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Myocarditis

Definitions

Simplest: Inflammation of the myocardium

Lieberman et al.
Definitions based on histological findings and clinical course

  1. Fulminaing myocarditis
    1. Acute illnesses after distinct viral prodrome and have severe cardiovascular compromise, histologic evidence of active myocarditis
  2. Acute myocarditis
    1. Present with established ventricular dysfunction and histologic evidence of active or borderline myocarditis
  3. Chronic active myocarditis
    1. Begins insidiously and results in left ventricular dysfunction but is most likely to become fibrotic and progress to dilated cardiomyopathy
  4. Chronic persistent myocarditis
    1. Continuing cardiovascular symptoms and a histologic infiltrate with foci of myocytes necrosis but without significant cardiovascular compromise
  5. Giant cell myocarditis
    1. Poor outcome and high likelihood of death or cardiac transplantation
  6. Eosinophilic myocarditis
    1. Dire prognosis and sometimes associated with prior exposure to drugs

 

Etiologies

  • Viral
    • Adenovirus
    • Enterovirus (Coxsackievirus)
    • Parvovirus
    • Hepatitis C
    • Influenza
    • HSV
    • HIV
    • EBV
    • CMV
  • Bacterial
    • Various
  • Parasitic
    • Trypanosoma cruzi

Pathophysiology

Myocarditis as a viral disease

Direct myocardial damage
Secondary virus induced myocardial injury

Initial myocardial injury -> Autoimmune myocarditis ->Dilated cardiomyopathy

 

Myocarditis as an autoimmune disease

Cardiac myosin antibodies
Antibodies against mitochondrial antigens
Anti-beta 1-adrenoreceptor autoantibodies
Antibodies to troponin I (an early indicator of myocardiocyte damage)

Clinical Manifestations

  • Chest pain
  • Arrythmias
  • Embolic events
  • Congestive heart failure
  • Cardiogenic shock

 

Diagnostics

Lab

ECG
Non-specific ST changes

Histology
Endomyocardial biopsy

Imaging
MRI

Treatment

Medical management to reverse left ventricular failure (ACEI, BB, diuretics)
Anti-arrhythmics
Immunosuppressives – no improvement
Immunoadsorption columns used to remove immunoglobulins
IVIG
Antibiotics - clarithromycin

 

References

Myocarditis: infection versus autoimmunity. Rose NR. J Clin Immunol. 2009 Nov;29(6):730-7. Review.

Myocarditis. Blauwet LA, Cooper LT. Prog Cardiovasc Dis. 2010 Jan-Feb;52(4):274-88. Review.

J Heart Lung Transplant. 2007 Jul;26(7):745-9.
Active bacterial myocarditis: a case report and review of the literature. Haddad F, Berry G

 



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