Differential Diagnosis
- Single most likely diagnosis
- Systemic Lupus Erythematosus (SLE) with immune thrombocytopenia: The patient's presentation with bicytopenia, positive ANA with a high titre, rheumatoid factor, and clinical features such as arthritis, Raynaud's phenomenon, and oral ulcers are consistent with SLE. The thrombocytopenia is likely due to immune-mediated destruction of platelets, which is a common feature of SLE.
- Other Likely diagnoses
- Antiphospholipid syndrome (APS): The patient's presentation with thrombocytopenia, oral ulcers, and distended veins over the chest wall could be suggestive of APS, which is often associated with SLE.
- Rheumatoid arthritis (RA): The patient's arthritis affecting multiple joints, including the PIPs, wrists, elbows, knees, ankles, and shoulders, could be suggestive of RA. However, the presence of other features such as oral ulcers, Raynaud's phenomenon, and a high ANA titre makes SLE a more likely diagnosis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Thrombotic thrombocytopenic purpura (TTP): Although the patient's presentation does not strongly suggest TTP, it is a potentially life-threatening condition that requires prompt diagnosis and treatment. The patient's thrombocytopenia, anemia, and renal function should be closely monitored to rule out TTP.
- Hemophagocytic lymphohistiocytosis (HLH): This is a rare but potentially life-threatening condition that can present with cytopenias, liver dysfunction, and coagulopathy. Although the patient's presentation does not strongly suggest HLH, it should be considered in the differential diagnosis.
- Rare diagnoses
- Evans syndrome: Although Evans syndrome was ruled out, it is a rare condition that can present with immune thrombocytopenia and autoimmune hemolytic anemia. The patient's presentation with bicytopenia and a positive ANA titre could be suggestive of Evans syndrome, although it is less likely given the other features of SLE.
- Mixed connective tissue disease (MCTD): This is a rare condition that can present with features of SLE, RA, and scleroderma. Although the patient's presentation does not strongly suggest MCTD, it should be considered in the differential diagnosis.
Key Learning Points
- SLE can present with a wide range of clinical features, including immune thrombocytopenia, and requires a high index of suspicion for diagnosis.
- The treatment of SLE-related immune thrombocytopenia typically involves corticosteroids, such as dexamethasone, and immunosuppressive agents, such as cyclophosphamide.
- The patient's HIV status and antiretroviral therapy should be carefully considered when managing SLE-related immune thrombocytopenia, as some antiretroviral agents can exacerbate thrombocytopenia.
- Regular monitoring of the patient's blood counts, liver function, and renal function is essential to detect potential complications of SLE and its treatment.