FACEM Toxicology and Poisoning 2

Question 1

A hiker in Australia is bitten by an unknown snake and develops local pain and systemic symptoms. Which first aid measure is MOST important?

Accepted Answer

Apply pressure immobilization bandaging to the entire bitten limb

Answer

Pressure immobilization bandaging slows lymphatic spread of venom and is the recommended first aid for Australian elapid snake envenomation; tourniquets and incision/suction are contraindicated.

Question 2

A patient with respiratory depression after benzodiazepine overdose is considered for flumazenil. What is the most important contraindication to its use?

Accepted Answer

Physical dependence on benzodiazepines

Answer

Flumazenil can precipitate acute benzodiazepine withdrawal seizures in physically dependent patients, making it dangerous without clear knowledge of the patient's benzodiazepine use history.

Question 3

A patient presents with visual disturbances, high anion gap metabolic acidosis, and osmolar gap after suspected methanol ingestion. What is the mechanism of methanol toxicity?

Accepted Answer

Accumulation of formaldehyde and formic acid via alcohol dehydrogenase metabolism

Answer

Methanol is metabolized by alcohol dehydrogenase to formaldehyde and then to formic acid, which inhibits cytochrome oxidase in the optic nerve and causes high anion gap metabolic acidosis.

Question 4

A patient with beta-blocker overdose has a heart rate of 32 bpm and BP of 70/40 mmHg, refractory to atropine 3mg IV. What is the next most appropriate treatment?

Accepted Answer

Glucagon 3–5mg IV bolus

Answer

Glucagon bypasses the blocked beta-adrenergic receptor to activate adenylyl cyclase via its own receptor, increasing intracellular cAMP and improving heart rate and contractility.

Question 5

A patient develops hyperthermia (39.8°C), clonus, hyperreflexia, mydriasis, and diaphoresis after starting tramadol and sertraline concurrently. What is the most likely diagnosis?

Accepted Answer

Serotonin syndrome

Answer

Serotonin syndrome presents with the triad of altered mental status, autonomic instability, and neuromuscular features including clonus and hyperreflexia, distinguishing it from neuroleptic malignant syndrome which features rigidity and bradyreflexia.

(FACEM) Fellowship of the Australasian College for Emergency Medicine Practice Test

(FACEM) Fellowship of the Australasian College for Emergency Medicine Practice Test

FACEM Toxicology and Poisoning 2