# Hypokalemia-Induced Rhabdomyolysis Following Prolonged Diarrhea in a Child With Congenital Heart Disease Receiving Loop Diuretics: A Case Report and Literature Review

## TL;DR

A child with heart disease developed muscle breakdown due to low potassium from diarrhea and diuretics, highlighting the importance of timely electrolyte correction.

## Contribution

This case report adds to the understanding of hypokalemia-induced rhabdomyolysis in children with congenital heart disease.

## Key findings

- Severe hypokalemia and rhabdomyolysis occurred in a child with heart disease after prolonged diarrhea.
- Intravenous potassium replacement and diuretic adjustment led to rapid recovery without kidney injury.
- Literature review suggests gastrointestinal or renal potassium loss increases rhabdomyolysis risk in children.

## Abstract

Hypokalemia is a rare but important cause of rhabdomyolysis in children. Unlike typical rhabdomyolysis, hyperkalemia may be absent because the triggering factor is hypokalemia, potentially delaying diagnosis. We report a five-year-old boy with hypoplastic left heart syndrome after a Fontan procedure who developed severe hypokalemia and rhabdomyolysis following prolonged diarrhea while receiving loop diuretics. He presented with acute lower extremity weakness and inability to stand. Laboratory evaluation revealed potassium 1.9 mmol/L and creatine kinase 9,013 U/L, peaking at 32,908 U/L. Urinalysis showed myoglobinuria, and electrocardiography demonstrated ST depression and prominent U waves. Intravenous potassium replacement and diuretic adjustment resulted in rapid clinical recovery without acute kidney injury. A review of previously reported pediatric cases suggests that potassium depletion from gastrointestinal losses or renal wasting predisposes children to rhabdomyolysis. Early recognition and prompt electrolyte correction are essential.