Infective Endocarditis: Key Factors & Prevention

• Antibiotic Prophylaxis against Infective Endocarditis will be discussed in these study notes.
• You will describe the risks of infective endocarditis (IE) and be able to apply the current antibiotic prophylaxis (AP) guidance to prevent IE in dental patients.
• You will also describe infective edocarditis (IE), specify the patient who are most at risk, outline the dental procedures that out a patient at risk of a bacteraemia, and the current antibiotic prophylaxis (AP) guidance to prevent IE

Infective Endocarditis

• A life-threatening bacterial infection of the heart that particularly affects the heart valves
• It is rare, affecting approximately 1 in 10,000 people per year
• Predisposing cardiac conditions increase the risk
• 50% of new cases have no known pre-existing cardiac disease
• The fatality rate is 30% of cases
• 50% of cases require cardiac surgery
• The incidence is rising in the UK
• Early symptoms are often vague and hard to diagnose
• Early symptoms include; feeling unwell, high temperature of 38C or above, sweats or chills (especially at night), breathlessness during physical activity, weight loss, tiredness/fatigue, and muscle, joint or back pain unrelated to physical activity
• Late complications; Heart problems such as valve damage and heart failure, stroke, seizure, paralysis, abscesses in heart, brain, lungs & other organs, pulmonary embolism, kidney damage, enlarged spleen and death
• In some cases, oral streptococci can be implicated
• Only 25% of IE cases have patients that had undergone an invasive dental procedure prior to diagnosis
• Cumulative low-grade bacteria triggered by toothbrushing, flossing, and chewing are of more significance, thus prevention is vital.

Antibiotic Prophylaxis

• Antibiotic prophylaxis involves giving patients high dose antibiotics 1 hour before to delivering invasive dental treatment that might cause a bacteremia
• It prevents bacteria infecting the damaged endocardium
• Amoxycillin or Clindamycin are typically prescribed
• A 2013 Cochrane review showed has insufficient evidence of effectiveness of AP in preventing IE
• There is a risk of adverse reactions
• Two key guidance documents:
  • National Institute for Health and Care Excellence (NICE) (2016) Prophylaxis against infective endocarditis: antimicrobial prophylaxis against infective endocarditis in adults and children undergoing interventional procedures., available at: https://www.nice.org.uk/guidance/cg64
  • Scottish Dental Clinical Effectiveness Programme (2018) Antibiotic Prophylaxis Against Infective Endocarditis, available at: https://www.sdcep.org.uk/wp-content/uploads/2018/08/SDCEP-Antibiotic-Prophylaxis-Implementation-Advice.pdf
• From the National Institute for Health and Care Excellence (NICE):
  • Prior to 2008, AP was routinely prescribed for all patients at risk of IE
  • From 2008-2016, AP was not recommended for any patient at risk of IE
  • From 2016 onward, antibiotic prophylaxis is not recommended routinely for people undergoing dental procedures
• SDCEP Antibiotic prophylaxis can be found here: sdcep.org.uk

Patients At Risk

• Patients with the following require AP:
  • Acquired valvular heart disease with stenosis or regurgitation
  • Hypertrophic cardiomyopathy
  • Previous infective endocarditis
  • Structural congenital heart disease, including surgically corrected or palliated structural conditions, but excluding isolated atrial septal defect, fully repaired ventricular septal defect, or fully repaired patent ductus arteriosus, and closure devices that are judged to be endothelialised
  • Valve replacement
• Sub-group requiring special consideration;
  • Prosthetic valve, including transcatheter valves, or where any prosthetic material was used for valve repair
  • Previous infective endocarditis
  • Congenital heart disease (CHD)
  • Any type of cyanotic CHD
  • Any type of CHD repaired with a prosthetic material, whether placed surgically or by percutaneous techniques, up to 6 months after the procedure or lifelong if residual shunt or valvular regurgitation remains
• AP is required only for specific invasive dental procedures
  • Invasive dental procedures that require Antibiotic Prophylaxis are;
    • Placement of matrix bands and sub gingival rubber dam clamps
    • Sub-gingival restorations including fixed prosthodontics
    • Endodontic treatment before apical stop has been established
    • Preformed metal crowns (PMC/SSCs)
    • Full periodontal examinations (including pocket charting in diseased tissues)
    • Root surface instrumentation/sub-gingival scaling
    • Incision and drainage of abscess and dental extractions
    • Surgery involving elevation of a muco-periosteal flap or muco-gingival area
    • Placement of dental implants including temporary anchorage devices, mini-implants
    • Uncovering implant sub-structures
• Non-invasive dental procedures that do not requiring antibiotic prophylaxis are;
  • Infiltration or block local anaesthetic injections in non-infected soft tissues
  • BPE screening and Supra-gingival scale and polish
  • Supra-gingival restorations
  • Supra-gingival orthodontic bands and separators
  • Removal of sutures and Radiographs
  • Placement or adjustment of orthodontic or removable prosthodontic appliances
• Antibiotic prophylaxis isn't recommended following exfoliation of primary teeth or trauma to the lips or oral mucosa
• AP is not typically given with joint replacements, pacemakers, coronary artery stents / bypass grafts, renal dialysis, intravenous access devices, immunocompromised patients or solid organ transplants
• It is given with care when post H&N radiotherapy is needed to prevent MRONJ
• Standard antibiotic regime:
  • Amoxicillin, 3 g Oral Powder Sachet, give 3 g (1 sachet) 60 minutes before procedure (3 g prophylactic dose)
  • Dose for children - Amoxicillin Oral Suspension, 250 mg/5 ml or 3 g Oral Powder Sachet
  • 6 months – 17 years - 50 mg/kg; maximum dose 3 g (prophylactic dose)
• Amoxicillin, like other penicillins, can result in hypersensitivity reactions
• It can cause antibiotic-associated colitis, which may be fatal
• Amoxicillin can alter the anticoagulant effect of warfarin and the INR of a patient taking warfarin should be monitored
• Refer to Appendix 1 of the BNF and BNFC for details of drug interactions.
• Antibiotic regime if allergic to amoxicillin:
  • Clindamycin Capsules, 300 mg
  • Give: 600 mg (2 capsules) 60 minutes before procedure (600 mg prophylactic dose)
  • Dose for children: - 6 months – 17 years - 20 mg/kg; maximum dose 600 mg (prophylactic dose)
• Advise a patient that capsules should be swallowed with a glass of water
• They are not supposed to prescribe clindamycin to patients with diarrhoeal states, can cause antibiotic-associated colitis which may be fatal
• Important that patients are not discouraged from having dental treatment, by liaising with referring GDP and cardiologist about AP and IE prevention
• Give informed consent (Montgomery) – 'material risks', find out what specific patient wants to know
• After discussing benefits (prevention of IE) and risks (hypersensitivity, anaphylaxis and antibiotic-related colitis), give information leaflet, document all discussions and think about how to maximise the amount of treatment in each visit
• Prescriptions should be written by referring GDP
• Should a patient has had a course of antibiotics in preceding 6 weeks, select antibiotic from a different antibiotic class
• If patients require sequential invasive treatments over a short time period, the same antibiotic can be prescribed for each treatment episode
• In Eastman, take ABC in hospital and wait 1 hour
• In general dental practice; first time, the patient should take AP in the dental practice and wait 1 hour, however subsequent times, patients can take AP at home 1 hour prior to appointment
• Discuss risk of IE, potential benefits and risks of AP with patients who are at increased risk of IE
• Follow SDCEP guidelines and consider writing a patient's cardiology consultant/cardiac surgeon/local cardiology centre for advice
• Explain that AP is no longer routinely recommended.
• Emphasise good oral health and prevention
• Discuss symptoms of endocarditis, give information leaflet and ensure any dental infections are treated promptly to reduce the risk of IE developing