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Emergency and Acute Medicine – Legg–Calvé–Perthes Disease
Basic description
Legg–Calvé–Perthes disease is an idiopathic avascular necrosis of the femoral head occurring exclusively in children. It is thought to result from repeated vascular insults to the developing femoral head, leading to ischemia, collapse, and subsequent remodeling. Genetic associations include increased frequency in children with factor V Leiden mutation and anticardiolipin antibodies, supporting a possible hypercoagulable contribution.
Etiology
The condition is believed to arise from successive vascular occlusions of the femoral head and is likely multifactorial. Risk factors include male sex, Caucasian race, exposure to tobacco or wood smoke, low birth weight, and short birth length. The disease progresses through four stages: an initial ischemic stage with dense femoral head and synovitis, a fragmentation stage with femoral head softening and deformation, a healing stage with reossification, and a residual stage with variable permanent deformity. It most commonly affects children aged 3–7 years, with a male predominance of approximately 4:1, and is bilateral in 10–15% of cases.
Diagnosis: signs and symptoms
Presentation is often insidious. Limping is the most common initial complaint. Pain is typically dull or aching and may localize to the hip, groin, anteromedial thigh, or knee. Pain is activity related and improves with rest. Muscle spasm is common early in the disease course. On examination, children are usually afebrile and well appearing. Early findings include limited internal rotation and abduction of the hip. Later findings may include adductor contractures, muscle atrophy, and leg-length discrepancy. Some patients may be minimally symptomatic or asymptomatic.
Essential workup
Plain radiographs of the hips are the most important initial diagnostic study in the emergency setting. Septic arthritis must be considered and excluded, particularly in children with fever, acute onset, or toxic appearance.
Diagnostic tests and interpretation
No laboratory test is diagnostic for Legg–Calvé–Perthes disease. CBC, ESR, and CRP may be obtained if infection is a concern. Imaging establishes the diagnosis. AP and frog-leg lateral radiographs of both hips should be obtained to assess disease stage and detect bilateral involvement. Early radiographs may be normal in the first 3–6 months. MRI is more sensitive and can detect early ischemic changes and assess the extent of femoral head infarction. Bone scintigraphy can identify disease before radiographic changes but is less commonly used. Ultrasound may show a hip effusion but is nonspecific. CT and arthrography are primarily used for surgical planning rather than initial diagnosis.
Differential diagnosis
Unilateral disease considerations include transient synovitis, septic arthritis, osteomyelitis, sickle cell disease, juvenile idiopathic arthritis, trauma, slipped capital femoral epiphysis, tuberculosis, and malignancy. Bilateral disease raises consideration of hypothyroidism, epiphyseal dysplasia, and Gaucher disease.
Treatment
This is not a life-threatening condition, and emergency management focuses on symptom control. Pain management with NSAIDs is the primary intervention. Activity restriction is recommended, and crutches may be required if weight bearing is painful. Clinical instability, fever, or toxic appearance should prompt evaluation for alternative diagnoses.
Medications
First-line therapy is ibuprofen at 10 mg/kg per dose orally every 6–8 hours as needed for pain. Diazepam may be used as a second-line agent for significant muscle spasm.
Disposition and follow-up
Admission is rarely required and is reserved for severe pain not controlled with oral medications or social situations where home care is not feasible. Most patients can be discharged once pain is controlled, with orthopedic follow-up arranged within 1–2 weeks. Long-term management is determined by orthopedics and may include observation, activity modification, bracing, traction, or surgical intervention depending on age at onset and disease severity.
Pearls and pitfalls
Acute onset, fever, toxic appearance, or inability to bear weight should raise concern for diagnoses other than Legg–Calvé–Perthes disease, particularly septic arthritis. Early disease may have normal radiographs, so persistent symptoms warrant close follow-up and repeat imaging.
Basic description
Legg–Calvé–Perthes disease is an idiopathic avascular necrosis of the femoral head occurring exclusively in children. It is thought to result from repeated vascular insults to the developing femoral head, leading to ischemia, collapse, and subsequent remodeling. Genetic associations include increased frequency in children with factor V Leiden mutation and anticardiolipin antibodies, supporting a possible hypercoagulable contribution.
Etiology
The condition is believed to arise from successive vascular occlusions of the femoral head and is likely multifactorial. Risk factors include male sex, Caucasian race, exposure to tobacco or wood smoke, low birth weight, and short birth length. The disease progresses through four stages: an initial ischemic stage with dense femoral head and synovitis, a fragmentation stage with femoral head softening and deformation, a healing stage with reossification, and a residual stage with variable permanent deformity. It most commonly affects children aged 3–7 years, with a male predominance of approximately 4:1, and is bilateral in 10–15% of cases.
Diagnosis: signs and symptoms
Presentation is often insidious. Limping is the most common initial complaint. Pain is typically dull or aching and may localize to the hip, groin, anteromedial thigh, or knee. Pain is activity related and improves with rest. Muscle spasm is common early in the disease course. On examination, children are usually afebrile and well appearing. Early findings include limited internal rotation and abduction of the hip. Later findings may include adductor contractures, muscle atrophy, and leg-length discrepancy. Some patients may be minimally symptomatic or asymptomatic.
Essential workup
Plain radiographs of the hips are the most important initial diagnostic study in the emergency setting. Septic arthritis must be considered and excluded, particularly in children with fever, acute onset, or toxic appearance.
Diagnostic tests and interpretation
No laboratory test is diagnostic for Legg–Calvé–Perthes disease. CBC, ESR, and CRP may be obtained if infection is a concern. Imaging establishes the diagnosis. AP and frog-leg lateral radiographs of both hips should be obtained to assess disease stage and detect bilateral involvement. Early radiographs may be normal in the first 3–6 months. MRI is more sensitive and can detect early ischemic changes and assess the extent of femoral head infarction. Bone scintigraphy can identify disease before radiographic changes but is less commonly used. Ultrasound may show a hip effusion but is nonspecific. CT and arthrography are primarily used for surgical planning rather than initial diagnosis.
Differential diagnosis
Unilateral disease considerations include transient synovitis, septic arthritis, osteomyelitis, sickle cell disease, juvenile idiopathic arthritis, trauma, slipped capital femoral epiphysis, tuberculosis, and malignancy. Bilateral disease raises consideration of hypothyroidism, epiphyseal dysplasia, and Gaucher disease.
Treatment
This is not a life-threatening condition, and emergency management focuses on symptom control. Pain management with NSAIDs is the primary intervention. Activity restriction is recommended, and crutches may be required if weight bearing is painful. Clinical instability, fever, or toxic appearance should prompt evaluation for alternative diagnoses.
Medications
First-line therapy is ibuprofen at 10 mg/kg per dose orally every 6–8 hours as needed for pain. Diazepam may be used as a second-line agent for significant muscle spasm.
Disposition and follow-up
Admission is rarely required and is reserved for severe pain not controlled with oral medications or social situations where home care is not feasible. Most patients can be discharged once pain is controlled, with orthopedic follow-up arranged within 1–2 weeks. Long-term management is determined by orthopedics and may include observation, activity modification, bracing, traction, or surgical intervention depending on age at onset and disease severity.
Pearls and pitfalls
Acute onset, fever, toxic appearance, or inability to bear weight should raise concern for diagnoses other than Legg–Calvé–Perthes disease, particularly septic arthritis. Early disease may have normal radiographs, so persistent symptoms warrant close follow-up and repeat imaging.
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