Cases from the Osler Medical Service at Johns Hopkins University. Antiglomerular basement membrane disease.

A 47-year-old Taiwanese man with no notable medical history was admitted with low-grade fevers and night sweats that had persisted for 5 to 6 weeks. An extensive investigation at another hospital could not determine the cause of the fevers, but documented acute renal failure with a blood urea nitrogen level of 60 mg/dL and a serum creatinine level of 5.6 mg/dL. He was admitted to the Johns Hopkins Hospital for further evaluation.The patient, who had been living in the United States for the past 20 years, reported no recent travel and no behaviors that are associated with transmission of human immunodeficiency virus. He was not taking any medications, and he denied using herbal or nutritional supplements. He had no recent weight loss. There were no specific complaints on review of systems. On physical examination, he was a thin, middle-aged man in no distress. Vital signs included a temperature of 37.5 degrees C, a blood pressure of 166/86 mm Hg, a pulse of 70 beats per minute, a respiratory rate of 16 breaths per minute, and 99% oxygen saturation on room air. Sclera were anicteric, and he had no palpable adenopathy. His lungs were clear, and his heart rate was regular without extra sounds. His abdomen was thin, nontender, and without masses or organomegaly. There was no edema or signs of embolism in the extremities. Laboratory studies revealed a white blood cell count of 14,200/mL(3), a hematocrit of 23.1%, and a platelet count of 456,000/mL(3). Blood chemistries were notable for a blood urea nitrogen level of 61 mg/dL and a serum creatinine level of 7.6 mg/dL. Levels of aminotransferases, total bilirubin, and alkaline phosphatase were within normal limits. Urinalysis revealed large hemoglobin, 1+ protein, numerous red blood cells, and 3 to 5 white blood cells. Numerous red blood cell casts were seen on microscopic examination of the urine sediment. The patient's erythrocyte sedimentation rate was >130 mm/h, and his C-reactive protein level was elevated at 12.6 mg/dL. Serologies were negative for antinuclear antibodies and antineutrophil cytoplasmic antibodies; serum complement levels were normal. What is the diagnosis?