Enema-Induced Hypocalcemic Tetany

Department of Nephrology, Vail d’Hebron General Hospital, Barcelona, Spain Dr. Jordi de Otero, Huelva 87 3° 3, E-08020 Barcelona (Spain) Dear Sir, Phosphate enemas are usually recommended for alleviation of constipation and sometimes they are used at the patient’s home. Apparently safe, their use could be uncontrolled in some circumstances. Local intolerance of self-limited abdominal pain are the commonest side effects observed. Few cases of hypocalcemic tetany in adults are known [1-3]. We present a patient with severe chronic renal insufficiency who developed enema-induced hypocalcemic tetany. A 62-year-old woman with diabetic neuropathy, retinopathy and nephropathy was admitted to our hospital for constipation and acute urinary retention. Upon examination she had peripheral edema. Serum creati-nine was 7.3 mg/dl (645.32 μmol/l) with cre-atinine clearance 8 ml/min (1.3 × 10-4l/s), ionic calcium 5.01 mg/l00 ml (1.24 mmol/l), phosphate 7.3 mg/l00 ml (2.35 mmol/l), potassium 4.8 mmol/l, sodium 135 mmol/l, hemoglobin 7 g/dl (70 g/l), white blood cell count 26 × 109/1, proteins 4.67 g/dl (46.7 g/l), albumin 2.3 g/dl (23 g/l). By the passage of a urethral catheter, 2,300 ml of urine were obtained. Severe bilateral dilatation of the collecting system was observed by ultraso-nography. After 1 week, her abdomen became distended without peristalsis. A plain abdominal X-ray revealed colonic distended bowels. The patient received three consecutive phosphate enemas, containing 20 g of sodium biphosphate and 40 g of sodium phosphate each within 36 h. The patient’s general condition deteriorated and both Chvostek’s and Trousseau’s signs were positive. Consequently, the enemas were stopped. Blood test results showed ionic calcium 3.42 mg/l00 ml (0.85 mmol/l) and phosphate 11.8 mg/l00 ml (3.8 mmol/l). Intravenous fluids and calcium gluconate were administered. The severe metabolic perturbations normalized in the following days and the colonic ileus resolved by itself. Serum electrolyte levels returned to normal values. The obstructive uropathy was attributed to neurogenic bladder. Hyperphosphatemia with hypocalcemia is often related to compromised renal function [4], but hypocalcemic tetany is rare and requires a precipiting factor to occur. Most of the documented reports of hyperphosphatemia and hypocalcemia after usage of phosphate