A case of sarcoidosis with severe acute renal failure requiring dialysis

We report a 79-year-old male having sarcoidosis without presentation of typical findings, such as respiratory symptoms, ocular signs, or skin lesions. Two weeks prior to admission to our hospital, he presented to a different hospital with acute renal failure, with blood urea nitrogen (BUN) and serum creatinine (Cr) levels of 67.9 mg/dL and 7.97 mg/dL, respectively, and was initiated on hemodialysis. The patient also exhibited fever, severe anorexia, and fatigue. We initially experienced difficulty in performing kidney biopsy due to a thrombocytopenia complication and severe general debility. Tuberculosis and other malignancies were not found. However, bone marrow biopsy revealed noncaseating granuloma with multinucleated giant cells, and the patient's serum angiotensin converting enzyme (ACE) level was slightly elevated at 24.3 U/L. We informed the patient and his family of the risk of a kidney biopsy and subsequently received informed consent for the procedure. The biopsy showed many epitheloid granulomas with multinucleated giant cells in the interstitium, from which we diagnosed sarcoidosis. The thrombocytopenia was subsequently found to be due to heparin-induced thrombocytopenia (HIT). After administering 20 mg/day of oral prednisolone, the patient's general condition improved rapidly. Therefore, it is important to take sarcoidosis into account as a differential diagnosis of acute renal failure, and kidney biopsy offers useful information in these cases.