Practice Lesson of the Week

Acute phosphate nephropathy after sodium phosphate preparations

BMJ 2008; 337 doi: (Published 17 July 2008) Cite this as: BMJ 2008;337:a182
  1. Andrew Connor, registrar in renal medicine1,
  2. Lucy Sykes, senior house officer in renal medicine1,
  3. Ian S D Roberts, consultant histopathologist2,
  4. Charles E Weston, consultant nephrologist1
  1. 1Department of Renal Medicine, Dorset County Hospital, Dorchester DT1 2JY
  2. 2Department of Cellular Pathology, John Radcliffe Hospital, Oxford OX3 9DU
  1. Correspondence to: A Connor, 3 Hope Terrace, Martinstown, Dorset DT2 9JN andrewconnor1974{at}
  • Accepted 25 March 2008

Predisposed individuals may develop chronic kidney disease after administration of sodium phosphate purgative before colonoscopy

Oral sodium phosphate preparations are used as bowel purgatives before colonoscopy. Subsequent renal impairment is increasingly being reported.1 We describe a case of acute phosphate nephropathy with persistent renal impairment after administration of sodium phosphate.

Case report

A 76 year old woman was admitted with rectal bleeding. Her past medical history included hypertension—treated with nifedipine—and long standing use of tobacco. Physical examination was unremarkable.

Laboratory results were normal—haemoglobin 106 g/l, white cell count 7.2×109/l, platelets 357×109/l, sodium 132 mmol/l, potassium 4.3 mmol/l, urea 6.2 mmol/l, and creatinine 98 µmol/l.

She underwent flexible sigmoidoscopy after being given a sodium phosphate enema (Fleet Ready-to-use; De Witt) the night before (day 1). Colonoscopy was performed on day 4 after she took two sachets of oral sodium phosphate solution (Fleet Phospho-soda; De Witt). Histological findings were consistent with chronic active ulcerative colitis. She was discharged and prescribed mesalazine.

On day 6 she presented with acute renal failure (creatinine 541 µmol/l). She received intravenous fluids and mesalazine was replaced by prednisolone enemas. A renal consultation was obtained.

Urinalysis was unremarkable. She was normocalcaemic (2.4 mmol/l) but mildly hyperphosphataemic (1.54 mmol/l). Results of a screen for glomerulonephritis and renal tract ultrasonography were normal. Interstitial nephritis secondary to mesalazine was considered and she underwent renal biopsy.

Twenty seven glomeruli were …

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