Nephrocalcinosis and Foam Cell-Rich Medullary Interstitial Nephropathy in a Patient with Laxative-Induced Hypokalemia: A Case Report

Chronic laxative abuse is a known cause of hypokalemia; however, the full spectrum of kidney-related consequences remains underexplored. We herein report the incidental identification of hypokalemia and kidney dysfunction in a 62-year-old woman with long-standing laxative dependence. Imaging revealed bilateral multifocal renal calcification and a renal biopsy demonstrated extensive tubulointerstitial fibrosis with prominent clustering of CD68-positive foam cells in the medullary interstitium. These findings suggest a potential link between laxative-induced hypokalemia, renal calcification, and foam cell infiltration. Therefore, this case may represent a rare or underrecognized presentation, thereby underscoring the need for the clinical awareness of laxative abuse.