Objective To alert readers to the possibility of rebound hyperkalemia following pancreatic resection for neonatal hyperinsulinism. Design Case report. Setting Intensive care unit of tertiary pediatric hospital. Patient A term neonate with severe hyperinsulinism complicated by hypokalemia, fluid overload, and necrotizing enterocolitis. Interventions Preoperative management consisted of glucose 20.8 mg/kg/min, diazoxide 15 mg/kg/day, octreotide 27 mug/kg/day, and potassium (>10 mmol/kg/day) to maintain normoglycemia and normokalemia. The large glucose requirement, administered as 20% glucose, contributed to congestive heart failure, which was treated with frusemide. Attempts to feed enterally were abandoned because of necrotizing enterocolitis. Partial colectomy and subtotal pancreatectomy were performed on day 20. Measurements and main results Serum potassium rose rapidly within 2 hrs of surgery to reach 12.3 mmol/L, causing ventricular tachycardia (240 beats/min) on electrocardiogram. There was no evidence of renal failure or adrenal insufficiency. Management consisted of insulin 0.1 units/kg intravenously, 10% calcium gluconate 0.1 mmol/kg intravenously, sodium bicarbonate 3 mmol/kg intravenously, frusemide 2 mg/kg intravenously, and resonium 0.6 g/kg per rectum with good outcome. Conclusions This report highlights the rapid electrolyte shifts possible after sudden cessation of hormones regulating Na/K-ATPase activity.
