# Case Report: Acute myocarditis in a patient with Duchenne muscular dystrophy

## TL;DR

A young boy with Duchenne muscular dystrophy developed acute myocarditis, likely from a respiratory infection, and improved with treatment.

## Contribution

This case report highlights the rare occurrence of acute myocarditis in Duchenne muscular dystrophy patients.

## Key findings

- An 11-year-old DMD patient presented with acute myocarditis confirmed by elevated troponin and CMR findings.
- The patient improved after treatment with immunoglobulin, steroids, and heart failure medications.
- The case suggests upper respiratory infection may have triggered myocarditis in this DMD patient.

## Abstract

Cardiovascular complications are the leading cause of death among individuals with Duchenne muscular dystrophy (DMD). However, due to the difficulty in evaluating individuals with inactive DMD, acute myocardial injury may be overlooked.

An 11-year-old boy with DMD presented to the emergency department with a 5-day history of persistent nasal congestion, runny nose, and cough. He was regularly taking prednisolone acetate, angiotensin-converting enzyme (ACE) inhibitors, and β-blockers for suspected DMD-associated cardiomyopathy. Upon presentation, a substantially elevated cardiac troponin I (cTnI) level of 19.8 μg/L and abnormal electrocardiogram (ECG) results were detected. Further cardiac magnetic resonance imaging (CMR) showed myocardial inflammation with localized T2 hyperintensity from the basal to middle lateral and inferior walls, as well as late gadolinium enhancement (LGE) from the basal to apical inferior lateral walls, supporting a diagnosis of acute myocarditis. Subsequently, the patient showed clinical improvement in response to combination treatment with intravenous immunoglobulin, oral prednisolone acetate, potassium chloride sustained-release tablets, anti-heart failure medication, and broad-spectrum antibiotics.

We report a rare case of acute myocarditis in a patient with DMD, potentially due to upper respiratory tract infection. This case highlights the importance of early myocarditis recognition and treatment in patients with DMD.