Infectious Complications of Bite

By Arash Nematollahi

HARRISON 19th EditionCHAPTER 167e

Contents• Dog Bites• Cat Bites• Other Animals• Human Bites• Treatment

Introduction Skin’s Nonspecific Immunity An Immunocompromise Inoculation 300 bites per 100’000 population Few may be life threatening Mostly the Oropharyngeal flora

Dog Bites 80% of All Animal Bites 15 to 20% become Infected More Prevalent in Children 8 to 24 Hour After

Pain & Cellulitisby

purulentand sometimes

foul-smelling discharge

Septic Arthritis & Osteomyelitis Systemic Manifestations:• Fever • Lymphadenopahty• Lymphangitis

Systemic Infections like Bactremeia, meningitis, Brain Abscess Or Endocarditis & Chorioamnionitis Edema or reduced Lymphatic Drainage Immunocompromised

Capnocytophaga canimorsus

Fulminant Sepsis, Disseminated Intravascular Coagulation & Renal Failure

Diagnonsis:Peripheral Blood

Culture in Liquid Media

Thin gram-negative rod

Cat Bites Bites & Scratches 50% Infectious Teeth Penetrate Deeply Over or Near a Joint Pasteurella multocida

Pasteurealla Infections

Advance RapidlyWithin hours

Severe InflammationPurulent DischargeRepiratory Droplets

Bartonella henselae

Cat-scratch Disease swollen lymph nodes, fever headache, fatigue, and loss of appetite

RabiesTularemiaTetanus

Other Animal Bites Occupational :• Farmers, Laboratory Workers, Veterinarians Recreational :• Hunters, Trappers, Wilderness Campers &… Oral Flora of the Biting Animal

Aquatic AnimalsAlligators

Aeromonas hydrophila

Venomous SnakeBitesSevere inflammatory

responseTissue Necrosis

Prone to InfectionMany aerobes & Anaerobes

As Pseudomonas

Small RodentsRats, Mice & Gerbils Streptobacillus

moniliformis Microaerophil, gram-negative rod Common in United States 3-10 days Incubation period Severe migratory

arthralgias, Fever, Chills, Myalgias &

Headache Maculopapular Rash Complications

Spirillum minor Spirochete more Common in Asia Both cause Rat-bite

Fever Initial Infection has healed Pain & Purple Swelling 1-4 Weeks Incubation

period Fever, Chills, Headache

Human Bites Self-inflicted, Medical Personnel, Fights,

Domestic Abuse or Sexual Activity More frequently become Infected Diverse Microflora of humans Multiple Aerobic & Anaerobic E. Corrodens Clenched-fist Injury Many Produce beta-lactamase

Occlusional vs Clenched-fist• Fight Bites result in

Serious Infection• Deep spaces

including Bone, tendons, joints frequently inoculated

• Tendons Retraction• Medical attention

sought late

TREATMENT Wound Closure is

Controversial Irrigation Removing Foregin body Debride dead tissue Approximate wound

edges Puncture Wounds Must

not Be Sutured Suture Facial wounds

Antibiotic Therapy• Dog and Cat Bites:

• S. aureus, Pasteurella species, c. canimorsus, streptococci, and Oral anaerobes

• Human Bites:• S. aureus, H. influenzae, beta-lactamase positive oral

anaerobes• Most reliable coverage:

• An extended-spectrum penicillin with a beta-lactamase Inhibitor

• Second Generation Cephalosporins as Cefuroxime• Hypersensitivity: Clindamycin plus TMP-SMX or a

fluoroquinolone• For a period of generally 10-14 days

The End