Differential Diagnosis for a 5-year-old Patient with Intermittent Fevers and Right Hip Pain
Single Most Likely Diagnosis
- Post-viral syndrome or reactive arthritis: Given the patient's recent history of influenza B with pneumonia and an upper respiratory viral infection, it's plausible that the current symptoms are a post-viral complication. The presence of right hip pain, especially after active days or prolonged sitting, could be indicative of reactive arthritis, which sometimes follows viral infections.
Other Likely Diagnoses
- Viral syndrome: The patient's symptoms of intermittent fevers, lethargy, and malaise could still be part of a viral syndrome, given the recent upper respiratory infection.
- Musculoskeletal strain: The right hip pain could be due to a musculoskeletal strain, especially if the patient has been more active than usual.
- Growing pains: Although less common in the hip, growing pains could be a consideration, especially given the patient's age and the nature of the pain.
Do Not Miss Diagnoses
- Septic arthritis or osteomyelitis: Although the CRP is <0.5 and the sedimentation rate is 3, which makes these conditions less likely, they are critical to rule out due to their potential for serious complications. The history of recent infections and the presence of hip pain necessitate consideration of these diagnoses.
- Juvenile idiopathic arthritis (JIA): This condition can present with intermittent fevers, malaise, and joint pain. The patient's symptoms and recent history of infections could be an initial presentation of JIA.
- Lyme disease: If the patient has been exposed to ticks, Lyme disease could be a consideration, as it can cause intermittent fevers, malaise, and joint pain.
Rare Diagnoses
- Chronic recurrent multifocal osteomyelitis (CRMO): A rare condition characterized by recurrent episodes of osteomyelitis, which could explain the patient's intermittent hip pain and fevers.
- Sickle cell disease or other hemoglobinopathies: Although the hemoglobin level is slightly low, other parameters do not strongly suggest a hemoglobinopathy. However, given the patient's symptoms, it's worth considering, especially if there's a family history.
- Leukemia or lymphoma: These conditions can present with intermittent fevers, malaise, and bone or joint pain. Although the bloodwork does not strongly suggest a malignancy, it's always a consideration in a child with persistent or recurrent symptoms.