Nephrocalcinosis, oral sodium phosphate solution, and phosphate nephropathy (original) (raw)

Nephrocalcinosis, a syndrome of renal parenchymal calcification, is associated with both acute and chronic kidney disease. Traditionally seen in patients with hypercalciuric disorders, medullary sponge kidney, or tumor lysis syndrome, recent reports have documented nephrocalcinosis following bowel preparation with oral sodium phosphate solution (OSPS), in a syndrome termed "phosphate nephropathy." This preventable complication is not benign; one retrospective series revealed that 20% of patients progressed to endstage renal disease (ESRD) with variable degrees of chronic kidney disease (CKD) in the remainder. Safe and effective bowel preparation is challenging and OSPS, while effective and generally well tolerated, can induce hyperphosphatemia, hypokalemia, metabolic acidosis, and volume depletion, in addition to renal calcification. The Federal Drug Administration (FDA), plaintiffs' attorneys, and the manufacturers of OSPS products have responded vigorously to the reports of kidney disease following OSPS. Although rare, internists, gastroenterologists, and nephrologists must be aware of this syndrome because it may be underdiagnosed and it is preventable by substituting OSPS with nonphosphate-containing preparative regimens in at-risk patients. This issue of Nephrology Rounds will address some of the gaps in our understanding of the incidence, risk factors, pathophysiology, and outcomes of phosphate nephropathy.