Infectious Disease Compendium

Myocarditis

Diagnosis

Infection of the heart muscle.

Epidemiologic Risks

Depends on the organism.

Microbiology

An enormous number of organisms can involve the heart. NEJM review (PubMed).

A list, not inclusive, but of the important ones to consider, include:

- Viral: Adenovirus, Coxsackie A, Coxsackie B, Cytomegalovirus, Echovirus, Epstein-Barr, Hepatitis B, Hepatitis C, Herpes simplex, Human immunodeficiency virus, Influenza A and B, Lymphocytic choriomeningitis, Mumps, Nonpolio enterovirus, Parvovirus B19, Polio, Respiratory Syncytial virus, Rubella, Rubeola, Varicella-zoster.

-Bacteria and rickettsiae: Borrelia burgdorferi, Brucella, Chlamydia pneumoniae, Chlamydia psittaci, Clostridium perfringens, Corynebacterium diphtheriae, Coxiella burnetti, Ehrlichia, Legionella pneumophila, Listeria monocytogenes, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Neisseria meningitidis, Orientia tsutsugamushi, Rickettsia prowazekii, Rickettsia rickettsii, Salmonella, Staphylococcus aureus, Streptococcus pyogenes, Treponema pallidum, Tropheryma whippeli.

- "Acute nonrheumatic streptococcal myocarditis is an under recognized and treatable cause of ST segment elevation and chest pain in young adults with a history of recent pharyngitis (PubMed).

- Fungi: Aspergillus, Blastomyces, Candida species, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum.

-Parasites: Toxocara canis, Toxoplasma gondii, Trichinella spiralis, Trypanosoma cruzi (common in the US South), Trypanosoma gambiense, Trypanosoma rhodesiense.

Empiric Therapy

Depends on the presumed etiology. Bed rest is important, do not stress that heart.

Pearls

Fortunately the heart is hard to infect with bacteria. Usually acute disease of most of the bacterial organisms listed above leads to death. For the viral causes, usually get the diagnosis after the disease had come and gone and we have to deal with the resultant 'idiopathic' cardiomyopathy. It is rare indeed to get a positive and treatable acutely from a cardiac biopsy.

Rants