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The endocardium is a smooth layer of tissue that covers the insides
of the heart covering the heart muscles. It leads to reduced friction
of blood as it passes against the heart wall. Bacterial infection of the
endocardial lining of the heart is known as infective endocarditis.
Subacute form: this is a disease caused by the
infection of previously deformed valves by weak bacterial organisms
Acute infective endocarditis: this is a disease
caused infection of normal valves by strong, aggressive bacterial organisms.
When bacteria reach the blood during the course of
any infection it disseminates on sterile vegetations (little projections
on the endocardium) that result from any form of injury. Bacteria are
trapped in the vegetations and infect it.
The infection requires high pressure areas and hence
is common in mitral and aortic valve lesions (as the left side of the
heart is stronger) and in weak incompetent valves more than tight valves
It never occurs in a failing heart and never occurs
with atrial fibrillation (AF) as the atrial muscles become inefficient
and do not produce the required pressure. It is also common in
congenital heart diseases with significant
shunting of blood (VSD, PDA,
Predisposing factors include deformed valves, intravenous
drug abusers (in which the acute form is common as injections may carry
the aggressive forms of bacteria mentioned above), prosthesis (which are
generally due to skin organisms but may be due to fungi etc.)
What are the symptoms?
This is not very easy, but generally any one
that is predisposed or develops heart symptoms in addition to fever then
infective endocarditis (IE) should be suspected. These should be examined
for a change in the character of a previous heart murmur or the appearance
of a new one. Other manifestations of the disease include Roth spots,
Osler?s nodes, Janeway nodules, splinter hemorrhage and clubbing. Septic
emboli to Brain, Lung, Kidney and Spleen and mycotic aneurysms.
Rheumatoid factor is positive in ? patients with
endocarditis for > 6weeks.
How is infective endocarditis diagnosed?
The definitive diagnosis
requires blood cultures to test for the existence bacterial organisms
in the blood and to indicate the proper antibiotic.
How is it treated?
Antibiotics are indicated for patients with predisposing
lesions before undergoing surgical manipulation leading to bacteremia.
Dental, urinary tract infections
High risk patients with prosthetic valves undergoing
genitourinary or GIT procedures
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Cultures are drawn and empiric antibiotics are given.
Many antibiotic regimens exist. (Search the
Once the results of cultures appear therapy is continued
according to the results and the response of the patient to empiric treatment.
Replacement of the infected valve or prosthesis
may be indicated.