Myocarditis

Basics

Description

  • An inflammatory infiltrate of the myocardium with necrosis or degeneration of myocytes not typical of ischemic changes. Direct cytotoxic effect of causative agent followed by a secondary immune response
  • True incidence is unknown because many cases are asymptomatic
  • Autopsy studies have demonstrated evidence of myocarditis in 1–7% of cases and >50% in HIV patients
  • Male > female (1.5:1)
  • Average age of patients with myocarditis is 42 yr
  • Major cause of unexpected sudden death (15–20% of cases) <40 yr old

Etiology

  • Viral:
    • Enteroviruses (coxsackie B)
    • Adenovirus
    • Parvovirus B19
    • Herpesvirus (including cytomegalovirus [CMV])
    • Herpes virus 6
    • Hepatitis C
    • Influenza
    • Echovirus
    • Herpes simplex virus
    • Varicella-zoster
    • Epstein–Barr virus
    • Cytomegalovirus
    • Mumps
    • Rubeola
    • Variola/vaccinia
    • Yellow fever
    • Rabies
    • HIV
  • Bacteria:
    • Diphtheria
    • Tuberculosis
    • Brucellosis
    • Psittacosis
    • Meningococcus
    • Mycoplasma
    • Group A streptococcus
  • Protozoa:
    • Leishmaniasis
    • Malaria
    • Toxoplasmosis in the immunocompromised host
    • Treponema cruzi (Chagas disease):
      • Most common cause of heart failure and myocarditis worldwide
      • 20 million persons infected in Central and South America
    • Trichinosis
    • Trypanosomiasis
  • Spirochetes:
    • Borrelia burgdorferi, the spirochete agent in Lyme disease
    • Syphilis
  • Rickettsial:
    • Scrub typhus
    • Rocky Mountain spotted fever
    • Q fever
  • Fungal:
    • Candidiasis
    • Aspergillosis
    • Cryptococcosis
    • Histoplasmosis
    • Actinomycosis
    • Helminthic
    • Trichinosis
    • Echinococcosis
    • Schistosomiasis
    • Cysticercosis
  • Drugs:
    • Acetaminophen
    • Ampicillin
    • Chemotherapeutic agents (anthracyclines)
    • Cocaine
    • Hydrochlorothiazide
    • Lithium
    • Methyldopa
    • Penicillin
    • Sulfamethoxazole
    • Sulfonamides
    • Zidovudine
    • Radiation
    • Hypersensitivity
    • Heavy metals
    • Hydrocarbons
    • Carbon monoxide
    • Arsenic
  • Autoimmune disorders:
    • Systemic lupus erythematosus (SLE)
    • Wegener granulomatosis
    • Kawasaki disease
    • Giant cell arteritis
    • Sarcoidosis
  • Peripartum cardiomyopathy
  • Bites/stings:
    • Scorpion
    • Snake
    • Black widow venom

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