[Acute phosphate nephropathy (APN)]

Abstract

Acute phosphate nephropathy (APN) is a clinical condition, appeared in the last decade, in patients under treatment with oral sodium phosphate bowel purgative (OSPS). Renal damage induced by OSPS may occur as acute or chronic disease. The former commonly appears within few hours after bowel cleansing with OSPS. It is clinically characterized by severe hyperphospatemia (4.519.4 mmol/l) and hypocalcemia (11.17mmol/l). Recovery of renal function may occur in some patients, while others develop chronic kidney disease (CKD), with possible evolution towards end-stage renal disease (ESRD). Renal biopsy reveals acute nephrocalcinosis characterized by abundant distal tubular calcium phosphate deposits, associated with tubular athrophy and interstitial fibrosis. Predisposing factors for the onset of APN include female sex, senescence, diabetes mellitus, arterial hypertension, CKD and use of diuretic or drugs acting on renin-angiotensin system (RAS). The diagnosis is suggested by the timely association between assumption of OSPS for bowel cleansing and acute kidney injury. However, chronic complications may remain unrecognized, without periodic control of renal function after OSPS assumption.Most importantly, the definitive diagnosis needs to be confirmed by renal biopsy. In 2006, FDA published an alert, recommending caution in the use of OSPS in patients with impaired renal function.