Pericarditis is an inflammation of the pericardium, the saclike membrane around the heart. Pericarditis can be triggered by many, very different medical conditions. Often the exact cause cannot be identified. Doctors call this idiopathic pericarditis.
In many people with pericarditis, the initial trigger is a viral infection. However, the inflammation may not be a direct result of the infection. Instead, the virus may stimulate the immune system to attack and inflame the pericardium.
Other medical conditions associated with pericarditis include:
An autoimmune disease. Several diseases are caused by the immune system attacking our own organs, including the pericardium. Examples include systemic lupus erythematosus (SLE) and rheumatoid arthritis.
A bacterial infection. This is called pyogenic (pus-producing) pericarditis. An infection can spread directly into the pericardium from a heart valve (endocarditis), the lung or a tear in the esophagus. Also a blood infection, especially staph, can get into the lining around the heart. Pyogenic pericarditis is rare today, but it remains a very serious condition.
Tuberculosis. Tuberculous pericarditis can occur as part of an active tuberculosis infection.
Uremia. Uremic pericarditis can occur in people with uremia, an accumulation of urea and other waste products in the blood caused by kidney failure.
Heart attack (myocardial infarction). Sometimes a major heart attack will inflame the pericardium next to the area of the heart that is damaged.
Cardiac injury. As in heart attack, heart damage caused by trauma (a stab wound or severe blow to the chest) or cardiac surgery also can trigger pericarditis.
Dressler's syndrome (also called post cardiac surgery or post cardiac injury syndrome). The pericarditis of Dressler's syndrome can begin within a couple weeks or up to many months after open heart surgery, heart trauma or a heart attack. In this syndrome, prior heart injury stimulates the immune system to attack and inflame the pericardium.
Other rare causes of pericarditis include radiation therapy to treat cancers in the chest, cancer in the chest area, a fungal infection or a parasitic infection.
Pericarditis can be:
Acute -- New onset of an inflamed pericardium causing symptoms over several hours to a couple weeks.
Chronic -- Persistent inflammation of the pericardium over many weeks and sometimes months.
Recurrent -- Repeated episodes of acute pericarditis. In between, episodes there are no symptoms and no obvious inflammation of the pericardium.
The inflammation of pericarditis usually causes fluid to weep into the pericardial sac. This is known as a pericardial effusion. If the pericardial effusion is large enough, it can interfere with the heart's ability to fill normally and to pump blood, a condition called cardiac tamponade.
Sometimes, pericarditis leads to scarring of the lining around the heart. The inflamed pericardium thicken can thicken and contract around the heart, interfering with heart function. This condition is called constrictive pericarditis.