Anaphylaxis
A-to-E Assessments
SimulationUse this resource in conjunction with your real-world training
Experience Summary
In this experience you are introduced to this simulated A to E assessment series. Watch as a candidate undertakes a simulated A to E assessment of a patient presenting with anaphylaxis.
Clinical Context
Anaphylaxis is a severe, life-threatening systemic hypersensitivity reaction that can occur rapidly after exposure to an allergen such as foods, medications, or insect stings. It is characterised by airway, breathing, and circulatory compromise, and requires immediate recognition and treatment to prevent cardiac arrest.
Assessment
Management follows an ABC approach (Airway, Breathing, Circulation). Patients may present with sudden hypotension, tachycardia, bronchospasm, hypoxia, and airway swelling (e.g., stridor, tongue or lip oedema). Skin changes such as urticaria, flushing, or angioedema are common but may be absent. Immediate help should be called, and high-flow oxygen administered. Airway support is critical, and early escalation to senior clinicians is essential if airway compromise is suspected.
Assessment is rapid and focused, as anaphylaxis is a clinical diagnosis. A history of recent allergen exposure is important but should not delay treatment. Examination should assess airway patency, respiratory effort, oxygen saturation, and circulatory status. Differential diagnoses include asthma exacerbation, syncope, or other causes of shock, but the combination of respiratory compromise and skin or mucosal features strongly supports anaphylaxis.
Early Management
First-line treatment is immediate intramuscular administration of adrenaline into the anterolateral thigh. This should be repeated every 5 minutes if there is no improvement. Simultaneously, establish intravenous access and begin rapid infusion of intravenous fluids (crystalloids) to counteract vasodilation and capillary leak. Adjunctive treatments include antihistamines and corticosteroids, though these are not life-saving in the acute phase. Bronchodilators (e.g., salbutamol) may be used for persistent bronchospasm. Continuous monitoring is essential throughout.
Longer Term Management
Patients with refractory symptoms may require intravenous adrenaline infusions and advanced airway management, often in a critical care setting. Blood tests such as serum tryptase (taken after stabilisation) can help confirm the diagnosis retrospectively.
Patients should be observed for biphasic reactions, typically for at least 6–12 hours depending on severity. Referral to an allergy specialist is recommended to identify triggers and reduce recurrence risk. Clear documentation and patient education are essential, including avoidance strategies and provision of an adrenaline auto-injector where appropriate.
Learning Outcomes
- Observe a simulated A to E assessment of a patient presenting with anaphylaxis.
- Reflect on the candidates A to E assessment - what did you think went well? What didn’t?
- Understand the initial assessment and management of a patient with anaphylaxis.
External Resources