Bowel cleansing in patients with chronic renal failure--an often overlooked hazard.

Bowel cleansing in patients with chronic renal failure – an often overlooked hazard Sir, Bowel cleansing is a common almost routine procedure that is used in ambulatory as well as in hospitalized patients in preparation for abdominal surgery, radiological examination of the lower gastrointestinal tract and colonoscopy. Bowel cleansing is also commonly used as a 'relieving' measure in elderly patients with constipation and faecal impaction. Many of the preparations used for bowel cleansing, whether oral or per enema, contain large amounts of phosphate. When ingested orally, two thirds of the phosphate that is ingested is normally absorbed in the gastrointestinal tract, whereas one third is excreted in the faeces. Bowel cleansing thus constitutes an acute phosphate load. This phosphate load is normally dealt with predominantly by the kidneys. In patients with normal renal function, the kidneys excrete the excess phosphate and maintain normophosphataemia. When renal function is impaired, however, the phosphate load becomes clinically significant and life-threatening hyperphosphataemia can develop. A number of reports have appeared during the past decade describing severe life-threatening complications as result of the use of phosphate containing bowel cleansers in patients with renal insufficiency [1–5]. Unfortunately, these reports have failed to achieve the necessary awareness of health-care providers insofar as the danger involved in bowel cleansing. One of the reasons may be that bowel cleansing is usually carried out by nursing or ancillary medical staff who are unaware of the hazards involved when renal function is impaired. We recently came across three additional cases of patients with impaired renal function in whom an oral phosphate containing bowel cleansing preparation was used in preparation for colonoscopy in a hospital setting. Severe life-threatening hyperphosphataemia developed, resulting in the death of two of the three patients. A 74-year-old female patient was suspected to have gastrointestinal blood loss. Colonoscopy was scheduled. In preparation for the examination, the patient was admitted to the hospital and underwent bowel cleansing. A 45 ml dose of an oral phosphate containing solution (Soffodex) was administered on the evening prior to and 45 ml on the morning of the examination. Colonoscopy was uneventful. The patient felt well during and after the procedure and was discharged from the hospital in good general condition one day later. A routine blood test taken prior to her discharge, the results of which were received by the medical staff only one day after discharge, indicated that serum phosphate level had …