Nephroquiz 5: a 51-year-old man with kidney failure.

1Department of Nephrology, Hormozgan University of Medical Sciences, BandarAbbas, Iran 2Department of Nephrology, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3Department of Pathology, Shahid Beheshti University of Medical Sciences, Tehran, Iran CASE A 51-year-old cigarette-smoker man was admitted because of progressive generalized weakness and early fatigability since 3 months earlier. He denoted that his symptoms developed after 2 days of fasting. He also complained of headache, lower extremities bone pain, and a recent episode of respiratory tract infection. The patient was not on any specific medications, and physical examination was unremarkable. Laboratory results are shown in the Table. Results of hepatitis B and C viruses serology, serum complements 3 and 4, total hemolytic complement, antinuclear antibody, antineutrophilic cytoplasmic antibody, and anti-double-stranded DNA were all negative or in normal range. Urinalysis revealed proteinuria (2+) with 5 to 10 erythrocytes and 5 to10 leukocytes per high-power field. Serum protein electrophoresis demonstrated hypoalbuminemia, hypogmmaglobulinemia, and a monoclonal peak in the beta 2 region (Figure 1). With immunotyping, a high level of immunoglobulin A (IgA) was demonstrated (IgG, 196 mg/dL; IgA, 5965 mg/dL [reference range, 60 mg/dL to 490 mg/dL]; IgM, 6 mg/dL; and IgE, 14.2 mg/ dL). Result of urine protein electrophoresis also revealed beta, 97.0%; alpha 2, 1.0%; and albumin, 2.0%. There was no evidence of lytic bone lesions in skull radiography. Chest radiography was negative for cardiomegaly, pulmonary infiltrates, effusions, or bony abnormalities in the ribs. Because of increasing serum creatinine despite adequate hydration and