Myocarditis is a rare inflammation of the muscular layer of the heart wall, called the myocardium. The inflammation is generally a result of another infection in the body.

A healthy heart is a strong, muscular pump that continuously pushes blood through the circulatory system to deliver oxygen and nutrients to the body. After circulating through the body to deliver oxygen, blood is returns to the heart and is pumped into the lungs to pick up more oxygen. It is then pumped back out into the body again.

Myocarditis weakens the heart’s pumping ability so that it is unable to supply the body with enough oxygen-rich blood. This inability is called congestive heart failure.

Severe myocarditis that goes unchecked can cause permanent damage to the heart muscle. It can weaken the heart’s ability to pump blood efficiently and trigger dangerous blood clots and heart rhythm problems that may lead to a heart attack or stroke. However, with proper diagnosis and treatment, many children with myocarditis recover to grow and develop normally.

What causes myocarditis?

In most cases, myocarditis is caused by another infection in the body, such as:

  • Bacteria. Myocarditis is especially common with the bacteria that cause diphtheria and Lyme disease.
  • Viruses. The coxsackievirus B virus is the most frequent cause of myocarditis, and it can also be caused by echovirus, adenovirus, Epstein-Barr, HIV, rubella, and the flu.
  • Parasites. Myocarditis can be caused by insect-borne parasites such as those that cause Chagas disease (a disease most common in Mexico, Central America, and South America).
  • Fungi. Uncommonly, the fungi candida, aspergillus and histoplasma may cause myocarditis.

In some cases, myocarditis can also be caused by:

  • Allergy to medications such as penicillin or sulfonamides,
  • Reactions to illegal drugs such as cocaine, or
  • Exposure to chemicals such as arsenic or hydrocarbons,
  • Systemic diseases such as vasculitis, Wegener’s granulomatosis, tuberculosis, rheumatic fever, lupus, and other disorders of the connective tissue and inflammatory conditions.

You can reduce your child’s risk of myocarditis by:

  • Avoiding people who have viral (flu-like) illnesses.
  • Washing your hands and your child’s hands to avoid the spread of illness.
  • Dressing your child sensibly for the outdoors to protect him or her from ticks and insects.
  • Staying current on your child’s immunizations.

What are the signs and symptoms of myocarditis?

The symptoms of myocarditis vary for each child, but may commonly include:

  • Chest pains
  • Arrhythmia (irregular or rapid heartbeat)
  • Swelling of the legs, ankles and feet
  • Difficult or rapid breathing, especially with exertion
  • Cyanosis (a blue or gray tone to the skin, lips, or nails)
  • Loss of appetite and insufficient weight gain
  • Fatigue

Occasionally, symptoms may also include:

  • Fainting associated with arrhythmia
  • Head and body aches, fever, joint pain, sore throat or diarrhea
  • Sharp pains in the center of the chest

If your child’s case is mild, he or she may have no noticeable symptoms. It is possible to have only the symptoms of a viral infection (head and body aches, fever, joint pain, sore throat or diarrhea) and not know the heart is being affected. In cases where myocarditis does not present noticeable symptoms of its own, the inflammation generally clears up without treatment.

How is myocarditis diagnosed?

Your child’s doctor may suspect myocarditis if your child is exhibiting symptoms of an inflamed heart muscle and recently has had a viral or other infection.

A clear diagnosis is the first step to treatment. A pediatric cardiologist (a children’s heart doctor) can use several tests to confirm your child’s diagnosis. These tests may include:

  • Chest X-ray: A beam of electromagnetic energy creates images on film that show the inside structures of your baby’s body. A chest X-ray helps the doctor determine whether there is fluid building up in the lungs.
  • Electrocardiogram (ECG or EKG): This test, conducted by attaching patches with wires (electrodes) to the skin, records the heart’s electrical activity. It will show if there are abnormal heart rhythms (arrhythmias or dysrhythmias) and heart muscle stress.
  • Echocardiogram (Echo): This test uses high-pitched sound waves to produce a moving image of the heart on a video screen. It is similar to an ultrasound and can be used to assess the structure of the heart as well as pumping problems and fluid buildup.
  • Blood tests: Blood tests can help analyze your baby’s red and white blood cell counts, harmful enzyme levels, and antibodies that may help determine a related infection.
  • Cardiac catheterization: In this procedure, the doctor inserts a thin flexible tube (a catheter) into a blood vessel in the groin, then guides it to the inside of the heart.
  • Biopsy: During catheterizations, a biopsy (a tiny sample) of heart tissue can be taken for laboratory analysis to check for inflammation and infection.

How is myocarditis treated?

Once diagnosed, your child’s specific treatment may vary, depending on his or her individual needs. However, treating myocarditis usually starts with treating the infection responsible for it.

In mild cases of myocarditis, your child’s doctor may simply prescribe medications to treat the underlying infection and ask you to restrain your child from strenuous play while the heart recovers. Medications may be prescribed to reduce the heart’s workload, decrease fluid retention and strengthen pumping. When the inflammation of the heart’s muscle wall subsides, your child can become more active again.

In the less common instances where myocarditis is severe and advanced, treatment may include intravenous medications to assist heart function, the use of a temporary artificial heart, the insertion of a pump inside the heart’s aorta, or even heart transplant surgery. If there is long-term damage to the heart muscle, lifelong medications and treatments may be necessary.

About treatment for myocarditis at Children’s

Myocarditis left heart syndrome is treated through Children’s cardiovascular program one of the largest and oldest pediatric cardiovascular programs in the region. Team members consistently achieve treatment results that are among the best in the nation. Each year, care is provided for thousands of the region¹s sickest children with heart conditions, including fetuses, newborns, infants, children, adolescents, and adult, long-term patients with pediatric cardiovascular conditions.

Contact us

For more information, please call Children’s Heart Clinic at 1-800-938-0301.