# Acute fatal ventricular arrhythmia induced by severe hyperkalemia in a toddler with decompensated methylmalonic acidemia

## TL;DR

A 4-year-old boy with methylmalonic acidemia experienced life-threatening arrhythmia due to severe hyperkalemia, which was successfully treated by lowering potassium levels.

## Contribution

The paper highlights a rare but fatal complication of methylmalonic acidemia and provides insights into its management.

## Key findings

- Severe hyperkalemia can induce acute fatal ventricular arrhythmia in methylmalonic acidemia patients.
- Effective reduction of serum potassium levels restored normal sinus rhythm in the patient.
- Regular monitoring of electrolytes and cardiac screening is essential during metabolic decompensation.

## Abstract

Methylmalonic acidemia is a very rare genetic metabolic disease. Patients with isolated methylmalonic acidemia typically present with acute alterations of consciousness, failure to thrive, anorexia, vomiting, respiratory distress, and muscular hypotonia. Despite the evidence-based management, affected individuals experience significant morbidity and mortality. Hyperkalemia is one of the unusual complications of methylmalonic acidemia.

In this paper, we describe a 4-year-old Persian boy with methylmalonic acidemia who developed life-threatening arrhythmia following severe hyperkalemia and metabolic acidosis. Emergent management of the condition was successfully carried out, and the rhythm changed to normal sinus rhythm by effectively reducing the serum potassium level. We discuss the possible etiology of this lethal condition and describe its management on the basis of the available evidence.

During metabolic decompensation in methylmalonic acidemia, frequent blood gas and electrolyte testing to prescribe and adjust therapy and annual echocardiogram and electrocardiogram screening are essential.