Myocarditis (my-oh-kar-DYE-tis) is inflammation of the heart muscle, and pericarditis (per-ih-kar-DYE-tis) is inflammation of the smooth sac surrounding the heart.
Myocarditis, or inflammation of the muscular walls of the heart, is most commonly caused by viruses; however, it can also be caused by bacteria, parasites, and fungi. Other causes of the condition include radiation, chemicals, cocaine use, and prescription medications. Conditions that affect several parts of the body, such as autoimmune disease * , also can be associated with both myocarditis and pericarditis.
When the pericardium (per-ih-KAR-dee-um), the smooth, doublelayered sac-like covering that surrounds the heart, becomes inflamed—known as pericarditis—fluid usually accumulates in the space between its layers. As the amount of fluid increases, the buildup puts pressure on the beating heart and can limit its ability to function. Many of the same infections that cause myocarditis can cause pericarditis as well, and the two can appear together. In addition to the infectious causes of pericarditis, heart surgery or a heart attack * can lead to an inflamed pericardium and accumulation of fluid around the heart.
Myocarditis and pericarditis are uncommon complications of many infectious diseases. Many cases of myocarditis are mild and go undetected when the person is sick. In fact, it is difficult to determine exactly how many people develop myocarditis or pericarditis. However, some evidence of myocarditis is found in 1 to 4 percent of autopsies * . In almost all of these cases, there were no symptoms of the disease while the person was alive.
Neither myocarditis nor pericarditis is directly contagious. However, many of the organisms that cause infections that can lead to myocarditis or pericarditis are spread from person to person by coughing or sneezing. It is not clear why myocarditis or pericarditis develops in some people but not in others. A combination of the infection, a person's genes * , and an individual's immune response probably determines who will develop these conditions.
A doctor suspects myocarditis based on symptoms and a physical exam. For instance, a rapid heartbeat, fluid in the lungs, and swollen ankles and feet may point to heart failure, which can occur with myocarditis. The history of the patient's illness is another important clue, as the patient often has had symptoms of a viral infection within the previous two weeks to six months.
To assess the heart's condition, the doctor may order any of a variety of tests. Although a chest x-ray often appears normal in the early stages of the illness, it may show an enlarged heart or fluid-filled lungs. An electrocardiogram * (EKG) may show evidence of heart inflammation and can help identify a heart attack as the possible cause of the symptoms. An echocardiogram * may show the decreased heart function seen in myocarditis. Blood tests that reveal inflammation of the heart muscle are often abnormal in people with myocarditis and can help in making the diagnosis. A biopsy * of a piece of heart muscle can provide a definitive diagnosis. Other tests may be done to identify a specific virus or other infectious organism, but in many cases, the exact cause of the inflammation is never found.
To diagnose pericarditis, doctors look for signs of fluid around the heart. During a physical exam, physicians also listen for a rubbing sound that can be heard when the pericardial sac is inflamed. If enough fluid is present, the heart may appear enlarged on a chest x-ray. The fluid itself can be seen on an echocardiogram, a computed tomography * (CT) scan, or a magnetic resonance imaging * (MRI) scan. An EKG can be helpful in making the diagnosis as well.
Myocarditis and pericarditis may be difficult or impossible to prevent, but prompt recognition and treatment of these conditions will improve the chances of recovery. With both myocarditis and pericarditis, doctors strive to identify and treat the underlying cause, reduce the inflammation, and improve the heart's function. These are serious conditions that usually require hospitalization once the patient has developed detectable symptoms.
Anti-inflammatory medicines such as aspirin, nonsteroidal antiinflammatory medications, or corticosteroids * may be prescribed to reduce inflammation. Patients also may receive medicine to ease pain and diuretics *
Some cases of pericarditis may require pericardiocentesis (per-ih-KAR-dee-o-sen-tee-sis), or the removal of fluid from the pericardial sac with a needle. This procedure relieves pressure on the heart and collects fluid for tests. In chronic or recurrent cases, the doctor may recommend surgery to cut or remove part of the pericardium. During recovery, the patient's activity usually is restricted, and doctors typically recommend diet changes such as eating less salt. Cases of myocarditis and pericarditis may last from two weeks to three months, although some people never fully recover their prior heart function.
Complications of these conditions can be very serious. The heart muscle may become damaged and unable to pump effectively. Heart failure, irregular heartbeat, and death may occur. In some cases, if the heart muscle has been severely and permanently damaged, a heart transplant may be considered.
See also Bacterial Infections • Endocarditis, Infectious • Fungal Infections • Heart Disease: Overview • Viral Infections
Blanco, Christina Cartaya, and Jillian Bandler Parekh. “Pericarditis.” Pediatrics in Review 31, 2 (February 2010). http://pedsinreview.aappublications.org/content/31/2/83.full (accessed November 21, 2015).
Parks, John L. “Constrictive Pericarditis.” Medscape, December 23, 2014. http://emedicine.medscape.com/article/157096-overview (accessed October 28, 2015).
Tang, Wai Hong Wilson. “Myocarditis.” Medscape, September 5, 2014. http://emedicine.medscape.com/article/156330-overview (accessed October 28, 2015).
Wilson, Jeff. Myocarditis: Detection and Treatment. Jersey City, NJ: Foster Academics, 2015.
MedlinePlus. “Myocarditis.” U.S. National Library of Medicine, National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000149.htm (accessed October 28, 2015).
MedlinePlus. “Pericarditis.” U.S. National Library of Medicine, National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000182.htm (accessed October 28, 2015).
National Organization for Rare Disorders. “Myocarditis.” https://rarediseases.org/rare-diseases/myocarditis/ (accessed November 21, 2015).
NHS Choices. “Pericarditis.” National Health Services. (accessed November 21, 2015).
PubMed Health. “Pericarditis.” U.S. National Library of Medicine. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH006992/ (accessed October 28, 2015).
American Heart Association. 7272 Greenville Ave., Dallas, TX 75231. Toll-free: 800-AHA-USA1. Website: http://www.heart.org (accessed October 28, 2015).
Myocarditis Foundation. 3518 Echo Mountain Dr., Kingwood, TX 77345. Telephone: 281-713-2962. Website: http://www.myocarditisfoundation.org (accessed October 28, 2015).
National Organization for Rare Disorders. 55 Kenosia Ave., PO Box 1968, Danbury, CT 06813. Telephone: 203-744-0100. Website: http://www.rarediseases.org (accessed November 13, 2015).
* autoimmune disease (awtoh-ih-MYOON) is a disease in which the body's immune system attacks some of the body's own condition in which the body's own normal tissues and cells.
* heart attack is a general term that usually refers to a sudden, intense episode of heart injury. It is usually caused by a blockage of a coronary artery, which stops blood from supplying the heart muscle with oxygen.
* autopsies (AW-top-seez) are examinations of bodies after death to look for causes of death or the effects of diseases.
* genes (JEENS) are chemical structures composed of deoxyribonucleic acid (DNA) that help determine a person's body structure and physical characteristics such as hair or eye color. Inherited from a person's parents, genes are contained in the chromosomes found in the body's cells.
* congestive heart failure (kon-JES-tiv), or heart failure, is a condition in which a damaged or overworked heart cannot pump enough blood to meet the oxygen and nutrient needs of the body. People with heart failure may find it hard to exercise due to the insufficient blood flow, but many people live a long time with this condition.
* electrocardiogram (e-lek-tro-KAR-dee-o-gram), also known as an EKG, is a test that records and displays the electrical activity of the heart.
* echocardiogram (eh-ko-KAR-dee-uh-gram) is a diagnostic test that uses sound waves to produce images of the heart's chambers and valves and blood flow through the heart.
* biopsy (BI-op-see) is a test in which a small sample of skin or other body tissue is removed and examined for signs of disease.
* computed tomography (kom-PYOO-ted toe-MAH-gruh-fee), or CT, also called computerized axial tomography (CAT), is a technique in which a machine takes many x-rays of the body to create a three-dimensional picture.
* magnetic resonance imaging (or MRI) uses magnetic waves, instead of x-rays, to scan the body and produce detailed pictures of the body's structures.
* corticosteroids (kor-tih-ko-STIRoyds) are chemical substances made by the adrenal glands that have several functions in the body, including maintaining blood pressure during stress and controlling inflammation. They can also be given to people as medication to treat certain illnesses.
* diuretics (dye-yoor-EH-tiks) are medications that increase the body's output of urine.