Infective endocarditis
Alternative names:
acute endocarditis; bacterial endocarditis; subacute endocarditis
Definition:
An infection of the lining of the heart chambers and heart valves by bacteria, fungi, viruses, or other microorganisms. Bacterial endocarditis refers specifically to infection by a bacterial agent.
Causes, incidence, and risk factors:
Infectious endocarditis may involve the heart muscle, heart valves, or lining of the heart. Most people who develop infectious endocarditis have underlying heart disease. Sources of the infection may be transient bacteremia, which is common during dental, upper respiratory, urologic, and lower gastrointestinal diagnostic and surgical procedures. The infection causes growths on the heart valves, the lining of the heart, or the lining of the blood vessels. These growths may be dislodged and send clots to the brain, lungs, kidneys, or spleen. The incidence is 5 out of 100,000 people.
Many bacteria can cause endocarditis but a common mouth organism, Streptococcus viridans, is responsible for approximately half of all bacterial endocarditis. Other common organisms include staphylococcus and group D streptococcus. Less common organisms include Pseudomonas, Serratia, Candida, and many others.
Endocarditis may develop symptoms slowly (subacute) or suddenly (acute). Fever is a hallmark of both. In the slower form, fever may be present on a daily basis for months before other symptoms appear. Other symptoms are nonspecific such as fatigue, malaise (general discomfort), headache, and night sweats. As the illness progresses, small dark lines, called splinter hemorrhages, may appear under the fingernails. The health care provider may hear changing murmurs and detect an enlarged spleen and mild anemia. Murmurs are caused when clumps of bacteria, fibrin and cellular debris, called vegetations, collect on the heart valves. The mitral valve is the most common valve affected, followed by the aortic valve.
Preexisting conditions that increase the likelihood of developing endocarditis include: Since Streptococcus viridans is a common mouth organism and the most common cause of bacterial endocarditis, dental procedures can put children with congenital heart conditions at risk for endocarditis. It is common practice for children with some forms of congenital heart disease to start on antibiotics prior to any dental procedures.
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