Endiocarditis

Bacterial Endocarditis

by Ernest G. Brookfield, M.D.
Division of Pediatric Cardiology
Medical College of Ohio
Toledo, Ohio
From CHASER News V.2-No.1; 2/94 - © Copyrighted Material
Bacterial endocarditis is an infection of the inner surface of the heart or the heart valves caused by bacteria usually found in the mouth, intestinal tract or urinary tract. This infection results in a seriousillness which requires prolonged treatment and on occasion produces injury to the heart or even death. Endocarditis is a major concern in almost all unrepaired congenital heart defects as well as in most repaired defects with a few exceptions. Endocarditis is generally preventable with simple measures, but the implementation of these measures is often confusing for the parents of thechild, thephysician, and the dentist. Hopefully this brief article will decrease some of that confusion.
Endocarditis occurs when bacteria grow on the edges of a heart defect or on the surface of an abnormal valve after the bacteria enter the blood stream, most commonly from dental procedures but also from procedures involving the gastrointestinal or urinary tract. Once the bacteria infect the innersurfaceof the heart, they continue to grow producing large particles called vegetation that may then break off and travel to the lungs, brain, kidneys andskin. The continuing infection may also seriously damage the heart valve on which the vegetations have grown. Symptoms and signs of endocarditis vary butprolonged fever (more then 2-3 days) without an obvious cause is a most important sign and shouldalways be investigated in a child with congenital heart disease. Other signs and symptoms include poor appetite, feeling weak or tired, joint pains, skin rashes, and changes in the nature of a previously present heart murmur. The chance that these signs and symptoms are caused by endocarditis is more likely if they occur soon after a dental cleaning or procedure involving the gastrointestinal orurinary tract.

Bacterial endocarditis can usually be diagnosed if the physician suspects its presence in a child with a congenital heart defect and a prolonged fever. Blood tests show signs of inflammation such as an elevated sedimentation rate,while anemia and blood cells in the urine are often present. The most important diagnostic test for endocarditis involves a positive blood culture. A bloodculture is a small sample of blood drawn from the vein which is grown in a special solution so that bacteria can be detected. Three to five blood cultures are obtained in a 24 hour period and will generally confirm the diagnosis. Previous antibiotic may result in negative cultures.

Bacterial endocarditis can occur with many heart defects but is most common inaortic valve lesions, a patentductus arteriosus (unrepaired), Tetralogy of Fallot, ventricular septal defects, coarctation of the aorta, and mitral valveprolapse with mitral regurgitation. Endocarditis rarely occurs in an isolatedsecundum atrial septal defect or pulmonic stenosis. Endocarditis may occur inmost congenital heart lesions after surgical repair with the exception of completely repaired ventricular septal defects andpatent ductus arteriosus (after 6 months have elapsed from the time of surgery).

Endocarditis is usually prevented by giving your child an antibiotic just prior to a procedure that would release bacteria into the blood stream, and repeating a smaller dose of the antibiotic six hours after the procedure. Themost common procedure causing endocarditis is dental cleaning where bacteria in the gums arereleased into the blood stream. Tonsillectomy and adenoidectomy may also be a source of bacteria producing endocarditis as well as previously mentioned urinary and gastrointestinal tract procedures. On the other hand ear tube insertion, the most common surgical procedure in children, presents less risk of endocarditis and does not require preventive antibiotics. Orthodontic procedures generally...