Heart Valves and Infective Endocarditis

Updated:May 4,2016
1 What's the problem?orange stethescope

grandparents at beach with grandsonWhat is infective endocarditis?
Infective endocarditis (IE), also called bacterial endocarditis (BE), is an infection caused by bacteria that enter the bloodstream and settle in the heart lining, a heart valve or a blood vessel. IE is uncommon, but people with some heart conditions have a greater risk of developing it.

Infective endocarditis refers specifically to infection in the lining of the heart, but IE also affects the valves and often affects the muscles of the heart.

View an illustration of endocarditis.

There are two forms of IE:

  1. Acute IE — develops suddenly and may become life threatening within days
  2. Subacute IE (or subacute bacterial endocarditis) — develops gradually and subtly over a period of weeks to several months.

How do people contract infective endocarditis?
The infection is caused by bacteria introduced into the blood stream, usually through normal activity such as injury to the skin or damage to the lining of the mouth or gums. I.E. can be contracted through everyday activities such as brushing the teeth or even chewing for those who are at risk of developing the condition. These bacteria can lodge on heart valves and cause infection of the endocardium. 

Endocarditis illustration
View an illustration of endocarditis

Why does endocarditis pose a threat to the heart valves?
The heart valves are not supplied directly with blood. Therefore, the body’s immunity response system, such as the infection-fighting white blood cells, cannot directly reach the valves through the bloodstream. If bacteria begins to grow on the valves, it is difficult to fight the infection, whether through the body’s own immune system or through medications that rely on the blood system for delivery. 

Who is at risk for infective endocarditis?
IE affects twice as many men as women and eight times as many older men as older women. More than one-fourth of all cases occur in people older than 60. 

Risk factors for children and young adults include birth defects of the heart that allow blood to leak from one part of the heart to another.

Risk factors for adults include valve surgeries or transplants, calcium deposits in the mitral valve (which opens from the left atrium into the left ventricle) or in the aortic valve (which opens from the left ventricle to the left aorta).

Illegal drug use and IE
If the cause of IE is injection of illicit drugs or prolonged use of I.V. drugs, the tricuspid valve (which opens from the right atrium into the right ventricle) is most often infected. Street drugs, including narcotics, can also affect the mitral or aortic valve.

What are the symptoms of infective endocarditis?
The symptoms of acute IE usually begin suddenly with high fever (102°–104°F), fast heart rate, fatigue, and rapid, intensive valve disease.

The symptoms of subacute IE may be such things as fatigue, mild fever (99°–101°F), a moderately fast heart rate, weight loss, sweating, a low red blood cell count (anemia) and can take place over as much as a period of months.

Treatment usually consists of at least two weeks and as much as six weeks of high doses of I.V. antibiotics.

Prevention for those at risk usually involves awareness of the risks, and preventative antibiotics prior to certain surgical, dental and medical procedures.

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This content was last reviewed on 03/26/14.

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