chapter 33: environmental emergencies [bug/animal bites]

what is are the defining feature(s) of a black widow and where do they usually reside? what are the common symptoms, the systemic symptoms, and the main danger of the bite? to who should antivenin be administered? what is emergency treatment for the bite?

• black widow spider is black and has a distinctive, bright red-orange hourglass marking on its abdomen

  • female is larger [2cm with legs extended] and more toxic than the male

  • found in every state except alaska

  • they prefer dim, dry places around buildings, in woodpiles, and among debris

• the bite is sometimes overlooked; if site becomes numb right away, pt may not even recall being bit

• signs and symptoms:

  • most bites cause localized pain and symptoms, including muscle spasms

  • main danger is its ability to damage nerve tissues

    • other systemic symptoms: dizziness, sweating, nausea, vomiting, rashes

  • tightness in the chest, difficulty breathing, and severe cramps with board-like rigidity of abdominal muscles develop within 24 hrs and subside over 48 hrs

• if necessary, physicians can administer a specific antivenin → only used for very severe bites, older or very feeble pts, and children younger than 5

• emergency treatment:

  • BLS for pt in respiratory distress, but usually, pt only requires pain relief

  • transport to ED asap for treatment

• if possible, spider should be brought along or a photo should be taken

what are the defining features of a brown recluse spider and where do they normally reside? how does the bite progress? what are signs and symptoms? what is emergency treatment for the bite?

• brown recluse spider is a dull brown, 1 inch-long spider that has a short-haired body and a violin-shaped mark [brown to yellow] on its back

  • lives mostly in southern and central parts of the country, it can be found throughout the US

  • prefers dark areas

• venom is cytotoxic, causing severe local tissue damage

  • bite is not typically painful at first but becomes so within hours

  • area becomes swollen and tender, developing pale, mottled, cyanotic center and a small blister

  • then a scab of dead skin, fat, and debris forms and digs into the skin, producing a large ulcer that may not heal without treatment

• bites rarely cause systemic symptoms and signs, but if they do, provide BLS and promptly transport

• either bring spider along with pt or take picture of spider

what are hymenoptera stings like? how do you best remove the stinger? what are the signs and symptoms of anaphylaxis and how should you treat it?

• hymenoptera [bees, wasps, yellow jackets, and ants] have painful stings, but they are not medical emergencies

• remove stinger, and if still present, the venom sac via scraping with a firm-edged item like a credit card

  • use ice packs to assist in controlling pain

• signs and symptoms of anaphylaxis:

  • flushed skin

  • low BP

  • difficulty breathing usually associated with reactive airway sounds [wheezes, or diminished/absent breath sounds for severe cases]

  • hives may develop near site of envenomation or centrally on body

  • swelling to throat or tongue

• anaphylaxis is a true emergency and can be fatal if not recognized and treated quickly

  • assist pt in administration of an EpiPen and support the airway and breathing

what are the 4 types of venomous snakes in the US? where are they found? why do so few snake bites result in significant local or systemic injuries?

• venomous snakes in the US include:

  • rattlesnake

    • easily provoked

  • copperhead

  • cottonmouth, or water moccasin

    • often aggressive

  • coral snakes

    • only bite when being handled

• at least one of these venomous species is found in every state except alaska, hawaii, and maine

• use extreme caution on these calls and wear proper PPE

• in general, only 1/3 of snake bites result in significant local or systemic injuries

  • often envenomation does not occur because snake has recently struck another animal and has exhausted its supply of venom for the time being

how do venomous snakes bite people and how do the bites present? how do nonvenomous snake bites present? when should you assume a snake bite was venomous? why should you notify the hospital asap?

• venomous snakes native to US all have hollow fangs in the roof of the mouth that inject the venom from two sacs at the back of the head

  • classic appearance of a venomous snake bite is 2 small puncture wounds, usually 0.5 inches apart, with dislocation and swelling, and pt has pain surrounding the bite

  • nonvenomous snakes may have other tooth marks involved

• if unsure whether the bite was venomous, proceed as if it was and promptly transport

• notify hospital asap if a pt has been bitten by a pit viper or coral snake

  • some venoms can cause paralysis of nervous system, and hospitals may not have appropriate antivenin on hand

how do pit vipers fangs distribute venom and what structures are involved? how do rattlesnakes appear? how do copperheads appear, and are their bites life-threatening? how do cotton mouths appear, and are their bites life-threatening?

• fangs of pit vipers are hinged to swing back and forth as mouth opens

  • fangs are connected to a sac containing venom, which is attached to a poison gland, which is a specially adapted salivary gland that produced enzymes that digest and destroy tissue

• purpose of the venom is to kill small animals and facilitate digestive process

• rattlesnakes: many patterns of color, often with a diamond pattern

• copperheads: red-copped color crossed with brown or red bands, usually inhabiting woodpiles and abandoned dwellings close to areas of habitation

  • bites almost never fatal, but venom can cause significant damage to tissues in the extremities

• cotton mouths [water moccasins]: olive or brown, with black cross-bands and a yellow undersurface, as well as a tendency for aggression

  • fatalities from these bites are rare, but tissue destruction from the venom may be severe

what are the signs and symptoms of pit viper envenomation? what should you do if there is swelling? what can you assume no envenomation took place? why are children more affected by a bite than adults?

• signs and symptoms of pit viper envenomation?

  • burning pain at injury site, followed by swelling and blue discoloration that signals bleeding under the skin

  • weakness

  • nausea and vomiting

  • sweating

  • seizures

  • fainting

  • vision problems

  • changes in LOC

  • shock

• if swelling has occurred, use a pen to mark its edges on the skin

• if pt has no local signs an hour after being bitten, you can assume envenomation did not take place

• toxicity is related to the amount of toxin injected

  • bite will affect children more than adults because there is less body mass to absorb the toxin

how do you treat a pit viper bite?

• calm the pt and assure them that snake bites are rarely fatal

  • place pt in supine position and explain that staying still will slow the spread of venom

  • determine approximate time of bite and document your time en route to a receiving facility → helps determine severity and amount of antivenin to be used

• locate the bite, clean it gently with soap and water → DO NOT apply ice

• if bite occurred on an arm or leg, use pressure immobilization bandage of the extremity [40-70 mmHg in arms and 55-70 mmHg in legs] and place the extremity below the level of the heart

• be alert for anaphylaxis and treat with EpiPen

• do not give anything by mouth and be alert for vomiting

• if pt was bitten on the trunk, keep them supine and quiet and transport quick

• monitor vitals and park skin with a pen around swollen area

• if any signs of shock, place pt supine and administer oxygen

• if snake has been killed, bring it with you in a secure, hard-sided container or take a picture and send it ahead of time

  • notify hospital you have a pt with a snake bite and describe the snake

• if pt shows no sign of envenomation, provide BLS as needed, place a sterile dressing over suspected bite area, and immobilize the site

what does coral snake venom do and what symptoms will a bitten pt exhibit? what does successful treatment depend on? why should you notify a hospital asap about a coral snake bite victim? what are emergency care steps?

• coral snake venom is a powerful toxin that causes paralysis of the nervous system

  • within a few hours of being bitten, a pt will exhibit bizarre behavior, followed by progressive paralysis of eye movements and respirations

  • often, there are limited or no local symptoms

• successful treatment [either emergency or long term] depends on positive identification of the snake and respiratory sypport

• antivenin is available, but most hospitals don’t stock it → notify hospital asap

• emergency care steps are same as pit viper

what is the only venomous scorpion in the US and where is it found? what symptoms can its venom cause? how do you treat it?

• Centrurodes sculpturatus is the only venomous scorpion in the US

  • found naturally in arizona and new mexico, as well as part of texas, california, and nevada → may also be kept as a pet by anyone

• venom can produce severe systemic reaction that leads to:

  • circulatory collapse

  • severe muscle contractions

  • excessive salivation

  • hypertension

  • convulsions

  • cardiac failure

• antivenin is available and must be administered by a physician

• as an EMT, administer BLS and provide rapid transport to ED

what diseases do ticks carry? how are the diseases spread? how do you remove a tick properly for treatment?

• tick bites carry 2 infectious diseases:

  • rocky mountain spotted fever

  • lyme disease

• both are spread through tick’s saliva, which is injected into the skin when the tick attaches itself

  • the longer a tick stays embedded, the greater the chance a disease will be transmitted

  • bites usually occur during the summer months

• to remove a tick:

  • using fine tweezers, grasp the tick by the head and pull gently but firmly straight up so skin is tented

  • hold this position until tick releases

  • cleanse the area with antiseptic and save the tick in a glass jar or other container so it can be identified

• DO NOT handle tick with your fingers

• advise pt to follow up with their healthcare provider asap

how long does it take rocky mountain spotted fever to occur and what are the signs and symptoms? where did lyme disease originate, where is now reported, and what are the signs and symptoms?

• rocky mountain spotted fever: occurs within 7-10 days after a bite by an infected tick

  • symptoms include:

    • nausea and vomiting

    • headache

    • weakness

    • paralysis

    • possible cardiorespiratory collapse

• lyme disease: originally only seen in connecticut, but has now been reported in all states except hawaii [most commonly occurs in northeast and great lake states]

  • first symptoms: fever and flulike symptoms sometimes associated with a bulls-eye rash that may spread to several other parts of the body

  • after a few days or weeks, painful swelling of the joints, particularly the knees occurs

how do you provide emergency treatment from envenomations from marine animals?

• limit further discharge of nematocysts [microscopic venom-filled stinging organelles from jellyfish, anemones, and corals] by avoiding freshwater, wet sand, showers, or careless manipulation of tentacles

  • keep pt calm and reduce motion of affected extremity

• remove remaining tentacles by scraping them off with the edge of a stiff object such as a credit card

  • do not use ungloved hand to remove tentacles, because self-envenomation will occur

• toxins from the spines of urchins, stingrays, and certain spiny fish such as lionfish, scorpion fish, or stonefish are head sensitive

  • persistent pain may respond to immersion in hot water for 30 mins

  • if available, immersion in vinegar may also help alleviate symptoms

• provide transport to ED