Recognise the pattern, not the bottle — paediatric drug toxicity

Station status

This is one MedVellum formative structured clinical encounter. The scoring, prompts and performance descriptions are educational feedback tools. They are not an official college station, timing, mark allocation, pass score or reproduced examination format. The encounter assesses first-impression toxidrome recognition, leadership of the ABCDE primary survey, naloxone titration to effective ventilation with an infusion for a long-acting opioid, the flumazenil caution, communication with an adolescent and parent, and a structured handover and disposition. [1] [2]

Candidate instructions

You are the paediatric registrar called to the acute assessment room. Assess the adolescent from the doorway and say aloud what you see. Recognise the toxidrome from the bedside pattern, not the drug name. Lead the ABCDE primary survey: secure the airway and oxygenate, ventilate if breathing is inadequate, check bedside glucose, establish access, and titrate naloxone to effective ventilation. Decline flumazenil if the picture is mixed or unknown. Speak directly to the adolescent and the friends or parent. Reassess after every action. Call senior, intensive-care or retrieval help and the Poisons Information Centre early. Finish with a structured handover and disposition plan. Say what you would assess or do; do not perform painful manoeuvres on the actor. [1]

Room setup and observable starting state

The encounter. Sam is 16 and is brought to the assessment trolley by two friends, who say Sam collapsed at a party after taking something. Sam is unconscious, with slow shallow breathing and pinpoint pupils. These are abnormalities in appearance, work of breathing and circulation that the candidate should describe objectively, declare concern, recognise the opioid toxidrome, and begin the ABCDE survey and naloxone immediately. [2]

Simulation safety. Sam remains on the trolley and is never forcibly positioned. Cards or the assessor supply pupil size, respiratory findings, monitor readings and examination findings. The friends do not obstruct urgent care. [1]

Actor cues

Friend actors

• Begin with "Sam just collapsed after taking something at the party." If asked what Sam took, answer: "I think it was something from a relative's medicine cupboard, maybe a painkiller, and maybe a benzodiazepine too — I am not sure." [1]

Adolescent actor

• Remain unresponsive with slow shallow breathing early in the encounter; recover towards adequate breathing as naloxone is titrated, following the assessor's cue card, while remaining drowsy rather than fully awake. [2]

Assessor cues and clinical data

Release findings as the candidate reaches each step. Reward recognition of the opioid toxidrome from the bedside pattern and the titration of naloxone to effective ventilation; penalise reversing to full wakefulness or reaching for flumazenil in a mixed ingestion. [2]

A and B — Airway and breathing

Airway is patent but breathing is inadequate: respiratory rate 8 and shallow, oxygen saturation 85% on air. Expected strong behaviour: open and protect the airway; give high-flow oxygen; start bag-mask ventilation because breathing is inadequate; prepare for a definitive airway if ventilation fails; do not wait for an antidote to protect the airway. [1]

C and bedside glucose — Circulation and metabolism

Heart rate 95, blood pressure low-normal, capillary refill 2 seconds, pinpoint pupils at 1 millimetre, glucose 4.8 millimoles per litre. Expected strong behaviour: establish intravenous access; note the opioid toxidrome from pinpoint pupils, slow shallow breathing and reduced conscious level; recognise that glucose is normal; give naloxone titrated to effective ventilation. [2]

Escalation event — naloxone titration and the long-acting agent

A friend confirms the source was a relative's sustained-release morphine, and possibly a benzodiazepine. Expected strong behaviour: titrate naloxone starting at 10 micrograms per kilogram, repeating every two to three minutes until ventilation is effective (not full wakefulness); recognise the sustained-release agent as a long-acting opioid with a high recurrence risk; plan a naloxone infusion at about two-thirds of the effective bolus per hour and prolonged observation; call the senior team, a toxicologist and the Poisons Information Centre. [2]

Escalation event — the flumazenil caution

The registrar asks whether flumazenil should be given to reverse the possible benzodiazepine. Expected strong behaviour: decline flumazenil because this is a mixed overdose with a possible proconvulsant co-ingestion; state the contraindications (chronic benzodiazepine use, mixed or unknown overdose, co-ingested proconvulsant, seizure disorder); confirm supportive airway and ventilation as the default. [8] [9]

Escalation event — evolving MDMA features

As the opioid component reverses, Sam becomes agitated and warm with a heart rate of 130 and temperature of 38.5 degrees Celsius; a friend mentions MDMA. Expected strong behaviour: recognise emerging sympathomimetic and serotonergic toxicity; give titrated benzodiazepines, cool actively, give intravenous fluids; avoid beta-blocker monotherapy; send creatine kinase, renal function and sodium; escalate to intensive care. [10]

Weight, retrieval and handover

The candidate must obtain a working weight for drug and device sizing, and must call retrieval and the Poisons Information Centre before local support is exceeded. Expected strong behaviour: state the working weight and its source; agree destination, treatment, escort, expected deterioration and the plan if transfer is delayed; run a structured handover covering the toxidrome, the timed actions and response, the working differential and pending tests, and the next contingency and its named owner. [1]

Marking domains

Debrief prompts

• What made you confident this was the opioid toxidrome before you had a drug name?
• Why did you ventilate before giving naloxone?
• Why did you titrate naloxone to ventilation rather than to full wakefulness, and what did you plan for the long-acting agent?
• Why did you decline flumazenil, and under what narrow circumstance would you consider it?
• What contingency did you agree with retrieval for recurrence during transport? [1]