Myocarditis in Children
Basics of Myocarditis
Myocarditis is inflammation of the heart muscle, which rarely occurs in young children. The condition tends to be more severe in newborns and young infants than in children over age two.
Causes of Myocarditis
In children, the most common cause of myocarditis is a virus that has reached the heart such as; a flu virus, Coxsackie virus, parvovirus B19 or adenovirus. The condition can also be triggered by bacterial infections, including Lyme disease.
The damage to the heart can occur one of two ways.
- A virus or bacteria that infects the heart can cause direct damage to the heart
- The body’s own immune cells can damage the heart muscle (or “myocardium”) as the body fights to get rid of an infection.
Other causes include:
- Allergic reactions to certain medications
- Exposure to certain chemicals in the environment
- Infections due to fungus or parasites
- Excessive exposure to radiation
- Some diseases (autoimmune disorders) that cause inflammation throughout the body
- Some drugs such as; antibiotics (penicillin and sulfonamide), some anti-seizure medications as well as some illegal substances (cocaine)
Symptoms of Myocarditis
Symptoms may be mild at first and hard to detect. However, for some newborns and infants, symptoms show up suddenly and may include:
- Failure to thrive or poor weight gain
- Feeding difficulties
- Fever and other symptoms of infection
- Low urine volume (a sign of decreasing kidney function)
- Pale, cool hands and feet (a sign of poor circulation)
- Rapid breathing
- Rapid heart rate
Symptoms in children over age 2 may include:
- Stomach pain and nausea
- Chest pain
- Swelling (edema) in the legs, feet and face
Health Problems Associated with Myocarditis
Myocarditis affects children differently, depending on the cause and child’s overall health and age. Most children fully recover from myocarditis with appropriate treatment, while a few develop permanent heart disease. Newborns are at greatest risk for developing serious complications stemming from myocarditis. In rare cases, the condition damages the heart so severely that a heart transplant is needed to save the child’s life.
Myocarditis can lead to other heart problems, including:
- Dilated cardiomyopathy, enlargement of the heart muscle that leads to reduced heart function
- Heart failure
- Heart rhythm problems
Tests, Procedures and Diagnosis of Myocarditis
It can be challenging to diagnose myocarditis because its signs and symptoms often mimic those of other heart and lung diseases — or even a bad case of the flu. To diagnose the condition, a physician listens to a child’s chest with a stethoscope and may hear a rapid heartbeat or abnormal heart sounds. The physician may see signs of infection, including fever and rashes, during a physical examination. The physician may order a chest X-ray, which can show enlargement (or swelling) of the heart, and/or an electrocardiogram.
Other diagnostic tests may include:
- Blood cultures to check for infection
- Blood tests to look for antibodies against viruses or the heart muscle itself, or to check for liver and kidney function
- Complete blood count
- Heart biopsy
- Special tests that detect viruses in the blood (viral PCR)
Treatment for Myocarditis
The goal of treatment is to support heart function until the heart muscle inflammation goes away on its own over time.
Many children with the condition are admitted to the hospital for treatment, which may include:
- Antibiotics to fight bacterial infection
- Steroids, a type of anti-inflammatory medication, to control inflammation
- Intravenous immunoglobulin (IVIG), a medicine made of antibodies that the body uses to fight infection
- Medicines to treat symptoms of heart failure
- Medicines to treat abnormal heart rhythms