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What are Autoimmune Diseases?
There are about 80 types of autoimmune diseases that affect many people, but mostly women, African-Americans, Hispanics and whites. Family history of autoimmune diseases and exposure to certain viruses, bacteria and chemicals also predispose some individuals to acquire these.
Normally the body’s immune system protects the body from common infections and diseases by activating mechanisms to destroy the offending cause of disease. However, abnormalities in genetic factors and infections make one susceptible to autoimmune responses where the immune system cannot differentiate extrinsic factors from self, or one’s own cells. This results in the immune cells attacking normal body cells, causing inflammation and damage to the tissues.
Attack on normal cells can occur in any tissue or organ, and multiple organs may even be involved. One of the major organs involved in autoimmune responses is the heart, and the result may lead to inflammation of the cardiac muscles, the inner lining of the heart including the valves and the covering of the heart or pericardium.
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Autoimmune Heart Disease
Inflammatory changes as a result of previous viral or bacterial infections and autoimmune disease can affect the different parts of the heart and cause heart disease. This condition may be associated with autoimmune diseases like lupus, rheumatoid arthritis and scleroderma. These inflammatory changes may be in the form of:
Inflammation of the outer covering of the heart or pericardium leads to pericarditis. This is usually an acute condition but can persist for several months.
The pericardium is a fluid-filled sac that protects the heart. When inflamed it can cause constriction of the heart and produce symptoms like chest pain that may radiate to the back, neck and left shoulder. Difficulty in breathing, coughing and fatigue may also be experienced.
The condition may be diagnosed by history, physical exam and imaging exams like chest x-ray, CT scan and MRI. It must be differentiated from a possible heart attack so that proper management may be done.
Medical treatment includes non-steroidal anti-inflammatory drugs, antibiotics and steroids if needed. In some cases, evacuation of excess fluid in the sac may be done with a procedure called pericardiocentesis.
When the heart muscle or myocardium is inflamed, a condition called myocarditis results. Chronic destruction of the muscles can lead to changes in the shape and structure of the heart resulting in enlargement or dilatation, also called dilated cardiomyopathy.
Symptoms may be mild initially but can later manifest as chest pain and eventually leading to symptoms of congestive heart failure. The individual may have difficulty in breathing, fatigue, palpitations and discomfort in lying flat or sleeping.
Laboratory studies will show cardiac enlargement and increased blood levels of biomarkers indicating an inflammatory process. ECG will show evidences of heart block or delay in transmission of impulses.
Medical treatment consists of management of congestive heart failure and is geared towards improving myocardial function. Examples of types of drugs used are diuretics, calcium channel blockers and digitalis.
Endocarditis and Heart Valve Disease
Bacterial infection and autoimmune response can affect the inner lining of the heart including the heart valves. These valves normally open to allow blood to leave the upper chambers (atria), enter the lower chambers (ventricles) and prevent backflow of blood. With chronic inflammation and scarring, the valves are deformed or destroyed and this may result in backflow to the upper chambers and the lungs. Eventually this leads to congestive heart failure.
The condition of the valves may be viewed by using transesophageal echocardiogram. Other imaging tests and ECG will show cardiac enlargement.
Antibiotics are needed to control the infection. When the heart valves are severely damaged, repair or valve replacement may be done by surgical methods.
In summary, infection and genetic disorders leading to autoimmune diseases like rheumatic fever, rheumatoid arthritis, lupus and scleroderma can have cardiac sequelae. These cardiac complications may affect the pericardium, the myocardium or the heart valves which may result in heart failure. Early diagnosis and treatment of infection and inflammatory responses are needed to prevent this complication.
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eMedicine, “Myocarditis in Emergency Medicine” http://emedicine.medscape.com/article/759212-overview
CDC, “Women and Autoimmune Diseases” http://www.cdc.gov/ncidod/EID/vol10no11/04-0367.htm
Cleveland Clinic, “Pericarditis” http://my.clevelandclinic.org/heart/disorders/other/pericarditis.aspx
Cleveland Clinic, “Valve Disease” http://my.clevelandclinic.org/heart/disorders/valve/valve_types.aspx