Myocarditis

• What is myocarditis?


  Inflammation of the myocardium
• Pathophys of myocarditis


  Initial inflammation may cause severe, acute cardiac failure (requires organ support, pts may deteriorate & die rapidly or may require emergency heart transplantation)

  After initial inflammation has settled, dilated cardiomyopathy may arise
• What are the possible causes of myocarditis?

  Viral infections (most common)

  • enteroviruses, Human Herpes virus 6, Parvovirus B-19, flu A, HIV, COVID

  Bacterial/parasitic infections

  • rheumatic fever
  • chagas disease
  • diphtheria (most common outside UK?)

  Radiation to chest

  Autoimmune disorders

  • SLE
  • Sarcoidosis
  • Giant cell myocarditis
  • Kawasaki disease

  Drugs (clozapine, pembrolizumab)
• What is pembrolizumab used to treat?


  Various malignant processes
• What are the Inx for myocarditis?


  Obs

  Full Hx & examination

  ECG

  Urine dip

  Swabs

  Bloods (FBC, LFTs, U&Es, CRP, troponin, autoimmune screen, viral screen)

  CXR

  Echo

  CT

  Cardiac MRI

  Consider endomyocardial biopsy
• What may be shown in an ECG for myocarditis?


  ST elevation/depression

  T wave inversion

  Atrial arrhythmias

  Transient AV block
• Myocarditis often presents the same as NSTEMI/STEMI & troponin will be raised. So, pts are often treated for MI (that's fine, as it is MI until proven otherwise).
• What are the DDx of myocarditis?


  ACS

  Dilated cardiomyopathy

  Pericarditis

  Stress-induced cardiomyopathy
• What are the RFs for myocarditis?


  Infection

  HIV infection

  Autoimmune/immune-mediated diseases

  Peripartum or postnatal periods

  Age < 50
• What are the signs & symptoms of myocarditis?


  Chest pain

  Fatigue

  Fever

  SOB

  Reduced exercise tolerance

  Palpitations

  Orthopnoea

  Tachypnoea

  Tachycardia

  Hepatomegaly

  Raised JVP

  Syncope
• What are the complications of myocarditis?


  Cardiogenic shock

  • myocardial dysfunction -> insufficient CO & organ hypoperfusion

  Arrhythmias

  • signif cause of mortality & morbidity in myocarditis

  Sudden cardiac death

  • myocarditis may progress to rapid cardiac dysfunction -> death

  Dilated cardiomyopathy

  HF
• What is the treatment for myocarditis?


  O2 (if required)

  Treat underlying cause

  Monitor & control arrhythmias

  Fluid balance management

  Early escalation to specialist intensive care physicians

  Organ support (if needed)
• What is the most common viral cause of myocarditis?

  Coxsackievirus B