Anaphylaxis following shellfish ingestion — elderly male

Patient Information

Dispatch: A 75YO male has come to the FAP at the Fremantle Seafood Festival reporting difficulty breathing and a rash after eating prawns approximately 10 minutes ago. (Barry Hutchinson)
Patient: Barry Hutchinson — 75yr (75kg)
Incident History: Pt reports eating a prawn skewer at a food stall approximately 10 minutes ago. Shortly after, he noticed his lips tingling, skin becoming itchy with raised welts across his chest and arms, and progressive shortness of breath. He denies taking any antihistamines prior to arrival.
Emergency Contact: Margaret Hutchinson (Wife) — 0412 883 541

Initial Rapid Assessment

Response: Alert
Airway: Patent. Audible stridor on deep inspiration. Pt reports throat feels 'tight'. Nil visible foreign body. Mild lip swelling noted.
Breathing: Increased work of breathing. Audible wheeze bilaterally. RR elevated. Accessory muscle use present. Pt speaking in short sentences.
Circulation: Radial pulse rapid and weak. Skin flushed with raised urticarial welts across chest, arms and neck. Diaphoretic.
Disability: GCS 14 (E4V4M6). Alert but anxious and restless. Oriented to time, place and person.
Exposure: Urticarial rash (wheals) across chest, bilateral forearms and neck. Mild periorbital swelling bilaterally. No evidence of external haemorrhage or trauma.

Vitals

Time	SpO2	Resp Dist	RR	Pulse	BP	CRT	GCS	PERL	Temp	BGL	Pain
Initial	91% (RA)	Moderate	24	118	88/60	3s	14	4 4 ++	37.1	–	5
10 mins	97% (O2 NRB 15L)	Mild	18	98	102/68	2s	15	4 4 ++	37.1	–	2

History Taking

Treatment Response

Diagnosis

This patient is suffering from anaphylaxis secondary to shellfish (prawn) ingestion, presenting with multi-system involvement including respiratory (wheeze, stridor, dyspnoea), cardiovascular (hypotension, tachycardia), and cutaneous (urticaria, angioedema) features.

Facilitator Triggers — if trainees miss a critical step

! (If the trainee does not identify hypotension on the initial BP and fails to administer adrenaline within 2 minutes — patient becomes increasingly distressed, GCS drops to 12, stridor becomes louder and more pronounced, BP drops to 78 systolic. Facilitator prompts: 'Barry is telling you his throat feels like it is closing.')
! (If the trainee attempts to administer Loratadine (antihistamine) instead of adrenaline — facilitator reminds trainee that antihistamines have no role in the treatment of anaphylaxis with respiratory or cardiovascular involvement and that adrenaline must be administered first.)
! (If the trainee positions the patient upright or allows the patient to stand/walk — facilitator states: 'Barry attempts to stand up, saying he feels a bit better.' Trainee must instruct patient to remain supine with legs outstretched and not mobilise.)
! (If oxygen is not applied after adrenaline administration — SpO2 remains at 91% at the 5-minute reassessment and the trainee should be prompted to reassess oxygen delivery.)
! (If the trainee does not reassess BP and pulse after adrenaline administration — facilitator prompts: 'Your partner asks if you want to check obs again after the injection.')
! (If the trainee does not advise that the patient must not walk or stand for a minimum of one hour following adrenaline and must be transported to hospital for 4-hour observation — facilitator prompts: 'Barry says he feels much better and wants to go back and find his wife.')

Treatment Objectives

1 Ensure scene safety and don appropriate PPE.
2 Perform Primary Survey — identify patent airway with stridor, increased work of breathing with wheeze, hypotension and tachycardia, urticarial rash indicating multi-system anaphylaxis.
3 Recognise anaphylaxis: multi-system involvement (respiratory + cardiovascular + cutaneous) following allergen exposure (shellfish ingestion).
4 Position patient supine with legs outstretched — do NOT allow patient to sit upright in a chair, stand or walk. If respiratory distress is severe, allow semi-recumbent with legs still outstretched.
5 Administer Adrenaline Auto-Injector (EpiPen 300 MICROg) IM into outer mid-thigh — indication: anaphylaxis with hypotension, wheeze, stridor and urticaria. Confirm 6 medication rights: right patient, right drug, right dose, right route, right time, right documentation.
6 Apply oxygen via Non-Rebreather Mask at 10–15 litres per minute — titrate to SpO2 target 94–98%.
7 Perform Vital Sign Survey — record BP, HR, RR, SpO2, GCS, skin findings.
8 Reassess BP before considering any further treatment. Document pre- and post-intervention vitals.
9 If symptoms not significantly improved at 5 minutes and BP permits, prepare second EpiPen (300 MICROg IM) for administration at 5-minute interval if available.
10 Contact CSP for further advice and to arrange urgent ambulance via CSP.
11 Monitor patient persistently — record full observations every 5 minutes given time-critical presentation.
12 Advise patient he must not stand or walk. Explain he requires monitoring at hospital for a minimum of 4 hours after last dose of adrenaline due to risk of biphasic reaction.
13 Do NOT administer Loratadine — antihistamines have no role in treatment of anaphylaxis with respiratory or cardiovascular involvement.
14 Note: Ramipril (ACE inhibitor) may potentiate anaphylaxis severity — communicate to receiving hospital at handover.
15 Scenario ends on arrival of ambulance and IMISTAMBO handover.
16 Attention to hand hygiene will be given throughout the scenario.

Clinical references: Anaphylaxis · Adrenaline Auto-Injector (EpiPen) · Oxygen · Loratadine

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