INFECTIVE ENDOCARDITIS.<br />The dentists goal is to prevent BE from occurring in susceptible patients. Any dental procedure that causes injury to the soft tissue or bone resulting in bleeding can produce a transient bacteremia that in susceptible patients can result in endocarditis. Even minor dental manipulations such as cleaning of the teeth or the placement of matrix band can result in a transient bacteremia. In normal patients, the body’s defenses handle these bacteremias & usually no serious problem develops. However in the patients with a heart defect such as rheumatic heart disease the anatomy & the function of the affect valve are altered because f the scarring that occurs after the acute rheumatic fever attack. When bacteremias occur the altered valvular tissue with NBTE provides an ideal location for attachment & growth of bacteria. <br />Dental procedures resulting in injury to the oral tissues & bleeding can lead to transient bacteremias usually lasting 10 minutes or less. The risk of transient bacteremias has been estimated to be as high as 85 %of the time when the teeth are extracted, 88 % with periodontal surgery, & less often for other procedures.<br />ANTIBIOTIC PROPHYLAXIS.<br />Antibiotics may prevent endocarditis by killing bacteria or damaging them so that they can be destroyed by host defenses. These effects could occur in the oral cavity, in the blood stream, or after the bacteria adhere to the heart. Antibiotics also may prevent adherence.<br />Antibiotic prophylaxis in general should be considered when the following three clinical situations exist. <br /><ul><li>A complication is common but not fatal.
A complication is rare but has a high mortality rate, &
A single type of organism is usually involved.</li></ul>In practice, effective prophylaxis is complicated by several factors <br /><ul><li>Often a no of organisms are involved.
No controlled studies exist to show the efficacy of antibiotic prophylaxis. </li></ul>Several important general principles are involved in ideal antibiotic prophylaxis. The specific organism involved should be known, and an antibiotic effective against that organism should be selected. The proper dosage of the antibiotic should be used, and the antibiotic should be given just before the procedure to provide maximum blood levels at the time of injury. The antibiotic should be continued as long as bacteria can be released, which is usually for a short duration. The benefit to risk ratio must be considered for each procedure.<br />The American heart association guide lines for the prevention of BE meets most of the preceding principles for effective prophylaxis. BE, although a rare disease has a significant mortality risk. Prophylaxis is designed against alpha – hemolytic streptococci, the most common ones. Amoxicillin is effective against these bacteria. High doses at the time of bacteremia is provided & continued for a adequate length of the time.<br />The complications associated with antibiotic use include toxicity, allergy, super infections, resistant bacteria, high cost & in some cases, careless surgery. <br />If anticipated bleeding occurs with a procedure not recommended for prophylaxis, the dentist can give antimicrobial prophylaxis within the first 2 hour s with the belief that it will be effective based on data from experimental animal models. Antibiotics given more than 4 hours after the procedure probably will have no prophylactic benefit. <br />Edentulous patients may develop bacteremia from ulcers caused by ill-fitting dentures. When new dentures are inserted, the patient should return to the dentist to correct any problems that could cause mucosal ulceration. Denture wearers should be encouraged to return to the practitioner if discomfort develops.<br />The recommended standard prophylactic regimen is a single 2-gram dose of oral amoxicillin given 1 hour before the dental procedure. The pediatric dose is 50 mg/ kg not to exceed the adult dose. For patients who are unable to absorb the oral medications, intramuscular /intravenous ampicillin sodium is recommended. Individuals allergic to penicillin should be treated with alternative oral regimens. <br />Clindamycin, azithromycin, clarithromycin are recommended alternative oral regimens. Also, first regimen cephalosporin (cephalexin & cefadroxil) can be used in patients provided they have not had an immediate local or systemic immunoglobulin e mediated allergic reaction to penicillin. The newer azalides, azithromycin & clarithromycin, are more expensive than the other regimens.<br />Clindamycin phosphate is recommended when parenteral administration is needed for a patient with a history of penicillin allergy. Parenteral cefazolin may be used in the patient who did not have an immediate type 1 hypersensitivity reaction to penicillin. Erythromycin is no longer recommended because of gastrointerestinal upset & complicated pharmacokinetics.<br />Patients taking oral penicillin for secondary prevention of rheumatic fever or for other purposes such as acute infection may have viridians streptococci in their oral cavities that are resistant to amoxicillin or ampicillin. In these cases the dentist should select clindamycin, azithromycin, or clarithromycin. Because of possible cross resistance with the cephalosporins, this class of antibiotics should be avoided. In patients being treated for a short time such as for acute infection, the dental procedure should be delayed until at least 9-14 days after completion of antibiotics. The amoxicillin or ampicillin can be used as the oral flora is reestablished.<br />Intramuscular injections for endocarditic prophylaxis should be avoided in patients receiving anticoagulants such as heparin or warfarin sodium. Oral or intra venous regimens should be used for these patients whenever possible.<br />A careful preoperative dental evaluation is recommended for all patients undergoing cardiac surgery. All required dental treatment should be completed before cardiac surgery. <br />Reparative cardiac procedures may not modify the patients long term risk for endocarditis. In the cases of prosthetic valve replacement , the risk of endocarditis increases postoperatively . in other conditions , such as closure of ventricular septal defect or patent ductus arteriosus without residual leak, the risk of endocarditis diminishes to the level of general population after a 6 month healing period. No evidence exists that coronary artery bypass graft surgery or stents introduces a risk for endocarditis . synthetic vascular grafts may merit antibiotic prophylaxis for the first 6 months after implantation. <br />Conditions considered by the American Heart Association for Antibiotic prophylaxis for Endocardits Prevention<br />Antibiotic Prophylaxis RecommendedHigh – Risk ConditionsProsthetic cardiac valvesBiorostheticHomograftPrevious bacterial endocarditisComplex cyanotic congenital heart disease (tetralogy of Fallot)Surgically constructed systemic-pulmonary shuntsModerate-risk conditionsMost other congenital cardiac malformations (other than above and those listed below)Acquired valvar dysfunction (eg; rheumatic heart disease)Hypertrophic cardiomyopathyMitral valve prolapsed with valvar regurgitation and/or thickened leafletsAntibiotic Prophylaxis Not RecommendedLow or Negligible Risk ConditionsIsolated secundum atrial septal defectSurgical repair without sesidua beyond 6 monthsVentricular septal defectPatent ductus arteriosusPrevious coronary artery bypasss graft surheryMitral valve prolapsed without valvar regurgitationPhysiologic, functional or innocent heart murmursPrevious Kawaski disease without valvar dysfunctionPrevious rheumatic fever without valvar dysfunction(RHD)Cardiac pacemakers and implanted defibrillators<br />American Heart Association Recommendation Regarding Dental Produres and Antibiotic.<br />Endocarditis prophylaxis recommendedDental extrationsPeriodontal surgery, scalling, root planning, probing, and recall maintenancePlacement of dental implantsReimplantation of avulsed teethEndodontic instrumentation or surgery only beyond the apex of teethSubgingival placement of orthodontic bands but not bracketsIntraligamentary local anesthetic injectionsProphylactic cleaning of teeth or implants where bleeding is anticipatedEndocarditis prophylaxis not recommendedRestorative dentistry* (operative and prosthodontic) with or without retraction cordLocal anesthetic injections (non Intraligamentary)Intracanal endodonic treatment, post placement, and crown buildupPlacement of rubber damsPostoperative suture removalPlacement of removable prosthodontic or orthodontic appliancesTaking of oral impressionsFluoride treatmentsTaking of oral radiographsOrthontic appliance adjustmentShedding of primary teeth<br />American Heart Association Recommended Standard prophylactic regimen for dental procedures<br />AdultsAmoxicillin 2g, orally, I hour before procedureChildrenAmoxicillin 50mg/kg, orally, I hour before procedure <br />Alternate Prophylactic Regimen For Patients Given General Anesthesia for oral Surgical or Dental Procedure or Who Are Unable To Use Oral Medications<br />Not allergic to PenicillinAdultsAmpicillin 2g IV or IM 30 minutes before procedureAllergic tp penicillinAdultsCilindamycin 600 mg/kg IV 30 minutes before procedure<br />Alternate prophylactic Regimen for Oral Surgical or Dental Procedures or who are Unable to Use Oral Medications<br />Not Allergic to PenicillinAdultsAmpicillin 2 g iv or IM 30 minutes before procedureChildren Ampicillin 50 mg/kg Iv or im 30 minutes before procedureAllergic to PenicillinAdultsClindamycin 600 mg/kg IV 30 minutes before procedureChildrenClindamycin phosphate 10 mg/kg 30 minutes before procedure<br />Alternate prophylactic Regimen to prevent endocarditis for dental procedures in Patients Allergic to Penicillin<br />AdultsClindamycin 600 mg orally 1 hour before procedure orCephalexin or cefadroxil 2.0g orally I hour before procedureorAzithromycin or clarithromycin 5000mg orally I hour before procedureChildrenClindamycin 10 mg/ kg orally I hour before procedure then half dose 6 hours after initial doseOrcephlexin OR cefadroxil 50mg/kg orally I hour before procedureOr Azithromycin or clarithromycin 15 mg/kg orally I hour before procedure<br />