Myocarditis is the inflammation of the myocardium, which is the tissue located in the heart. 

Causes

Myocarditis can either be caused by a viral, bacterial, or parasitic infection.  Infections such as polio, influenza, or rubella can cause Myocarditis.  Allergic reaction, being around certain chemicals, and other diseases that cause inflammation throughout the body can cause Myocarditis as well.

When a body becomes aware of an infection, the immune system produces special cells that release chemicals to fight off the disease.  If the infection is in the heart, the chemicals enter the heart.  These chemicals can damage the heart muscle, causing it to become thick, swollen, and weak.  This can lead to heart failure. 

Symptoms

There is a chance no symptoms may be presented. Some symptoms that may occur are fever, headaches, muscle aches, sore throats, diarrhea, chest and joint pain, leg swelling, irregular heart beats (arrhythmia), fatigue/shortness of breath, fainting, and low urine output.

Examination

Exams and tests are used to reveal some irregularities that may occur in the body due to this disease.   Some irregulars that may be detected are rapid heartbeats, heart murmurs or extra heart sounds, fluid in the lungs, swelling (edema) in the legs.  Tests that are used to detect these irregularities are electrocardiograms, chest x-rays, echocardiograms, white and red blood cell counts, blood cultures.

Treatment

Bacterial infections are treated with antibiotics.  Most viral infections cannot be treated with directed therapy, and therefore rest is essential.  Reduced activity and following a low salt diet is recommended. 

NSAID’s are used for the inflammatory component.  Diuretics and/or inotropes are used for ventricular failure.  ACE inhibitors maybe aid in the healing process as well.

If an abnormal heart rhythm is present, a pacemaker or a defibrillator maybe be required.

Long Term Effects

Long term effects depend on the person and the degree of the disease.  Many people recover their heart function without any long term effects and reduced symptoms.  In few cases, heart function may not recover fully and heart transplantation may be required. 

There is a small possibility that myocarditis can recur, and can lead to a chronically enlarged heart, also called dilated cardiomyopathy.