I. Definition and Sites of Infection
II. Diagnosis
III. Therapy
IV. Prevention
GLOSSARY
endocarditis infection of the endocardial lining of heart valves. endocardium the interior lining of the heart (see the chapter.
Anatomy of the Heart and Circulation). nosocomial pertaining to or originating in a hospital.

• I. DEFINITION AND SITES OF INFECTION
  Valves previously affected by rheumatic fever and other valve diseases are thick, rough, and swollen. Bacteria that gain entry into the bloodstream on their way through the heart may attach to the roughened valve surface and set up an area of infection. This bacteria may grow to form an ‘‘abscess’’ on the valve. The abscess resembles a clump of moss that swings and sways on the valve leaflet as it opens and closes.
• II. DIAGNOSIS
  The diagnosis of endocarditis requires a high index of suspicion. The condition must be considered and carefully excluded in all patients with a heart murmur and fever of undetermined origin that persists for more than a few days. Diagnosis is made in the majority of patients by three or four separate sets of blood cultures taken from a separate vein puncture site over 24 h.
• III. THERAPY
  Intravenous antibiotics are commenced soon after suffi¬cient blood cultures are obtained; usually a combination of nafcillin (oxacillin or flucloxacillin), ampicillin, and gentamicin is administered. Changes are made when the organism and antibiotic sensitivities are established.
• IV. PREVENTION
  Prevention of some cases of bacterial endocarditis is achieved by intelligent use of appropriate antibiotics on the day of dental or other surgery. Approximately 25% of cases of endocarditis are believed to be of dental origin and in approximately 75% of cases the portal of entry cannot be identified. In over 40% of cases infection occurs on valves not known to be abnormal, especially on bicuspid aortic valves and in patients with mitral valve prolapse. Except for prosthetic valves in which a powerful antibiotic regime is administered, prophylaxis is aimed at streptococci, which accounts for only about 65% of all cases of endocarditis.
• BIBLIOGRAPHY
  Cabell, C. H., Abrutyn, E., and Karchmer, A. W. Bacterial endocardi¬tis. The disease, treatment, and prevention. Circulation, 107:e185, 2003.