Adverse drug reactions OSCE — suspected anaphylaxis and reporting

Candidate instructions (2 minutes reading, 8 minutes each station)

You are the general paediatric registrar. A 5-year-old (weight 18 kg) has received a first dose of oral amoxicillin for an ear infection in the emergency department. Within fifteen minutes the child has developed widespread urticaria, wheeze, and become pale and drowsy. Manage the child and communicate with the parent. [1]

Station A — Immediate assessment and management

Encounter. The child is on the bed, flushed, with an audible wheeze, widespread urticaria, tachycardia, and a capillary refill of three seconds. The parent is anxious. [1]

Expected actions and the marking domains. [1]

1. Recognise anaphylaxis promptly. Identify the temporal link to amoxicillin and the combination of skin change plus respiratory and circulatory compromise as anaphylaxis, not a simple rash. Stop further amoxicillin.
2. First-line treatment — intramuscular adrenaline. Give adrenaline 10 microgram per kilogram of 1:1000 solution intramuscularly into the anterolateral thigh (for 18 kg this is approximately 180 microgram, so the 150 microgram autoinjector approximates the dose), repeatable every five minutes. This is the pass-or-fail action of the station.
3. Adjuncts in the correct order. Lay the child flat with legs raised, give high-flow oxygen, establish intravenous access, and give an isotonic fluid bolus of 10 to 20 mL per kilogram for shock. Add an antihistamine and a corticosteroid as adjuncts only after adrenaline. Give nebulised salbutamol for persistent bronchospasm.
4. Observation and disposition. Observe for at least six hours for a biphasic reaction. Admit or observe depending on response. Arrange an adrenaline autoinjector (150 microgram for 7.5 to 20 kg), an action plan, and allergy service follow-up before discharge. [1]

Station B — Communication and reporting

Encounter. The child has stabilised. The parent asks what happened, whether the child is allergic to penicillin, and what to tell other doctors. [1]

Expected communication and marking domains. [1]

1. Explain the diagnosis in plain language. The child had a severe allergic reaction to amoxicillin (an adverse drug reaction, immune-mediated), which is why it came on quickly. Adrenaline reversed it. Use teach-back to confirm understanding.
2. Address the penicillin label accurately. Record the reaction in detail (timing, features, severity, treatment given) and document a penicillin allergy. Explain that a formal allergy review can later confirm whether all penicillins must be avoided or whether some can be safely reintroduced. Avoid permanent over-restriction on the basis of a single episode.
3. Autoinjector and action plan. Prescribe a 150 microgram adrenaline autoinjector for a child of this weight (7.5 to 20 kg), give a written action plan, and demonstrate its use to the parent with a trainer device. Confirm the school and carers are informed.
4. Reporting duty. Explain that you will report this reaction to the national pharmacovigilance system — the TGA in ANZ, the MHRA Yellow Card in the UK, the FDA MedWatch in the US — so that pooled data in WHO VigiBase can detect signals and protect other children. Emphasise that reporting is a professional responsibility and does not depend on certainty.
5. Safety-net. Give clear guidance on when to call an ambulance (any breathing difficulty, collapse, or recurrence after discharge) and confirm follow-up with the allergy service. [8]

Examiner global scoring anchors

• Recognition and first-line therapy: did the candidate give intramuscular adrenaline first and into the correct site, at the correct weight-based dose?
• Causality reasoning: did the candidate stop the drug, recognise the reaction as an ADR, and avoid inappropriate rechallenge?
• Communication: did the candidate explain the diagnosis, the action plan, and the reporting duty in language the parent could repeat back?
• Professional and systems practice: did the candidate report the reaction and arrange safe documentation and follow-up? [1]