Burns, Bites and Stings of Animals and Insects

Patrick C. Obasi

Rabies

Wild animals constitute the most potential source of infection for both humans and domestic animals in US

About 10,000 pts receive post exposure prophylaxis for rabies annually

Most domestic animal bites are provoked by attack.

Post exposure prophylaxis combining local wound treatment, passive immunization, and vaccination is very effective

Any wild animal that bites or scratches a person should be killed at once

Table of Rabies Prophylaxis Guide

Animal Type Evaluation and Disposition of

Animal Postexposure Prophylaxis

Recommendations

Dogs and cats Healthy and available

Should not begin prophylaxis for 10 days observation unless animal develops symptoms of rabies

Rabid or suspected rabid Immediate vaccination

Unknown (escaped) Consult public health officials

Skunks, raccoons, bats, foxes, and most other carnivores; woodchucks

Regarded as rabid unless geographic area is known to be free of rabies or until animal proven negative by laboratory tests

Immediate vaccination

Livestock, rodents, and lagomorphs (rabbits and hares) Consider individually

Consult public health officials; bites of squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, mice, other rodents, rabbits, and hares almost never require antirabies treatment

Rabies:Local Care of Animal Bites

Thorough irrigation Cleansing with soap solution Debridement Administration of tetanus toxoid Abx

Rabies Vaccination

2 rabies vaccines currently available in US Rabies vaccine adsorbed (RVA) (Imovax) Human diploid cell rabies vaccine (HDCV)

Either administered with HRIG (Imogan rabies)

Vaccine administered intramuscularly in deltoid area for adult and anterolateral aspect of thigh for children

SFX of Vaccines

Muscle aches Headache Nausea Abdominal pain Pain, erythema, swelling, itching at

injection site Neurologic illness Note: Steroids can interfere with the

development of active immunity

Manifestations of Rabies

Paresthesia Headache Stiff neck Lethargy Pulmonary sxs Maniacal behavior Muscle spasm of throat with dysphasia Convulsion →coma →paralysis →death

Snakebites

Poisonous snakes of medical importance are of members of the family crotalidae or pit vipers

Coral snakes of the elapidae family also important

Poisonous snakes identified by their elliptical pupil

Non poisonous snakes do not have pits and fangs

Poisonous snakes have single row of sub caudal plates

Clinical Manifestation of Envenomation

Hypotension Weakness Nausea/vomiting Pain, swelling, tenderness and

ecchymosis at site of bite Paresthesia and muscle fasciculations Defect in blood coagulation Pulmonary edema

Grading of EnvenomationGrade Signs and Sxs0 – No envenomation Fang marks, min pain, small edema and

erythema

I – Minimal

envenomation

Fang marks, mod to severe pain, surrounding edema and erythema

II – Moderate

envenomation

Fang marks, severe pain, edema, erythema, possible systemic involvement (nausea, vomiting, shock)

III – Severe

envenomation

Fang marks, large surrounding edema and erythema with generalized petechiae and ecchymosis

IV – Very severe

envenomation

Systemic effect present. Sx may include renal failure, coma, death

Management of Snakebites

Application of a tourniquet, incision and suction are appropriate if done within one hour from time of bite

The most important treatment for snakebite is antivenin (crotalidae polyvalent immune fab)

IVF required to replace the decreased extra cellular fluid volume resulting from edema formation

Fascial planes may become tense with obstruction of venoms and later arterial flow, requiring fasciotomy

Vit K may be required to correct bleeding and clotting abnormalities

Tetanus toxoid administered and abx recommended to prevent secondary infection

Insect Stings

Group includes the honey bee, bumblebee, wasp, hornets and fire ants

Venom is just as potent a that of snakes Sxs consist of

*Localized pain *Petechial hemorrhages

*Swelling of skin and mucus membrane

*Generalized erythema *Abdominal cramps

*H/A *Pulmonary and cerebral edema

*Blurred vision *Vascular collapse

Insect Stings

Death results from combination of shock, respiratory failure and CNS changes

Most death from insect sting occur within 15 to 30 minutes

Early application of a tourniquet may prevent rapid spread of venom

Emergency kit containing epinephrine commercially available

Black Widow Spider

Spider Bites:Black Widow Spider The most biting spider in US is the black widow

(latrodetus mataus) Its venom is neurotoxic Generalized muscle spasm is the most prominent

physical finding Other sxs are nausea/vomiting, headache Priapism and ejaculation (have been reported) Tx:

Narcotics for pain Muscle relaxant for spasm Calcium gluconate relieves most sxs

Most pts recover within 24 hrs

Brown Recluse Spider

Spider Bites:Brown Recluse Spider Severe bite results in necrosis and sloughing of

skin with residual ulcer formation Pathophysiology of bite: intravascular

coagulation →formation of micro thrombi → capillary occlusion → hemorrhage → necrosis

Sxs include fever, nausea, vomiting, weakness, arthralgia, malaise, petechiae

Hemolysis and thrombocytopenia responsible for death

Brown Recluse Spider

Tx: Early excision Corticosteroids Heparin Dapsone (reduces inflammation at site of

venom injection)

Scorpion Stings

Only the bark scorpion (centraroides exilicanda) medically important

Found mainly in the desert of Southwest Venom is neurotoxic Diagnosis reinforced by the “tap test” Sxs include anxiety, blurred vision, or

temporary blindness, dyspnea, wheezing, involuntary urination and defecation, SVT, SZ

Scorpion Stings

Tx: Airway management Treat arrhythmias and HTN if indicated Calcium gluconate for muscle spasms No narcotics (aggravate neurotoxic effects) Goat-derived antivenin available only in

Arizona

Burns-Classification

Burns-Classification

Rule of Nines

Rule of Nines

Topical Treatment of Burns

Silver Nitrate Causes electrolyte imbalances (Na+, Ca+, Po4-, Cl-) No Pseudomonas sp. coverage Limited eschar penetration

Silvadene (Silver Sulfadiazine)

Can cause neutropenia and thrombocytopenia Limited eschar penetration and ineffective against Pseudomonas sp Sulfa allergy

Sulfamylon (Mafenide Sodium) Carbonic anhydrase inhibitor Coverage against Pseudomonas sp Painful For burns over cartilage

Parkland Formula

Measure of adequate resuscitation

Escharotomy –(indication, timings)

Indications for Intubation

Complications after Burns (ulcer types)

Parkland Formula

For burns > 20% 4cc/kg x % body burn x 24 hrs Give half in 8 hrs

Parkland Formula

Measure of adequate resuscitation Urine Output

1cc/kg in adult and 2-4 cc/kg in peds Escharotomy –(indication, timings)

Circumferential burns Problem with ventilation with chest burns

Indications for Intubation Upper airway stridor or obstruction, hypoxemia,

Complications after Burns (ulcer types) Curling’s Marjolin’s