Differential Diagnosis
The patient's presentation of fatigue, weight loss, low-grade fevers, joint pain, lymphadenopathy, oral ulcers, and abnormal laboratory findings suggests a systemic illness. The following differential diagnoses are considered:
Single Most Likely Diagnosis
- Systemic Lupus Erythematosus (SLE): The combination of symptoms such as fatigue, weight loss, low-grade fevers, joint pain, lymphadenopathy, oral ulcers, and laboratory findings like anemia (low hemoglobin), leukopenia, thrombocytopenia, and proteinuria are highly suggestive of SLE. The presence of anti-dsDNA antibodies (option C) is a specific marker for SLE.
Other Likely Diagnoses
- Juvenile Idiopathic Arthritis (JIA): Although the patient's aunt has rheumatoid arthritis, the patient's symptoms and laboratory findings could also suggest JIA, particularly the systemic form. However, the presence of oral ulcers and significant lymphadenopathy is less typical for JIA.
- Infectious Mononucleosis: The presence of fever, fatigue, lymphadenopathy, and oral ulcers could suggest infectious mononucleosis, which can be confirmed by a positive monospot test (option B). However, the significant weight loss, joint involvement, and specific laboratory abnormalities (e.g., proteinuria) are less characteristic.
- Hematologic Malignancy: The patient's pancytopenia (anemia, leukopenia, thrombocytopenia) and lymphadenopathy could raise concern for a hematologic malignancy, but the presence of oral ulcers and proteinuria is less typical.
Do Not Miss Diagnoses
- Hodgkin Lymphoma: Although less likely, the presence of diffuse lymphadenopathy, fever, and significant weight loss necessitates consideration of Hodgkin lymphoma, which could be confirmed by the presence of Reed-Sternberg cells (option E). Missing this diagnosis could have severe consequences.
- Leukemia/Lymphoma: The patient's pancytopenia and lymphadenopathy also warrant consideration of other leukemias or lymphomas, which could be indicated by excessive lymphoblasts (option D) or other specific markers.
Rare Diagnoses
- Anti-citrullinated Peptide Antibody Positive Arthritis: This is less likely given the patient's age and the broader range of symptoms beyond joint involvement, but it could be considered if there's a strong family history of rheumatoid arthritis (option A).
- IgA Nephropathy or Other Vasculitides: Elevated serum IgA levels (option F) could suggest IgA nephropathy or other vasculitides, but these would be less likely given the patient's systemic symptoms and laboratory findings.