Endocarditis is an inflammation of the lining of the heart valves that is most often caused by infection. Most people who develop this condition already have heart problems and are over 50 years old, but it can occur at any age, including in children. While not very common, this can be a very serious disease. Men are twice as likely to be affected as women.
There are two types of endocarditis: infective and non-infective. With prompt treatment, the majority of people with infective endocarditis will survive. Non-infective endocarditis is more difficult to treat.
Some people are more likely than others to develop endocarditis. The following conditions increase the risk:
Endocarditis develops in the endocardium, the inner tissue of the heart. It starts if this tissue has been damaged, injured, or infected. Much as a cut on the skin causes a scab to form, damage to the endocardium can lead to the formation of a blood and tissue clot (thrombus).
In infective endocarditis, the clots are caused by bacterial or fungal infection, inflaming and damaging the heart cells. The infection reaches the heart through blood that's carrying a concentration of bacteria, a condition called bacteremia. Once the infectious agent reaches the heart via the blood, it tends to concentrate around the valves, the blood's points of entry and exit. Despite the name, infective endocarditis isn't contagious.
The infecting agent can get into the blood through:
In non-infective endocarditis, the clot may not be infected but interferes with heart valve function anyway. Some conditions make the formation of scar tissue on the heart valves more likely:
Endocarditis can start slowly and gradually, over the course of several months. This is called subacute infective endocarditis. Symptoms include:
If the disease goes untreated for some time, further symptoms may appear:
At other times, infection progresses very quickly. This is known as acute endocarditis, and causes:
Although most people with infectious endocarditis have a fever, older people and those with long-lasting (chronic) conditions like kidney disease or congestive heart failure may not.