Dog Bites

Dogs• Prominent canine teeth

• Enormous pressure when biting

• Large breeds tend to cause

wounds in the head and neck

• Powerful jaws can penetrate the skull and destroy deep tissue

Victims

• Males are more likely to be bitten by dogs.

• Females are more likely to be bitten by cats.

• Animal bites are most common in children aged 5-14 years

Cause

• Causes of provoked attacks – Antagonizing an animal – Hurting an animal

• Causes of unprovoked attacks – Approaching the young of an animal – Approaching an animal that is eating – Entering the property of a territorial animal – Nearing an animal with rabies

Mortality/Morbidity

• Wound infection and cellulitis – Puncture wounds have a higher rate of infecti

on than lacerations– Lacerations cause more damage to tissues th

an puncture wounds – Septic arthritis from wounds in joint spaces

• Osteomyelitis from deep wounds • Meningitis from penetrating skull wounds• Rabies

Exams and Tests

• Inspection the wound

• X-rays to look for fractures or foreign body in the wound.

Rabies contacted Category

Category Contact

Category Itouching or feeding suspect animals,but skin is intact

Category IIminor scratches without bleeding from contact, or licks on broken skin

Category III

one or more bites, scratches, licks on broken skin, or other contact that breaks the skin; or exposure to bats

Treatment• Wound care

– Irrigation and Debridement

• Suture: – Primary closure in facial wounds

( rarely infected because of well vascularized)

– Delayed closure • heavily contaminated (dirty) • significant amount of tissue damage • hands or lower extremities or • wound older than 6 hours

– Some wounds are never sutured

Medical treatment

• Antibiotic coverage for – staphylococci – anaerobes

• Tetanus prophylaxis

• Rabies prophylaxis

Antibiotics commonly used

• Amoxicillin clavulanate (Augmentin ®) • Ampicillin-sulbactam (Unasyn ®) • Trimethoprim and sulfamethoxazole (Bactrim ® ) • Clindamycin (Cleocin ®) • Erythromycin (E-Mycin, Ery-Tab, Erythrocin)• Ceftriaxone (Rocephin ®) • Tetracycline (Sumycin ®)

Vaccines and immune globulins

• Tetanus toxoid

• Rabies vaccine

• Rabies immune globulin

Tetanus vaccine

Dose 1 Dose 2 Dose 3

Day 0 Month 1-2 Month 6-12

Intramuscular injection

Tetanus prophylaxis consideration

IMMUNIZATION HISTORYCLEAN MINOR

WOUND

ALL OTHER WOUNDS

1. Fewer than 3 doses; or2. Uncertain number of doses; or3. No immunization

TT only TT +TIG*

At least 3 previous doses of tetanus vaccine, but the most recent more than 10 years ago

TT only TT only

At least 3 previous doses of tetanus vaccine, but the most recent more than 5 and less than 10 years ago

no immunization

required

TT only

At least 3 doses of tetanus, with the most recent 5 years ago or less

no immunization

required

no immunization

required

http://www.health.gov.nl.ca/health/publications/immunization/S5/tetanus_prophylaxis_in_wound_man.htm

TIG*= Tetanus Immune Globolin

Rabies vaccine

• Protection level should be achieved by day 14 of a post-exposure immunization regimen, with or without simultaneous administration of RIG and irrespective of age.

Vaccine & RIG consideration

Category Contact Immunization

Category Itouching or feeding suspect animals,but skin is intact

None

Category IIminor scratches without bleeding from contact, or licks on broken skin

Vaccine

Category III

one or more bites, scratches, licks on broken skin, or other contact that breaks the skin; or exposure to bats

Vaccine + RIG

Post-exposure rabies vaccination schedule

Day Regimen

dose 0 3 7 14 30 90

5 dose IM 0.5 1 1 1 1 1

4 dose IM 0.5 2 0 1 0 1 (21)

8 site ID 0.1 8 0 4 0 1 1

2 site ID 0.1 2 2 2 0 1 1

04/12/23 17

8 sites Intradermal administration

Day 0

Day 0

Day 0 7

Day 0 7

30Day 0 7 90

Rabies immunoglobulin• Passive antibody is present 24 hours after injection • Half-life of approximately 21 days. • Dosage

– HRIG 20 IU/kg – ERIG 40 IU/kg, admin as soon as possible at the same time as vaccine, or up to 7

days after vaccine inj.

HRIG 300 IU/2ml ~ 4000 baht

(1 vial / 15 kg BW)

ERIG 1000IU/5ml~ 1900 baht

(1 vial / 25 kg BW)

Should not inject RIG

• Later than 7 days after the initiation of post-exposure vaccination.

• Previously immunized

as this may reduce the immunologic response to the vaccine.

Precuation

• RIG may interfere with the body's immune response to certain live virus vaccines such as measles, mumps, and rubella, should be administered at least 14 days prior to, or at least 3 months after administration of RIG

• If IM inj is contra-indicated, inj may be given by SC with pressure and compress applied to site after inj.

• Do not exceed recommended doses as this may reduce the immune response to rabies vaccine.

Previously immunized person

• 2 IM / ID doses – Day 0 and day 3

• RIG should not be given.

Full PEP should be given to persons :– who received pre-or post-exposure prophylaxis with v

accines of unproven potency – patients whom immunological memory is not longer a

ssured as a result of HIV/AIDS or other immunosuppressive causes

OPD or IPD

I am a Pit bull

Another pit bull attack

Rabies

• A viral, zoonotic

neroinvasive disease

• Mortality rate of 100%

35,000-50,000 deaths

annually worldwide

Transmission

• Humans most often become infected with rabies through the bite or scratch of an infected dog or cat.

• Routes of transmission have been documented and include contamination of mucous membranes (i.e., eyes, nose, mouth), aerosol transmission, and corneal transplantations

• Rabies virus can be excreted in the saliva of infected animals several days before illness is apparent

• Figure 2. The cycle of rabies infection begins with viral entry at a peripheral site and proceeds through retrograde axonal transport. Viral replication occurs in the cell body of the primary neuron. Infection proceeds by transsynaptic spread through several neurons before spreading to the acinar cells, which then shed the virus into the saliva (Dietzschold et al. 2005).

Rabies virus

• Rabies virus travels along axons at a rate of 12-24 mm/d* to enter the spinal ganglion

• From here, the rabies virus spreads quickly, at a rate of 200-400 mm/d* into the CNS

• Average incubation is 20-90 days. – > 90% of cases, incubation is less than 1 year – Rarely, incubation lasts as long as 19 years.

*http://emedicine.medscape.com

Test for rabies

• Rabies diagnosis in animals(after the animal is dead).– Direct Fluorescent Antibody (DFA) is the “gold standard” diagnostic method for rabies– Tissue from at least two locations in the brain, preferably the brain stem and cerebellum.

• Rabies diagnosis in humans– Tests are performed on samples of saliva, serum, spinal fluid.

– Skin biopsy specimens are examined for rabies antigen in the

cutaneous nerves at the base of hair follicles • Rabies virus is not found in blood, urine, or feces.

SymptomsIncubation period ( 20-90 day)

asymptomatic

Prodromal period (enters the CNS, 2-10 day)

fever malaise anorexia headaches nausea emesis oagitation diarrhea

Neurologic period (objective signs of

developing CNS disease , 2-7 days)

psychosis, restlessness ,seizures, aphasia hydrophobia and aerophobia signs of cranial nerve involvement: diplopia facial palsy, and optic neuritis

Coma and death