Thursday, July 6, 2006
Case: 54 year old essentially healthy female admitted to floor with abdominal pain, and found to have only constipation as all major workup reported negative. Primary care physician wrote for fleet enemas till constipation get resolved. You have been called as patient was found in bed having "seizure like symptoms"(which you later diagnosed as tetany). On arrival, you found monitor showing arrhythmias and systolic BP in 70s. You asked for STAT labs, started IVF bolus and pressor. Lab shows phophate level of 12 mg/dl (3.87 mmol/L), magnesium of 0.8 meq/L (0.4 mmol/L) and calcium of 4.5 meq/L (2.25 mmol/L)and Cr of 2.4 mg/dl (pt. had normal kidney function on admission). Patient recovered as electrolytes were replaced and kidney function recovered with hemodynamic support.
Ans: Enema induced hyperphosphatemia
The Fleet enema contains 19 g of monobasic sodium phosphate and 7 g of dibasic sodium phosphate per 118 mL of fluid. If series of enemas given, inorganic phosphate salts can readily get absorbed from the gastrointestinal tract and can cause hyperphosphatemia even in patients with normal kidneys. Severe hyperphosphatemia results in acute hypocalcemia and hypomagnesemia. Tetany, seizures, bradycardia prolonged QT interval, dysrhythmias, coma, and cardiac arrest are the possible consequences. Treatment is supportive and replacement of electrolytes. Dialysis may be needed if other measures fail.