Bites and Infestations

Question 1

Why are most spiders not a threat to humans?

Answer 1

too small, have too little poison, and fangs aren’t powerful enough to penetrate skin

Question 2

Most common sequelae of a spider bite

Answer 2

minor local reaction that lasts 7-10 days

Question 3

What spider is known for causing necrotic lesions?

Answer 3

brown recluse (Loxosceles)

Question 4

Found predominantly in warmer climates. Live in piles of firewood, old lumber, rock piles, bales of hay. Only bite when bothered.

Answer 4

black widows (latrodectus)

Question 5

Phase of latrodectism (the systemic reaction to black widow bite) characterized by muscle spasms, autonomic stimulation, and possibly coma in the first 24 hrs following a bite

Answer 5

exacerbation phase

Question 6

Phase of latrodectism (the systemic reaction to black widow bite) where symptoms decline and occurs 1-3 days after bite

Answer 6

dissipation phase

Question 7

Phase of latrodectism (the systemic reaction to black widow bite) in the weeks to months following a widow bite characterized by muscle spasms, tingling, nervousness, and weakness

Answer 7

residual phase

Question 8

Live in human dwellings. Distributed in Midwest and South Central region of the United States. 95% of bites are trivial but a few result in necrosis

Answer 8

brown recluse (loxosceles)

Question 9

Associated with the systemic reaction of a brown recluse bite

Answer 9

hemolysis

Question 10

Common inhabitants of houses. Some species in northwest but the bite does not generally cause serious reactions in humans. AKA hoboe spiders

Answer 10

funnel web spider (Atrax, Agelendiae)

Question 11

Treatment for local nonnecrotic simple reactions to spider bites

Answer 11

clean w/soap and water, ice packs, tetanus prophylaxis

Question 12

Pharmacological treatment for a necrotic lesion > 2 cm

Answer 12

systemic corticosteroids 5-7 days

Question 13

used to address spasms and pain with latrodectism

Answer 13

benzos and opioids

Question 14

considered for black widow bite IF patient having typical muscle spasms AND bite was noticed or fang markings are identified

Answer 14

antivenom

Question 15

Serious side effects of black widow antivenom

Answer 15

serum sickness and anaphylaxis

Question 16

The only dangerous scorpion in the US Found mostly in Arizona, spilling over into western New Mexico, southeastern California, Texas and Mexico. Use venom only for defense

Answer 16

bark scorpion (Centruroides exilicauda)

Question 17

How long might symptoms of pain, paresthesias, abnormal EOMs, blurred vision, drooling, N/V, and agitation last after a bark scorpion bite without antivenom?

Answer 17

24 to 48 hours. Deaths are rare

Question 18

Stings from this group result in more fatalities than by stings and bites from any other arthropods including spiders and scorpions.

Answer 18

hymenopterans

Question 19

Subgroup of hymenopterans responsible for most of the allergic reactions reported each year

Answer 19

wasps and relatives (hornets/yellowjackets)

Question 20

What is a major difference between wasp and honeybees that makes wasps more deadly?

Answer 20

unlike bees, they are able to withdraw stinger, which allows them to sting multiple times

Question 21

Major component of hymenopterans that causes degranulation of basophils and mast cells

Answer 21

melittin

Question 22

Management of local reaction caused by hymenopterans (bees, wasps, ants)

Answer 22

remove stinger, wash w/soap & water, ice packs, antihistamines

Question 23

When do the majority of anaphylactic reactions to hymenopterans occur?

Answer 23

within first 15 minutes and nearly ALL occur within 6 hours

Question 24

situation where there are multiple stings and therefore the person has a systemic response. Can mimic anaphylaxis but there is generally greater frequency of nausea, vomiting, and diarrhea

Answer 24

toxic reaction

Question 25

Immune complex-mediated reaction. Appears 5-14 days following the sting. Symptoms include fever, malaise, headache, urticaria, lymphadenopathy, and polyarthritis

Answer 25

delayed reaction

Question 26

Tendency to attack in great numbers when provoked. Local lesions: papule that may become sterile pustul in 6 – 24 hours

Answer 26

ants

Question 27

Mostly found in the southwest US but several species in the eastern US.
Cardinal manifestations include presence of one or more fang marks, localized pain, and progressive edema extending from the bite site

Answer 27

rattlesnakes

Question 28

Mainstay of therapy for rattlesnake bite that should not be delayed

Answer 28

antivenim (Polyvalent Crotalidae Immune Fab). Fluids and pressors as needed for aggressive treatment of hypotension

Question 29

Primarily found in southeast US, Texas, and AZ. Venom primarily composed of neurotoxic components that do NOT cause marked local injury.
Death can result from paralysis of respiratory muscles

Answer 29

coral snakes

Question 30

Management for patient with coral snake bite

Answer 30

pulmonary function measures and ventilatory support as needed

Question 31

leading carriers (vectors) of diseases to humans in the United States, second only to mosquitoes worldwide

Answer 31

Ticks

Question 32

usally a salmon color and expands over a few days or weeks and reach 20 cm in diameter. The center of the rash can then appear a lighter color than its edges giving it a “bull’s eye” appearance

Answer 32

erythema migrans (occurs in 80% of lymes)

Question 33

What is the recommended treatment for a person who had tick attached for more than 36 hrs and identified as an adult or nymphal deer tick?

Answer 33

doxycycline. 200mg for non-pregnant adults and 4mg/kg for children > 8 years

Question 34

Extremely itchy rash with crusting, linear burrows, and crusting lesions that occurs between the fingers and toes, the buttocks, the creases of the elbows and the waist and genitals

Answer 34

scabies

Question 35

Most common treatment of scabies

Answer 35

5% permethrin cream (Elimite) left on for 10-14 hrs