References wider area. Third, extensor tendon and articular cartilage are relatively avascular structures that have limited ability to fight infection. Fourth, there is a high concentration of pathogenic organisms in human saliva. Lastly, patients tend to present later because they underestimate the injury and are uncomfortable with the potentially law breaking circumstances surrounding their injury. Radiographic examination is a must to look for foreign bodies in the form of animal teeth parts and assess integrity of the bone cortices whose absence may indicate penetration to the bone. Dog and human bites are usually polymicrobial with a mixture of aerobes such as Pasteurella sp, Eikenella corrodens, Staphylococcus sp and Streptococcus sp and anaerobes while cat bites Pasteurella multiocida is the main isolate in cat bites.
procedure under general anaesthesia so as not to spread the inoculums by wound infiltration with local anaesthetic. Antibiotic and tetanus prophylaxis Amoxicillin-clavulanic acid is the mainstay of prophylaxis as it provides excellent coverage against the usual organisms that are inoculated. Doxycycline with metronidazole is a good alternative in penicillin-allergic individuals. While the oral route has been recommended as sufficient, intravenous antibiotics is the rule for patients managed by us for the increased bio-availability and non-interference with patient fasting for general anaesthesia. Tetanus booster is a must if original three-dose series has been given but none in the past year prior to the bite. Repair of damaged tissue
1. Wong T. Dog attacks on the rise. The Straits Times 19 Nov 2009. 2. Gilchrist J, Sacks JJ, White D, Kresnow MJ. Dog bites: still a problem? Inj Prev 2008; 14: 296-301. 3. Benson LS, Edwards SL, Schiff AP, Williams CS, Visotsky JL. Dog and cat bites to the hand: treatment and cost assessment. J Hand Surg Am 2006; 31: 468-473. 4. Marr JS, Beck AM, Lugo JA. An epidemiological study of the human bite. Public Health Rep 1979; 94: 514-521. 5. Fleischer GR. The management of bite wounds. N Engl J Med 1999; 340: 138-140. 6. Perron AD, Miller MD, Brady WJ. Orthopedic pitfalls in the ED: fight bite. Am J Emerg Med 2002; 20: 114-117. 7. Dendle C, Looke D. Review article: animal bites: an update for management with a focus on infections. Emerg Med Australas 2008; 20: 458-467. 8. Oehler RL, Velez AP, Mizrachi M, Lamarche J, Gompf S. Bite-related and septic syndromes caused by cats and dogs. Lancet Infect Dis 2009; 9: 439-447. 9. Center for Disease Control and Prevention. Travelersʼ health yellow book on Rabies. wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/rabies.aspx (accessed on 12 Sep 2010).
Management Clearance of contamination “There are two types of bites in general. First is the one you debride and second is the one you wish you had debrided.” This adage, drummed into us doyens of our community, sums up the first and arguably most important principle in the management of bites. This is especially true in the hand where 30-40% of bites become infected. The reason for this is the many tight and enclosed spaces that exist to allow inoculated bacteria to fester as well as the proximity of bone and joints to the skin, making them more susceptible to penetration by teeth. Timely and crucial surgical treatment involves excision of all tissue that is devitalised and most tissue that has been inoculated by the animal’s teeth including curettage of affected bone and lavage of joints that have been breached. Provided the patient is fit enough, the preference is to perform this
10 • ME D ICO
J U N E 2 013
Structures, including skin injured by the bite will need to be repaired. However, in the face of the intrinsically high infection risk linked to bites, placement of internal fixation in fractures and suture material for tendon, nerves and skin will no doubt exacerbate this risk and should be deferred until the wound is deemed clean after at least one adequate surgical debridement. In other words, all reconstruction is staged except vascular repair in the face of a devascularised part. How about Rabies? Rabies virus is present in the saliva of the biting animal and has to be taken up by the nerve synapses to travel to the brain where it can cause fatal encephalitis. The hand, along with the face, has a large number of nerve endings and hence is considered a higher risk exposure when the biting animal is infected with rabies. Fortunately, the latest data in 2005 from
the Centers of Disease Control and Prevention place Singapore on the list of countries that report no indigenous cases. As such, it is reasonable to omit rabies prophylaxis if the patient has been bitten by an animal in Singapore. Have we gotten away with doing less? While we definitely do not advocate anything less than prophylactic antibiotics, tetanus prophylaxis and surgical debridement, anecdotes of less optimal treatment being carried out without subsequent serious infection taking place have been told. Nonetheless, such a strategy is unpredictable at the very least and is, in fact, potentially disastrous.