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Inflammation - heart muscle
Causes, incidence, and risk factors
Myocarditis is an uncommon disorder that is usually caused by viral, bacterial, or fungal infections that reach the heart.
When you have an infection, your immune system produces special cells that release chemicals to fight off disease. If the infection affects your heart, the disease-fighting cells enter the heart. However, the chemicals produced by an immune response can damage the heart muscle. As a result, the heart can become thick, swollen, and weak. This leads to symptoms of heart failure.
Other causes of myocarditis may include:
Allergic reactions to certain medications or toxins (alcohol, cocaine, certain chemotherapy drugs, heavy metals, and catecholamines)
Being around certain chemicals
Certain diseases that cause inflammation throughout the body (
There may be no symptoms. Symptoms may be similar to the flu. If symptoms occur, they may include:
- Fever and other signs of infection including headache, muscle aches, sore throat, diarrhea, or rashes
- Joint pain or swelling
- Leg swelling
- Shortness of breath
Other symptoms that may occur with this disease:
Signs and tests
A physical examination may show no abnormalities, or may reveal the following:
Tests used to diagnosis myocarditis include:
Treatment is aimed at the cause of the problem, and may involve:
If the heart muscle is very weak, your health care provider will prescribe medicines to treat heart failure. Abnormal heart rhythms may require the use of additional medications, a pacemaker, or an implantable cardioverter-defibrillator. If a blood clot is in the heart chamber, you will also receive blood thinning medicine.
How well you do depends on the cause of the problem and your overall health. The outlook varies. Some people may recover completely. Others may have permanent heart failure.
Calling your health care provider
Call your health care provider if you have symptoms of myocarditis, especially after a recent infection.
Seek immediate medical help if you have severe symptoms or have been diagnosed with myocarditis and have increased:
Promptly treating conditions that cause myocarditis may reduce the risk.
Liu P, Baughman KL. Myocarditis. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 70.
McKenna W. Diseases of the myocardium and endocardium. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 60.
- Last reviewed on 6/7/2012
- Glenn Gandelman, MD, MPH, FACC Assistant Clinical Professor of Medicine at New York Medical College, and in private practice specializing in cardiovascular disease in Greenwich, CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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This page was last updated: May 20, 2014