TOC | Cardiology   

Myocarditis 

Causes of Myocarditis

Viral agents and disorders

• Adenovirus, Arbovirus, Coscackieviruts B, Cytomegalovirus (CMV), Dengue virus, Echovirus, Epstein-Barr virus, Hepatitis C, Herpesvirus, HIV, Influenza virus, Mumps, Parvorisus B19, Poliomyelitis, Rabies, Rubella, Rubeola, Varicella, Variola, Yellow fever  

Bacterial agents and disorders

• Brucella, Chlamydia, Cholelra, Clostridia, Diphtheria, Hemophlus, Legionella, Meningococcus, Mycoplasma, Neisseria gonorroeae, Psittacosis, Salmonella, Staphylococcus, Streptococcus, Tetanus, Tuberculosis, Tularemia

Spirochetal disorders

• Leptospirosis, Lyme disease, Relapsing fever, Syphilis

Myocotic agents and disorders

• Actinomyces, Aspergillus, Blastomyces, Candida, Coccidiodomycosis, Cruptococcosis, Histoplasma, Mucormycosis, Nocardia, Sporotrichosis

Rickettsial disease

• Q-fever, Rocky Mountain Spotted fever, Typhus

Protozoal disease

• African sleeping sickness, Amebiasis, Chagas disease, Leishmaniasis, Malaria, Toxoplasmosis  

Helminthic agents and diseases

• Ascariasis, Echinococcosis, Filariasis, Paragonimiasis, Schistosomiasis, Strongyloides, Trihinosis  

Cardiotoxins

• Alcohol, Anthracyclines, Arsenic, Carbon monoxide, Catecholamines, Cocaine, Heavy metals

Causes of hpersensitivity reactions

• Antibiotics, CLozapine, Diuretics, Isect bites, Lithium, Snake bites, Tetanus toxoid, Mesalamine

Systemic disorders

Celiac disease, Connective tissue disorders, Hypereosinophilia, Kawasaki disease, Sarcoidodis, Thyrotoxidosis, Wgener granumlomatosis

Symptoms and Signs:

Most patients are asymptomatic; some have Sx mimics myocardial infarction, with acute onset of chest pain, tachyarrhythmia, or sudden death, some with heart failure Sx.

Lab Abnormalities:

Abnormal ECG with nonspecific ST-T changes, ST elevation mimicking acute MI, various degrees of blockade of the AV node.  The presence of Q waves or buble brach block is associated with increased rates of heart transplant or death.

Elevated serum Troponin I, troponin T, and CK-MB

Echocardiography may show left ventricular dysfunction with global hypokinesis with or without pericardial effusion.

To diagnose myocarditis with 80% sensitivity, an estimated 17 endomyocardial biopsies are necessary.

Cardiac MRI may be useful for diagnosing myocarditis associated with edema, hypremia, and fibrosis sensitive sequences.

Focal myocardial gasolinium enhancement, couple with regional wall motion abnormalities on echocardiography, yielded a positive predictive value of 71% and a negative predictive value of 100%.

Treatment of Myocarditis  

In viral myocarditis, because patients generally present days to weeks after the initial viral infection, antiviral therapy has limited applicability in patients with acture viral mnyocarditis.

Azathoprine and prednisone improved cardiac function in some patients.

REF: Mayo Clin Proc Nov 2009;84(11):1001

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2010