DOG BITE AND ITS MANAGEMENT Medical students.pptx

Dog bite and its management for medical students and young doctors

1. DOG BITE AND ITS MANAGEMENT DR OFOH-OGHOUNU UYOYOU

2. OUTLINE INTRODUCTION EPIDEMIOLOGY MODE OF TRANSMISSION OF RABIES PATHOPHYSIOLOGY CLINICAL PRESENTATION MANAGEMENT PREVENTION REFERNCES

3. INTRODUCTION Dog bite is an injury inflicted by a dog on humans. The profile of such bites varies by country or region, based on the living condition, indigenous species and opportunity for encounter. Bites from dog and other animals such as cat are linked to rabies exposure as dogs are the main reservoir of the rabies virus. In Nigeria, dog bite is an important public health issue as rabies is endemic.

4. EPIDEMIOLOGY Males are more often bitten than females. Dog bite is experienced mainly among children. In Asaba specialist hospital , 10 cases of dog bites were seen in AnE over the last 4 months (6 of whom were children). Rabies has the largest impact on Asian and African populations and causes an estimated 59,000 deaths yearly worldwide. In USA, two human rabies death was reported in 2017 and three in 2018.

5. MODE OF TRANSMISSION OF RABIES Rabies virus is a bullet shaped, negative-sense, single stranded, enveloped RNA virus from the family Rhadoviridae , genus lyssavirus. Rabies is found in large quantities in the saliva of infected animals and transmitted through bite or scratch from a rabid mammal. Rabies is an acute, rapidly progressive infection of the central in humans and animals.

6. PATHOPHYSIOLOGY After inoculation rabies virus replicates slowly and at a low level in the skin and muscle The virus then enters the peripheral motor nerve, utilizing the nicotinic acetylcholine receptors for entry. It travels by fast axonal transport, crossing synapses every 12hr. Rapid dissemination occurs throughout the brain and spinal cord before symptoms appear. It also travels through the peripheral nervous system to virtually all innervated organs, further exacerbating dysautonomia.

7. PATHOPHYSIOLOGY The pathologic hallmark of rabies; the Negri body , is composed of clumped viral nucleocapsids that create cytoplasmic inclusions on histology. Incubation period for rabies is 1-3 months and occasionally it may extend to 8 years. In severe wound to the head , symptoms can occur within 5 days of exposure.

8. NEGRI BODIES

9. SIGNS AND SYMPTOMS OF RABIES Rabies has two clinical forms; Encephalitic or furious rabies :- non-specific symptoms like fever, sore throat, malaise, headache, nausea, vomiting and weakness. Paresthesia and pruritus at or near the site of the bite that then extend along the affected limb. Seen in 40%-80% of patient with rabies. Periods of lucidity alternating with periods of profound encephalopathy . Hydrophobia and aerophobia can lead to spasm of the pharynx , neck and diaphragm.

10. SIGNS AND SYMPTOMS OF RABIES Paralytic or dumb rabies :- Seen much less frequently. Characterized by: - fever. - ascending motor weakness affecting both limbs and the cranial nerves.

11. CLINICAL PRESENTATION Dog bite can present with abrasion, puncture wound, and laceration with or without an associated avulsion of tissue. It can also involve crush injury to tissue or bones History of presenting complain will include : Time of the event. Type of dog if possible and its state [ health, behavior, whereabout] Circumstances surrounding the bites [ provoked/defensive versus unprovoked]

12. CLINICAL PRESENTATION Location of the injury. Pre-hospital treatment. Patient medical history [ Immunocomprised , pre-existing diabetes , tetanus immunization history]. Physical examination: general examination - distal neurovascular status - tendon or tendon sheath involvement - bone involvement - foreign bodies [ e.g teeth] in the wound.

13. DIAGNOSIS TESTING Rabies Virus-Specific Antibodies. RT-PCR Amplification: Highly sensitive and specific. Direct fluorescent antibody testing .

14. MANAGEMENT OF DOG BITE Aim of management is to prevent severe complications. Management includes: Culture for aerobes and anaerobes should be done for infected wound. Irrigate wound copiously with normal saline . Devitalized or necrotic tissue should be cautiously debrided. Plain radiographs should be obtained if bony penetration is possible and to provide a baseline for future evaluation of osteomyelitis .

15. MANAGEMENT OF DOG BITE Primary wound closure is not advocated. Initiate prophylactic antibiotics; amoxicillin/clavulanic[first choice], Tab clindamycin with either ciprofloxacin or levofloxacin or trimethoprim-sulfamethoxazole. Hospitalization is indicated if there is systemic toxicity or worsening infection. Administer tetanus booster. Administer rabies vaccine (post exposure prophylaxis): [ Rabies immunoglobulin (RIG) and Inactivated rabies vaccine ]

16. MANAGEMENT OF DOG BITE RIG: administered at a dose of 20IU/kg . As much of the dose is infused around the wound as possible and the remainder is injected IM in a limb distant from the one injected with the killed vaccine . Inactivated Vaccine : [ RabAvert , Imovax ] is also given IM in a 1ml volume into the deltoid or anterolateral thigh on days 0, 3, 7, and 14 after presentation. Rabies vaccine can be safely administered during pregnancy.

17. DIFFERENTIAL DIAGNOSIS Cerebral infection. Tetanus. Drug Abuse. Guillian -barre syndrome.

18. PREVENTION General prevention : i . Sensitizing the public to avoid wild or stray animals and animals with unusual behavior. ii. Vaccination of domestic animals with attenuated rabies vaccine . Specific prevention: Pre-exposure prophylaxis; killed rabies vaccine is given to high risk individuals, given IM at days 0,7,21 and 28 .

19. CONCLUSION Rabies is a zoonotic vaccine-preventable illness but once clinical symptoms appear, it is often fatal. Prognosis remains exceedingly poor despite aggressive and intensive care management.

20. REFERENCE Peters V, Sottiaux M, Appelboom J, Kahn A. Post-traumatic stress disorder after dog bite in children 2004;144:121-122 Alan C Jackso . Harrison Principles of Internal Medicine 2021;208:6068-6088 David A. Hunstad . Nelson Textbook for Pediatric 2020;743:3816-3819 Murphy J. Qaisi M. Management of Human and animal bites 2021 Aug . 33[3] 373-380 .