Bacterial Endocarditis

Definition of Bacterial Endocarditis

Bacterial endocarditis is an infection in the hearts valves or in the surfaces of the heart.

Clinical Importance of Bacterial Endocarditis

Despite aggressive medical and surgical therapy, bacterial endocarditis still carries a 10 % mortality rate.
Pathogenesis of Bacterial Endocarditis

• Sterile platelet-fibrin clot implants on the damage surface of the heart in susceptible patients.
• The thrombus acts as a nidus for bacterial proliferation if transient bacterimia occurs in these suspectable patients.

Organism Causing of Bacterial Endocarditis

• Oral organisms account for a sizable proportion of causative agent of bacterial endocarditis.
• Dental manipulative have been demonstrated to result in the transient bacterimia.
• The risk of dental manipulations of inducing bacterimia depends on the amount of soft tissue trauma induced by the procedure and pre-exciting local inflammatory disease.
• However, any dental manipulation likely to result in gingival bleeding can lead to transient bacterimia.

Complications of Bacterial Endocarditis

• Cardiac complications: valvular incompetence, such as aortic insufficiency, mitral insufficiency, and tricuspid insufficiency.
• Congestive heart failure: usually secondary to aortic insufficiency myocardial abscesses
• Conduction abnormalities: usually as a result of myocardial abscesses invading the conducting pathway
• Pericarditis (rarely)

Embolic Complications of Bacterial Endocarditis

• Cerebral embolic infarction
• Renal infarction
• Splenic infarction
• Other systemic emboli

Immune Complex Formation of Bacterial Endocarditis

• Arthritis
• Glomerulonephritis

Theoretical Considerations in the Choice of Drugs for Dental Prophylaxis

• Drugs chosen should be directed at organisms commonly found in the oral cavity.
• Drugs chosen should bactericidal.
• Drugs should be administered at an appropriate interval prior to the procedure to ensure maximal blood level at the time of surgery.
• Drugs should not be administered for long periods of time before surgery in order to avoid development of resistant organisms.
• Antibiotics should be continued for a period of time following the procedure to allow for tissue healing.

Patient at Risk for Bacterial Endocarditis

• Patient with Rheumatic valvular disease: Incidence estimated at 4 – 7 % per year before antibiotics.
• Patient with other acquired valvular diseases: calcilic aortic stenosis in the elderly patient, aortic insufficiency secondary to trauma, and aortic insufficiency seen in syphilis.
• Patients with congenital heart disease: mitral valve prolapse, ventricular septal defect, idiopathic hypertrophic subaortic stenosis, bicuspid aortic valve, tetralogy of Fallot, and other cyanotic heart diseases.
• Patients with previous endocarditis: incidence estimated at 10 % per year.
• Patients with vascular anomalies or intravascular prostheses: coarctation of the aorta, patent ductus arteriosus, systemic-to-pulmonary artery stunts, vascular bypass grafts.

Relative risk of Bacterial Endocarditis based upon underlying cardiac lesion.

Patient at High Risk for Bacterial Endocarditis

• Patient with previous bacterial endocarditis.
• Patient with prosthetic heart valves.

Patient at Significant Risk for Bacterial Endocarditis

• Patients with rheumatic valvular diseases.
• Patients with other acquired valvular diseases.
• Patients with congenital heart diseases.
• Patients with intravascular prostheses.
• Patients with coarctation of the aorta.

Patients at Minimal Risk for Bacterial Endocarditis

• Patients with transvenous pacemakers.
• Patients with a history of rheumatic fever but without documented rheumatic heart disease.

Patients with Minimal Risks for Bacterial Endocarditis Who Do Not Require Antibiotic Prophylaxis

• Patients with innocent of functional murmurs.
• Patients with uncomplicated atrial septal defect.
• Patients who have undergone coronary artery bypass graft operations.

Prophylaxis for Dental Procedures

Regimen A : Penicillin

• ORAL
• Adults : Penicillin V (2 g orally 30 minutes to 1 hour prior to procedure and then 500 mg every 6 hours for 8 doses)

Regimen B : Penicillin plus Streptomycin

• Adults : Aqueous crystalline Penicillin G (1.000.000 U intramuscularly) mixed with procaine penicillin G (600.000 U intramuscularly) plus streptomycin (1 g intramuscularly).
• Give 30 minutes to 1 hour prior to the procedure, then penicillin V 500 mg orally every 6 hours for 8 doses

General Principle of Dental Management for Bacterial Endocarditis

The selection of Regimen A or the more rigorous Regimen B depends on the risk associated with the particular cardiovascular defect and the risk of bacterimia for a particular procedure and oral health setting.

Specific Guidelines of Dental Management for Bacterial Endocarditis

• High risk patient with procedure I-IV use regimen B.
• Significant risk patient with procedure I-III use regimen A.
• Significant risk patient with procedure IV-VI use regimen A or B.
• Low risk patient with procedure I-IV use regimen A.

Procedure Categories for Bacterial Endocarditis

A. Non Surgical Procedures

• Type I: examination/ radiograph, oral hygiene instruction, study model impression
• Type II: simple operative dentistry, prophylaxis (supragingival), Orthodontics
• Type III: advanced operative dentistry, scaling and root planning (subgingival), endodontics

B. Surgical Procedures

• Type IV: simple etractions, curettage/ gingivopasty.
• Type V: multiple extraction, flap surgery or gingivectomy, extraction of single bony impaction, apicoectomy.
• Type VI: full-arch / full mouth extraction or flap surgery, extraction of multiple bony impaction, orthognathic surgery

References: Principle and Practice of Oral Medicine, by Stephen T. Sonis et all.

Adapted from Lecture Note on Bacterial Endocarditis by drg. Pradipto Subiyantoro, Sp.BM