––––––– Point of Care ––––– For patients with “stable” cardiac disease, it is THE AUTHOR still prudent to administer a minimal amount of epinephrine while always avoiding intravascular Dr. Ben Davis is associate professor in the depart- injections. Although pain control is of paramount ment of oral and maxillofacial sciences and head of the division of oral and maxillofacial surgery, importance, the potentially deleterious effect of Dalhousie University, Halifax, Nova Scotia. epinephrine can be minimized by limiting the Email: [email protected] amount to 40 μg. There is no evidence to support References exceeding this dose for such patients. This amount 1. Fleisher LA, Beckman JA, Brown KA, Calkins H, Chaikof EL, is contained in 2 cartridges of 1:100 000 or 4 car- Fleishmann KE, et al. 2009 ACCF/AHA focused update on periopera- tive beta blockade incorporated into the ACC/AHA 2007 guidelines tridges of 1:200 000 (there is little benefit from on perioperative cardiovascular evaluation and care for noncardiac using the 1:100 000 concentration of epinephrine surgery: a report of the American college of cardiology founda- 3 tion/American heart association task force on practice guidelines. for routine dentistry). Although the half life of Circulation. 2009;120(21):e169-276. Epub 2009 Nov 2. epinephrine is short, exceeding 40 μg epinephrine 2. Pharmacology of vasoconstrictors. In: Malamed SF, editor. Handbook of local anesthesia. 5th ed. St. Louis: Elsevier Mosby; per appointment cannot be recommended unless 2004. p. 41-54. the patient’s cardiac status is monitored continu- 3. Becker DE, Reed KL. Essentials of local anesthetic pharmacology. ously during the procedure. a Anesth Prog. 2006;53(3):98-108. Cite this as: QUESTION 3 J Can Dent Assoc 2010;76:a37 How are odontogenic infections best managed? Background anaerobic bacteria and only 6% by aerobic bac- ental infections, including gingivitis, peri- teria alone.1 The most common species of bacteria odontitis, dental caries and odontogenic isolated in odontogenic infections are the anaer- Dinfections, result in numerous dental visits obic gram-positive cocci Streptococcus milleri each year in Canada. They can range in severity group and Peptostreptococcus.2 Anaerobic gram- from a mild buccal space infection to a severe negative rods, such as Bacteroides (Prevotella) also life-threatening multi-space infection. All dentists play an important role. Anaerobic gram-negative should be comfortable with prompt diagnosis and cocci and anaerobic gram-positive rods have little management of these types of infections. This re- effect.2 view of odontogenic infections describes causative Odontogenic infections progress through 3 organisms, management including appropriate 3 antibiotic selection and the indications for referral stages: inoculation, cellulitis and abscess (Table 1). to a specialist. Bacteria gain entrance to the surrounding facial Most odontogenic infections are caused by spaces by direct extension from the periapical re- more than 1 species of the bacteria normally found gion of the involved tooth. The pattern of spread is within the oral cavity. Roughly 50% of odonto- predictable depending on the relationship between genic infections are caused by anaerobic bac- the point of attachment of the adjacent muscle and teria alone, 44% by a combination of aerobic and the tooth apex.4 Table 1 Characteristics of the 3 stages of infection Characteristic Inoculation Cellulitis Abscess Duration (days) 0–3 2–5 4–10 Discomfort Mild Severe, diffuse Mild, localized Palpation Soft, doughy Firm, indurated Fluctuant, tender Pus None None Present Skin Normal Red Red periphery Severity Minimal Greater Less Bacterial species Aerobic Mixed Anaerobic 114 JCDA • www.jcda.ca • 2010 • Vol. 76, No. 2 • ––––––– Point of Care ––––– Table 2 Antibiotics commonly prescribed for odontogenic infections5 Antibiotic Usual adult dosage Usual pediatric dosage Penicillin V 600 mg every 6 h 25–50 mg/kg/day divided into 4 doses Amoxicillin 500 mg every 8 h 25–50 mg/kg/day divided into 4 doses Cephalexin 500 mg every 6 h 25–50 mg/kg/day divided into 4 doses 2 g 1 h pre-op (joint prophylaxis) Metronidazole 500 mg twice daily 15–30 mg/kg/day divided into 3 doses Clindamycin 300–450 mg every 6 h 10–30 mg/kg/day divided into 3 or 4 doses Moxifloxacin 400 mg daily Not established Erythromycin 500 mg enteric coated every 8 h 30–50 mg/kg/day divided into 2–4 doses 333 mg enteric coated every 6 h 250 mg (base) every 6 h Treatment of odontogenic infections includes Beta Lactam Antibiotics diagnosis and management of the causative factor Penicillins: Penicillins are considered the first and, usually, prescription of appropriate anti- line of treatment for odontogenic infections. They biotics. It is imperative that the source of infection produce their effect by inhibiting cross-linking in be addressed immediately. Placing a patient on the bacterial cell wall and are, thus, bactericidal. antibiotics and rescheduling to have the source They have a fairly narrow antimicrobial spectrum, dealt with at a later time is not sound practice, but cover most bacteria associated with odonto- as most often the infection will worsen. In genic infections. Penicillin resistance has been re- addition, the patient’s medical status must ported recently.6 This occurs primarily through the be optimized. The patient’s fluid and nutrition production of beta lactamase. Evidence suggests status should also be addressed, as many patients a high incidence of penicillin resistance among with odontogenic infections have decreased oral patients previously treated with beta lactam anti- intake due to pain and difficulty in chewing or biotics in in vitro studies.7 swallowing. In culture and sensitivity testing on 94 patients The decision to place the patient on antibiotics with odontogenic abscesses, penicillin V was the depends on the location and severity of the infec- least effective antibiotic for eradicating bacterial tion and the patient’s medical conditions. A mild isolates.7 Despite this, more than 95% of patients vestibular space infection may not require anti- treated with surgical incision and drainage in con- biotics after the offending tooth has been removed. junction with penicillin V recovered satisfactorily. However, more serious infections do require The discord between in vitro testing and clin- appropriate antibiotics. The clinician must be ical response was thought to be due to the sus- aware of the most likely causative organisms and ceptibility to penicillin of the dominant causative prescribe the narrowest spectrum of antibiotics strains of bacteria isolated from the abscesses. that will cover all possible offending organisms. Amoxicillin has a broader spectrum of activity Table 2 lists the antibiotics most commonly used than penicillin V, but does not provide any better to treat odontogenic infections and their usual coverage in treating odontogenic infections. Its oral adult and pediatric dosages.5 Antibiotics are dosing schedule and ability to be taken with food typically prescribed for 7 days or until 3 days after may make it more acceptable for patients, resulting symptoms have resolved. in better compliance. Severe infections must be identified and re- ferred to a specialist in a timely manner. The signs Cephalosporins: The mechanism of action of ceph- and symptoms of a severe infection are fever (tem- alosporins is similar to that of penicillins. There perature > 38°C), stridor, odynophagia, rapid pro- are 4 generations of cephalosporins; their spec- gression and the involvement of multiple spaces trum of antibacterial coverage, especially against and secondary anatomic spaces.3 The presence of gram-negative bacteria, generally increases from any of these warrants referral to an oral and max- the first to the fourth generation. The reported in- illofacial surgeon. cidence of cross-reactivity with penicillin is about JCDA • www.jcda.ca • 2010 • Vol. 76, No. 2 • 115 ––––––– Point of Care ––––– 7%–18%,8 which should be considered when a pa- trum of activity similar to that of penicillin V. tient reports an allergy to penicillin. Like penicillin-resistance, resistance to erythro- Cephalosporins are not a first-line treatment mycin has become a clinical concern. Kuriyama in the management of odontogenic infections. and colleagues10 found that erythromycin was in- Cephalexin is more commonly used for sinus com- effective against Streptococcus viridans and most munications and for antibiotic prophylaxis in pa- Fusobacterium species. Thus, erythromycin should tients with prosthetic joints. be considered a historical antibiotic in the man- agement of odontogenic infections. Metronidazole: Metronidazole is a synthetic anti- biotic that is effective against anaerobic bacteria. Conclusion It disrupts bacterial DNA, thus inhibiting nucleic Odontogenic infections are polymicrobial in acid synthesis. It provides excellent anaerobic nature. Prompt diagnosis and treatment, including coverage and should be used in conjunction with elimination of the causative factor, are crucial to penicillin. their successful management. Antibiotics are a Clindamycin: Clindamycin inhibits bacterial useful adjunct in the treatment of odontogenic protein synthesis and is bactericidal at high dos- infections, but should not replace removal of the ages. Its use has increased in recent years due causative factor. All dentists should know when to increasing concern over penicillin resistance. referral to a specialist is warranted. For example, it has replaced penicillin