Myocarditis

“Acute or chronic inflammation of the myocardium”

Aetiology

• Infection
  • Most commonly due to viral infection if acute (Coxsackie virus most common in Europe and the USA but most viruses are potential causes).
  • May also be bacterial (diphtheria most common) or fungal/ parasitic
• Toxic
  • Medication
  • Exposure to heavy metals
  • Shock
  • Radiation
• Immune-Related
  • Allergy
  • Heart transplant rejection
  • Autoimmune disorders

Pathophysiology

1. The infection causes inflammation and injury to the myocytes.
2. This leads to decreased myocardial contractility and cardiomyopathy.
3. Arrhythmias occur when the injury heals by scarring

Clinical Presentation

• MAY PRESENT SIMILAR TO MYOCARDIAL INFARCTION

• Ranges from asymptomatic (incidental finding on ECG) to heart failure/ arrhythmia/ sudden cardiac death

• Fatigue
• Chest pain
• Fever
• Dyspnoea
• Palpitations
• Tachycardia
• Signs of heart failure
• Soft S1/ S4 gallop on auscultation

Investigations

• On Examination:
  • Soft S1/ S4 gallop on auscultation
• Bloods:
  • FBC, U+E, CK, CRP, LFT, Troponin
• Imaging:
  • Chest X-Ray
• Special:
  • ECG – serial changes of ST-elevation/depression, T wave inversion, atrial arrhythmias or transient AV block.
  • Myocardial biopsy

Management

• Supportive treatment for symptom relief and treatment of the underlying cause
• Treatment of heart failure if present
• If severe may require a transplant

Complications

• Dilated cardiomyopathy due to myocardial destruction
• Congestive heart failure
• Pulmonary oedema
• Cardiogenic shock
• Arrhythmias
• Recurrent myositis