Terrestrial Bites and Stings Brian Costello MD Department

Terrestrial Bites and Stings Brian Costello, MD Department of Pediatric Emergency Medicine June 24, 2010

Objectives By the end of this lecture you should be able to: § Describe the management and treatment for • Reptile envenomations • Arthropod envenomations • Mammalian bites and common associated infections § Understand perform initial management of these injuries, such as • Local wound care • Venom specific antidotes • Stinger and tick removal 2

Snakes § US has 120 different species of snakes • Only 15% poisonous § Two families: • Crotalidae (pit vipers) 99% of snakebites • Elapidae 1% of snakebites 3

Identifying Poisonous Snakes 4

Crotalids § Include Water Moccasin (aka Cottonmouth), Rattlesnake, and Copperhead § Venom is a combination of necrotizing, hemotoxic, neurotoxic, nephrotoxic and cardiotoxic substances • Mojave rattlesnake has a large fraction of neurotoxin • Neurotoxin prevents depolarizing action of acetylcholine (paralytic) • Proteolytic enzyme acts like hyaluronidase causing local tissue destruction, swelling • Increased capillary leak – shock, respiratory failure • Hemotoxic effects include hemolysis, thrombocytopenia and fibrinogen proteolysis leading to bleeding diathesis 5

Crotalids § Small children are more susceptible to venom given their size compared to adults causing more systemic symptoms § Bites on the head, neck or trunk hasten systemic absorption § Most bites are on the extremities § Measure the distance between the two fang marks to estimate snake size • 8 mm = small snake • 8 -12 mm = medium snake • >12 mm = large snake § 10 -20% of rattlesnake strikes are “dry” (no venom) 6

Crotalid Bites - Symptoms 7 § 5 -10 min – Intense pain, erythema, and edema § Perioral numbness with metallic taste § N/V, chills, weakness, syncope, sweating § Neuromuscular symptoms after a few hours: • Diplopia, difficulty swallowing, lethargy, progressive weakness § Next 8 hours – Progressive edema at wound site § Shock – usually 6 -24 hrs (may be as soon as 1 hr) § Vesicles and hemorrhagic blebs by 24 hours § Edema may lead to compartment syndrome and necrosis § Secondary infection – gram-negative bacteria

Crotalid - Management 8 § Pre-Hospital • ABCs • Rest • Take off jewelry and clothing from affected extremity • Immobilize extremity and keep below level of heart • Keep warm • NPO • Constriction band (experienced hands only) • Incision and Suction kit if available (must use within 5 -10 minutes of bite) • Rapid transport to medical facility

Snake Bite Kits 9

Crotalid - Management § ED • IV access, fluids, (central line & CVP? ), morphine • If snake is brought to ED, treat it with respect s Many people bitten by “dead” snake s Decapitated snakes bite reflexively for up to 1 hour • Measure circumference of extremity at leading point of edema and 10 cm proximal Q 30 min X 6 hours, then Q 4 for 24 hours • CBC with platelets, coags, type and cross, U/A • If moderate or severe poisoning, then also get BMP, fibrinogen and ABG • Repeat labs Q 4 -6 hours 10

Crotalid Antivenin § AVCP polyvalent antivenom • Horse serum, highly antigenic – needs skin testing prior to giving • Don’t use it if you can get Cro. FAB § Cro. FAB • Sheep derived antibody with cleaved Fc portion s Cleared from kidneys fast • Less adverse reactions § For maximal binding, use antivenom within 4 hours of bite. § Dosage NOT based on weight. Kids need more. 11

Crotalid - Management § Cro. FAB • Initial dose is 4 -6 vials • Repeat initial dose if there is progression of symptoms • Once there is no progression, then give either: s 2 vials Q 6 h for 3 doses OR s 2 -6 vials if progression of symptoms recur • Admit to PICU • All patients must be reexamined in 2 -5 days after bite • Watch for serum sickness up to 3 weeks out 12

Crotalid - Management § Local wound care § Tetanus prophylaxis § NO ice to wound § Watch for signs of compartment syndrome, call surgery § Superficial debridement needed in 3 -6 days • Local oxygen, aluminum acetate 1: 20 solution, triple dye § Blood products for coagulopathy § No prophylactic antibiotics (current thinking) § Physical therapy in healing phase 13

Elapids § Only 3 poisonous Elapids in US: • Eastern Coral Snake – Found in Georgia • Texas Coral Snake • Arizona Coral Snake • “Red on yellow, kill a fellow; Red on black, venom lack” 14

Elapids § Coral snakes are relatively passive (10 -15 bites/yr in US) § Share physical characteristics of non-venomous snakes (round pupils, blunt head) but have fangs § Uses a potent neurotoxin § Local signs are minimal with little pain § Several hours later, pt will develop malaise, N/V, muscle fasiculations and weakness § Neurologic signs include diplopia, difficulty talking or swallowing, bulbar dysfunction, and generalized weakness § Risk of respiratory failure 15

Elapids - Management § Tourniquets, incision & suction, etc. don’t work for coral snakes § If eastern or Texas coral snake is suspected, give antivenin • Horse serum derived, requires skin testing before giving • Dosage is 3 -5 vials IV • Repeat if signs of venom toxicity continue • Antivenin not in production as of 2008 § No antivenin available for Arizona coral snake § Admit to PICU 16

Quiz: Name Georgia’s Venomous Snakes… 17

Georgia Venomous Snakes § Georgia § Carolina Pygmy Rattlesnake - Sistrurus miliarius § § § § § 18 Dusky Pygmy Rattlesnake - Sistrurus miliarius barbouri Eastern Coral Snake - Micrurus fulvius Eastern Cottonmouth - Agkistrodon piscivorus Eastern Diamondback Rattlesnake - Crotalus adamanteus Florida Cottonmouth - Agkistrodon piscivorus conanti Northern Copperhead - Agkistrodon contortrix mokasen Southern Copperhead - Agkistrodon contortrix Timber Rattlesnake - Crotalus horridus Western Cottonmouth - Agkistrodon piscivorus leucostoma

Exotic Snakes § Consult a medical herpetologist or poison control (1 -800 -222 -1222) § Contact your local zoo • Required by law to carry antivenin for the snakes they have § Report illegally possessed reptiles to the police 19

Arthropods (“Bugs”) § Largest phylum in the animal kingdom § Terrestrial Invertebrates • Centipedes/Millipedes • Ticks • Spiders • Scorpions § Insects • Bees • Hornets • Yellow Jackets • Wasps • Fire Ants 20

Scorpions § Very few are dangerous to humans in North America • Centruroides sculpturatus (“Arizona bark scorpion”) -- southwestern U. S. § Grasps prey by pincers and then stings with tail § Nocturnal • Crawl into sleeping bags and unoccupied clothing § Injects an excitatory neurotoxin affecting autonomic and skeletal nervous systems -minimal local edema • Pain, restlessness, hyperactivity, roving eye movements, respiratory distress/failure • Convulsions, drooling, hyperthermia, HTN/tachycardia 21

Scorpions - Management 22 § Cryotherapy (ice) at sting site and supportive care § Antivenin if symptoms persist after supportive care • Tachycardia • Fever • Severe hypertension • Agitation • Available from Antivenom Production Laboratory, Arizona State University, Tempe, Az. § Phenobarbital or other sedative/anticonvulsants for persistent hyperactivity, convulsions or agitation § Calcium gluconate 10% 0. 1 ml/kg for muscle contractions (used but unproven)

Brown Recluse Spider (Loxosceles) Loxosceles reclusa 23 § Brown violin shaped mark on dorsum of cephalothorax (“Fiddleback”) § Usually outdoors, but make indoor nests in closets § Shy and will only attack when provoked § Venom is cytotoxic (hyaluronidase-like factor)

Loxosceles Geographic Distribution 24

Brown Recluse – Clinical Signs 25 § 2 -8 hours • Local reaction with mild-moderate pain • Erythema, central blister or pustule § 24 hours • Fever, chills, malaise weakness, N/V, rash with petechiae, joint pain, DIC, hematuria, renal failure, hemolysis, respiratory failure • Subcutaneous discoloration that spreads over § 3 -4 days • Spreads to 10 -15 cm • Pustule drains leaving ulcerated crater that scars § Scar formation is rare if no necrosis after 72 hrs § Reaction varies according to amount of envenomation

Brown Recluse Bite Mimics in Children § Staph/strep (MRSA) § Herpes simplex § Herpes zoster § E. multiforme § Lyme disease § Fungal infection § P. gangrenosum § Chemical burn § Poison ivy/oak § Other spider bite: 1. 2. 3. 4. 5. 6. 7. 26 Golden orb weaver (North America) Running (or sac) spider (U. S. ) Wolf spider (U. S. ) Black jumping spider (Atlantic coast to Rocky Mountains) Hobo spider (Pacific Northwest) Fishing spider (U. S. — lakes and streams) Green lynx spider (Southern U. S. )

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It’s NOT a brown recluse if… § It's really BIG! The size of the body, not including legs, of a recluse is smaller than a dime. § It's really HAIRY! Brown recluses have only very fine hairs that are invisible to the naked eye. § It JUMPS! Jumping spiders live up to their name, and some other spiders including wolf spiders occasionally jump, but recluses don't. § I found it in a WEB! Brown recluses don't spin a web to catch prey; they spin silk retreats and egg cases, but don't form a typical recognizable web. § It has DISTINCT MARKINGS VISIBLE TO THE NAKED EYE, such as stripes, diamonds, chevrons, spots, etc. that are easily seen! The "violin" is very small and located on the front half of the body. The violin is also indistinct in some, especially young spiders. They're really pretty dull looking. 28 http: //department. monm. edu/biology/recluse-project/identify. htm

Quiz: Indentify 2 Brown Recluses… 29

Brown Recluse - Management 30 § Unless spider is brought for ID, definitive diagnosis cannot be made § Good local wound care § If systemic symptoms, then CBC with platelets, U/A, BUN, creatinine • Vigorous supportive care in PICU as needed § Surgical excision and (rarely) skin grafting after necrosis is demarcated § Steroids, heparin, and hyperbaric O 2 don’t work § No Dapsone for kids – methemoglobinemia § No antivenom available § Have wound rechecked daily for progression

Black Widow (Latrodectus) Latrodectus mactans 31 § Shiny black spider with brilliant red hourglass marking on abdomen § Only the female bite is dangerous • Male spiders are ¼ the size of females and bite cannot penetrate human skin § Females not aggressive unless provoked or guarding egg sac § Produces a neurotoxin— stimulates myoneuronal junctions, nerve endings

Black Widow – Clinical Signs 32 § No local symptoms § 1 -8 hours after bite • Generalized pain and muscle rigidity s Cramping pain to abdomen, flanks, thighs, chest – “rigid abdomen” • Chills, N/V • HTN, Tachycardia • Respiratory distress • Urinary retention • Priapism • Death from cardiovascular collapse § Mortality 50% in young children

Black Widow - Management 33 § Children < 40 kg: Antivenin given as soon as bite confirmed • Dose: 2. 5 ml (one vial) § Children >40 kg: not as urgent to give immediately; indicated in age <16, respiratory difficulty, significant hypertension § Morphine or Demerol § Calcium gluconate 10% solution 0. 1 ml/kg IV over 5 minutes for muscle cramps • Recent series showed effective in only 4% of cases • Valium can be used, but is short lived with variable effects; Robaxin is ineffective § Admit to PICU

Other Spiders § Tarantulas • Do not bite unless provoked • Venom is mild and not a problem § Wolf Spider and Jumping spider • Mild venom only causes local reaction § Treatment is good local wound care 34

Centipede/Millipede § Centipedes • Bites with jaws that act like stinging pincers • Extremely painful • Toxin is innocuous – local reaction only § Millipedes - harmless § Treatment • Local anesthetic at wound site • Local wound care 35

Ticks 36 § Transmit many other infectious diseases: • Spirochetes – Lyme Disease, relapsing fever • Viruses – Colorado tick fever • Rickettsiae – Rocky Mountain spotted fever • Bacteria – tularemia, ehrlichiosis, babesiosis • Protozoa § Tick paralysis – wood tick, dog tick, deer tick • Tick releases neurotoxin producing cerebellar dysfunction and ASCENDING Weakness • Latent period for 4 -7 days • Restlessness, irritability, ascending flaccid paralysis, respiratory paralysis, death

Tick Paralysis - Management § Diligently search for the tick § Remove using blunt forceps held close to skin § Do not squeeze – can release infective agents § Admit to hospital for ascending paralysis, PICU if worried about respiration 37

Bees, Hornets, Yellow Jackets, & Wasps § Bees have a barbed stinger next to a venom sac which can remain in the victim’s skin § Bees die after the stinger is dislodged § The stinger must be removed if seen – don’t delay, move venom is released with time • Scraping works best, don’t pull or squeeze § Wasps, Yellow Jackets, and Hornets can sting multiple times 38

Insects § Venoms contain protein antigens which elicit an Ig. E antibody response § Major problem is allergic reactions and anaphylaxis • Group I – local response • Group II – Mild systemic reactions s Generalized itching and urticaria • Group III – Severe systemic reactions s Wheezing, angioneurotic edema, N/V • Group IV – Life threatening reactions s Laryngoedema, hypotension, shock § Occurs in 0. 5 -5% of the population from insects 39

Insect - Management § Group I – cold compresses § Group II – Benadryl 4 -5 mg/kg/day divided QID § Group III • Epinephrine 1: 1000 0. 01 ml SQ (max 0. 3 ml) (IM? ) • Benadryl PO • H 2 blockers • Steroids (? ) • Admit to hospital for 23 hr obs 40

Insects - Management § Group IV – may need intubation • All of the above, plus • Wheezing refractory to epinephrine may need aminophylline s 6 mg/kg bolus over 20 minutes, then s 1. 1 mg/kg/hr infusion • Hypotension s Fluid bolus s IV epinephrine 1: 10, 000 s IV Hydrocortisone 2 mg/kg Q 6 h • Admit to PICU 41

Insects - Management 42 § Group III or IV reactions need referral to an allergist for hyposensitization § After obs, D/C home with Epi. Pen Jr. • Spring loaded autoinjectors self-administered in the thigh • Always write for the twin pack s Contains practice syringe and 2 loaded syringes • Parents should give this in the field AND seek further care § Avoid wearing bright colored clothing, perfumes § Wear long sleeved garments, gloves when gardening and hats § Medical alert bracelets or necklaces

Fire Ants § Wingless member of Hymenoptera § Bites with jaws and pivots head to give multiple stings § Venom is an alkaloid with direct effect on mast cell membranes Solenopsis richteri and Solenopsis invicta 43

Red Imported Fire Ant (RIFA) § Arrived in 1930 s from South America via port of Mobile, Ala. § Build mounds in sunny, open areas (e. g. , lawns and parks) § Aggressively attack anyone who disrupts their mound 44

Fire Ants – Clinical Presentation § Immediate – wheal and flare § 4 hrs – vesicle § 8 -10 hours – vesicle becomes umbilicated pustule § 24 hrs – vesicle surrounded by painful erythematous area that lasts 3 -10 days 45

Fire Ants - Treatment § Symptomatic care • Ice • Cleansing • Antihistamines for itching • Steroids, antibiotics and antihistamines don’t have an effect on the lesions § Occasional systemic reactions (hives, anaphylaxis) 46

Mammalian Bites § Dog bites account for 80 -90% of all mammal bites § Cats 5 -10% § Rodents 2 -3% § Humans 2 -3% § Other wild or domestic animals make up the rest 47

Mammal Bites § Dogs generate strong forces and cause local crush injuries § Only 5 -10% of bites become infected because wound is easily cared for and not very deep § Cat bites cause deep puncture wounds with 50% infection rate • May penetrate fascial compartments, tendons, vessels and bones § Most common bacteria: Staphylococcus & Pasturella species § Human bites are Strep viridans or Staph aureus § Also many anaerobes are mixed in: Bacteroides, Peptostreptococcus, Eikenella corrodens 48

Dog Bites § Usually attack head and neck in most victims § Cause lacerations of lips, nose and cheek § May penetrate the skull and cause depressed skull fracture 49

Cat Bites 50 § Usually attack upper extremities § Pasturella infections are very aggressive • Symptoms begin at 12 -24 hours with erythema, significant edema and intense pain § Cats also scratch, especially the face § Consider corneal abrasions § Bartonella henselae • Papule at site of scratch with later regional lymphadenopathy • Self limited, resolves in 2 -3 months • May have unusual manifestations: encephalopathy, hepatitis, atypical pneumonia

Human Bites § Typically involve the hand when punching someone in the mouth • Wound overlies the MCP joint, consider Boxer’s fracture • Mild swelling in 1 -2 days to site • If there is pain with active or passive finger motion, then consider tendonitis or deep compartment infection • Also consider Hepatitis B and syphilis being spread by bites 51

Rodent Bites and Other Mammals § Rat-bite fever (rare) § Pet owners and lab workers • 2 forms: s Haverhill fever (Streptobacillus moniliformis) s Sodoku (spirullum minus) • 1 -3 week incubation period • Chills, fever, malaise, rash, headache • Both forms responsive to IV penicillin § Rabbits – tularemia 52

Mammal Bites - Treatment § Meticulous and prompt wound care • Scrubbing with soft sponge and 1% povidoneiodine solution s Stronger solutions retard wound healing • Pressure irrigation § Facial wounds require primary closure for cosmesis § Hand wounds should have delayed primary closure or heal by secondary intention due to infection rate • Place a few deep sutures to bring wound together • Skin sutures placed in 3 -5 days 53

Mammal Bites - Treatment 54 § Antibiotic prophylaxis • No perfect drug, but Augmentin is close • If allergic, then a combination of clindamycin PLUS a 2 nd or 3 rd gen cephalosporin OR Bactrim • First dose should be given in the ED § Infected bites require aggressive drainage and debridement • Obtain aerobic and anaerobic deep would cultures • Leading edge would culture for cellulitis • Admit for IV antibiotics § Tetanus prophylaxis

Rabies § Rabies virus • Virus transmitted through scratches, abrasions and animal saliva contact with mucous membranes • Causes an progressive, irreversible encephalopathy traveling up peripheral nerves to the brain s Anxiety, insomnia, confusion, agitation, hypersalivation, hydrophobia • Unprovoked attacks • Wild carnivorous animals, BATS • Rodents, squirrels and rabbits are considered norisk 55

Rabies § If the animal can be observed, then prophylaxis can be delayed § If the animal shows signs of rabid behavior, then start the patient on prophylaxis immediately • Animal will be sacrificed and brain biopsy will be done to look for rabies § Prophylaxis is with passive antibody (RIG) and vaccine HDCV • RIG is given once, half IM and the other half infiltrated around bite • HDVC is given 1. 0 ml IM on days 0, 3, 7, 14 (Reduced 4 -dose vaccine schedule as of 2010) 56

Questions? 57