Endocarditis is an inflammation or infection of the endocardium, which is the inner lining of the heart muscle and, most commonly, the heart valves. It is usually caused by bacterial infection, but can be caused by fungus.
The heart is made up of three cellular layers: the epicardium (outermost layer), the myocardium (middle, muscular layer), and the endocardium (innermost layer).
The endocardium lines all of the chambers and valves of the heart, and its cells are continuous with those of blood vessels leaving the heart.
If bacterial endocarditis is not adequately treated, it may be fatal. This is dependent on the infecting organism. Even when treated, further damage to a heart valve may lead to heart failure. In addition, blood clots may form and travel throughout the bloodstream to the brain or lungs.
In infective endocarditis, the bacteria cluster on and around the heart valves; this may impair their ability to function properly. Although bacterial endocarditis may occur in anyone at any time, it is unusual in persons who do not have valvular heart disease.
Valves deformed by a previous attack of rheumatic fever were once a major predisposing factor, but this is less so today since rheumatic fever has become much less common.
Other predisposing factors include artificial heart valves, some congenital heart disorders, hypertrophic cardiomyopathy, and mitral valve prolapse with regurgitation. People with such risk factors are more likely to develop endocarditis when exposed to an infection from any source.
Dental surgery, urologic or gynecologic surgery, colonoscopy, and skin infections increase the risk of endocarditis, even if there is no pre-existing anatomic valve deformity.
Intravenous drug users are also at significant risk.
The acute form of endocarditis may cause more severe symptoms, while symptoms of the chronic form may be milder, making it more difficult to diagnose.
Symptoms of bacterial endocarditis may include fever, fatigue, loss of appetite, night sweats, chills, headaches, joint discomfort, and tiny pinpoint-sized hemorrhages on the chest and back, fingers, or toes. Upon examination, the physician may also detect a new heart murmur and small hemorrhages in the mucous membranes of the eyes.
Diagnosis is usually suspected based upon the patient's history, symptoms, and findings such as a new murmur. It may be confirmed by blood tests (blood cultures) to identify an infectious organism. An echocardiogram (an ultrasound study of the heart muscle and valves) may be helpful in identifying a clump of bacteria on the heart valve.
Bacterial endocarditis almost always requires hospitalization for antibiotic therapy, generally given intravenously, at least at the outset. Occasionally, therapy with oral antibiotics at home will be successful.
Antibiotic therapy usually must continue for at least a month. Most patients respond rapidly to institution of appropriate antibiotics, with over 70 percent of patients becoming afebrile (without a fever) within one week. In unusual cases, surgery may be necessary to repair or replace a damaged heart valve.
It is important that you mention to your physician or dentist any risk factors you may have for endocarditis.
Those who have any predisposing factors for bacterial endocarditis (including prosthetic heart valves, previous bacterial endocarditis, congenital heart disease, rheumatic valve dysfunction, hypertrophic cardiomyopathy, and mitral valve prolapse with valvular regurgitation) should be given antibiotics before most medical or dental surgeries and whenever any significant skin infection occurs. Your physician will recommend which antibiotic(s) to take before, and in some cases, after your procedure.