Chronic interstitial nephritis and mixed cryoglobulinemia associated with drug abuse

Two cases of chronic interstitial nephritis with renal insufficiency were associated with mixed cryoglobulinemia and parenteral drug abuse. Previously recognized causes of interstitial nephritis were not present in either case. Despite extensive interstitial inflammatory infiltrates, no substantial glomerular abnormalities or immune deposits were present in either patient. One patient had a history of intravenous injection of suspended methadone tablets containing talc crystals, and there was evidence of talc embolization in biopsy specimens of liver, spleen, and kidney. Interstitial nephritis associated with drug abuse has not been previously described to our knowledge, but the association in these cases seems not to have been fortuitous and warrants consideration in the evaluation of both parenteral drug abusers and patients with unexplained interstitial nephritis.