Noninfective endocarditis is formation of blood clots on heart valves and the lining of the heart.

  • Symptoms occur when a blood clot breaks loose and blocks arteries elsewhere in the body.

  • Diagnosis is by echocardiography and blood cultures.

  • Treatment is with anticoagulants.

Endocarditis usually involves infection of the inner lining of the heart (endocardium) and/or heart valves (infective endocarditis). However, endocarditis also can occur without infection. This form is called noninfective endocarditis.

Noninfective endocarditis develops when fibrous blood clots without microorganisms (sterile vegetations) form on damaged heart valves. Damage may be due to a birth defect, rheumatic fever, or an autoimmune disorder (in which antibodies attack the heart valves). Rarely, damage results from insertion of a catheter into the heart. People most at risk include those with the following:

  • Autoimmune disorders such as systemic lupus erythematosus or antiphospholipid syndrome (a disorder that causes excessive blood clots)

  • Cancers of the lung, stomach, or pancreas

  • Other disorders that cause excessive blood clots, such as sepsis (a severe blood infection), uremia (the buildup of wastes in the blood caused by kidney dysfunction), burns, or disseminated intravascular coagulation (when multiple small blood clots form throughout the bloodstream)

Noninfective endocarditis, like infective endocarditis, may cause heart valves to leak or not open normally. Arteries may become blocked if vegetations break loose (becoming emboli), travel through the bloodstream to other parts of the body, and lodge in an artery, blocking it. Sometimes blockage can have serious consequences. Blockage of an artery to the brain can cause a stroke, and blockage of an artery to the heart can cause a heart attack. Organs that are often affected include the lungs, kidneys, spleen, and brain. Fingers and toes may also be affected. Emboli also often travel to the skin and back of the eye (retina).

Malfunction of the heart valves can cause heart failure. Symptoms of heart failure include cough, shortness of breath, and swelling of the legs.

Symptoms of noninfectious endocarditis occur when emboli form. The symptoms depend on what part of the body is affected.

Diagnosis of Noninfective Endocarditis

  • Echocardiography

  • Blood cultures

Distinguishing between noninfective and infective endocarditis is difficult but important because treatment differs. Noninfective endocarditis may be diagnosed when echocardiography detects vegetations on the heart valves. Echocardiography cannot determine whether vegetations are infected. In order to detect whether microorganisms are present, blood cultures are done. If no bacteria or other microorganisms are detected by blood culture, it is more likely that the endocarditis is noninfectious. Blood tests for substances that may indicate the cause of noninfective endocarditis may be needed.

Treatment of Noninfective Endocarditis

Prognosis is generally poor, more because of the seriousness of the underlying disorder than because of the heart problem.