Venomous Animal Injuries

Snakes

Five Types of Snakes throughout the World

1. Colubridae Rear Fixed fangs African boomslang is the only truly dangerous one

2. Elapidae front fixed fangs the poisonous family

3. Hydrophidae Sea Snakes front, fixed fangs Paralysis and myonecrosis

4. Atractaspididae front, mobile fangs

5. Viperidae front, mobile fangs Pit Vipers and True Vipers

CBC, PT/PTT, Fibrin Splits, Fibrinogen, T+C 4 units

Copperhead-often do not need to be treated

Timber Rattlesnake-rocky bluffs or ridges, Cause PLT destruction

Eastern Diamondback-most dangerous in US, dont retreat from humans

Western Diamondback-also will attack humans

Cottonmouth-swims and crawls

Eastern Coral-red on yellow kills a fellow, neurotoxic. Has to chew instead of inject venom

4 Rows of scratches=non-venomous snake

Pseudosnake bite-self-inflicted puncture wounds to get pain meds

Typical snake bite victim: 99% men, 99% white, 40% with tattoo on L forearm

Venom injected SC not IM

snake bite extractors do not work (Annals EM February 2004 Volume 43 Number 2)

Pit Vipers

Crotalinae of viperidae family: Rattlesnakes, sidewinders, diamondbacks

Agkistrodon: copperheads and cottonmouths

Pit between eye and nostril

Bite is immediately painful

Toxin disrupts coagulation path leading to DIC, shock, and NCPE

Paresthesias, muscle fasiculations, weakness, paralysis, respiratory failure, renal failure

Antivenin for patients with moderate or severe envenomation

CroFab

best if administered within 6 hrs of bite.

6 vials to start, if initial control, give 2 vials at 6, 12, and 18 hours

If no control (systemic effects, Lab abnormalities, Spread of Local Swelling), give additional 6 vials and repeat until control. Starts to work in 1-2 hours, no pretreatment needed. Antibiotics only if signs of infection. Same crofag dose in peds.

Contraindicated if allergic to papayas.

$800 per vial

timber rattler not included in the antivenin, ? of cross reactivity

test dose has 10% rate of false positive and false negative. Can cause anaphylaxis, most will get serum sickness.

Necrosis, hemolysis, PLT destruction, edema, dry gangrene, early Hypotension (bradykinin), shock, and bleeding diatheses

Coral Snakes

Eastern and Sonoran coral snakes

Red next to yellow kills a fellow, Red next to black, venom lack. (Only here does the rhyme apply, not Africa)

Block neuromuscular transmission. Ptosis, diplopia, dysphagia, paresthesias and paralysis.

Antivenin for eastern coral, recommended to give before symptoms, as symptoms can be delayed and severe

Never discharge secondary to late morbidity

Neurotoxin, can cause paralysis

If bitten on finger, swelling to the midpalm is minor, the wrist moderate, above is severe

Acute compartment syndrome-muscle injuries not necessarily associated with compartment pressures, so do not perform empirically

Finger dermotomy is recommended. Call hand surgeon.

Lizards

Gila monster and Mexican beaded lizard

Hymenoptera

Bees, wasps, hornets-remove stinger c back of scalpel blade

Remove bee stings as rapidly as possible regardless of method, no increase in venom in blood by method, definitely increases with time to removal (JB 23, Also Lancet Article)

Fire ants-hemolysis and complement activation

Refer severe sting allergies to allergist for desensitization

Spiders (Arthropods)

Black Widow

Shiny black with red or yellow hourglass on rounded abdomen

Only the female has long enough fangs to bite humans

Neurotoxic venom

Initially only small sting. 15-30 minutes after the bite, dull crampy pain spreading outwards

Abd and chest get rigid

CNS abnormalities and autonomic dystability

Give tetanus toxoid

Monitor 4 hours

One amp CaGluc Q2-4 hrs

Consider valium or dantrolene

<16 or >65 get antivenin, or life threatening complications

Brown Recluse or Fiddleback

Little brown spider with violin marking on back

Prefer dark, dry places: basements, woodpiles, barns

Venom is tissue destructive. Bite is initially painless. 2-6 hours later, get itching, mild tenderness, and erythema

1-7 days erythematous area is now large necrotic lesion

Systemic effects can occur 24 hours after bite and include: n/v, malaise, hemolysis, DIC, ATN

Vasoconstrictive area around bite then necrosis spreads outwards.

Systemic effects, can get DIC

Local wound care, dT,

Give dapsone 25 to 100 mg PO BID for 2 weeks, make sure not G6PD

Tarantulas

Not venomous, but their abdomens are covered with urticating hairs, will cause inflammatory response if they flick them at you. Explorers club ate them and got pharyngeal tingling.

Scorpions

Worst sequelae is respiratory failure. Venom causes prolonged and excessive firing of nerves.

Antivenin available, but usually supportive care, benzos, and intubation if needed are sufficient

Marine

Venomous Vertebrates

Stingrays

Tail barbs can penetrate the hulls of boats

Has heat labile toxin containing phosphodiesterase and serotonin causing bradycardia, resp depression, and seizures

Severe pain with a wound that is first dusky then red and hemorrhagic to necrosis

Muscle cramps, syncope, paralysis, seizures. Severe bacterial infection can also result often with Vibrio vulnificans.

Give Pain control, immerse limb in warm water to deactivate toxin, treat for any infections

Marine Snakes

Myotoxins cause rhabdomyolysis or paralysis

Supportive care and antitoxin

Scorpion fish

Lionfish: complex venom that causes severe pain, swelling, and tissue loss locally

Stonefish: heat labile toxin. N/V, hypotension, dysrhythmias, syncope, dyspnea, seizures, coma, paralysis. Soak limb in hot water. Irrigate vigorously. Remove any spines in wound, Tetanus proph, Antivenom available, dose based on number of spines.

Weeverfish: most venomous fish in the temperate zone. Causes severe local inflammation with tissue loss and possible gangrene

Venomous Invertebrates

Cnidaria (Coelenterates)

Contain Nematocysts used to immobilize their prey. Even detached tentacles retain toxicity for months. Venom contains bradykinin, hemolysin, serotonin, histamine, etc.

Localized dermatitis with severe pain and eventual scarring. Systemically, paralysis, CNS changes, seizures, respiratory failure, muscle spasm, coma, and death.

Rinse with seawater or urine, fresh water will cause further discharge of venom

Inactivate with vinegar

Remove tentacles with forceps

Cover nermatocysts with shaving cream or talcum poweder

Shave off with razor blade

are treated by removing the nematocysts without allowing them to discharge. The area should first be washed with sea water; fresh water may cause the nematocysts to discharge. Tentacles should be removed with a gloved hand or forceps. The area should not be rubbed with sand, because this old form of therapy actually makes the condition worse. The remaining nematocysts should be fixed by pouring vinegar over the wound area. Sodium bicarbonate may be used for sea nettle stings. The area should be dusted with talcum powder or covered with shaving cream, and the nematocysts, now adherent to the powder or cream, can be scraped off with a knife. The area should then be washed with sea water, and a steroid cream applied. Most lifeguard stations in areas where coelenterate stings are common have the necessary materials for this regimen. Most EDs have the equipment, but by the time the victim arrives at the hospital the damage may be already done.

Tetanus

Antivenin for chironex (most deadly of jellyfish)

Irukandji Syndrome

severe local and systemic symptoms after carukia barnes (box jellyfish) sting.

Nonspecific ekg changes with elevated troponin

pain, restlessness, diaphoresis, vomiting, coughing

phentolamine for sympathetic excess

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