Bites, Stings, Envenomation, and Plant and Mushroom Poisoning Practice Questions

25 multiple-choice questions on Bites, stings, envenomation, and plant and mushroom poisoning for paramedic and EMT students, from Chapter 28 (Toxicology). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. The most common cause of death from insect stings in the United States is:

   1. A. Direct venom toxicity
   2. B. Secondary wound infection
   3. C. Anaphylaxis
   4. D. Kidney failure from venom
   Show answer

   Answer: C. Anaphylaxis

   Hymenoptera stings kill mainly through allergic reactions, not venom volume. Massive stinging by hundreds of bees can cause direct toxicity, but that is rare.

2. A man was stung by a honeybee and the stinger is still in the skin. You should:

   1. A. Remove it quickly by scraping or pulling
   2. B. Leave it in place for the hospital to remove
   3. C. Apply a tourniquet above the sting site
   4. D. Cut the skin to drain the venom
   Show answer

   Answer: A. Remove it quickly by scraping or pulling

   The venom sac keeps pumping while attached, so prompt removal by any method limits the dose. Speed matters more than technique.

3. A 40-year-old man has severe abdominal cramping and rigidity, sweating, and hypertension 1 hour after reaching into a woodpile. A small red mark is on his hand. The most likely cause is:

   1. A. Brown recluse spider bite
   2. B. Bark scorpion sting
   3. C. Fire ant stings
   4. D. Black widow spider bite
   Show answer

   Answer: D. Black widow spider bite

   Black widow neurotoxin causes muscle cramps and a rigid abdomen that can mimic an acute abdomen. Brown recluse bites cause local necrosis rather than systemic cramping.

4. The black widow spider is recognized by:

   1. A. A violin-shaped mark on a brown back
   2. B. A red hourglass on a shiny black abdomen
   3. C. Bright yellow bands across all eight legs
   4. D. Two large red spots on the head
   Show answer

   Answer: B. A red hourglass on a shiny black abdomen

   The female black widow is the dangerous one. The violin mark identifies the brown recluse.

5. A woman has a painless bite on her arm that became a blister with a dark necrotic center over 3 days. This is most consistent with a:

   1. A. Black widow spider bite
   2. B. Arizona bark scorpion sting
   3. C. Brown recluse spider bite
   4. D. Rattlesnake bite
   Show answer

   Answer: C. Brown recluse spider bite

   Brown recluse venom destroys tissue and can leave a slowly healing ulcer, often with little early pain. Black widow bites cause systemic muscle pain, not necrosis.

6. A child stung by a bark scorpion in Arizona has roving eye movements, drooling, and uncontrolled limb jerking. You should:

   1. A. Apply ice to the site and release him at the scene
   2. B. Incise the sting site and suction out the venom
   3. C. Give naloxone to reverse the effects of the toxin
   4. D. Support the airway and transport for antivenom
   Show answer

   Answer: D. Support the airway and transport for antivenom

   Centruroides venom is neurotoxic, and children are at highest risk of airway compromise. Antivenom is available in the hospital for severe cases.

7. Pit vipers, such as rattlesnakes, copperheads, and cottonmouths, are recognized by:

   1. A. A triangular head, elliptical pupils, heat pits
   2. B. A round head, round pupils, and red and yellow bands
   3. C. A narrow head, round pupils, and no fangs
   4. D. A flat head, slit pupils, and a hood behind the head
   Show answer

   Answer: A. A triangular head, elliptical pupils, heat pits

   Pit vipers account for most venomous snakebites in the United States. Round pupils and colored bands describe the coral snake.

8. A hiker bitten on the ankle by a rattlesnake has pain and swelling spreading up the leg. The correct prehospital care is to:

   1. A. Apply ice packs and a tight tourniquet above the bite
   2. B. Cut over the fang marks and suction the wound
   3. C. Keep him calm, splint the limb, mark the swelling
   4. D. Have him walk out quickly to the trailhead
   Show answer

   Answer: C. Keep him calm, splint the limb, mark the swelling

   Calm the patient, remove rings and tight items, splint the limb near heart level, and mark the swelling edge over time. Ice, tourniquets, and incision cause more tissue damage.

9. Pit viper venom commonly causes:

   1. A. Paralysis with little or no local swelling
   2. B. Local tissue damage, swelling, coagulopathy
   3. C. Pinpoint pupils and heavy airway secretions
   4. D. Severe hypoglycemia and seizures only
   Show answer

   Answer: B. Local tissue damage, swelling, coagulopathy

   Rattlesnake venom destroys tissue and disrupts clotting, causing bleeding and low platelets. Little local swelling with neurotoxicity is more typical of coral snakes.

10. The definitive treatment for significant pit viper envenomation is:

    1. A. Electric shock applied at the bite
    2. B. Antivenom given in the hospital
    3. C. Steroids given at the scene
    4. D. Antibiotics given by EMS en route
    Show answer

    Answer: B. Antivenom given in the hospital

    Crotalidae antivenom neutralizes venom and reverses coagulopathy, so early transport to a facility that stocks it is key. Electric shock is an old myth.

11. A boy was bitten by a snake with red bands touching yellow bands. He has little pain and no swelling. You should anticipate:

    1. A. Immediate severe swelling of the limb
    2. B. Rapid bleeding from the gums and nose
    3. C. Delayed paralysis and respiratory failure
    4. D. No effects at all because there is no swelling
    Show answer

    Answer: C. Delayed paralysis and respiratory failure

    Coral snake venom is neurotoxic, and symptoms may be delayed for hours, so all bites need transport and observation. Lack of local findings is falsely reassuring.

12. The use of a pressure immobilization bandage is generally NOT recommended for North American pit viper bites because it may:

    1. A. Concentrate venom and worsen local tissue damage
    2. B. Spread the venom more rapidly through the body
    3. C. Cause the antivenom to be less effective later
    4. D. Increase the chance of an allergic reaction
    Show answer

    Answer: A. Concentrate venom and worsen local tissue damage

    Pit viper venom is mainly cytotoxic, and trapping it locally increases tissue injury. The technique may help with neurotoxic venoms such as coral snakes or Australian elapids.

13. A swimmer stung by a jellyfish has painful red welts on his leg. A widely recommended first step for many species is to:

    1. A. Rinse the area with plenty of fresh tap water
    2. B. Rub the area firmly with sand and a towel
    3. C. Apply ice wrapped in a cloth to the welts
    4. D. Rinse with vinegar to inactivate stingers
    Show answer

    Answer: D. Rinse with vinegar to inactivate stingers

    Vinegar inactivates undischarged nematocysts in many species, especially box jellyfish. Fresh water and rubbing can trigger more nematocysts to fire.

14. A fisherman stepped on a stingray and has intense foot pain. The best way to relieve the pain is to:

    1. A. Immerse the foot in water as hot as tolerated
    2. B. Apply ice packs to the wound for 20 minutes
    3. C. Apply a tight elastic bandage above the wound
    4. D. Soak the foot in cold salt water
    Show answer

    Answer: A. Immerse the foot in water as hot as tolerated

    Marine venoms are heat labile, and immersion at about 43 to 45°C (110 to 113°F) for 30 to 90 minutes relieves pain. Check temperature carefully to avoid burns. Ice worsens pain.

15. A cat bite to the hand is especially concerning because cat bites:

    1. A. Rarely break through the skin
    2. B. Transmit rabies in most cases
    3. C. Have a high rate of deep infection
    4. D. Cause severe crush injuries to bone
    Show answer

    Answer: C. Have a high rate of deep infection

    Cats' sharp teeth create deep punctures that seed bacteria such as Pasteurella into tendons and joints. Dog bites cause more crush injury.

16. A tick should be removed by:

    1. A. Covering it with petroleum jelly until it detaches
    2. B. Burning it with a match until it lets go
    3. C. Twisting it sharply to break the head off
    4. D. Pulling steadily with tweezers near the skin
    Show answer

    Answer: D. Pulling steadily with tweezers near the skin

    Grasp the tick close to the skin with fine tweezers and pull with steady traction, which removes the whole tick and reduces disease transmission. Petroleum jelly or burning with a match may make the tick release more saliva. Twisting sharply tends to break the mouthparts off in the skin.

17. A gardener who ate leaves from a foxglove plant has nausea, bradycardia, and visual changes. The plant most closely mimics poisoning from:

    1. A. Atropine
    2. B. Digoxin
    3. C. Cyanide
    4. D. Nicotine
    Show answer

    Answer: B. Digoxin

    Foxglove and oleander contain cardiac glycosides that act like digoxin, and digoxin Fab may be used. Atropine-like plants such as jimsonweed cause anticholinergic signs.

18. A 4-year-old chewed the leaves of a dieffenbachia houseplant and has burning, drooling, and swelling of the lips. Your main concern is:

    1. A. Delayed liver failure in 2 to 3 days time
    2. B. Severe bradycardia and heart block
    3. C. Seizures within the next 30 minutes
    4. D. Swelling that could threaten the airway
    Show answer

    Answer: D. Swelling that could threaten the airway

    Dieffenbachia contains calcium oxalate crystals that irritate the mouth and can swell the tongue and throat. It rarely causes systemic toxicity.

19. A man who ate a wild plant he thought was wild carrot is now seizing. This is a classic presentation of:

    1. A. Poison ivy exposure on the skin
    2. B. Pokeweed ingestion
    3. C. Water hemlock poisoning
    4. D. Mistletoe ingestion
    Show answer

    Answer: C. Water hemlock poisoning

    Water hemlock contains cicutoxin, which causes violent seizures and can be fatal within hours. It resembles edible wild carrot and parsnip.

20. Ricin, which can be made from castor beans, is dangerous because it:

    1. A. Stops protein synthesis in cells
    2. B. Blocks acetylcholine release at nerves
    3. C. Binds hemoglobin in place of oxygen
    4. D. Causes immediate anaphylaxis
    Show answer

    Answer: A. Stops protein synthesis in cells

    Ricin inhibits ribosomes and kills cells, causing severe GI illness or, if inhaled, lung injury. There is no antidote, and care is supportive.

21. A family who ate wild mushrooms 10 hours ago now has severe vomiting and watery diarrhea. You should be most concerned about:

    1. A. A benign mushroom that causes brief nausea
    2. B. Amatoxin poisoning and liver failure
    3. C. An allergic reaction to the mushrooms
    4. D. Hallucinogenic psilocybin mushrooms
    Show answer

    Answer: B. Amatoxin poisoning and liver failure

    Delayed onset 6 to 24 hours after eating suggests Amanita phalloides, which can cause liver failure after a brief recovery. Symptoms within 2 hours usually mean a less dangerous species.

22. A man was attacked by a swarm of Africanized bees and has hundreds of stings. He has vomiting, muscle pain, and dark urine, but no hives or wheezing. The main concern is:

    1. A. Anaphylaxis needing antihistamines
    2. B. Infection from the many stingers
    3. C. Direct venom toxicity to muscle
    4. D. A panic attack from the swarm
    Show answer

    Answer: C. Direct venom toxicity to muscle

    With hundreds of stings, the venom dose itself is toxic and can cause rhabdomyolysis, hemolysis, kidney injury, and shock even without allergy; these patients need IV fluids, monitoring, and transport. Anaphylaxis would bring hives, wheezing, or hypotension, and antihistamines are not its main treatment. Infection, if it occurs, takes days. Dark urine and muscle pain are not caused by panic.

23. A mushroom forager has heavy sweating, salivation, tearing, and bradycardia 30 minutes after eating. The antidote you would expect to give is:

    1. A. N-acetylcysteine
    2. B. Atropine
    3. C. Hydroxocobalamin
    4. D. Naloxone
    Show answer

    Answer: B. Atropine

    Some mushrooms, such as Clitocybe and Inocybe species, contain muscarine and cause a cholinergic syndrome that responds to atropine. NAC is used for acetaminophen and sometimes amatoxin liver injury.

24. When a patient has ingested an unknown plant or mushroom, you should:

    1. A. Bring a sample or photo of the plant
    2. B. Induce vomiting before leaving the scene
    3. C. Discard the plant to prevent further exposure
    4. D. Wait until symptoms develop before transporting
    Show answer

    Answer: A. Bring a sample or photo of the plant

    Identification by poison control or a mycologist guides treatment, especially for deadly mushrooms that cause delayed symptoms. Inducing vomiting is no longer recommended, and waiting for symptoms can miss the treatment window.

25. A man was bitten by a rattlesnake 15 minutes ago. Two fang marks are visible, but he has no pain, swelling, or other symptoms. The best plan is to:

    1. A. Release him, since it is a dry bite
    2. B. Apply a tight tourniquet above it
    3. C. Cut and suction the fang marks
    4. D. Transport; signs may still appear
    Show answer

    Answer: D. Transport; signs may still appear

    Some pit viper bites inject little or no venom, but early on a dry bite cannot be told from a delayed envenomation, so patients are transported and observed for several hours. A tourniquet and cutting or suctioning the wound are harmful and not recommended. Keep him calm, remove rings, splint the limb, and mark the edge of any swelling.