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  1. 1. Medicines Q&As Q&A 76.3Do patients with hydrocephalus shunts need antibiotic prophylaxis before undergoing dental procedures? Prepared by UK Medicines Information (UKMi) pharmacists for NHS healthcare professionals Expiry: December 2011Summary ♦ Hydrocephalus is a neurological condition resulting from an accumulation of cerebrospinal fluid (CSF) which is managed by implanting a shunt system to remove the excess CSF. ♦ There are two types of shunt system; ventriculo-atrial (VA) which discharges CSF into the right atrium and ventriculo-peritoneal (VP) which discharges CSF into the peritoneum. ♦ There have been no randomised controlled trials evaluating the use of antibiotic prophylaxis to prevent secondary infection from a distant source, including the mouth, in patients with VP or VA shunts. ♦ The risk of CSF shunt infection following dental procedures appears to be almost negligible. There are no reported cases of CSF shunt infection following a dental procedure. There is no evidence that S.viridans bacteria isolated from CSF shunt infections have been of oral origin. ♦ There are risks associated with use of antibiotic prophylaxis. ♦ On this basis, patients who have either a VP or VA shunt do not require antibiotic prophylaxis prior to dental procedures to prevent shunt infections.BackgroundHydrocephalus is a neurological condition resulting from an accumulation of cerebrospinal fluid (CSF)within the ventricles and/or subarachnoid space, leading to raised pressure within the brain.Accumulation occurs either due to over production of CSF or to obstruction of normal drainage (1,2).Hydrocephalus occurs in approximately 1 in every 1,000 births (2).Hydrocephalus is managed by implanting a shunt system to remove excess CSF. There are two typesof shunt. Each system comprises three components; a proximal drainage tube usually inserted into thelateral ventricle of the brain, a valve situated on the surface of the skull and a distal catheter, which istunnelled subcutaneously via one of two routes (1,3,4). In ventriculo-atrial (VA) shunts the catheterenters the internal jugular vein and is placed in the right atrium of the heart where it discharges theCSF directly into the bloodstream. It is continuously and directly exposed to potential infection by silentbacteraemias (1,3). In ventriculo-peritoneal (VP) shunts the catheter is tunnelled subcutaneously fromthe valve to the abdomen where it discharges into the peritoneal cavity and never comes directly intocontact with blood (1,3,4). VA shunts were the first shunts to be used in hydrocephalus but today themajority of shunts fitted are VP shunts (1,4). Theoretically, VA shunts are more susceptible to infectionthan VP shunts (5). Complications of infection associated with VA shunts are serious due tocardiopulmonary sequalae such as infective endocarditis (6). Estimated rates for shunt-associatedinfection in early shunts (VA and VP) ranged from 1.5 to 39% but this rate has fallen in recent years to2 to 9% (3).AnswerWhat causes shunt infections?About 70% of shunt infections are diagnosed within two months following shunt placement. Theseinfections are usually caused by skin or airborne bacteria entering the CSF or shunt during theplacement operation. Most infections occurring after shunt surgery are internal and are secondary to From the National electronic Library for Medicines
  2. 2. colonisation of the shunt lumen; infections involving the tissues adjacent to the shunt tubing are rare(7). VP shunts can also be infected after local injury and occasionally from peritonitis, appendicitis andperforation of the bowel (4).Up to 90% of infective episodes are caused by coagulase-negative staphylococci (e.g. S.epidermidis).Other common pathogens include S.aureus (13-27%) and aerobic gram-negative bacilli (10-20%) plusstreptococci (7).Have oral bacteria been associated with shunt infection?Streptococci are the largest group of bacteria isolated from the oral cavity and comprise almost 50% ofthe organisms isolated from plaque and the gingival sulcus (the crevice that surrounds the tooth). Themost abundant oral streptococci are the alpha-haemolytic (S.viridans) streptococci (e.g. S.mitis,S.mutans, S.sanguis, S.salivarius). Gamma-haemolytic and beta-haemolytic streptococci are usuallypresent but in small numbers.Many dental procedures produce transient bacteraemia (e.g. dental extractions, scaling andperiodontal surgery). However, levels of bacteraemia associated with non-invasive procedures (e.g.tooth brushing, dental flossing and chewing) often approach those following invasive dentalprocedures (8,9). If oral health is poor, the frequency and magnitude of bacteraemia is thought to behigh.Oral microflora, such as S.viridans, have been isolated in up to 4% of shunt infections, but as part of amixed infection (6).A review of the published literature in 1998 (4) found that over the previous 30 years there were noreported cases of CSF shunt infections caused by a dental procedure. In a small pilot study, 14patients with VP shunts underwent minor dental procedures (prophylactic procedures and fluorideapplication) with no antibiotic prophylaxis. Over the 12 months follow up no patients showed signs ofinfection (4).There have been no randomised controlled trials evaluating the use of antibiotic prophylaxis to preventsecondary infection from a distant source, including the mouth, in patients with VP or VA shunts.When should antibiotic prophylaxis be used?Antibiotic prophylaxis is defined as the use of an antimicrobial agent before any infection has occurredfor the purpose of preventing a subsequent infection (9). Criteria for antibiotic prophylaxis againstinfection have been developed and include (9):• the health benefits must outweigh the antibiotic risks,• the choice of antibiotic should be made on the single microorganism most likely to cause an infection,• the cost–benefit ratio must be acceptable.Is antibiotic prophylaxis used to prevent other distant site infections following dentalprocedures?In March 2008 the National Institute for Health and Clinical Excellence (NICE) advised that antibioticprophylaxis to prevent endocarditis is not recommended for any dental procedure (9). This was aparadigm shift in practice. Reasons for the recommended change in practice included:• Everyday activities, such as chewing and brushing teeth, cause bacteraemia far more frequently than dental procedures. Therefore these everyday activities almost certainly present a far greater risk of infective endocarditis than a dental procedure.• The causal link between a recent dental procedure and the development of infective endocarditis has not been proved.• Routinely prescribing antibiotic prophylaxis for patients at risk of infective endocarditis increases the likelihood that antibiotic resistance will emerge.All the above points are relevant when assessing the need for antibiotic prophylaxis in patients withhydrocephalus shunts requiring dental procedures. Although the consequence of shunt infection isserious (mortality rate of 20 to 50% (3)), the risk associated with dental procedures appears to bealmost negligible. From the National Electronic Library for Medicines.
  3. 3. What are the arguments against the use of prophylactic antibiotics?♦ Adverse effects There is an increasing realisation that a risk is associated with use of prophylactic antibiotics. A study has shown that patients receiving amoxicillin to prevent infective endocarditis are five times more likely to die from an anaphylactic reaction to the drug than to die from contracting endocarditis following a dental procedure when no antibiotic prophylaxis was given (8). Applying this principle to patients with CSF shunts, so few cases of shunt infection have been shown to involve oral streptococci that the risk of anaphylaxis and other serious adverse effects resulting from the use of antibiotics would be much higher than the risk of a serious shunt infection. Antibiotic use can lead to Clostridium difficile associated diarrhoea. Patients treated with broad spectrum antibiotics are at greatest risk (10). Risk is also increased in the elderly; patients with compromised immune systems, following recent gastrointestinal surgery and in patients who have a prolonged stay in hospital.♦ Antibiotic resistance Antibiotic resistance is widespread and increasing worldwide at an accelerating pace. The prevalence of antibiotic resistance in any population is proportional to the population that receives antibiotics and the total antibiotic exposure (10). In situations where antibiotics are required they should be used within the confines of sound policies and in conjunction with robust infection control procedures.♦ Cost The costs of using prophylaxis vs. not using prophylaxis must be considered. For serious but rare complications the cost of prevention in terms of patient morbidity and mortality and in monetary terms may be considerably more than if no prophylactic treatment was given.♦ Inappropriate medico-legal influences It is known that the fear of medico-legal consequences leads many dentists to use antibiotic prophylaxis whenever there is a theoretical chance of a distant site infection; using prophylactic antibiotics is thought by many to be the cautious option (11). However, given the known risks associated with antibiotics, dentists may find themselves being sued if a patient suffers a serious adverse effect following what evidence indicates is unnecessary antibiotic prophylaxis.Limitations♦ There have been no randomised controlled trials evaluating the use of antibiotic prophylaxis to prevent secondary infection from a distant source, including the mouth, in patients with VP or VA shunts.♦ There are no national or international guidelines advising on antibiotic prophylaxis required to cover invasive procedures undertaken at sites distant to CSF shunts.♦ The conclusions of this Q & A have been arrived at after consideration of the available evidence and consultation with local specialists.References. The Association for Spina Bifida and Hydrocephalus. Hydrocephalus Accessed 14/12/07 and 11/11/09.2. Toporek C and Robinson K. Hydrocephalus: A Guide for Patients, Families, and Friends 1999,O’Reilly & Associates Inc. Chapters One and Four. Downloaded from ‘Patient Centered Guides,Hydrocephalus Center’. Accessed 14/12/07 and11/11/09.3. Finch RG, Greenwood D, Ragnar Norrby S and Whitley RJ, editors. Antibiotic and chemotherapy,anti-infective agents and their use in therapy. 8th edition: Churchill Livingstone; 2003. Chapter 45Pages 594 -598.4. Helpin ML, Rosenberg HM, Sayany Z and Sanford RA. Antibiotic prophylaxis in dental patients withventriculo-peritoneal shunts: A pilot study. ASDC J Dent Child 1998; 65: 224-227.5. Acs G and Cozzi C. Antibiotic prophylaxis for patients with hydrocephalus shunts: a survey ofpediatric dentistry and neurosurgery program directors. Pediatr Dent 1992; 14: 246-250. From the National Electronic Library for Medicines.
  4. 4. 6. Proctor R, Kumar N, Davies R and Porter S. Cerebrospinal fluid shunts and dentistry – a shortreview of relevant literature. J Disability Oral Health 2004; 5: 27-30.7. BSAC working party on infection in neurosurgery. Antimicrobial prophylaxis in neurosurgery andafter head injury. Lancet 1994; 344: 1547-1551.8. Seymour RA, Lowry R, Whitworth JM and Martin MV. Infective endocarditis, dentistry and antibioticprophylaxis; time for a rethink? Br Dent J 2000; 189: 610-616.9. NICE Clinical Guideline No.64. Prophylaxis against infective endocarditis: antimicrobial prophylaxisagainst infective endocarditis in adults and children undergoing interventional procedures. March2008. London: National Institute for Health and Clinical Accessed 2/12/09.10. SIGN Guideline 104: Antibiotic prophylaxis in surgery (July 2008). Edinburgh: ScottishIntercollegiate Guideline Network Accessed 2/12/09.11. Lockhart PB et al. Decision-making on the use of antimicrobial prophylaxis for dental procedures:A survey of infectious disease consultants and review. Clin Infect Dis 2002; 34: 1621-1626.Quality AssurancePrepared byChristine Randall, Senior Medicines Information Pharmacist,North West Medicines Information Centre, Pharmacy Practice Unit, 70 Pembroke Place, Liverpool,L69 3GF.ContactEmail: preparedNovember 2005Searches updated December 2007 and November 2009Checked byJoanne McEntee and Christine Proudlove, North West Medicines Information Centre, PharmacyPractice Unit, 70 Pembroke Place, Liverpool, L69 3GF.Date of checkNovember 2005December 2007January 2010Search strategyMedline (1951 to date)(ANTIBIOTIC-PROPHYLAXIS#.DE. OR DENTAL-PROPHYLAXIS#.DE.) AND((VENTRICULOPERITONEAL-SHUNT#.DE. OR Cerebrospinal-Fluid-Shunts#.DE.) ORHYDROCEPHALUS#.W..DE.)Embase (1974 to date)ANTIBIOTIC-PROPHYLAXIS#.DE. AND (BRAIN-VENTRICLE-PERITONEUM-SHUNT#.DE. ORCEREBROSPINAL-FLUID-SHUNTING#.DE. OR VENTRICULOATRIAL-SHUNT#.DE. ORHYDROCEPHALUS#.W..DE.)Google UK: Hydrocephalus; “ventriculoperitoneal shunt” and “dental prophylaxis”Textbooks:Scully C & Cawson RA, Medical Problems in Dentistry, 5th edition: Churchill Livingstone; 2005Lockhart PB, editor. Dental Care of the Medically Complex Patient, 5th edition: Wright; 2004Finch RG, Greenwood D, Ragnar Norrby S and Whitley RJ, editors. Antibiotic and chemotherapy Anti-infective agents and their use in therapy 8th edition: Churchill Livingstone; 2003.Micromedex: HydrocephalusClinical experts (2005):Dr Mike Martin, Consultant in Oral Microbiology, Liverpool University Dental HospitalPaediatric and Adult Neurologists. From the National Electronic Library for Medicines.