Endocrine Abstracts

Fleet Phospho-soda is frequently used to prepare bowel for gastrointestinal investigations or surgery. We report an 85 year old male who had severe life threatening hypocalcemia after using fleet. He was admitted for bowel preparation for colonoscopy due to altered bowel habits, weight loss and anaemia. Clinical examination was unremarkable. His investigations showed Hb-12.0 gm/dl, normal renal function (Serum creatinine -105 μmol/l), normal liver function but for a raised alkaline phosphatase of - 350 IU/l, Calcium - 2.31 mmol/l, Albumin - 45 g/l and Phosphate - 1.17 mmol/l. He was given 2 standard doses of Fleet phosphosoda orally and a phosphate enema. The next morning he felt unwell, lethargic with pins and needles in both hands. Clinical examination revealed positive Trousseau’s sign and Chvostek’s sign. ECG showed prolonged QTc - 642 ms. His corrected Calcium was 1.33, phosphate - 3.38 and a low Magnesium of 0.55. He needed cardiac monitoring and was treated with intravenous calcium gluconate and magnesium. He improved after 24 hours and calcium was normal at 72 hours. His vitamin D levels were normal (51 nmol/l, normal summer range – 15–75) and PTH raised appropriately (plasma PTH =321 ng/l, normal 10–60).

Inorganic phosphate salts can be readily absorbed from the gastrointestinal tract causing severe hyperphosphatemia. leading to serious hypocalcemia and hypomagnesemia. Bradyarrythmias, prolonged QT interval, and cardiac arrest are serious complications. Caution is advised on subjects with impaired renal function, heart disease, pre-existing electrolyte imbalances, elderly and debilitated patients. Severe hypocalcemia has been reported with use of fleet in severe renal impairment, hypomagnesmia and children. Here we report severe life threatening hypocalcemia in an elderly gentleman with no identifiable risk factors. Due to the common use of these drugs in bowel preparations, awareness of this serious complication is important to diagnose and manage appropriately.