Fig. 2

a Segmental glomerular necrosis and early crescent formation (arrow) in a heroin abuser who developed glomerulonephritis secondary to MRSA tricuspid endocarditis. There were glomerular IgA and C3 deposits. The patient was also ANCA positive, which may occur in Up to 30% of patients with endocarditis associated glomerulonephritis. b Heavy glomerular amyloid A protein deposits (brown color) in an IV drug user and “skin popper” who presented with nephrotic syndrome and was diagnosed with AA amyloidosis. Immunoperoxidase stain with antibody to Amyloid A protein. c Severe obliterative vascular changes secondary to chronic stage thromobotic microangiopathy in a young patient with Opana abuse. d Myoglobin positive (brown) casts in a young female patient with heavy cocaine use and acute kidney injury. Her CK on presentation was 120,000 and her serum creatinine was 7.9 mg/dl. Immunoperoxidase stain with an antibody to myoglobin