A Case of Severe Hyperphosphatemia and Hypocalcemic Tetany after Sodium Phosphate Administration in a Patient with Normal Renal Function

Choi, Hyun Jong; Park, Jong Pil; Lee, Youn Jeong; John, Sung Hee; Jung, Gum Mo; Kim, Jung Hwa; Lee, Kwang Young

Abstract

Oral sodium phosphate (NaP) is increasingly used to prepare patients for gastrointestinal procedures such as colonoscopy. Severe hyperphosphatemia may complicate bowel-cleansing preparation using oral NaP. The risk of hyperphosphatemia is known to increase with excessive and/or repeated doses, increased intestinal absorption, or impaired renal excretion of phosphate. Hyperphosphatemia may produce acute renal failure, but the mechanism is not yet clear. Some authors suggest that renal injury is caused by intrarenal calcium-phosphate deposition, but others suggest that direct tubular toxicity or a disturbance in renal hemodynamics may induce renal injury. A 74-year-old woman was admitted with generalized weakness after taking NaP for colonoscopy. She had no underlying diseases such as renal disease. She was hypotensive and had carpopedal spasm with hypocalcemia, severe hyperphosphatemia, metabolic acidosis, and non-oliguric acute renal failure. She was treated with aggressive hydration, calcium replacement and aluminum-containing antacid, but hyperphosphatemia was aggravated (35.6 mg/ dL). Hemodialysis was done and phophate concentration was lowered to 5.5 mg/dL. It is suggested that caution should be taken when using phosphate- containing laxatives especially for elderly patients even if they have no underlying diseases.