Q1. Which toxidrome features PINPOINT pupils with profuse secretions and bradycardia? A. Opioid B. Cholinergic C. Anticholinergic D. Sympathomimetic ANSWER: B — cholinergic. Why: organophosphates cause salivation, lacrimation, urination, diarrhoea and bronchorrhoea with pinpoint pupils and bradycardia. A: opioids also give pinpoint pupils but the patient is DRY. C, D: both cause dilated pupils. LEARNING POINT: pinpoint plus WET is cholinergic; pinpoint plus dry is opioid.

Q2. The antidote for paracetamol poisoning acts by: A. Binding paracetamol in the gut B. Replenishing glutathione C. Blocking hepatic enzymes D. Increasing renal excretion ANSWER: B — replenishing glutathione. Why: in overdose, conjugation saturates and the toxic metabolite NAPQI accumulates once glutathione is depleted. N-acetylcysteine restores glutathione, allowing NAPQI to be detoxified. LEARNING POINT: knowing the mechanism explains why NAC works best before hepatocyte injury is established.

Q3. A patient took a large paracetamol overdose 6 hours ago and feels completely well with normal observations. The correct action is: A. Discharge — she is asymptomatic B. Timed paracetamol level, baseline bloods, treat per nomogram and protocol C. Give charcoal only D. Repeat assessment in 48 hours ANSWER: B. Why: paracetamol poisoning is silent for the first 24 hours. Feeling well says nothing about the risk of hepatic injury, and treatment is most effective before injury develops. A: the specific error this question targets. LEARNING POINT: the well patient is the one to worry about.

Q4. A heroin overdose patient wakes fully after naloxone and asks to leave. The correct action is: A. Discharge immediately — he is alert B. Observe for an appropriate period; re-sedation can occur as naloxone wears off C. Give a second dose and discharge D. Admit for a week routinely ANSWER: B — observe. Why: naloxone has a shorter duration of action than most opioids, so respiratory depression can recur after apparent recovery. A: a recognised cause of preventable death after discharge. LEARNING POINT: reversal buys time; it does not remove the opioid.

Q5. A farmer presents drowsy with pinpoint pupils, profuse secretions and wet crackles throughout the chest. The priority in atropine dosing is titration to: A. A target heart rate B. Pupil dilation C. Drying of bronchial secretions D. A fixed weight-based total ANSWER: C — drying of the secretions. Why: death in organophosphate poisoning is usually from bronchorrhoea and respiratory failure. Atropine is titrated to a dry chest, which frequently requires far more than a conventional dose. A, B: neither reflects the lethal problem. LEARNING POINT: treat what kills — the airway and the secretions.

Q6. Three people from one household have headache, nausea and confusion after using an indoor charcoal stove. Pulse oximetry reads 98% in each. This means: A. Oxygenation is adequate and CO poisoning is excluded B. Oximetry cannot distinguish carboxyhaemoglobin, so a normal reading does not exclude CO poisoning C. The symptoms must be from a virus D. The oximeter is faulty ANSWER: B. Why: pulse oximetry measures light absorbance and reads carboxyhaemoglobin as if it were oxyhaemoglobin, producing a falsely reassuring saturation while oxygen delivery is severely impaired. LEARNING POINT: several people, one building, one heat source — give high-flow oxygen and measure carboxyhaemoglobin directly.

Q7. A patient with tricyclic antidepressant overdose has a QRS duration of 140 ms and is hypotensive. The most appropriate specific treatment is: A. Sodium bicarbonate B. Flumazenil C. Naloxone D. Calcium gluconate ANSWER: A — sodium bicarbonate. Why: tricyclics block cardiac sodium channels, widening the QRS and predisposing to arrhythmia. Sodium bicarbonate increases extracellular sodium and raises pH, both of which reduce that blockade. B: dangerous here — flumazenil can precipitate seizures, particularly with co-ingested tricyclics. LEARNING POINT: the widening QRS is the finding that triggers treatment, not the drug level.