hematocrit may be admitted for observation or, in select cases, discharged with close follow-up and outpatient endoscopy.
Key points and cautions
Early placement of large-bore intravenous access and prompt resuscitation are critical in upper gastrointestinal bleeding. Early gastroenterology consultation is essential when bleeding is significant. Rebleeding most often occurs within the first 24 hours and is more likely in patients with coagulopathy or portal hypertension.
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KembaraXtra-Medicine – Autoimmune Hemolytic Anemia
Autoimmune hemolytic anemia (AIHA) is a condition in which autoantibodies and/or complement bind to red blood cells (RBCs), leading to their premature destruction. About half of cases are primary (idiopathic), while the rest are secondary to underlying diseases or drugs. AIHA is commonly categorized into warm antibody–mediated disease (usually IgG, reacting best at 37°C), cold antibody–mediated disease (typically IgM with complement), and drug-induced immune hemolysis.
AIHA is uncommon, with an annual incidence of about 1 to 3 cases per 100,000 people and an estimated mortality around 10%. It is reported more often in women younger than 50 years. Patients most commonly present with fatigue and dyspnea. Pallor and jaundice may be present, and tachycardia with a flow murmur can occur when anemia is significant. Intravascular hemolysis may cause dark urine and back pain. Hepatomegaly or lymphadenopathy suggests a lymphoproliferative disorder or malignancy, while splenomegaly may suggest hypersplenism. The course is often chronic with relapses.
Warm AIHA is usually mediated by IgG antibodies and may be idiopathic or associated with leukemia/lymphoma, thymoma, myeloma, viral infections, babesiosis, and collagen-vascular diseases. Cold AIHA is commonly IgM- and complement-mediated and may be idiopathic or linked to infections, lymphoma, or cold agglutinin disease. Drug-induced AIHA can occur through different immune mechanisms, including antibodies directed against RBC antigens (e.g., methyldopa), antibodies against an RBC–drug complex (hapten type, e.g., penicillin), or immune complex mechanisms (e.g., quinidine).
The differential diagnosis includes non-immune causes of hemolysis such as microangiopathic hemolytic anemia (e.g., TTP/HUS), hypersplenism, prosthetic valve hemolysis, infections, toxins, and inherited causes such as membrane disorders (e.g., hereditary spherocytosis), hemoglobinopathies, and enzyme deficiencies (e.g., G6PD). Chronic lymphocytic leukemia (CLL) can cause a positive direct antiglobulin test (DAT) without true AIHA, so labs and clinical evidence of hemolysis are important.
Evaluation focuses on confirming hemolysis and establishing immune causation. Typical hemolysis findings include reticulocytosis (or reticulocytopenia if marrow suppression is present), low haptoglobin, elevated indirect bilirubin, and elevated LDH. Initial tests include CBC, reticulocyte count, bilirubin/LDH, and a peripheral smear (spherocytes are typical in warm AIHA). The key diagnostic test is the direct antiglobulin test (DAT/Coombs), performed initially with a polyspecific reagent to detect IgG and/or complement on RBCs. A positive DAT supports AIHA: IgG ± C3d suggests warm AIHA, while C3d alone suggests cold AIHA. Additional evaluation may include hepatitis serologies, HIV testing, ANA, urine testing for hemoglobinuria/hemosiderinuria, and imaging (such as CT chest/abdomen/pelvis) if an underlying lymphoproliferative disorder is suspected.
Management includes stopping any offending drug when drug-induced disease is possible. Severe, life-threatening cases may rarely require plasmapheresis or exchange transfusion. Patients with cold antibody AIHA should avoid cold exposure. Warm AIHA is typically treated first with prednisone 1 to 2 mg/kg/day, with tapering after response. Some evidence supports upfront combination therapy with steroids plus rituximab to improve outcomes and durability of response. For relapse or steroid-refractory disease, rituximab is commonly used and has high response rates, with a substantial portion maintaining remission years later. Splenectomy is now usually reserved for cases refractory to both steroids and rituximab, and further options include immunosuppressive agents such as mycophenolate, cyclosporine, cyclophosphamide, IVIG, and sometimes danazol as an adjunct.
Cold AIHA generally responds poorly to corticosteroids, and treating underlying infection or lymphoproliferative disease is important. In primary cold agglutinin disease, rituximab-based regimens (often with bendamustine in fit patients) are commonly used, while rituximab alone may be used in older or frailer patients. IVIG or plasmapheresis can be used temporarily in severe cases while waiting for a durable therapy to work. Complement-directed therapies may be considered in severe disease; sutimlimab (targeting C1s) has been shown to rapidly reduce hemolysis and improve hemoglobin and fatigue in cold agglutinin disease. Splenectomy is generally ineffective in cold AIHA because clearance occurs mainly in the liver.
Prognosis is generally good unless AIHA is driven by a serious underlying condition such as leukemia or myeloma. Hematology referral is recommended for all AIHA cases, and surgical referral may be needed if splenectomy is being considered for refractory warm AIHA.
Autoimmune hemolytic anemia (AIHA) is a condition in which autoantibodies and/or complement bind to red blood cells (RBCs), leading to their premature destruction. About half of cases are primary (idiopathic), while the rest are secondary to underlying diseases or drugs. AIHA is commonly categorized into warm antibody–mediated disease (usually IgG, reacting best at 37°C), cold antibody–mediated disease (typically IgM with complement), and drug-induced immune hemolysis.
AIHA is uncommon, with an annual incidence of about 1 to 3 cases per 100,000 people and an estimated mortality around 10%. It is reported more often in women younger than 50 years. Patients most commonly present with fatigue and dyspnea. Pallor and jaundice may be present, and tachycardia with a flow murmur can occur when anemia is significant. Intravascular hemolysis may cause dark urine and back pain. Hepatomegaly or lymphadenopathy suggests a lymphoproliferative disorder or malignancy, while splenomegaly may suggest hypersplenism. The course is often chronic with relapses.
Warm AIHA is usually mediated by IgG antibodies and may be idiopathic or associated with leukemia/lymphoma, thymoma, myeloma, viral infections, babesiosis, and collagen-vascular diseases. Cold AIHA is commonly IgM- and complement-mediated and may be idiopathic or linked to infections, lymphoma, or cold agglutinin disease. Drug-induced AIHA can occur through different immune mechanisms, including antibodies directed against RBC antigens (e.g., methyldopa), antibodies against an RBC–drug complex (hapten type, e.g., penicillin), or immune complex mechanisms (e.g., quinidine).
The differential diagnosis includes non-immune causes of hemolysis such as microangiopathic hemolytic anemia (e.g., TTP/HUS), hypersplenism, prosthetic valve hemolysis, infections, toxins, and inherited causes such as membrane disorders (e.g., hereditary spherocytosis), hemoglobinopathies, and enzyme deficiencies (e.g., G6PD). Chronic lymphocytic leukemia (CLL) can cause a positive direct antiglobulin test (DAT) without true AIHA, so labs and clinical evidence of hemolysis are important.
Evaluation focuses on confirming hemolysis and establishing immune causation. Typical hemolysis findings include reticulocytosis (or reticulocytopenia if marrow suppression is present), low haptoglobin, elevated indirect bilirubin, and elevated LDH. Initial tests include CBC, reticulocyte count, bilirubin/LDH, and a peripheral smear (spherocytes are typical in warm AIHA). The key diagnostic test is the direct antiglobulin test (DAT/Coombs), performed initially with a polyspecific reagent to detect IgG and/or complement on RBCs. A positive DAT supports AIHA: IgG ± C3d suggests warm AIHA, while C3d alone suggests cold AIHA. Additional evaluation may include hepatitis serologies, HIV testing, ANA, urine testing for hemoglobinuria/hemosiderinuria, and imaging (such as CT chest/abdomen/pelvis) if an underlying lymphoproliferative disorder is suspected.
Management includes stopping any offending drug when drug-induced disease is possible. Severe, life-threatening cases may rarely require plasmapheresis or exchange transfusion. Patients with cold antibody AIHA should avoid cold exposure. Warm AIHA is typically treated first with prednisone 1 to 2 mg/kg/day, with tapering after response. Some evidence supports upfront combination therapy with steroids plus rituximab to improve outcomes and durability of response. For relapse or steroid-refractory disease, rituximab is commonly used and has high response rates, with a substantial portion maintaining remission years later. Splenectomy is now usually reserved for cases refractory to both steroids and rituximab, and further options include immunosuppressive agents such as mycophenolate, cyclosporine, cyclophosphamide, IVIG, and sometimes danazol as an adjunct.
Cold AIHA generally responds poorly to corticosteroids, and treating underlying infection or lymphoproliferative disease is important. In primary cold agglutinin disease, rituximab-based regimens (often with bendamustine in fit patients) are commonly used, while rituximab alone may be used in older or frailer patients. IVIG or plasmapheresis can be used temporarily in severe cases while waiting for a durable therapy to work. Complement-directed therapies may be considered in severe disease; sutimlimab (targeting C1s) has been shown to rapidly reduce hemolysis and improve hemoglobin and fatigue in cold agglutinin disease. Splenectomy is generally ineffective in cold AIHA because clearance occurs mainly in the liver.
Prognosis is generally good unless AIHA is driven by a serious underlying condition such as leukemia or myeloma. Hematology referral is recommended for all AIHA cases, and surgical referral may be needed if splenectomy is being considered for refractory warm AIHA.
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KembaraXtra-Medicine – Autoimmune Polyendocrine Syndromes
Autoimmune polyendocrine syndrome (APS) refers to a group of disorders characterized by autoimmune-mediated functional impairment of multiple endocrine glands occurring in specific patterns. These conditions are also known as autoimmune polyglandular syndrome or autoimmune polyglandular failure and include autoimmune polyendocrine syndrome type 1 (APS-1) and type 2 (APS-2). The ICD-10-CM code for autoimmune polyglandular failure is E31.0.
APS-1 may occur at any stage of life but most commonly presents in early childhood or early adulthood. Clinical expression is highly variable, even among family members. Its estimated prevalence is about 1 in 100,000 in most countries, with much higher rates in genetically isolated populations such as Finland, Sardinia, and Persian Jewish communities. APS-2 is more common, with a prevalence ranging from 1 in 1,000 to 1 in 20,000. It predominantly affects women and usually presents between 20 and 40 years of age. Rare cases of APS-2 have been reported following treatment with immune checkpoint inhibitors.
Genetically, APS-1 is most often a monogenic disorder inherited in an autosomal recessive pattern, although autosomal dominant cases have been reported due to dominant-negative mutations of the AIRE gene. APS-2 has a polygenic inheritance pattern with heterogeneous clinical expression resulting from interactions between multiple genetic loci and environmental factors.
APS-1 is defined by the presence of at least two of three major features: hypoparathyroidism, chronic mucocutaneous candidiasis, and primary adrenal insufficiency. Hypoparathyroidism is the most common endocrine manifestation, while chronic mucocutaneous candidiasis is often the first clinical feature to appear. Primary hypogonadism is also common. Other associated features include enamel hypoplasia, bilateral keratitis, autoimmune hepatitis, pneumonitis, nephritis, and functional asplenia. Most patients present by five years of age, with nonendocrine manifestations often preceding endocrine disease. On average, individuals develop four to five associated disorders, with diabetes mellitus usually occurring later in the disease course.
APS-2 is characterized by the triad of autoimmune adrenal insufficiency, autoimmune thyroid disease, and type 1 diabetes mellitus, with adrenal insufficiency required for diagnosis. It typically presents later than APS-1, most often between 20 and 40 years of age. APS-3 differs in that adrenal insufficiency is absent; patients have autoimmune thyroid disease along with other autoimmune conditions such as type 1 diabetes, atrophic gastritis, pernicious anemia, alopecia, vitiligo, or myasthenia gravis.
Individual endocrine disorders present with characteristic clinical features. Hypocalcemia from primary hypoparathyroidism may cause tetany, perioral paresthesias, prolonged QT interval, basal ganglia calcifications, seizures, and arrhythmias. Autoimmune hypothyroidism commonly presents with fatigue, weight gain, constipation, cold intolerance, menstrual irregularities, and hair or nail changes, with myxedema coma representing the most severe manifestation. Autoimmune adrenal insufficiency may present with weight loss, fatigue, nausea, anorexia, malaise, and skin hyperpigmentation, while adrenal crisis can cause hypotension, nausea, and vomiting. Type 1 diabetes mellitus typically presents with polyuria, polydipsia, and weight loss, with diabetic ketoacidosis being the most life-threatening complication. Hypogonadism may manifest as low libido and fatigue in males or oligomenorrhea in females.
The etiology of APS-1 involves inactivating mutations of the autoimmune regulator (AIRE) gene on chromosome 21, leading to defective negative selection of autoreactive T cells and impaired regulatory T-cell function. APS-2 is associated with mutations in the human leukocyte antigen (HLA) complex on chromosome 6, along with other immune regulatory genes, resulting in lymphocytic infiltration and organ-specific autoimmunity.
Diagnosis is often delayed due to the variable and sequential nature of disease manifestations. Rarely do adrenal, thyroid, and pancreatic endocrine disorders develop simultaneously. Once one autoimmune endocrinopathy is identified, regular screening for additional autoimmune conditions is essential. Hypoparathyroidism is diagnosed by low calcium levels with low or inappropriately normal parathyroid hormone levels, after correcting hypomagnesemia if present. Autoimmune hypothyroidism is diagnosed by elevated thyroid-stimulating hormone levels and may be supported by thyroid autoantibodies. Autoimmune adrenal insufficiency is diagnosed by low cortisol levels or inadequate response to cosyntropin stimulation, with elevated ACTH levels and possible electrolyte abnormalities; anti–21-hydroxylase antibodies may be present. Autoimmune hypogonadism is diagnosed by low sex hormone levels with elevated gonadotropins. Type 1 diabetes mellitus is diagnosed by elevated glucose or hemoglobin A1c levels, with diabetes-related autoantibodies often present.
Acute management focuses on life-threatening complications. Chronic mucocutaneous candidiasis requires antifungal therapy, good oral hygiene, and smoking cessation. Severe hypocalcemia is treated with intravenous calcium followed by oral calcium and calcitriol. Myxedema coma requires intravenous thyroid hormone, glucocorticoids, and intensive supportive care. Diabetic ketoacidosis is managed with intravenous fluids, insulin, and electrolyte correction. Suspected adrenal crisis must be treated immediately with intravenous hydrocortisone and volume resuscitation without waiting for laboratory confirmation.
Chronic management centers on lifelong hormone replacement and surveillance for new autoimmune conditions. Hypoparathyroidism is treated with calcitriol and calcium supplementation, with thiazide diuretics used for hypercalciuria and parathyroid hormone replacement reserved for refractory cases. Autoimmune hypothyroidism is treated with oral levothyroxine, ensuring adrenal insufficiency is excluded or treated first. Primary adrenal insufficiency requires glucocorticoid and mineralocorticoid replacement, sick-day education, emergency hydrocortisone access, and medical alert identification. Type 1 diabetes mellitus requires insulin therapy. Primary hypogonadism is treated with sex hormone replacement appropriate to patient anatomy. In APS-1 patients presenting initially with chronic mucocutaneous candidiasis, regular screening for adrenal insufficiency is recommended.
Because disease components accumulate over time, management should be coordinated by a multidisciplinary team led by an endocrinologist. Patient education is essential so individuals can recognize early symptoms of additional autoimmune conditions. APS is frequently diagnosed late due to its heterogeneous presentation, and once one disorder is identified, systematic screening for associated autoimmune diseases should be initiated. All siblings of patients with APS-1 should undergo genetic testing or regular clinical screening, and long-term follow-up is critical for optimizing outcomes.
Autoimmune polyendocrine syndrome (APS) refers to a group of disorders characterized by autoimmune-mediated functional impairment of multiple endocrine glands occurring in specific patterns. These conditions are also known as autoimmune polyglandular syndrome or autoimmune polyglandular failure and include autoimmune polyendocrine syndrome type 1 (APS-1) and type 2 (APS-2). The ICD-10-CM code for autoimmune polyglandular failure is E31.0.
APS-1 may occur at any stage of life but most commonly presents in early childhood or early adulthood. Clinical expression is highly variable, even among family members. Its estimated prevalence is about 1 in 100,000 in most countries, with much higher rates in genetically isolated populations such as Finland, Sardinia, and Persian Jewish communities. APS-2 is more common, with a prevalence ranging from 1 in 1,000 to 1 in 20,000. It predominantly affects women and usually presents between 20 and 40 years of age. Rare cases of APS-2 have been reported following treatment with immune checkpoint inhibitors.
Genetically, APS-1 is most often a monogenic disorder inherited in an autosomal recessive pattern, although autosomal dominant cases have been reported due to dominant-negative mutations of the AIRE gene. APS-2 has a polygenic inheritance pattern with heterogeneous clinical expression resulting from interactions between multiple genetic loci and environmental factors.
APS-1 is defined by the presence of at least two of three major features: hypoparathyroidism, chronic mucocutaneous candidiasis, and primary adrenal insufficiency. Hypoparathyroidism is the most common endocrine manifestation, while chronic mucocutaneous candidiasis is often the first clinical feature to appear. Primary hypogonadism is also common. Other associated features include enamel hypoplasia, bilateral keratitis, autoimmune hepatitis, pneumonitis, nephritis, and functional asplenia. Most patients present by five years of age, with nonendocrine manifestations often preceding endocrine disease. On average, individuals develop four to five associated disorders, with diabetes mellitus usually occurring later in the disease course.
APS-2 is characterized by the triad of autoimmune adrenal insufficiency, autoimmune thyroid disease, and type 1 diabetes mellitus, with adrenal insufficiency required for diagnosis. It typically presents later than APS-1, most often between 20 and 40 years of age. APS-3 differs in that adrenal insufficiency is absent; patients have autoimmune thyroid disease along with other autoimmune conditions such as type 1 diabetes, atrophic gastritis, pernicious anemia, alopecia, vitiligo, or myasthenia gravis.
Individual endocrine disorders present with characteristic clinical features. Hypocalcemia from primary hypoparathyroidism may cause tetany, perioral paresthesias, prolonged QT interval, basal ganglia calcifications, seizures, and arrhythmias. Autoimmune hypothyroidism commonly presents with fatigue, weight gain, constipation, cold intolerance, menstrual irregularities, and hair or nail changes, with myxedema coma representing the most severe manifestation. Autoimmune adrenal insufficiency may present with weight loss, fatigue, nausea, anorexia, malaise, and skin hyperpigmentation, while adrenal crisis can cause hypotension, nausea, and vomiting. Type 1 diabetes mellitus typically presents with polyuria, polydipsia, and weight loss, with diabetic ketoacidosis being the most life-threatening complication. Hypogonadism may manifest as low libido and fatigue in males or oligomenorrhea in females.
The etiology of APS-1 involves inactivating mutations of the autoimmune regulator (AIRE) gene on chromosome 21, leading to defective negative selection of autoreactive T cells and impaired regulatory T-cell function. APS-2 is associated with mutations in the human leukocyte antigen (HLA) complex on chromosome 6, along with other immune regulatory genes, resulting in lymphocytic infiltration and organ-specific autoimmunity.
Diagnosis is often delayed due to the variable and sequential nature of disease manifestations. Rarely do adrenal, thyroid, and pancreatic endocrine disorders develop simultaneously. Once one autoimmune endocrinopathy is identified, regular screening for additional autoimmune conditions is essential. Hypoparathyroidism is diagnosed by low calcium levels with low or inappropriately normal parathyroid hormone levels, after correcting hypomagnesemia if present. Autoimmune hypothyroidism is diagnosed by elevated thyroid-stimulating hormone levels and may be supported by thyroid autoantibodies. Autoimmune adrenal insufficiency is diagnosed by low cortisol levels or inadequate response to cosyntropin stimulation, with elevated ACTH levels and possible electrolyte abnormalities; anti–21-hydroxylase antibodies may be present. Autoimmune hypogonadism is diagnosed by low sex hormone levels with elevated gonadotropins. Type 1 diabetes mellitus is diagnosed by elevated glucose or hemoglobin A1c levels, with diabetes-related autoantibodies often present.
Acute management focuses on life-threatening complications. Chronic mucocutaneous candidiasis requires antifungal therapy, good oral hygiene, and smoking cessation. Severe hypocalcemia is treated with intravenous calcium followed by oral calcium and calcitriol. Myxedema coma requires intravenous thyroid hormone, glucocorticoids, and intensive supportive care. Diabetic ketoacidosis is managed with intravenous fluids, insulin, and electrolyte correction. Suspected adrenal crisis must be treated immediately with intravenous hydrocortisone and volume resuscitation without waiting for laboratory confirmation.
Chronic management centers on lifelong hormone replacement and surveillance for new autoimmune conditions. Hypoparathyroidism is treated with calcitriol and calcium supplementation, with thiazide diuretics used for hypercalciuria and parathyroid hormone replacement reserved for refractory cases. Autoimmune hypothyroidism is treated with oral levothyroxine, ensuring adrenal insufficiency is excluded or treated first. Primary adrenal insufficiency requires glucocorticoid and mineralocorticoid replacement, sick-day education, emergency hydrocortisone access, and medical alert identification. Type 1 diabetes mellitus requires insulin therapy. Primary hypogonadism is treated with sex hormone replacement appropriate to patient anatomy. In APS-1 patients presenting initially with chronic mucocutaneous candidiasis, regular screening for adrenal insufficiency is recommended.
Because disease components accumulate over time, management should be coordinated by a multidisciplinary team led by an endocrinologist. Patient education is essential so individuals can recognize early symptoms of additional autoimmune conditions. APS is frequently diagnosed late due to its heterogeneous presentation, and once one disorder is identified, systematic screening for associated autoimmune diseases should be initiated. All siblings of patients with APS-1 should undergo genetic testing or regular clinical screening, and long-term follow-up is critical for optimizing outcomes.
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KembaraXtra-Medicine – Autoimmune Hepatitis
Autoimmune hepatitis (AIH) is an immune-mediated inflammatory liver disease marked by elevated serum gamma globulins (especially IgG), characteristic circulating autoantibodies, and typical biopsy findings of interface hepatitis with plasma cell–rich inflammation, after other causes of hepatitis have been excluded. There are two main types. Type 1 AIH is the most common worldwide (about 90%) and can occur at any age; it is often associated with antinuclear antibodies (ANA) and/or smooth muscle antibodies (SMA), and sometimes anti–soluble liver antigen (anti-SLA) or anti–liver-pancreas (anti-LP) antibodies. Type 2 AIH is less common (up to 10%), mainly affects children and young adolescents, and is typically associated with anti-LKM-1 or anti-LC1 antibodies, while ANA and SMA are usually absent; it often presents more acutely and may be harder to treat, with frequent relapse requiring long-term maintenance therapy.
AIH is more common in females and can occur across all ethnicities and age groups. In the United States, prevalence is estimated around 31 per 100,000 people, and globally incidence is roughly 0.9 to 2 cases per 100,000 people per year, with prevalence estimates ranging widely. Type 1 AIH has a bimodal peak (around puberty and again in mid-to-late adulthood), while type 2 is more common from ages 2 to 14. AIH accounts for a small but important portion of liver transplants in the U.S. (about 4% to 6%).
The exact cause is unknown, but AIH is thought to result from genetic susceptibility plus an environmental trigger. A leading theory involves a T-cell–mediated immune attack on hepatocytes, possibly related to reduced or dysfunctional regulatory T cells; humoral immunity also appears involved given the range of autoantibodies. Proposed triggers include viral infections (hepatitis A, B, C) and medications (such as minocycline, nitrofurantoin, biologics, and TNF inhibitors). Certain HLA haplotypes are associated with increased risk, including HLA-DR3 and DR4 in type 1 AIH and HLA-DR3 and DR7 in type 2.
Clinical presentation is broad, ranging from asymptomatic liver enzyme elevations to cirrhosis or fulminant liver failure. Symptoms may include fatigue, anorexia, nausea, abdominal pain, pruritus, and arthralgias. Some patients have other autoimmune features such as arthritis, dry mouth, eye irritation (keratoconjunctivitis), vasculitis, or erythema nodosum. Advanced disease can present with hepatosplenomegaly, ascites, peripheral edema, easy bruising/bleeding, and jaundice.
Diagnosis is based on a combination of laboratory evidence of liver injury, elevated IgG or hypergammaglobulinemia, characteristic autoantibodies, and compatible liver histology, while excluding other causes of hepatitis. Both major liver societies (EASL and AASLD) require a liver biopsy to establish diagnosis. Histology is suggestive rather than pathognomonic, with findings such as lymphoplasmacytic infiltrates crossing the limiting plate (interface hepatitis), periportal inflammation/necrosis, rosetting of hepatocytes, and emperipolesis. If cholestatic features are present, primary biliary cholangitis and primary sclerosing cholangitis should be evaluated; MRCP is recommended in adults with cholestatic lab changes and in all children with AIH, with ERCP considered if MRCP is nondiagnostic.
Workup includes history and exam (including screening for other autoimmune diseases), liver function tests and serum gamma globulins/IgG, and autoantibody testing (ANA, SMA/ASMA, anti-LKM, anti-SLA/LP). Aminotransferases are usually elevated (often ALT > AST) and may fluctuate; bilirubin and alkaline phosphatase may be normal or moderately elevated. IgG is elevated in about 90% of patients. Ultrasound is commonly used to rule out obstruction or mass, and MRCP is used when cholestasis suggests overlap disease. Patients with AIH-related cirrhosis should undergo hepatocellular carcinoma surveillance (typically ultrasound and AFP every 6 months).
Treatment includes avoiding alcohol and hepatotoxic medications, and considering liver transplantation for fulminant liver failure or end-stage disease. Steroids are the cornerstone: prednisone/prednisolone is commonly started at 0.5 to 1 mg/kg/day (often up to 60 mg/day) for induction. Azathioprine can be started at the same time or about 2 weeks later (often beginning at 50 mg/day and titrating up to 1 to 2 mg/kg/day depending on response and toxicity). In noncirrhotic AIH, budesonide (6 to 9 mg/day) plus azathioprine can be used to induce and maintain remission with fewer systemic steroid side effects; budesonide should not be used in cirrhosis due to reduced first-pass metabolism and increased systemic effects. Steroids may be avoided or used cautiously in brittle diabetes, uncontrolled hypertension, severe osteopenia, psychosis, or prior severe intolerance, while azathioprine is contraindicated in TPMT deficiency and significant cytopenias. Alternatives for azathioprine intolerance include 6-mercaptopurine and mycophenolate mofetil, and other second-line options (e.g., calcineurin inhibitors, sirolimus/everolimus, rituximab, infliximab) have been used in select refractory cases.
Treatment response is monitored with symptoms and normalization of liver tests, but biopsy activity can lag behind lab improvement by up to 6 months. Because relapse is common after withdrawal (often requiring long-term maintenance therapy), repeat biopsy is often considered before stopping therapy. Persistent interface hepatitis on biopsy is associated with very high relapse risk, and multiple relapses are linked with a higher chance of cirrhosis, so repeated attempts at withdrawal are generally discouraged. Acute severe AIH should be treated early with high-dose corticosteroids, and if there is no improvement within about 7 days, urgent transplant evaluation is recommended; acute liver failure presentations should be evaluated directly for transplantation.
Long-term outlook is generally good with treatment: many patients achieve remission within 18 months to 3 years, but a minority do not respond to standard therapy. Patients with decompensated cirrhosis, acute liver failure, hepatocellular carcinoma, or progression despite therapy should be referred for liver transplant evaluation.
Autoimmune hepatitis (AIH) is an immune-mediated inflammatory liver disease marked by elevated serum gamma globulins (especially IgG), characteristic circulating autoantibodies, and typical biopsy findings of interface hepatitis with plasma cell–rich inflammation, after other causes of hepatitis have been excluded. There are two main types. Type 1 AIH is the most common worldwide (about 90%) and can occur at any age; it is often associated with antinuclear antibodies (ANA) and/or smooth muscle antibodies (SMA), and sometimes anti–soluble liver antigen (anti-SLA) or anti–liver-pancreas (anti-LP) antibodies. Type 2 AIH is less common (up to 10%), mainly affects children and young adolescents, and is typically associated with anti-LKM-1 or anti-LC1 antibodies, while ANA and SMA are usually absent; it often presents more acutely and may be harder to treat, with frequent relapse requiring long-term maintenance therapy.
AIH is more common in females and can occur across all ethnicities and age groups. In the United States, prevalence is estimated around 31 per 100,000 people, and globally incidence is roughly 0.9 to 2 cases per 100,000 people per year, with prevalence estimates ranging widely. Type 1 AIH has a bimodal peak (around puberty and again in mid-to-late adulthood), while type 2 is more common from ages 2 to 14. AIH accounts for a small but important portion of liver transplants in the U.S. (about 4% to 6%).
The exact cause is unknown, but AIH is thought to result from genetic susceptibility plus an environmental trigger. A leading theory involves a T-cell–mediated immune attack on hepatocytes, possibly related to reduced or dysfunctional regulatory T cells; humoral immunity also appears involved given the range of autoantibodies. Proposed triggers include viral infections (hepatitis A, B, C) and medications (such as minocycline, nitrofurantoin, biologics, and TNF inhibitors). Certain HLA haplotypes are associated with increased risk, including HLA-DR3 and DR4 in type 1 AIH and HLA-DR3 and DR7 in type 2.
Clinical presentation is broad, ranging from asymptomatic liver enzyme elevations to cirrhosis or fulminant liver failure. Symptoms may include fatigue, anorexia, nausea, abdominal pain, pruritus, and arthralgias. Some patients have other autoimmune features such as arthritis, dry mouth, eye irritation (keratoconjunctivitis), vasculitis, or erythema nodosum. Advanced disease can present with hepatosplenomegaly, ascites, peripheral edema, easy bruising/bleeding, and jaundice.
Diagnosis is based on a combination of laboratory evidence of liver injury, elevated IgG or hypergammaglobulinemia, characteristic autoantibodies, and compatible liver histology, while excluding other causes of hepatitis. Both major liver societies (EASL and AASLD) require a liver biopsy to establish diagnosis. Histology is suggestive rather than pathognomonic, with findings such as lymphoplasmacytic infiltrates crossing the limiting plate (interface hepatitis), periportal inflammation/necrosis, rosetting of hepatocytes, and emperipolesis. If cholestatic features are present, primary biliary cholangitis and primary sclerosing cholangitis should be evaluated; MRCP is recommended in adults with cholestatic lab changes and in all children with AIH, with ERCP considered if MRCP is nondiagnostic.
Workup includes history and exam (including screening for other autoimmune diseases), liver function tests and serum gamma globulins/IgG, and autoantibody testing (ANA, SMA/ASMA, anti-LKM, anti-SLA/LP). Aminotransferases are usually elevated (often ALT > AST) and may fluctuate; bilirubin and alkaline phosphatase may be normal or moderately elevated. IgG is elevated in about 90% of patients. Ultrasound is commonly used to rule out obstruction or mass, and MRCP is used when cholestasis suggests overlap disease. Patients with AIH-related cirrhosis should undergo hepatocellular carcinoma surveillance (typically ultrasound and AFP every 6 months).
Treatment includes avoiding alcohol and hepatotoxic medications, and considering liver transplantation for fulminant liver failure or end-stage disease. Steroids are the cornerstone: prednisone/prednisolone is commonly started at 0.5 to 1 mg/kg/day (often up to 60 mg/day) for induction. Azathioprine can be started at the same time or about 2 weeks later (often beginning at 50 mg/day and titrating up to 1 to 2 mg/kg/day depending on response and toxicity). In noncirrhotic AIH, budesonide (6 to 9 mg/day) plus azathioprine can be used to induce and maintain remission with fewer systemic steroid side effects; budesonide should not be used in cirrhosis due to reduced first-pass metabolism and increased systemic effects. Steroids may be avoided or used cautiously in brittle diabetes, uncontrolled hypertension, severe osteopenia, psychosis, or prior severe intolerance, while azathioprine is contraindicated in TPMT deficiency and significant cytopenias. Alternatives for azathioprine intolerance include 6-mercaptopurine and mycophenolate mofetil, and other second-line options (e.g., calcineurin inhibitors, sirolimus/everolimus, rituximab, infliximab) have been used in select refractory cases.
Treatment response is monitored with symptoms and normalization of liver tests, but biopsy activity can lag behind lab improvement by up to 6 months. Because relapse is common after withdrawal (often requiring long-term maintenance therapy), repeat biopsy is often considered before stopping therapy. Persistent interface hepatitis on biopsy is associated with very high relapse risk, and multiple relapses are linked with a higher chance of cirrhosis, so repeated attempts at withdrawal are generally discouraged. Acute severe AIH should be treated early with high-dose corticosteroids, and if there is no improvement within about 7 days, urgent transplant evaluation is recommended; acute liver failure presentations should be evaluated directly for transplantation.
Long-term outlook is generally good with treatment: many patients achieve remission within 18 months to 3 years, but a minority do not respond to standard therapy. Patients with decompensated cirrhosis, acute liver failure, hepatocellular carcinoma, or progression despite therapy should be referred for liver transplant evaluation.
- Published on
KembaraXtra-Medicine – Intestinal Malrotation
Intestinal malrotation is a congenital condition resulting from incomplete rotation and fixation of the intestine during embryogenesis, specifically during the transition from the extracolonic position around the tenth week of gestation. It is commonly associated with heterotaxia syndromes and frequently occurs alongside other congenital anomalies. Gastrointestinal associations include duodenal stenosis or atresia, duodenal web, Meckel diverticulum, intussusception, gastroesophageal reflux, omphalocele, gastroschisis, congenital diaphragmatic hernia, abdominal wall defects, and Hirschsprung disease. Congenital cardiac anomalies are present in approximately 27% of patients and significantly increase morbidity.
The underlying pathology involves abnormal positioning of the duodenojejunal junction, which remains to the right of the midline, and malposition of the cecum, which is often located in the upper left abdomen with abnormal mesenteric attachments. This abnormal anatomy predisposes patients to bowel obstruction and volvulus. Midgut volvulus is a serious complication that occurs when the small intestine twists around the superior mesenteric artery and vein, leading to vascular compromise and potential bowel ischemia. Malrotation is found in combination with other congenital anomalies in up to 70% of cases, particularly involving the cardiac, esophageal, urinary, and anorectal systems.
Malrotation occurs in approximately 1 in 500 live births. It is more common in males, with a male-to-female ratio of 2:1 in neonates. About 75% of cases are diagnosed during the newborn period, and 90% are identified by one year of age, although presentation can occur in adulthood. Mortality in infants can be as high as 24%, and the presence of necrotic bowel at surgery increases mortality risk significantly.
Clinical presentation varies by age. Neonates typically present with bilious vomiting, abdominal distention, bloody stools, constipation or obstipation, feeding difficulties, and poor weight gain. Infants and children older than one year may present with abdominal pain followed by bilious emesis. Older children and adolescents often experience chronic vomiting, intermittent colicky abdominal pain, diarrhea, hematemesis, or constipation. Adults usually present with vague and nonspecific gastrointestinal symptoms. Notably, up to 75% of patients may have a normal physical examination at presentation. Severe cases may show signs of dehydration, metabolic acidosis, peritonitis, ischemic bowel, sepsis, or shock.
Diagnosis is suggested by clinical history and physical examination and is confirmed through imaging, most commonly contrast radiography. Laboratory evaluation includes complete blood count, venous blood gas, electrolytes, renal function tests, glucose, coagulation profile, lactate, and type and screen. Plain abdominal radiographs are diagnostic in fewer than 30% of cases but may show signs suggestive of volvulus, such as duodenal obstruction, gastric distention, paucity of distal bowel gas, generalized small-bowel distention, or a double-bubble sign. Upper gastrointestinal contrast studies are the diagnostic test of choice, with high sensitivity and accuracy, demonstrating abnormal position of the duodenojejunal junction, corkscrew appearance of the duodenum in volvulus, or right-sided jejunum. Contrast enema may help identify cecal position but has a significant false-negative rate. Ultrasound can demonstrate abnormal superior mesenteric artery–vein relationships and the classic whirlpool sign in volvulus, although a normal study does not exclude malrotation. CT imaging is generally reserved for adults.
Differential diagnosis depends on age and presentation. In early life, considerations include Hirschsprung disease, necrotizing enterocolitis, and intussusception. In children with acute abdominal pain and peritoneal signs, appendicitis and sepsis must be considered. Older children and adults with chronic or vague symptoms may be misdiagnosed with irritable bowel syndrome, peptic ulcer disease, biliary or pancreatic disorders, or psychiatric conditions.
Management of malrotation, particularly with midgut volvulus, is a surgical emergency. Initial stabilization focuses on airway, breathing, and circulation, with rapid intravenous fluid resuscitation to correct hypovolemia and metabolic acidosis. Broad-spectrum antibiotics are initiated if there are signs of sepsis or peritonitis. Nasogastric decompression and prompt surgical consultation are essential. Definitive treatment involves emergent surgical correction, including detorsion of the volvulus, restoration of intestinal perfusion, resection of necrotic bowel if present, and reassessment of bowel viability when necessary. Patients are kept nil per os and require close postoperative monitoring.
Hospital admission is indicated for acute abdomen, need for surgical intervention, significant dehydration, acidosis, sepsis, or shock. Discharge is uncommon and reserved for stable, asymptomatic patients with incidental findings after thorough pediatric surgical evaluation. Early recognition, rapid resuscitation, and timely referral to a facility with pediatric surgical expertise are critical to improving outcomes and reducing morbidity and mortality.
Intestinal malrotation is a congenital condition resulting from incomplete rotation and fixation of the intestine during embryogenesis, specifically during the transition from the extracolonic position around the tenth week of gestation. It is commonly associated with heterotaxia syndromes and frequently occurs alongside other congenital anomalies. Gastrointestinal associations include duodenal stenosis or atresia, duodenal web, Meckel diverticulum, intussusception, gastroesophageal reflux, omphalocele, gastroschisis, congenital diaphragmatic hernia, abdominal wall defects, and Hirschsprung disease. Congenital cardiac anomalies are present in approximately 27% of patients and significantly increase morbidity.
The underlying pathology involves abnormal positioning of the duodenojejunal junction, which remains to the right of the midline, and malposition of the cecum, which is often located in the upper left abdomen with abnormal mesenteric attachments. This abnormal anatomy predisposes patients to bowel obstruction and volvulus. Midgut volvulus is a serious complication that occurs when the small intestine twists around the superior mesenteric artery and vein, leading to vascular compromise and potential bowel ischemia. Malrotation is found in combination with other congenital anomalies in up to 70% of cases, particularly involving the cardiac, esophageal, urinary, and anorectal systems.
Malrotation occurs in approximately 1 in 500 live births. It is more common in males, with a male-to-female ratio of 2:1 in neonates. About 75% of cases are diagnosed during the newborn period, and 90% are identified by one year of age, although presentation can occur in adulthood. Mortality in infants can be as high as 24%, and the presence of necrotic bowel at surgery increases mortality risk significantly.
Clinical presentation varies by age. Neonates typically present with bilious vomiting, abdominal distention, bloody stools, constipation or obstipation, feeding difficulties, and poor weight gain. Infants and children older than one year may present with abdominal pain followed by bilious emesis. Older children and adolescents often experience chronic vomiting, intermittent colicky abdominal pain, diarrhea, hematemesis, or constipation. Adults usually present with vague and nonspecific gastrointestinal symptoms. Notably, up to 75% of patients may have a normal physical examination at presentation. Severe cases may show signs of dehydration, metabolic acidosis, peritonitis, ischemic bowel, sepsis, or shock.
Diagnosis is suggested by clinical history and physical examination and is confirmed through imaging, most commonly contrast radiography. Laboratory evaluation includes complete blood count, venous blood gas, electrolytes, renal function tests, glucose, coagulation profile, lactate, and type and screen. Plain abdominal radiographs are diagnostic in fewer than 30% of cases but may show signs suggestive of volvulus, such as duodenal obstruction, gastric distention, paucity of distal bowel gas, generalized small-bowel distention, or a double-bubble sign. Upper gastrointestinal contrast studies are the diagnostic test of choice, with high sensitivity and accuracy, demonstrating abnormal position of the duodenojejunal junction, corkscrew appearance of the duodenum in volvulus, or right-sided jejunum. Contrast enema may help identify cecal position but has a significant false-negative rate. Ultrasound can demonstrate abnormal superior mesenteric artery–vein relationships and the classic whirlpool sign in volvulus, although a normal study does not exclude malrotation. CT imaging is generally reserved for adults.
Differential diagnosis depends on age and presentation. In early life, considerations include Hirschsprung disease, necrotizing enterocolitis, and intussusception. In children with acute abdominal pain and peritoneal signs, appendicitis and sepsis must be considered. Older children and adults with chronic or vague symptoms may be misdiagnosed with irritable bowel syndrome, peptic ulcer disease, biliary or pancreatic disorders, or psychiatric conditions.
Management of malrotation, particularly with midgut volvulus, is a surgical emergency. Initial stabilization focuses on airway, breathing, and circulation, with rapid intravenous fluid resuscitation to correct hypovolemia and metabolic acidosis. Broad-spectrum antibiotics are initiated if there are signs of sepsis or peritonitis. Nasogastric decompression and prompt surgical consultation are essential. Definitive treatment involves emergent surgical correction, including detorsion of the volvulus, restoration of intestinal perfusion, resection of necrotic bowel if present, and reassessment of bowel viability when necessary. Patients are kept nil per os and require close postoperative monitoring.
Hospital admission is indicated for acute abdomen, need for surgical intervention, significant dehydration, acidosis, sepsis, or shock. Discharge is uncommon and reserved for stable, asymptomatic patients with incidental findings after thorough pediatric surgical evaluation. Early recognition, rapid resuscitation, and timely referral to a facility with pediatric surgical expertise are critical to improving outcomes and reducing morbidity and mortality.
