RESUMEN
BACKGROUND: The use of furosemide is well recognized as a predisposing factor to nephrocalcinosis (NC) in infants. Although furosemide is widely used for various clinical settings in adults, the association of furosemide use and nephrocalcinosis in adults is not well established. METHODS: We studied 18 consecutive adult patients(male : female=1 : 17, age range 21-59 years) who took furosemide habitually to control their weights or edema for a long-term period(range 3-25 years). NC was evaluated using renal ultrasonography(US), computed tomography(CT) and/or kidney biopsies. Patients were categorized into NC(+) and NC(-) groups while the difference in clinical features were investigated. RESULTS: Renal US and CT revealed nephrocalcinosis in the bilateral medullary pyramids in 15(83.3 %) out of 18 patients. The duration of furosemide abuse was not different between NC(+) and NC(-) groups(10.1+/-1.7 years vs. 15.3+/-0.9, p>0.05). The daily dose of furosemide was higher in NC(+) group than the NC(-) group(538+/-174 vs. 67+/-13 mg/day, p0.05). The kidney biopsies performed in three patients showed focal tubulointerstitial fibrosis and atrophy and calcifications were observed at outer medullary tubulointerstitium. CONCLUSION: Long-term furosemide abuse could cause medullary nephrocalcinosis in adults and the risk of developing of nephrocalcinosis is correlated with the daily dose of furosemide. We suggest that long-term furosemide abuse should be suspected in adult patients when medullary nephrocalcinosis is incidentally detected by US and/or CT.