American Critter Bites and Stings

1. American Critter Bites and Stings Kalpesh Patel, MD Department of Pediatric Emergency Medicine June 14, 2006

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

3. Marine Invertebrates • Irritants • Hydras • Anemones • Common purple jellyfish • Sea nettle • Toxin producers • Portuguese man-of-war • True jellyfish • Lion’s mane • Handle with care • Corals • Sea Urchins

4. Irritants • Hydras • Maine to Florida and Texas coastline • Attaches to solid objects • Causes mild sting • Requires local care • Anemones • US tidal zones • Mildly toxic at worst – skin irritation • Sea nettle and common purple jellyfish • Atlantic coast • Mildly toxic - skin irritation

5. Irritants - Treatment • Wash copiously with sea water or normal saline • Benadryl • Topical/Oral Steroids

6. Toxin Producers • Nematocysts • Specialized organelles which have toxin-coated barbed threads that fire when a tentacle is touched. • Cannot penetrate human skin • May discharge even when the creature is dead and washed up on the beach

7. Toxin Producers • Size matters • Man of war can have tentacles up to 75 feet long with 750,000 nematocysts each

8. Toxin Producers • Toxin causes severe pain • Made of polypeptides and degradative enzymes • Causes release of inflammatory mediators, histamine and histamine-releasing agents, serotonin • May cause systemic symptoms • N/V, abdominal rigidity • Respiratory distress • Arthralgias • Hemolysis, renal failure • Coma • Severe envenomation can cause death

9. Toxin Producers • Lion’s mane • Found on both coasts • Highly toxic • Instrument of death in Sherlock Holmes classic Adventure of the Lion’s Mane • Causes severe burning • Prolonged exposure causes muscle cramps and respiratory failure

10. Toxin Producers - Treatment • 3 goals: • Control shock – IV, fluids, etc. • Control venom effects • Remove tentacles from skin • Inactivate unexploded nematocysts with vinegar, meat tenderizer, or baking soda slurry • Apply this to patient as well • Pain relief • Immobilize the wound area • Codeine, Morphine, or Demerol • Treat muscle spasms with 10% Calcium gluconate 0.1ml/kg IV • Topical/Oral steroids, Benadryl

11. Handle with Care • Corals, Sea Urchins, Starfish • Have jagged edges or hard spines • Cause deep puncture wounds or sea lacerations • Easily leave foreign bodies • Stinging sensation, wheal formation, itching • Wound infection very common • Vibrio species, Erysipelothrix rhusiopathiae, Mycobacterium marinum • Fever • Cellulitis • Lymphangitis

12. Handle with Care - Treatment • Copious irrigation with saline • X-ray for foreign bodies • Soak affected area in warm water • Use local anesthetic and explore sterilely • Wounds should be left open or loosely approximated • Antibiotics please • >8 y/o: Tetracycline for 10 mg/kg/dose QID • <8 y/o: Keflex or Bactrim • Add staphylococcal coverage for foreign bodies • Don’t forget tetanus prophylaxis

13. Marine Vertebrates • Stingrays • Catfish • Scorpaenidea • Sharks!

14. Stingrays • Most common marine vertebrate injury • Flat fish, bottom feeders, buried under sand or mud • Easily stepped on causing reflex envenomation • Venom apparatus is a serrated, retro-pointed caudal spine on the tail • Coated in venom sheath which ruptures on skin penetration • Heat labile toxin • Can depress medullary respiratory centers • Interfere with cardiac conduction • PAINFUL

15. Stingrays - Treatment • PreHospital: • Irrigate copiously with cold salt water • Flushing can help remove toxin • Control bleeding with pressure • ED: • IV fluids, Morphine 0.1mg/kg/dose for pain • Make an attempt to remove the spine • Soak extremity in hot water (104-113F) to inactivate the venom until pain relieved • X-ray for foreign body (spine fragments) • Re-explore wound after soaking • Tetanus prophylaxis • No prophylactic antibiotics

16. Scorpaenidae • Zebrafish, scorpionfish, stone fish • Non-migratory, slow swimming, buried in sand • Envenomation occurs when handling fish on fishing trips • Venom delivered by many small spines like the stingray • Venom also heat-labile • Symptoms • Pain, N/V • Hypotension • Tachypnea leading to apnea • MI with EKG changes

17. Scorpaenidae - Treatment • Copious irrigation with saline • Hot water immersion until pain relieved • Morphine 0.1mg/kg/dose • Close cardiopulmonary monitoring • Admit to PICU if having significant systemic effects

18. Catfish • Spines in the dorsal and pectoral fins • Puncture wounds and laceration • Easily break off as foreign body • Venom causes local inflammation, pain, edema, hemorrhage, tissue necrosis • Treatment • Irrigation • Hot water immersion • Morphine 0.1mg/kg/dose • Antibiotics for gram negatives • Delayed primary closure

19. Sharks! • 1 in 5,000,000 chance of attack in North America • Gray reef, great white, blue, mako sharks • Risk factors: • Swimming near sewer outlets • Swimming in the late afternoon/early evening • Murky warm water • Increased commotion • Deep channels • Wearing bright objects • Surfers – boards are mistaken for elephant seals, the shark’s usual diet in California

20. Sharks! • Two types of bites: • Tangential injury • Close pass slashing movement teeth of open shark mouth • Definitive bite • Vary according to the part of the body bitten • Lacerations • Soft tissue loss • Amputation of limb • Comminuted fractures • Hemicorpectomy

21. Sharks! • Hypovolemic shock • Control bleeding with pressure • DON’T EXPLORE WOUNDS PREHOSPITAL • IV fluids, blood products as soon as available • Warmth • Oxygen • Surgery • Prophylactic antibiotics – 3rd gen cephalosporin or bactrim • Tetanus prophylaxis • Admit to PICU for significant injury

22. Bugs • Largest phylum in the animal kingdom • Terrestrial Invertebrates • Centipedes/Millipedes • Ticks • Spiders • Scorpions • Insects • Bees • Hornets • Yellow Jackets • Wasps • Fire Ants

23. 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

24. Ticks • 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

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

26. Ticks – The Movie

27. Ticks – The Sequel

28. Revenge of the Tick

29. Brown Recluse Spider • Southern and mid-western states • Brown violin shaped mark on dorsum of cephalothorax • Usually outdoors, but make indoor nests in closets • Shy and will only attack when provoked • Venom is cytotoxic and contains hyaluronidase like factor Loxosceles reclusa

30. Brown Recluse – Clinical Signs • 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 • Subcutaneous discoloration that spreads over • 3-4 days • Spreads to 10-15 cm • Pustule drains leaving ulcerated crater that scars • Scar formation is rare after 72 hrs • Reaction varies according to amount of envenomation

31. Brown Recluse - Management • 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 • Surgical excision and skin grafting after necrosis is demarcated • Steroids, heparin, and hyperbaric O2 don’t work • No Dapsone for kids – methemoglobinemia • No antivenom available • Have wound rechecked daily for progression

32. Black Widow • 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 Latrodectus mactans

33. Black Widow – Clinical Signs • No local symptoms • 1-8 hours after bite • Generalized pain and muscle rigidity • Cramping pain to abdomen, flanks, thighs, chest • Chills • Urinary retention • Priapism • Death from cardiovascular collapse • Mortality 50% in young children

34. Black Widow - Management • Children < 40kg: Antivenin given as soon as bite confirmed • Dose: 2.5ml (one vial) • Children >40kg: not as urgent to give immediately unless having respiratory difficulty or significant hypertension • Morphine or Demerol • Calcium gluconate 10% solution 0.1ml/kg IV over 5 minutes for muscle cramps • Robaxin doesn’t work as well • Valium can be used, but is short lived with variable effects • Admit to PICU

35. 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

36. 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

37. Insects • Venoms contain protein antigens which elicit an IgE antibody response • Major problem is allergic reactions and anaphylaxis • Group I – local response • Group II – Mild systemic reactions • Generalized itching and urticaria • Group III – Severe systemic reactions • Wheezing, angioneurotic edema, N/V • Group IV – Life threatening reactions • Laryngoedema, hypotension, shock • Occurs in 0.5-5% of the population from insects

38. 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 0.3ml) • Benadryl PO • H2 blockers • No steroids • Admit to hospital for 23 hr obs

39. Insects - Management • Group IV – may need intubation • All of the above, plus • Wheezing refractory to epinephrine may need aminophylline • 6mg/kg bolus over 20 minutes, then • 1.1 mg/kg/hr infusion • Hypotension • Fluid bolus • IV epinephrine 1:10,000 • IV Hydrocortisone 2mg/kg Q6h • Admit to PICU

40. Insects - Management • Group III or IV reactions need referral to an allergist for hyposensitization • After obs, D/C home with EpiPen Jr. • Spring loaded autoinjectors self-administered in the thigh • Always write for the twin pack • 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

41. Fire Ants • Common in the South • 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

42. 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

43. Fire Ants - Treatment • Symptomatic care • Ice • Cleansing • Antihistamines for itching • Steroids, antibiotics and antihistamines don’t have an effect on the lesions • Systemic reactions are rare

44. Scorpions • Very few are dangerous to humans in North America • Centruroides sculpturatus • 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 • Pain, restlessness, hyperactivity, roving eye movements, respiratory distress • Convulsions, drooling, wheezing, fever, cyanosis, respiratory failure

45. Scorpions - Management • Cryotherapy at sting site and supportive care • Antivenin if symptoms persist after supportive care • Tachycardia • Fever • Severe hypertension • Agitation • Phenobarbital or other sedative/anticonvulsants for persistent hyperactivity, convulsions or agitation • Calcium gluconate 10% 0.1ml/kg for muscle contractions

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

47. Identifying Poisonous Snakes

48. Crotalids • Include Cottonmouth, Rattlesnake, Water moccasin, and Copperhead • Venom is a combination of necrotizing, hemotoxic, nephrotoxic and cardiotoxic substances • Mojave rattlesnake has a large fraction of neurotoxin • Neurotoxin prevents depolarizating action of acetylcholine (paralytic) • Proteolytic enzyme acts like hyaluronidase causing local tissue destruction • Hemotoxic effects include hemolysis, thrombocytopenia and fibrinogen proteolysis leading to bleeding diathesis

49. 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 • 8mm = small snake • 8-12mm = medium snake • >12mm = large snake • 10-20% of bites are “dry bites” (no venom)

50. Crotalid Bites - Symptoms • 5-10 min – Intense burning pain and erythema • Perioral numbness • 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 • Vesicles and Hemorrhagic blebs by 24 hours • Edema may lead to compartment syndrome and necrosis • Secondary infection – gram-negative bacteria