A 35-year-old man comes to the office due to 2 weeks of abdominal distension. He has been in a drug rehabilitation program for 2 years due to prior heroin abuse. Recent viral hepatitis and HIV profiles were negative. Temperature is 37.1 C (98.7 F), blood pressure is 145/82 mm Hg, pulse is 80/min, and respirations are 14/min. BMI is 40 kg/m². Examination shows periorbital edema, ascites, and 2+ pitting edema in both legs up to the knees. Breath sounds are decreased at the right lung base. Twenty-four-hour urine shows protein excretion of 7.5 g. Which of the following is most likely to be present on kidney biopsy?

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11ec25c8_d4da_d264_bc81_1d9124de9a21_MD0003_00 This patient's presentation is consistent with nephrotic syndrome, defined as heavy proteinuria (>3.5 g/24 hr) with hypoalbuminemia and edema. Other findings include hyperlipidemia and increased lipids in the urine. Causes of nephrotic syndrome in adults include primary glomerular (eg, membranous nephropathy, focal segmental glomerulosclerosis [FSGS], and minimal change disease) and secondary glomerular (eg, diabetes mellitus, amyloidosis) diseases. This patient has volume overload (periorbital edema, peripheral edema, and ascites) likely due to hypoalbuminemia. His pulmonary examination suggests a likely right pleural effusion. Because he does not have known diabetes or amyloidosis, he most likely has a primary renal etiology. Recent United States registry data indicate that FSGS is one of the most common causes of nephrotic syndrome in adults, especially in African Americans. FSGS can also be associated with HIV, heroin use, and morbid obesity. (Choice B) IgA nephropathy can present with nephrotic syndrome (<10%), but more commonly presents with hematuria following an upper respiratory infection (about 40%-50% of patients). (Choice C) Membranous nephropathy is the second leading cause of nephrotic syndrome in the overall population. FSGS is statistically more likely in this patient given his risk factors of obesity and heroin use. (Choice D) Minimal change disease is more common among children. In adults, it is associated with use of nonsteroidal anti-inflammatory drugs and lymphoma (usually Hodgkin). (Choice E) Amyloidosis is usually associated with multiple myeloma or a chronic inflammatory disease (eg, rheumatoid arthritis, bronchiectasis). Educational objective: Nephrotic syndrome is defined as heavy proteinuria (>3.5 g/24 hr) with hypoalbuminemia and edema. Focal segmental glomerulosclerosis (FSGS) and membranous nephropathy are the most common causes of nephrotic syndrome in adults in the absence of a systemic disease. FSGS is more common in African American patients and in those with obesity, heroin use, and HIV. References: Changing incidence of glomerular disease in Olmsted County, Minnesota: a 30-year renal biopsy study. (http://www.ncbi.nlm.nih.gov/pubmed/17699249) Focal segmental glomerulosclerosis in African Americans. (http://www.ncbi.nlm.nih.gov/pubmed/11863085)

A 35-Year-Old Man Comes to the Office Due to 2