Myocarditis: Inflammation of the heart muscle
What causes myocarditis?
Viral infections are an important cause of the disease. During epidemics of mosquito borne Dengue fever, some of the fatal cases are due to involvement of heart muscle. There are many other viral infections which cause myocarditis. Some bacterial diseases can also cause myocarditis. Immunologically mediated diseases like rheumatic fever can cause myocarditis, but often the manifestation is masked by those of associated valvular involvement. Tuberculosis can also involve the myocardium and so can human immunodeficiency virus. Bacterial infections of the valves and pericardium can spread to the myocardium, but manifestation is often that of the initial disease.
Vaccine for smallpox has been occasionally reported to cause myocarditis (vaccine associated myocarditis). Though smallpox has been eradicated, vaccine is used in some military forces as a precautionary measure in case of bio-terrorism attacks.
What are the symptoms?
When it occurs as a complication of another disease like Dengue fever, most of the manifestations will be that of the original disease. Severe weakness of the heart muscle can result in fatigue and breathlessness. Blood pressure may fall in severe cases. In rare cases there can be abnormalities of heart rhythm, some of which could be life threatening. Palpitations can occur if there is frequent abnormalities in heart rhythm.
How can it be treated?
When it is part of some other illness, treatment is that of the original disease. Treatment is mainly supportive to the heart. If there is breathlessness due to heart failure, medications for heart failure can be given. Close monitoring in the intensive care unit for heart rhythm abnormalities which could be life threatening is desirable in most cases of myocarditis. Severe cases may need invasive or non invasive ventilator (artificial respirator) support. If the blood pressure drops, medications to bring it up are given. Very severe cases may require a device known as ECMO (Extra Corporeal Membrane Oxygenator) which takes over the function of the heart and lungs when they are severely but reversibly damaged.