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Emergency And Acute Medicine – Henoch–Schönlein Purpura
Basics And Description
Henoch–Schönlein purpura is a small-vessel vasculitis characterized by IgA-mediated inflammation affecting the skin, gastrointestinal tract, kidneys, joints, and, less commonly, the central nervous system. Multisystem involvement may lead to acute, life-threatening complications or long-term sequelae, particularly renal disease. Although often self-limited, careful evaluation and follow-up are essential.
Etiology
The underlying mechanism involves increased serum IgA with formation of circulating IgA immune complexes and mesangial IgA deposition in the glomeruli. The exact cause is unknown, but multiple associations have been identified. These include infections such as group A streptococcus, Mycoplasma, and viral illnesses including varicella and Epstein–Barr virus. Drug associations include penicillin, tetracycline, aspirin, sulfonamides, and erythromycin. Allergens such as insect bites and certain foods including chocolate, milk, and wheat have also been implicated. The condition most commonly affects school-aged children and young adults, occurs more frequently in males than females, is more common in white populations, and has a higher incidence in winter and spring.
Diagnosis – Signs And Symptoms
Patients are often well appearing despite extensive rash. Constitutional symptoms may include malaise, low-grade fever, and recent or current upper respiratory infection. Hypertension may be present when renal involvement develops. Infants younger than 3 months may present with skin findings alone, while children under 2 years may present with isolated facial edema.
Skin Manifestations
A purpuric rash is the hallmark and presenting feature in approximately half of patients, with eventual development in nearly all cases. Lesions begin as blanching pink papules and evolve within 24 hours into palpable purpura measuring 2–3 cm. The rash is typically symmetric, involves gravity-dependent areas such as the lower extremities and buttocks, and may extend to the trunk or upper extremities. Facial involvement is rare. Recurrence occurs in up to 40% of patients, usually within six weeks.
Abdominal Involvement
Abdominal pain occurs in 70–80% of cases and may range from colicky to severe. Gastrointestinal symptoms may precede the rash by up to four weeks. Gastrointestinal bleeding is common and ranges from occult blood loss to severe hemorrhage. Intussusception, usually ileoileal or ileocolic, is a serious complication.
Renal And Genitourinary Involvement
Asymptomatic hematuria is common and occurs in up to 80% of patients. Proteinuria suggests glomerulonephritis. Other manifestations include scrotal pain, testicular swelling, and, in severe cases, renal failure.
Musculoskeletal Involvement
Arthritis or arthralgia occurs in 70–80% of patients, is typically migratory, periarticular, and most commonly affects the knees and ankles. Angioedema may also occur.
Neurologic Involvement
Less common manifestations include headache, seizures, altered mental status, focal neurologic deficits, and visual or speech disturbances. Intracranial hemorrhage is rare but serious.
History
Key elements include recent infections, onset and progression of rash, presence of abdominal pain, vomiting, edema, joint symptoms, and timing and progression of multisystem complaints.
Physical Examination
Assessment should include vital signs with attention to blood pressure, cardiovascular perfusion, abdominal tenderness or distention, palpable masses, evidence of gastrointestinal bleeding, genitourinary examination for testicular involvement, careful skin inspection for nonblanching purpura, and a focused neurologic examination.
Essential Workup
The primary goal is to exclude life-threatening causes of purpura, abdominal pain, hematuria, and neurologic findings.
Diagnostic Tests And Interpretation
Laboratory studies typically show a normal platelet count and may reveal leukocytosis. Coagulation studies are indicated if bleeding is present or diagnosis is uncertain. Electrolytes, blood urea nitrogen, and creatinine should be obtained if hypertension or abnormal urinalysis is present. Urinalysis frequently shows hematuria, and proteinuria suggests renal involvement. Cultures may be obtained to exclude infectious triggers. Abdominal imaging with ultrasound, contrast enema, or CT is indicated for abdominal pain or gastrointestinal bleeding to evaluate for intussusception. Testicular ultrasound is indicated for scrotal symptoms. Head CT is required for neurologic findings. Lumbar puncture is performed only when clinically indicated.
Differential Diagnosis
Important considerations include gastroenteritis, appendicitis, inflammatory bowel disease, Meckel diverticulum, acute glomerulonephritis, systemic lupus erythematosus, polyarteritis nodosa, meningococcemia, bacterial sepsis, Rocky Mountain spotted fever, viral exanthems, thrombocytopenia, drug reactions, testicular torsion, and incarcerated hernia.
Treatment – Prehospital Care
Stabilization should be provided as clinically indicated.
Initial Stabilization And Therapy
Intravenous fluids are administered for shock. Packed red blood cells are indicated for massive gastrointestinal hemorrhage.
Emergency Department Treatment And Procedures
Life-threatening complications require immediate intervention. NSAIDs such as ibuprofen are used for arthralgia. Corticosteroids, typically prednisone, are indicated for severe abdominal pain after exclusion of surgical causes, painful subcutaneous edema, arthritis, significant renal involvement, or central nervous system disease. Severe nephritis may require high-dose pulse methylprednisolone. Immunosuppressive agents and intravenous immunoglobulin may be considered in severe, life-threatening disease, though evidence is limited.
Medications
First-line therapy includes ibuprofen 600 mg orally every 6 hours, or 5–10 mg/kg per dose in children. Second-line therapy includes prednisone 60 mg daily in adults or 1–2 mg/kg/day in children for 5–7 days.
Follow-Up And Disposition
Admission is required for severe abdominal pain, gastrointestinal bleeding, intussusception, central nervous system involvement, or evidence of renal failure. Patients may be discharged if platelet count and renal function are normal and abdominal pain is minimal or absent. Patients started on steroids should have follow-up within 24 hours.
Follow-Up Recommendations
Close follow-up with a primary care physician is required, with regular monitoring of blood pressure and repeat urinalysis and laboratory studies as indicated. In children, monitoring is recommended for at least six months.
Clinical Insights And Common Errors
Always exclude life-threatening causes of purpura and abdominal pain. NSAIDs are sufficient for most patients. Systemic corticosteroids do not alter the long-term prognosis of Henoch–Schönlein purpura nephritis and should be reserved for specific indications.
Basics And Description
Henoch–Schönlein purpura is a small-vessel vasculitis characterized by IgA-mediated inflammation affecting the skin, gastrointestinal tract, kidneys, joints, and, less commonly, the central nervous system. Multisystem involvement may lead to acute, life-threatening complications or long-term sequelae, particularly renal disease. Although often self-limited, careful evaluation and follow-up are essential.
Etiology
The underlying mechanism involves increased serum IgA with formation of circulating IgA immune complexes and mesangial IgA deposition in the glomeruli. The exact cause is unknown, but multiple associations have been identified. These include infections such as group A streptococcus, Mycoplasma, and viral illnesses including varicella and Epstein–Barr virus. Drug associations include penicillin, tetracycline, aspirin, sulfonamides, and erythromycin. Allergens such as insect bites and certain foods including chocolate, milk, and wheat have also been implicated. The condition most commonly affects school-aged children and young adults, occurs more frequently in males than females, is more common in white populations, and has a higher incidence in winter and spring.
Diagnosis – Signs And Symptoms
Patients are often well appearing despite extensive rash. Constitutional symptoms may include malaise, low-grade fever, and recent or current upper respiratory infection. Hypertension may be present when renal involvement develops. Infants younger than 3 months may present with skin findings alone, while children under 2 years may present with isolated facial edema.
Skin Manifestations
A purpuric rash is the hallmark and presenting feature in approximately half of patients, with eventual development in nearly all cases. Lesions begin as blanching pink papules and evolve within 24 hours into palpable purpura measuring 2–3 cm. The rash is typically symmetric, involves gravity-dependent areas such as the lower extremities and buttocks, and may extend to the trunk or upper extremities. Facial involvement is rare. Recurrence occurs in up to 40% of patients, usually within six weeks.
Abdominal Involvement
Abdominal pain occurs in 70–80% of cases and may range from colicky to severe. Gastrointestinal symptoms may precede the rash by up to four weeks. Gastrointestinal bleeding is common and ranges from occult blood loss to severe hemorrhage. Intussusception, usually ileoileal or ileocolic, is a serious complication.
Renal And Genitourinary Involvement
Asymptomatic hematuria is common and occurs in up to 80% of patients. Proteinuria suggests glomerulonephritis. Other manifestations include scrotal pain, testicular swelling, and, in severe cases, renal failure.
Musculoskeletal Involvement
Arthritis or arthralgia occurs in 70–80% of patients, is typically migratory, periarticular, and most commonly affects the knees and ankles. Angioedema may also occur.
Neurologic Involvement
Less common manifestations include headache, seizures, altered mental status, focal neurologic deficits, and visual or speech disturbances. Intracranial hemorrhage is rare but serious.
History
Key elements include recent infections, onset and progression of rash, presence of abdominal pain, vomiting, edema, joint symptoms, and timing and progression of multisystem complaints.
Physical Examination
Assessment should include vital signs with attention to blood pressure, cardiovascular perfusion, abdominal tenderness or distention, palpable masses, evidence of gastrointestinal bleeding, genitourinary examination for testicular involvement, careful skin inspection for nonblanching purpura, and a focused neurologic examination.
Essential Workup
The primary goal is to exclude life-threatening causes of purpura, abdominal pain, hematuria, and neurologic findings.
Diagnostic Tests And Interpretation
Laboratory studies typically show a normal platelet count and may reveal leukocytosis. Coagulation studies are indicated if bleeding is present or diagnosis is uncertain. Electrolytes, blood urea nitrogen, and creatinine should be obtained if hypertension or abnormal urinalysis is present. Urinalysis frequently shows hematuria, and proteinuria suggests renal involvement. Cultures may be obtained to exclude infectious triggers. Abdominal imaging with ultrasound, contrast enema, or CT is indicated for abdominal pain or gastrointestinal bleeding to evaluate for intussusception. Testicular ultrasound is indicated for scrotal symptoms. Head CT is required for neurologic findings. Lumbar puncture is performed only when clinically indicated.
Differential Diagnosis
Important considerations include gastroenteritis, appendicitis, inflammatory bowel disease, Meckel diverticulum, acute glomerulonephritis, systemic lupus erythematosus, polyarteritis nodosa, meningococcemia, bacterial sepsis, Rocky Mountain spotted fever, viral exanthems, thrombocytopenia, drug reactions, testicular torsion, and incarcerated hernia.
Treatment – Prehospital Care
Stabilization should be provided as clinically indicated.
Initial Stabilization And Therapy
Intravenous fluids are administered for shock. Packed red blood cells are indicated for massive gastrointestinal hemorrhage.
Emergency Department Treatment And Procedures
Life-threatening complications require immediate intervention. NSAIDs such as ibuprofen are used for arthralgia. Corticosteroids, typically prednisone, are indicated for severe abdominal pain after exclusion of surgical causes, painful subcutaneous edema, arthritis, significant renal involvement, or central nervous system disease. Severe nephritis may require high-dose pulse methylprednisolone. Immunosuppressive agents and intravenous immunoglobulin may be considered in severe, life-threatening disease, though evidence is limited.
Medications
First-line therapy includes ibuprofen 600 mg orally every 6 hours, or 5–10 mg/kg per dose in children. Second-line therapy includes prednisone 60 mg daily in adults or 1–2 mg/kg/day in children for 5–7 days.
Follow-Up And Disposition
Admission is required for severe abdominal pain, gastrointestinal bleeding, intussusception, central nervous system involvement, or evidence of renal failure. Patients may be discharged if platelet count and renal function are normal and abdominal pain is minimal or absent. Patients started on steroids should have follow-up within 24 hours.
Follow-Up Recommendations
Close follow-up with a primary care physician is required, with regular monitoring of blood pressure and repeat urinalysis and laboratory studies as indicated. In children, monitoring is recommended for at least six months.
Clinical Insights And Common Errors
Always exclude life-threatening causes of purpura and abdominal pain. NSAIDs are sufficient for most patients. Systemic corticosteroids do not alter the long-term prognosis of Henoch–Schönlein purpura nephritis and should be reserved for specific indications.
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