Myocarditis – Causes and Symptoms

What is myocarditis?

The inflammation of the heart muscle is refered as the myocarditis. Myocardium is the muscular layer of the heart wall. This muscle is responsible for contraction and relaxation of heart to pump blood in and out of the heart and to the rest of the body.(1)

When inflammation occurs in this muscle , its ability to pump blood becomes less effective. This leads to various problems like an abnormal heartbeatchest pain, or trouble breathing. In extreme cases, it can cause blood clots leading to a heart attack or stroke, damage to the heart with heart failure, or even death.

Normally, inflammation is a response from your body to any type of injury or infection. Imagine when you cut your finger: within a small time, the tissue around the cut swells up and appears red, which are Cardinal signs of inflammation. The immune system in your body is producing special cells to travel at the site of the wound and to start repair.(2)

But sometimes the immune system or another reason of inflammation causes myocarditis.

What causes myocarditis?

In several cases, the exact cause of myocarditis is not clear. When the cause of myocarditis is found, it’s often an infection that goes to the heart muscle, such as a viral infection (the most common) or a bacterial, parasitic, or fungal infection.

As the infection tries to start an effect, the immune system fights back, trying to get rid of the disease. This results in an inflammatory response that may weaken heart muscle tissue. Some autoimmune diseases, like lupus (SLE), can lead to the immune system to turn against the heart, resulting in inflammation and damage to the myocardium.

It is usually difficult to determine exact cause of the myocarditis, but possible Causes include the following:


As stated by the Myocarditis Foundation, viruses are one of the most common causes of infectious myocarditis. The most common viruses that can lead to myocarditis include Coxsackievirus group B (an enterovirus), Human Herpes Virus 6, and Parvovirus B19 (which causes fifth disease).

Other potential causes include echoviruses (known to cause digestive tract infection), Epstein-Barr virus (causes infectious mononucleosis), and Rubella virus (causes German measles).


Myocarditis can also occur due to an infection with Staphylococcus aureus or Corynebacterium diptheriaeStaphylococcus aureus is the bacterium that can lead to impetigo and be a methicillin resistant strain (MRSA)Corynebacterium diptheriae is the bacterium that causes diphtheria, an acute infection that infects tonsils and throat cells.


Yeast infections, molds, and other fungi can sometimes also lead to myocarditis.


Parasites are microorganisms that depend on other organisms for their survival. They can also cause myocarditis. This is rare in the United States but more commonly seen in Central and South America (where the parasite Trypanosoma cruzi causes a disease known as Chagas disease).

Autoimmune diseases

Autoimmune diseases that cause inflammation in other parts of the body, such as rheumatoid arthritis or SLE, can also sometimes leads to myocarditis.

What are the symptoms?

The threatening thing about myocarditis is that it can affect anyone, occur at any age, and may develop without showing any symptoms. If symptoms do develop, usually they are similar to those symptoms one might experience with the flu, such as:

  • fatigue
  • breathlessness or dyspnea
  • fever
  • joint pain
  • swelling in lower extremities
  • feeling of pain in the chest

Many times, myocarditis may resolve on its own without any treatment, similarly like a cut on your finger gradually heals. Even some cases that go on for a long time may never produce sudden symptoms of heart failure.

But, privately, they may cause damage to the heart muscle where the heart failure symptoms gradually appear over time. In other cases, the heart may display its struggles earlier, with symptoms like chest pain, shortness of breath, heart palpitations, and heart failure.

How is it diagnosed?

Though myocarditis can be challenging to diagnose, your doctor can use various tests to reduce the source of your symptoms. These tests include:

  • blood testing: to check for signs of infection or sources of inflammation
  • chest X-ray: to show chest anatomy and possible signs of heart failure
  • electrocardiogram (ECG): to determine abnormal heart rates and rhythms that may indicate a damage to the heart muscle
  • echocardiogram (ultrasound imaging of the heart): to help determine structural or functional problems in the heart and adjacent vessels
  • myocardial biopsy (sampling of heart muscle tissue): in few cases, may be performed during a heart catheterization to allow the doctor to inspect a small piece of muscular tissue from the heart

Complications of myocarditis

Myocarditis can potentially cause remarkable damage to the heart. The body’s immune response, due to a virus or other infection leading to myocarditis, can cause significant damage as can certain chemicals or autoimmune diseases that can cause myocarditis. This can lead to heart failure and finally death. These cases are rare, as most patients who have myocarditis retrieve and restart healthy heart activity.

Other complications are problems with the heart’s rhythm or rate, heart attack, and stroke. In very few cases, an immediate heart transplant may be required.

Myocarditis is also associated with sudden death, with up to 9 percent of post-mortems of adults revealing inflammation of the heart muscle. This number increases to 12 percent for autopsies of young adults revealing heart muscle inflammation.

How is myocarditis treated?

Treatment for myocarditis may include the following:

  • corticosteroid therapy (to help lower inflammation)
  • cardiac medications, like beta-blockers, ACE inhibitors, or ARB
  • behavioral changes, such as rest, fluid restriction, and a low-salt diet
  • diuretic therapy to treate overload of fluid
  • antibiotic therapy

Treatment depends on the source and seriousness of the myocardial inflammation. In several cases, this improves with proper steps, and you will totally recover.

Almost all of these treatments work to ease the workload on the heart so it can heal itself.

If your myocarditis proceeds, your doctor may recommend a corticosteroid to help lower inflammation. They’ll also probably recommend rest, fluid restriction, and a low-salt diet. Antibiotic therapy may help treat the infection if you have bacterial myocarditis. Diuretic therapy may be recommended to remove the excessive fluid from the body. Your doctor may also prescribe medications that help the heart to function normally.

If the heart is declining, other more invasive procedures may be done in the hospital. Implantation of a pacemaker and/or a defibrillator may be essential. When the heart is excessively damaged, doctors may suggest a heart transplant.

Can it be prevented?

There are no steps to certainly prevent myocarditis, but avoiding severe infections may help. Some of the recommended ways to do so include:

  • having safe sexual intercourse
  • Properly following the date of vaccinations
  • proper hygiene
  • avoiding ticks

What is the outlook?

The viewpoint for myocarditis is generally positive. The chance of it repeating is thought to be approximately 10 to 15 percent, according to the Myocarditis Foundation. Most people with myocarditis recover and don’t have any long-term disadvantageous effects on their heart.

There is still much to be studied about myocarditis. Doctors think myocarditis is not inherited and haven’t found any genes specifying that it is.

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