Medicine Review Course Animal Bites (Dogs, Cats, Monkeys)
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Medicine review course Animal bites (dogs, cats, monkeys) 8/7/17 Assessment of a bite (the crude history) 1) Where (the circumstances) did the bite occur? 2) Where (on the body) did the bite occur? 3) Time from bite to presentation? 4) Extent of wound? 5) Host immunocompetence? 6) Host vaccination history? The answers to these questions will provide……. Assessment of a bite (the refined history) 1) The potential organisms (from the animal’s surroundings, from the animal’s flora, from the patient’s skin) 2) The need to image deeper tissues and activate more than the ID-on-call (Ortho, GS, vascular, ….) 3) The maximal potential extent of this injury 4) Wound treatment, antibiotics, vaccination and follow-up required. Dogs and cats 1) Potential organisms -Consider rabies in wild dogs, in non-rabies free countries, in unprovoked attacks. -Consider soil derived organisms(clostridium tetanus, melioidosis) in wild dogs -Consider bacillus anthracis in farm dogs -Consider capnocytophaga carnimorsus and pasteurella species in exams! 2) Deeper tissues imaging -Consider bone and joint involvement if wound is deep -Look out for presence of prosthetic joints. -cats can bite deep. Small wound can be deeply punctured 3) Maximal potential -Melioidosis in poorly controlled DM -Deeper infection in breast cancer patients post axillary clearance -Disseminated capnocytophaga carnimorsus in asplenia -Tetanus and rabies in bites close to face Rabies Duration (% of Stage Associated Findings Cases) <30 d (25%) 30-90 d (50%) Incubation period None. 90 d to 1 y (20%) >1 y (5%) Paresthesias or pain at the Prodrome and early wound site; fever; malaise; 2-10 d symptoms anorexia; nausea and vomiting. Hallucinations; bizarre behavior; anxiety; agitation; Acute neurologic disease; biting; hydrophobia; Furious rabies (80% of 2-7 d autonomic dysfunction; cases) syndrome of inappropriate antidiuretic hormone (SIADH). Myocarditis Paralytic rabies (20% of 2-7 d Ascending flaccid paralysis. cases) Coma, death* 0-14 d — Diagnosis of rabies 1) Clinical 2) Serology for rabies antibodies (RFFIT: rapid fluorescent focus inhibition test) -50% positive by day 8 and 100% positive by day 15 3) RT-PCR of CSF or saliva for rabies virus 4) MRI Brain is not specific. No pathogmnemonic findings. Treatment of rabies RISK CATEGORY NATURE OF RISK TYPICAL POPULATIONS PREEXPOSURE REGIMEN Continuous Virus present continuously, Rabies research Primary course; often in high concentrations laboratory serologic testing every 1 Specific exposures likely to workers, rabies 6 months; booster go unrecognized biologics production vaccination if antibody Bite, nonbite, or aerosol workers titer is below exposure acceptable level Frequent Exposure usually episodic Rabies diagnostic Primary course; with source recognized, but laboratory serologic testing every 1 exposure might also be workers, cavers, 2 years; booster unrecognized veterinarians and staff, vaccination if antibody Bite, nonbite, or aerosol and animal control and titer is below exposure possible wildlife workers in acceptable level areas where rabies is (0.5IU/ml OR complete enzootic. All people neutralization at 1:5 in who frequently handle the RFFIT) bats. RISK CATEGORY NATURE OF RISK TYPICAL POPULATIONS PREEXPOSURE REGIMEN Infrequent Exposure nearly always Veterinarians and animal Primary course; no (greater than episodic with source control staff working with serologic testing or general recognized terrestrial carnivores in booster vaccination population) Bite or nonbite exposure areas where rabies is uncommon to rare; veterinary students; and travelers visiting areas where rabies is enzootic and immediate access to medical care, including biologics, is limited Rare (general Exposure always US population at large, No preexposure population) episodic, with source including individuals in immunization recognized rabies-epizootic areas necessary Bit or nonbite exposure Types of contact are: category I – touching or feeding animals, licks on the skin category II - nibbling of uncovered skin, minor scratches or abrasions without bleeding, licks on broken skin category III – single or multiple transdermal bites or scratches, contamination of mucous membrane with saliva from licks; exposure to bat bites or scratches Vaccine details 1) IM rabies vaccines are given in deltoid not gluteus. 2) Rabies immune globulin should be given within 7 days of start of active immunization. 3) Different IM formulations are interchangeable. 4) Different ID formulations are interchangeable. 5) IM and ID formulations are NOT interchangeable. 6) Excess of immune globulins are injected into patient at a site distant from active immunization. 7) Missed doses in pre-exposure vaccination? Resume without repeating previous dose 8) Missed doses in post-exposure vaccination? Resume without repeating previous dose. If unsure, check antibodies levels 1-2 weeks after last dose Efficacy Anderson LJ, Sikes RK, Langkop CW, et al. Postexposure trial of a human diploid cell strain rabies vaccine. J Infect Dis 1980;142:133--8. Bahmanyar M, Fayaz A, Nour-Salehi S, Mohammadi M, Koprowski H. Successful protection of humans exposed to rabies infection. Postexposure treatment with the new human diploid cell rabies vaccine and anti-rabies serum. JAMA 1976;236:2751--4. Aoki FY, Rubin ME, Fast MV. Rabies neutralizing antibody in serum of children compared to adults following postexposure prophylaxis. Biologicals 1992;20:283--7. Benjavongkulchai M, Kositprapa C, Limsuwun K, et al. An immunogenicity and efficacy study of purified chick embryo cell culture rabies vaccine manufactured in Japan. Vaccine 1997;15:1816--9. Bijok U, Vodopija I, Smerdel S, et al. Purified chick embryo cell (PCEC) rabies vaccine for human use: clinical trials. Behring Inst Mitt 1984:155--64. Wasi C, Chaiprasithikul P, Auewarakul P, Puthavathana P, Thongcharoen P, Trishnananda M. The abbreviated 2-1-1 schedule of purified chick embryo cell rabies vaccination for rabies postexposure treatment. Southeast Asian J Trop Med Public Health 1993;24:461--6. Tanphaichitra D, Siristonpun Y. Study of the efficacy of a purified chick embryo cell vaccine in patients bitten by rabid animals. Intern Med J 1987;3:158--60 Total >222 patients. 0 deaths from rabies 5 bitten given active vaccine without antiserum3 died 12 bitten given active vaccine with antiserum1 died Fangtao L, Shubeng C, Yinzhon W, Chenze S, Fanzhen Z, Guanfu W. Use of serum and vaccine in combination for prophylaxis following exposure to rabies. Rev Infect Dis 1988;10:S766--70. 0/23 with IVIg died, 3/3 without died Who should receive abx prophylaxis? Without treatment, 16% of dog bites become infected.1 With treatment, RR 0.56 (95% confidence interval, 0.38 to 0.82) Prophylaxis to be considered within 24 hours of injury.2 Preemptive early antimicrobial therapy for 3–5 days is recommended for patients who3 1) Are immunocompromised 5) Hang injuries 2) Are asplenic 6) Bone and joint involvement 3) Have advanced liver disease 7) Moderate and severe injuries 4) Edematous in the biten limb 1) Antibiotics to prevent infection in patients with dog bite wounds: a meta-analysis of randomized trials Cummings P. Ann Emerg Med 1994; 23:535–40. 2) A comparative double blind study of amoxycillin/clavulanate vs placebo in the prevention of infection after animal bites Brakenbury PH, Muwanga C Arch Emerg Med. 1989;6(4):251 3) Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America Stevens et al CID June: 2014 Common organisms isolated Principle and Practice of Infectious Disease 7th edition Mandell et al Treatment Same antibiotics choice as prophylaxis Duration to be determined by extent of infection. Remember tetanus toxoid: Tetanus toxoid should be administered to patients without toxoid vaccination within 5 years. Wound care Primary wound closure is not recommended for wounds with the exception of those to the face, which should be managed with copious irrigation, cautious debridement, and preemptive antibiotics (strong, low). Other wounds may be approximated (weak, low). *lack of good controlled studies, heterogeneity in wounds undermine stregth of recommendation Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America Stevens et al CID June: 2014 Capnocytophaga carnimorsus or cynodegni Gram negative bacillus. Normal oral flora of dogs and cats. -more with dog bites Incubation period 3 days from bite Risk factors: asplenia, alcohol Septicemia and meningitis prominent Mortality for septicemia: 30% Mortality for meningitis: 5% Prolonged blood cultures needed -3-7 days to grow. Augmentin, 3 and 4th generation cephalosporins usually useful. Consider brain penetration when dosing Retiform purpura -occurs in about 20-40% of C. carnimorsus bacteremia. -clotted superficial veins in a background of purpura fulminans. Pasteurella multocida Gram negative bacillus. Normal oral flora of dogs and cats. More with cat bites. Skin and soft tissue infections Upper respiratory tract infection Lower respiratory tract infection in COPD and bronchiectasis Bacteremia in cirrhotic, immunocompromised host1 -mortality is 31% in this cohort b-lactam-b-lactamase inhibitor, penicillin, cefazolin, cefuroxime ceftriaxone, fluoroquinolones, doxycyclines active. Anti-staphylococcal penicillins not active. Scandinavian journal of infectious diseases 1987;19(4):385-93.: Pasteurella multocida bacteremia: report of thirteen