Differential Diagnosis for a 5-year-old Patient with Intermittent Fevers and Right Hip Pain
Single Most Likely Diagnosis
- Post-infectious or reactive arthritis: Given the patient's history of recent infections (influenza B with pneumonia and an upper respiratory viral infection) and the presence of right hip pain, especially after active days or prolonged sitting, this diagnosis is plausible. The symptoms and the timeframe following the infections support this possibility.
Other Likely Diagnoses
- Subacute osteomyelitis: The patient's history of recent infections and the presence of intermittent fevers, lethargy, and hip pain could suggest a bone infection. The fact that the hip pain persists and is exacerbated by activity or prolonged sitting supports this consideration.
- Transient synovitis of the hip: This condition is characterized by hip pain and limited mobility, often following a viral infection. The patient's symptoms of hip pain and difficulty bearing weight, especially after active days, could align with this diagnosis.
- Juvenile idiopathic arthritis (JIA): Although less common, JIA could be considered given the patient's age and the presence of joint pain and intermittent fevers. However, the diagnosis of JIA typically requires more prolonged and persistent symptoms.
Do Not Miss Diagnoses
- Septic arthritis: This is a medical emergency that requires prompt diagnosis and treatment. The patient's history of hip pain and fever, even if intermittent, necessitates consideration of this potentially life-threatening condition.
- Osteonecrosis (Legg-Calve-Perthes disease): Although more common in older children, this condition could present with hip pain and should be considered, especially if the pain is persistent and affects the child's mobility.
- Malignancy (e.g., leukemia or a bone tumor): While rare, these conditions can present with nonspecific symptoms such as fevers, lethargy, and bone or joint pain. The abnormal blood work (low hemoglobin and hematocrit) raises the concern for a more serious underlying condition.
Rare Diagnoses
- Chronic recurrent multifocal osteomyelitis (CRMO): A rare condition characterized by recurrent episodes of osteomyelitis, often without an identifiable infectious cause. This diagnosis would be considered if other more common causes are ruled out and the patient continues to experience recurrent bone pain and fevers.
- Sickle cell disease with bone infarcts: If the patient has not been screened for sickle cell disease and presents with recurrent episodes of pain and fevers, this condition could be considered, especially if there are abnormalities in the blood work suggestive of hemolysis or anemia.