Differential Diagnosis
- Single most likely diagnosis
- A IgG4-related disease: This is the most likely diagnosis due to the presence of dense lymphoplasmacytic infiltrates on kidney biopsy, which is a hallmark of IgG4-related disease. The patient's history of idiopathic acute pancreatitis also supports this diagnosis, as IgG4-related disease can cause pancreatitis.
- Other Likely diagnoses
- B Sarcoidosis: Sarcoidosis can cause chronic tubulointerstitial nephritis and granulomatous inflammation, which could explain the patient's kidney biopsy findings. However, the presence of dense lymphoplasmacytic infiltrates is more suggestive of IgG4-related disease.
- D Tubulointerstitial nephritis with uveitis: This diagnosis is possible, but the patient's presentation and biopsy findings are more consistent with IgG4-related disease.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- C Systemic lupus erythematosus (SLE): Although SLE is less likely given the patient's age and sex, it can cause tubulointerstitial nephritis and should be considered to avoid missing a potentially treatable disease.
- Infections (e.g., pyelonephritis, tuberculosis): Infections can cause chronic tubulointerstitial nephritis and should be considered, especially if the patient has risk factors or symptoms suggestive of infection.
- Rare diagnoses
- Idiopathic hypocomplementemic tubulointerstitial nephritis: This is a rare disease that can cause chronic tubulointerstitial nephritis, but it is less likely given the patient's biopsy findings and clinical presentation.
- Other rare causes of tubulointerstitial nephritis (e.g., hereditary diseases, toxic exposures): These diagnoses are unlikely, but should be considered if other more common causes are ruled out.