Myocarditis

• Alternative Names

  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.

  Viral infections:

  • Coxsackie
  • Cytomegalovirus
  • Hepatitis C
  • Herpes
  • HIV
  • Parvovirus

  Bacterial infections:

  • Chlamydia
  • Mycoplasma
  • Streptococcus
  • Treponema

  Fungal infections:

  • Aspergillus
  • Candida
  • Coccidioides
  • Cryptococcus
  • Histoplasma
  • Schistosomiasis

  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 (rheumatoid arthritis, sarcoidosis)
• Symptoms

  There may be no symptoms. If symptoms occur, they may include:

  • Abnormal heartbeat
  • Chest pain that may resemble a heart attack
  • Fatigue
  • 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:

  • Fainting, often related to irregular heart rhythms
  • Low urine output
• Signs and tests

  A physical examination may reveal the following:

  • Abnormal heartbeat or heart sounds (murmurs, extra heart sounds)
  • Fluid in the lungs
  • Rapid heartbeat (tachycardia)
  • Swelling (edema) in the legs

  Tests used to diagnosis myocarditis include:

  • Blood cultures for infection
  • Blood tests for antibodies against the heart muscle and the body itself
  • Chest x-ray
  • Electrocardiogram (ECG)
  • Heart muscle biopsy (endomyocardial biopsy)
  • Red blood cell count
  • Ultrasound of the heart (echocardiogram)
  • White blood cell count
• Treatment

  Treatment is aimed at the cause of the problem, and may involve:

  • Antibiotics
  • Anti-inflammatory medicines to reduce swelling
  • Diuretics to remove excess water from the body
  • Low-salt diet
  • Reduced activity

  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.

• Expectations (prognosis)

  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.

• Complications
  • Cardiomyopathy
  • Heart failure
  • Pericarditis
• 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:

  • Chest pain
  • Difficulty breathing
  • Swelling
• Prevention

  Promptly treating conditions that cause myocarditis may reduce the risk.

• References

  Liu PP, Schultheiss HP. Myocarditis. In: Libby P, Bonow RO, Mann DL, Zipes DP. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 66.

Review Date: 5/15/2008

Reviewed By: Alan Berger, MD, Assistant Professor, Divisions of Cardiology and Epidemiology, University of Minnesota, Minneapolis, MN. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.