Infectious endocarditis

Definition

Infectious endocarditis is an infection of the lining of the heart chambers and heart valves that is caused by bacteria, fungi, or other infectious substances.

See also:

• Culture-negative endocarditis
• Endocarditis

Alternative Names

Causes

Endocarditis is usually a result of a blood infection. Bacteria or other infectious substance can enter the bloodstream during certain medical procedures, including dental procedures, and travel to the heart, where it can settle on damaged heart valves. The bacteria can grow and may form infected clots that break off and travel to the brain, lungs, kidneys, or spleen.

Most people who develop infectious endocarditis have underlying heart disease or valve problems.

However, an organism commonly found in the mouth, Streptococcus viridans, is responsible for about 50% of all bacterial endocarditis cases. This is why dental procedures increase your chances for developing this condition. Such procedures are especially risk for children with congenital heart conditions. As a result, it is common practice for children with some forms of congenital heart disease and adults with certain heart-valve conditions to take antibiotics before any dental work.

Other common culprits include Staphylococcus aureus and enterococcus. Staphylococcus aureus can infect normal heart valves, and is the most common cause of infectious endocarditis in intravenous drug users.

Less common causes of infectious endocarditis include pseudomonas, serratia, and candida.

The following increase your chances for developing endocarditis:

• Artificial heart valves
• Congenital heart disease (atrial septal defect, patent ductus arteriosus, and others)
• Heart valve problems (such as mitral insufficiency)
• History of rheumatic heart disease

Intravenous drug users are also at risk for this condition, because unsterile needles can cause bacteria to enter the bloodstream.

References

Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 6th ed. London: Churchill Livingstone; 2005; pp 975-1022.

Karchmer AW. Infective Endocarditis. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007: chap 63.