 Endocarditis
is an infection that invades the innermost lining of the heart - the
endothelium. It can damage the heart valves, the rings of connective
tissue that surround the valves, as well as the inner linings of the
heart chambers themselves.
In
some congenital cardiac diseases, infection can also occur in the
lining of the arteries that come out of the heart. The prevalence
of infective endocarditis is between 1.7 and 4 per 100,000 persons,
most commonly affecting men in their fifties.
What
causes infective endocarditis?
Bacteria
are usually the source of infective endocarditis. For endocarditis
to occur, a microbial organism must be present in the blood (bacteremia).
When bacteremia occurs, bacteria in the blood come in contact with
the interior of the heart. However, not everyone who develops bacteremia
develops endocarditis.
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Cardiac Risk Factors For Infective
Endocarditis |
High risk
Prosthetic heart valve
Previous history of endocarditis |
Moderate risk
Rheumatic heart disease
Acquired valvular disease
Congenital heart disease
Hypertrophic cardiomyopathy |
Probable
Moderate risk
Mitral valve prolapse
Undiagnosed heart murmurs |
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Other risk factors include intravenous drug use, male
gender, African-American race, and pulmonary artery catheterization.
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Those
who do develop endocarditis often have a cardiac abnormality that
makes it easier for bacteria to invade the endothelium of the heart.
Approximately 65 percent of people with endocarditis have a predisposing
structural heart problem.
What
are the signs and symptoms?
The
signs and symptoms of infective endocarditis depend on the causative
organism. Symptoms may include fever, fatigue, weight loss, new
rashes (either painful or painless), headaches, backaches, joint
pains, and confusion. While these seem like nonspecific symptoms,
your doctor will consider them in the context of your own personal
risk factors as well as the results of a physical exam and laboratory
findings.
A new
heart murmur as well as new skin, fingernail, and retinal lesions
are typical physical findings in endocarditis. Doctors make the
diagnosis by finding microbial organisms in the blood and by performing
an echocardiogram
that shows evidence of endocarditis in the heart.
What
are the complications?
If
not treated, most patients with infective endocarditis will die.
Depending on when treatment is begun, there can be various complications.
The infection can destroy the heart valves, resulting in congestive
heart failure. Small masses of bacteria or fungus, as well as platelets
and fibrin can flick off the valves and cause problems throughout
the body.
These
are called emboli. They can result in strokes, kidney failure, heart
attacks, and damage to the gastrointestinal organs. Endocarditis
can also result in heart arrhythmias and inflammation of heart tissue.
Finally, infective endocarditis can result in abscesses in the heart
that are very hard to treat.
How
is endocarditis treated?
Infective
endocarditis is treated with antibiotics and with surgery in some
situations. Intravenous antibiotics are used for several weeks to
eradicate the organism that caused the condition. But in more serious
cases, urgent cardiac surgery is indicated to treat some patients.
Surgery
is considered particularly when a patient has an artificial heart
valve. However, there is new evidence to suggest that certain kinds
of bacterial infections of prosthetic valves can be treated with
just antibiotics.
Is
endocarditis preventable?
Yes.
As described above, infective endocarditis occurs when there is
an infection in the blood. Antibiotics can prevent such an infection
from occurring in the first place. Antibiotic prophylaxis is recommended
before medical procedures with a high probability of introducing
bacteria into the blood.
Dental
procedures that cause bleeding from the gums (even a simple cleaning);
rigid bronchoscopy; and surgery of the upper respiratory tract,
urinary tract procedures, and gastrointestinal procedures all confer
an increased risk of bacteremia, and therefore, an increased risk
of infective endocarditis in those individuals with predisposing
cardiac lesions.
If
you have a history of structural heart abnormalities, you should
talk to your primary care physician about taking prophylactic antibiotics
prior to any of these procedures.
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