Differential Diagnosis
- Single most likely diagnosis
- Systemic Lupus Erythematosus (SLE): The presence of a positive ANA with a reticular pattern, normocytic anemia, mild proteinuria, and the patient's symptoms (headache, lower extremity edema) which improved with irbesartan (an angiotensin II receptor antagonist that can help with blood pressure and potentially proteinuria), suggest SLE as a strong possibility. The mild ALT elevation could be related to SLE or another condition but is not uncommon in SLE patients.
- Other Likely diagnoses
- Hypertensive Heart Disease with Secondary Effects: The patient's hypertension (HTN) could explain the headache and lower extremity edema. The improvement with irbesartan supports this, but the presence of a positive ANA and proteinuria suggests there might be more than just hypertensive heart disease at play.
- Nephrotic Syndrome: The mild proteinuria could be an indicator of nephrotic syndrome, especially if the edema is significant. However, the normocytic anemia and positive ANA point towards a more systemic condition.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Vasculitis (e.g., ANCA-associated vasculitis): Although less likely given the positive ANA, vasculitis could explain some of the symptoms and lab findings. Missing this diagnosis could lead to severe consequences, including organ failure.
- Malignant Hypertension: Given the patient's hypertension and improvement with irbesartan, malignant hypertension is a possibility, especially if there are signs of end-organ damage. This condition requires immediate attention to prevent further complications.
- Rare diagnoses
- Mixed Connective Tissue Disease: This disease combines features of SLE, scleroderma, and polymyositis. The positive ANA and the variety of symptoms could fit, but it's less common than SLE.
- Sjögren's Syndrome: Although primarily known for its effects on exocrine glands, Sjögren's can have systemic manifestations, including renal involvement and positive ANA. However, the lack of specific symptoms like dry eyes or mouth makes this less likely.