Myocarditis

Introduction

Myocarditis is an acute inflammatory process affecting the myocardium that may occur in association with endocarditis and pericarditis.

Possible causes:

  • Infections: viral including HIV, bacterial, protozoa
  • Toxins e.g. scorpion sting
  • Poisons e.g. alcohol
  • Drugs/Allergy e.g. penicillin
  • Deficiencies e.g. thiamine
  • Physical agents e.g. radiation

Clinical features

  • Largely asymptomatic
  • A few may present with palpitations; symptoms of cardiac failure

Physical examination:

  • Arrhythmias
  • Raised JVP
  • Tachycardia
  • Cardiomegaly
  • S3 or S4 (with or without murmurs of regurgitation in the mitral/tricuspid areas)

Differential diagnoses

  • Other forms of cardiac failure, e.g.
    peripartum cardiomyopathy

Complications

  • Cardiac failure
  • Arrhythmias
  • Thrombus formation

Investigations

  • Electrocardiography
  • Echocardiography
  • Full Blood Count and differentials, ESR
  • Urea, Electrolytes and Creatinine
  • Cardiac enzymes
  • Endomyocardial biopsy

Treatment objectives

  • Eliminate/withdraw the offending agent(s)
  • Treat the effect on the heart
  • Treat complications

Non-drug treatment

  • Bed rest

Drug treatment

  • Treat underlying cause(s)
  • Anti arrhythmics (depends on the type of arrhythmias)
  • Anticoagulant: warfarin
  • Anti-cardiac failure: digoxin, diuretics, potassium supplements
  • Steroids: prednisolone (not in all cases)
  • Multivitamins
  • Anti-oxidants: ascorbic acid (vitamin C), vitamin E

Notable adverse drug reactions

  • Antiarrhythmics may be pro-arrhythmic
  • Anticoagulants: bleeding
  • Steroids: fluid retention, dyspepsia
  • Diuretics: dehydration, electrolyte imbalance

Prevention

  • Prevent infection (viral, bacterial, etc)
  • Prevent exposure to toxins
  • Nutrition education

PAEDIATRIC CARDIAC DISORDERS
(Refer for Specialist Care)