What is Myocarditis?

Myocarditis is the term used when inflammation is present in the middle layer of the heart wall. The most common cause is a viral infection related to an upper respiratory infection. It can also be the result of exposure to environmental toxins, autoimmune disorders, and harmful reactions to medications. Although the chances are relatively low (about ten to fifteen percent), myocarditis has been known to be a recurrent condition, and there is no way to prevent this from happening.

Fortunately, the disease is a rare one. Most often, it affects people who are otherwise perfectly healthy. Little is known as to the reasons for this, but there is no reason to believe that myocarditis is genetic or hereditary. Prognosis varies case by case, although chronic heart failure is a common long-term complication. Severe cases can lead to damage or weakening of the patient’s heart, and this in turn could lead to irregular heartbeat, heart failure, and even sudden death.

What are the Symptoms of Myocarditis?

Each case of myocarditis differs in severity. Many times there will be no symptoms and the condition is not detected until an ECG or blood test is done.

Symptoms include

  • Abnormal heartbeat
  • Chest pain
  • Shortness of breath
  • Fatigue
  • Dizziness
  • General discomfort
  • Heart murmur
  • Fast breathing
  • Heart palpitations
  • Swelling in extremities

Myocarditis Causes

The most common causes of myocarditis are viral and bacterial infections, particularly those that cause upper-respiratory disorders. People with autoimmune diseases are also more susceptible to developing myocarditis.

Viral infections that increase risk include hepatitis B and C, adenovirus (the cause of the common cold), parvovirus, herpes simplex virus, gastrointestinal infections, mononucleosis (Epstein-Barr), and rubella (measles). Myocarditis is also common in those with HIV.

Bacterial infections that can cause myocarditis include staphylococcus, streptococcus, and the bacteria that cause Lyme disease and diphtheria.

Autoimmune diseases, including lupus and rheumatoid arthritis, are often associated with myocarditis.

Less common causes include:

  • Parasites, particularly some which are prevalent in Central and South America.
  • Fungi, such as yeast (candida), molds, and other fungi, including those found in bird droppings.
  • Medications and other drugs that can cause an adverse reaction, such as antibiotics, anti-seizure medications, drugs used for cancer treatment, and some illegal drugs such as cocaine.
  • Some chemicals, such as carbon dioxide, and radiation.
  • Snake bites (rarely).
  • Heavy metal poisoning (rarely)

How is Myocarditis Treated?

Many myocarditis infections will clear up on their own without medical treatment.

Treatments include

Simple diet changes that restrict the amount of sodium intake will alleviate symptoms while the condition runs its course.

Other cases may require some form of medication. This could involve ACE inhibitors for relaxing blood vessels and lowering blood pressure, beta blockers for slowing heart rate, diuretics for increased urine production to rid the body of excess salt, and antiarrhythmic agents to control an irregular heartbeat.

Myocarditis Prevention

Although there is no fail-safe way to prevent myocarditis, the risk of developing it can be reduced by taking certain precautions, especially those that protect against viral illnesses.

  • Ensure that vaccines are up to date. Check with your health care provider to find out when any boosters are due.
  • Practice good hygiene. Wash your hands frequently and thoroughly, especially when you are around others who are ill.
  • Avoid exposure whenever possible to those with viral illnesses, including people with flu-like symptoms.
  • Avoid exposure to ticks when possible. Wear pants and long-sleeved shirts and use insect repellants with DEET in areas where the tick population is high.
  • Avoid risky behaviors, such as unprotected sex and illegal drug use.
  • When traveling in areas with a high incidence of parasites, avoid contaminated water and other areas where parasites thrive.
Last Reviewed:
October 07, 2016
Last Updated:
March 12, 2018