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 mild elevation in eosinophils could also suggest an allergic or post-infectious component.
Other Likely Diagnoses
- Viral syndrome or persistent upper respiratory infection: The patient's symptoms of intermittent fevers, mild lethargy, and malaise, along with a recent history of upper respiratory viral infection, could indicate a persistent or recurrent viral syndrome.
- Growing pains: Although the patient's age and symptoms of hip pain, especially after activity or prolonged sitting, could suggest growing pains, the presence of intermittent fevers makes this diagnosis less likely but still possible.
- Transient synovitis of the hip: This condition is characterized by hip pain and can follow a viral infection. However, the absence of significant elevation in inflammatory markers (CRP <0.5, sedimentation rate 3) makes this less likely.
Do Not Miss Diagnoses
- Septic arthritis or osteomyelitis: Although the patient's recent infections were treated, and the current inflammatory markers are not significantly elevated, it is crucial not to miss these serious conditions, especially given the hip pain. These diagnoses require urgent attention and would explain the fever and hip pain.
- Juvenile idiopathic arthritis (JIA): Early stages of JIA could present with intermittent fevers, malaise, and joint pain. The absence of significant laboratory findings does not rule out JIA, as it can be seronegative.
- Lyme disease: If the patient has been exposed to ticks, Lyme disease could be a consideration, especially with symptoms of fever, 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 fevers and hip pain.
- Sickle cell disease or other hemoglobinopathies: Although the patient's hemoglobin is slightly low (11.1), other symptoms such as intermittent fevers and hip pain could be seen in sickle cell disease, especially if the patient has not been previously diagnosed.
- Leukemia or lymphoma: These malignancies can present with non-specific symptoms such as fevers, malaise, and bone or joint pain. The slightly low hemoglobin and mild eosinophilia could be seen in some cases, although the rest of the bloodwork does not strongly suggest this diagnosis at present.