Be familiar with the various types of Crotalidae snakes that are present in our region



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Be familiar with the various types of Crotalidae snakes that are present in our region

  • Be familiar with the various types of Crotalidae snakes that are present in our region

  • Discuss the primary signs and symptoms of Crotalidae envenomation



Develop a treatment plan, for both stabilization and treatment of Crotalidae envenomations

  • Develop a treatment plan, for both stabilization and treatment of Crotalidae envenomations



Be familiar with the various types of Micrurus snakes that are present in our region

  • Be familiar with the various types of Micrurus snakes that are present in our region

  • Discuss the primary signs and symptoms of Micrurus envenomation



Develop a treatment plan, for both stabilization and treatment of Micrurus envenomation

  • Develop a treatment plan, for both stabilization and treatment of Micrurus envenomation



Snakes in Texas

  • Snakes in Texas

    • 155 species altogether
    • 15 species are venomous (10-15% of snakes)
    • deaths in Texas from snakebites = 2-3/year


Snakes in Texas

  • Snakes in Texas

    • compare to insect bites: 5-7/year
    • compare to lightning strikes: ~8/year






Venomous snakes bite 7000-8000 people annually

  • Venomous snakes bite 7000-8000 people annually

    • occurred while snake handling = ~3000
    • accidental = 4000-5000


Venomous snakes bite 7000-8000 people annually

  • Venomous snakes bite 7000-8000 people annually

    • 85% of natural bites are below the knee


Epidemiology

  • Epidemiology

    • male > female by 9:1
    • average age = 24
  • Significant rates of intoxication at time of bites (28%)



Most bites aren’t lethal!!

  • Most bites aren’t lethal!!

  • Be concerned about:

    • very old
    • very young
    • very sick
    • very pregnant


Anaphylaxis risk

  • Anaphylaxis risk

  • Good first aid/wound care avoid: ice, shock, cowboy treatment, and tourniquet

  • Remain calm and seek medical attention







Sistrurus

  • Sistrurus

    • massasauga
    • pygmy rattler


Agkistrodon: Copperhead

  • Agkistrodon: Copperhead



Agkistrodon: Cottonmouth

    • Agkistrodon: Cottonmouth


Usually rattle before biting but not always

  • Usually rattle before biting but not always

  • Rattles can fall off with trauma, so may not be present

  • Rattle done to give warning; may be startled



Accounts for average of 5.5 deaths/year in US

  • Accounts for average of 5.5 deaths/year in US

  • 50% of all bites occur in 18-28-year-old group; young males most common



Modified saliva: digests the tissue in the affected area

  • Modified saliva: digests the tissue in the affected area

    • 90% water
    • 5-15 enzymes
    • 3-12 proteins


Potency and effects vary by species and individual snake: ~25% of bites are “dry”

  • Potency and effects vary by species and individual snake: ~25% of bites are “dry”



Local symptoms

  • Local symptoms

    • skin necrosis
    • tissue sloughing


Histotoxic

  • Histotoxic

    • hyaluronidase
    • collagenase
    • metalloproteinase
  • Edema: stimulation of the inflammatory cascade



Hematologic mediators

  • Hematologic mediators

    • main one is fibrinolysis
    • defibrination, without DIC (disseminated intravascular coagulation)


Hematologic mediators



labs: abnormal for up to a week; reports of relapse

    • labs: abnormal for up to a week; reports of relapse
      • elevated fibrin split products
      • elevated PT (prothrombin time)
      • low fibrinogen


DIC is uncommon – if it occurs it is the primary reason for mortality

    • DIC is uncommon – if it occurs it is the primary reason for mortality


Local mediators

  • Local mediators

    • VMPs (venom metalloproteinases): cleave/activate TNF (tumor necrosis factor) alpha,…


Local mediators

  • Local mediators



Local mediators

  • Local mediators

    • myotoxin A
      • necrosis of skeletal muscle
      • may cause distant rhabdomyolysis


Local mediators

  • Local mediators

    • pain and edema
      • rapid edema indicative of severe envenomation
      • bullae formation/blebs not uncommon


Do nothing that delays getting to ED (emergency department)

  • Do nothing that delays getting to ED (emergency department)



Basic and advanced life support

  • Basic and advanced life support

  • Mark border of advancing edema with pen every 15 minutes



No benefit with negative pressure venom extraction device

  • No benefit with negative pressure venom extraction device



Fang marks not recommended

  • Fang marks not recommended

  • Mouth suction contraindicated



Constriction and pressure immobilization: may help impede spread of venom

  • Constriction and pressure immobilization: may help impede spread of venom

  • Tourniquets not recommended

  • Keep in neutral position



Do not give antivenom in field secondary to anaphylaxis risk

  • Do not give antivenom in field secondary to anaphylaxis risk



Do not try and find snake

  • Do not try and find snake

    • may result in more bites
    • may delay ED arrival


Grading based on clinical presentation

  • Grading based on clinical presentation

  • Dry bite

    • puncture wound only
    • no systemic effect
    • normal labs


Mild

  • Mild

    • local effects at bite site only
    • no systemic effects
    • normal labs


Moderate

  • Moderate

    • local effects beyond immediate bite area
    • vomiting, metallic taste, fasciculation


Moderate

  • Moderate

    • platelets <90,000, fibrinogen <90-100 mg/dl
    • PT >14 seconds
    • CPK (creatine phosphokinase) >500-1,000 U/L


Severe



Severe

  • Severe

    • renal failure
    • respiratory difficulty
    • altered mental status
    • platelets <20,000
    • rhabdomyolysis


Derived from horse serum immunized with venom from various species

  • Derived from horse serum immunized with venom from various species



Used for moderate to severe symptoms

  • Used for moderate to severe symptoms

    • test dose for anaphylaxis – skin testing


Used for moderate to severe symptoms

  • Used for moderate to severe symptoms

    • start with 10 vials (average 10-15 for moderate bite) – can go up to 25-30 vials




Used for moderate to severe symptoms

  • Used for moderate to severe symptoms

    • ~80% develop serum sickness


0-3 minimal severity

  • 0-3 minimal severity

  • 4-7 moderate severity

  • 8-20 severe





Fever 

  • Fever 

  • Redness of joints

  • Skin rash

  • Itching

  • Swollen glands 

  • Malaise

  • Anorexia



Patient has to be hospitalized to treat

  • Patient has to be hospitalized to treat



Sheep-derived antivenin



Because the antibodies are raised in sheep there is minimal to no serum sickness

    • Because the antibodies are raised in sheep there is minimal to no serum sickness
  • Start with 4-6 vials



Administer 4-6 more vials every hour until coagulopathies and edema have been controlled

  • Administer 4-6 more vials every hour until coagulopathies and edema have been controlled

  • After initial control, provide 2 vials every 6 hours for 18 hours





Increased pressure within the fixed compartment of the limb muscle fascia

  • Increased pressure within the fixed compartment of the limb muscle fascia



Symptoms

  • Symptoms

    • skin is taught, warm, blanched
    • distal to the swelling may have numbness, loss of blood supply


Diagnosis: made by percutaneous insertion of needle with measurement of internal pressure

  • Diagnosis: made by percutaneous insertion of needle with measurement of internal pressure



Treatment

  • Treatment

    • surgical release
    • fasciotomy


With antivenin, may have some disfigurement, rare functional impairment, and even rarer loss of a limb

  • With antivenin, may have some disfigurement, rare functional impairment, and even rarer loss of a limb







Red touches yellow: kill a fellow

  • Red touches yellow: kill a fellow

  • Red touches black: a friend of Jack





Micrurus sp.

  • Micrurus sp.

  • Moderate to severe neurologic symptoms usually seen with envenomation

  • Systemic effects may be delayed >12 hours

  • May require antivenin!!



Neurotoxic, neuromuscular dysfunction

  • Neurotoxic, neuromuscular dysfunction

  • Little enzymatic activity, low necrotic potential

  • Little venom delivered per bite



Primitive delivery system

  • Primitive delivery system

    • small mouth
    • pair of small, fixed hollow fangs on anterior mouth


Primitive delivery system

  • Primitive delivery system

    • venom released via chewing motion – must bite and temporarily hold and “chew” to get venom out


Respiratory distress

  • Respiratory distress

    • pharyngeal spasm
    • hypersalivation
    • cyanosis
    • trismus


Cardiovascular collapse

  • Cardiovascular collapse

    • hypotension
    • tachycardia
  • Onset: symptoms may be delayed up to 12 hours



Bite site: paucity of complaints

  • Bite site: paucity of complaints

    • little pain
    • no necrosis
    • paresthesias
    • swelling usually mild


Neurotoxic

  • Neurotoxic

    • altered mental status can occur
    • diplopia, ptosis
    • generalized weakness
    • muscle fasciculations




No advantage for giving antivenom for other snake species

  • No advantage for giving antivenom for other snake species



Wyeth® Antivenin (Micrurus fulvius)

  • Wyeth® Antivenin (Micrurus fulvius)

    • dose: 3-6 vials IV (intravenously) over 1-2 hours


Wyeth® Antivenin (Micrurus fulvius)

  • Wyeth® Antivenin (Micrurus fulvius)

    • if necessary, give extra 3-5 vials over 1-2 hours
    • rarely need >10 vials


Wyeth® Antivenin (Micrurus fulvius)

  • Wyeth® Antivenin (Micrurus fulvius)

    • must be started early – before any symptoms develop, as soon as they arrive at the ED


Be able to recognize the clinical symptoms associated with an envenomation from a brown recluse, black widow, tarantula, scorpion, and fire ant

  • Be able to recognize the clinical symptoms associated with an envenomation from a brown recluse, black widow, tarantula, scorpion, and fire ant



Define a basic treatment plan for individuals who are bitten by the insects listed in the first objective

  • Define a basic treatment plan for individuals who are bitten by the insects listed in the first objective



Recognize the clinical symptoms associated with insect bite-associated allergic reaction – be able to define a treatment plan for the individual undergoing anaphylaxis

  • Recognize the clinical symptoms associated with insect bite-associated allergic reaction – be able to define a treatment plan for the individual undergoing anaphylaxis





Loxosceles sp.

  • Loxosceles sp.

  • Venom

    • digestive enzymes
    • sphingomyelinase D


Proper wound care



Necrotic lesion

  • Necrotic lesion

  • Fever

  • Rash

  • Arthralgias









Latrodectus sp.

  • Latrodectus sp.

  • Neurotoxic venom

    • increased calcium influx
    • increased acetylcholine


Local pain

  • Local pain

  • Abdominal cramping

  • Diaphoresis

  • Nausea, vomiting, diarrhea



Treatment

  • Treatment

    • wound care
    • muscle relaxers
    • opiate analgesics
    • antivenin (rarely used)


There is little toxicity associated with North American tarantulas

  • There is little toxicity associated with North American tarantulas







Apidae: honey bees

  • Apidae: honey bees

  • Bombidae: bumble bees

  • Vespidae: wasps, hornets, yellow jackets

  • Formicoidea: ants



Symptoms

  • Symptoms

    • local pain, itching, and swelling
    • multiple stings or stings to the face  risks


Symptoms

  • Symptoms

    • vomiting, cyanosis, hypotension, syncope, dyspnea
    • anaphylaxis risk


Treatment

  • Treatment

    • wound care
    • remove stinger?
    • analgesics
    • antihistamines




Very painful sting

  • Very painful sting

  • Typically supportive care is all that is needed

  • If numbness or paresthesias persist for >48 hours need medical evaluation


























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