Spectrum of kidney biopsy findings associated with methamphetamine-use

Introduction Methamphetamine (METH) is one of the most used drugs of abuse worldwide. However, there are few reports and series examining the toxic kidney effects of METH and associated histopathological changes are not well described. Methods We retrospectively identified 112 patients with a history significant for methamphetamine (METH) abuse, of whom 62 were using METH-only and 60 METH + other drugs of abuse. Results In the METH-only cohort, the mean age was 41 years (IQR 33-49) and most were male (76%). Almost all cases (97%) showed evidence of kidney dysfunction at the time of biopsy. 65% had proteinuria, of which 53% were nephrotic-range and 10% had nephrotic syndrome. The most common biopsy diagnosis was acute tubular necrosis (ATN) (66%), of which 19% had myoglobin casts, followed by focal segmental glomerulosclerosis in 53% (NOS in 76% and collapsing in 18%). Biopsy findings also include tubulointerstitial nephritis (37%), thrombotic microangiopathy (24%), and diabetic glomerulosclerosis (DG) (31%).Glomerulonephritis (GN) was identified in one-third of cases, the most common of which were infection-related GN (15%) and IgA nephropathy (11%). 64% of GNs had underlying infection. Of interest, there was increased association for myoglobinuric ATN in those with concurrent ethanol-abuse (p=0.002). Moreover, the METH-only patients were more likely to have DG compared to those with multiple substance-use (p=0.01). More than half demonstrated at least moderate to severe tubulointerstitial scarring and marked hypertensive vascular disease. Conclusion Most patients with METH-use present with acute kidney injury and often have proteinuria associated with a wide spectrum of renal pathology.