Differential Diagnosis
The patient's symptoms of persistent fevers, evening rash, and splenomegaly, along with laboratory results indicating anemia, thrombocytosis, and leukocytosis, suggest an underlying infectious or inflammatory process. The following differential diagnoses are considered:
- Single most likely diagnosis
- E. Systemic juvenile idiopathic arthritis (sJIA): The patient's symptoms of daily fevers, rash, and joint swelling, along with laboratory results showing anemia, leukocytosis, and thrombocytosis, are consistent with sJIA. The rash and fever pattern, which worsen in the evening and resolve by morning, are classic for sJIA.
- Other Likely diagnoses
- B. Dengue virus infection: Although the patient's symptoms started after a trip to Costa Rica, where dengue is endemic, the prolonged duration of symptoms and the presence of joint swelling and splenomegaly make this diagnosis less likely.
- D. Parvovirus B19 infection: This infection can cause a rash and fever, but the presence of splenomegaly and joint swelling makes it less likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- C. Malaria: Although the patient traveled to Costa Rica, where malaria is not typically endemic, it is essential to consider this diagnosis due to the risk of severe morbidity and mortality if left untreated. The patient's fever and splenomegaly could be consistent with malaria.
- F. Systemic lupus erythematosus (SLE): SLE is a rare but potentially life-threatening condition that can present with fever, rash, and joint swelling. Although the patient's symptoms are not typical for SLE, it is essential to consider this diagnosis due to its potential severity.
- Rare diagnoses
- A. Acute rheumatic fever: This condition typically presents with a distinct set of symptoms, including migratory polyarthritis, carditis, and chorea, which are not evident in this patient.
- Other rare infections or inflammatory conditions: Such as lymphoma, leukemia, or other autoimmune disorders, which would require further evaluation and testing to diagnose.