Health Library

Myocarditis is an inflammation of the heart’s muscular wall (myocardium). Although rare, it can be devastating. Myocarditis can occur with no symptoms and remain undiagnosed.

Healthy Myocardium

Copyright © Nucleus Medical Media, Inc.

In most children, the condition is often caused by a viral infection. There are different ways a child can become infected. A child may get an infection while in the womb, when viruses can be transferred from mother to baby. Medicines and autoimmune disorders can also cause myocarditis. Sometimes the cause cannot be found.

There are no known risk factors for developing myocarditis.

Symptoms vary from person-to-person. They may appear slowly or come on suddenly. How bad the symptoms are may also depend on your child’s age. Children older than two years old may have fewer symptoms compared to babies. This is because a baby’s immune system is less developed to fight an infection. Contact the doctor right away if your child has any of these symptoms:

• Flu-like complaints, including fever, fatigue, muscle pain, vomiting, diarrhea , and weakness
• Rapid or irregular heart rate
• Chest pain
• Trouble breathing
• Loss of consciousness
• Swelling of the face, feet, or legs
• Abdominal pain
• Decreased urine output

Some children may have no symptoms.

There is no specific test for and diagnosis can be hard. Many other causes of heart problems must be ruled out. To do this, the doctor will ask about your child’s symptoms and medical history. She will also do a physical exam.

Tests may include the following:

• Electrocardiogram (ECG) —a test that records the heart’s activity by measuring electrical currents through the heart muscle
• Chest x-ray —a test that uses radiation to take pictures of structures inside the body
• Cardiac enzyme blood test—certain enzymes may be elevated, showing that the heart muscle is inflamed
• Other blood tests—to look for signs of infection
• Echocardiogram —a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
• Biopsy —removal of a sample of heart tissue to test for infection
• Cardiovascular magnetic resonance—the use of magnetic waves to take pictures of structures inside the body 

Your child will need bed rest. She should avoid physical activity. Treatment is directed at the underlying cause if possible. For instance:

• If bacteria are causing the infection, then your child may be given antibiotics.
• If a virus is causing the infection, then your child may be given antiviral agents.
• Immunosuppressive therapy may be used if myocarditis is caused by an autoimmune disorder.

Medicines might be given to support heart function and to remove extra fluid from the lungs or other body tissues.

Myocarditis is hard to prevent. Reduce exposure to identified causes to help reduce your child’s chances of myocarditis. One way to do this is to practice good hygiene to avoid the spread of infection. For example, have your child wash her hands regularly.