Level 1 of 6Core
Anaphylaxis: recognition and adrenaline
The core to-do list — diagnose and manage, at a glance
Diagnose— recognise it
- The bedside triad: sudden onset with rapid progression + a life-threatening airway, breathing or circulation problem + (in most but not all) skin or mucosal change. Generalised urticaria alone is not anaphylaxis — the moment any objective airway, breathing or circulatory involvement appears, adrenaline becomes mandatory.
- Skin and mucosa (over 90% of episodes): itch of palms, soles and genitalia first, then flushing, generalised urticaria and angio-oedema of lips, eyelids and mouth — in deeply pigmented skin palpate for weals rather than relying on inspection. No rash in up to 1 in 10 (commonest in fast intravenous drug reactions) — no rash never excludes the diagnosis.
- Airway in sequence: lump-in-throat, hoarseness or voice change, difficulty swallowing saliva, then inspiratory stridor — hoarseness is laryngeal oedema until proved otherwise. Breathing: wheeze, tachypnoea, falling SpO2. Circulation: tachycardia, systolic BP below 90 mmHg or a fall of more than 30%, warm flushed peripheries and a sense of impending doom — not the cold clammy skin of cardiogenic shock.
- Red flags to seek explicitly and repeatedly: hoarse or altered voice, inability to swallow saliva, visible tongue or palatal swelling, stridor, silent chest or exhaustion in a wheezing patient, SpO2 below 92% despite oxygen, systolic BP below 90 mmHg, any reduced conscious level, bradycardia in a shocked patient, and failure to improve after two doses of IM adrenaline.
- In a child, blood pressure is preserved until late: act on capillary refill, heart rate, conscious level, behaviour (he is not himself) and parental concern — waiting for hypotension is a recognised route to a paediatric death. Gastrointestinal features (vomiting, crampy abdominal pain, diarrhoea) are part of the syndrome after an ingested trigger.
- Know the mimics: vasovagal syncope (pale, cold, clammy, bradycardic, recovers within seconds of lying flat), acute severe asthma, septic shock, scombroid after dark-fleshed fish, panic attack with normal saturations and BP, and bradykinin-mediated angio-oedema (swelling without weals or itch, lasting over 24 hours, no response to adrenaline) — but do not dismiss the wheezing known asthmatic as an asthma attack: that trap kills.
Manage now— do this, in order
- Stop the exposure in seconds: disconnect the offending infusion, blood component or contrast at the cannula (not just the roller clamp), do not flush the line, scrape a retained bee sting out sideways — but if removing the trigger and giving adrenaline compete for time, adrenaline wins.
- Adrenaline 1:1000 (1 mg/mL) IM into the anterolateral middle third of the thigh, through clothing if necessary, needle at least 25 mm: adult and over 12 years 500 micrograms = 0.5 mL; 6–12 years 300 micrograms = 0.3 mL; 6 months–6 years 150 micrograms = 0.15 mL; under 6 months 100–150 micrograms. Cross-check 0.01 mg/kg to a maximum of 0.5 mg. Repeat every 5 minutes for as long as the patient remains unwell — there is no maximum number of IM doses.
- Never give 1 mg of adrenaline IV (10 mL of 1:10 000) to a patient with a pulse — that is a cardiac arrest dose causing hypertensive crisis, ischaemia, arrhythmia and death; the titrated IV dose, for expert use only, is 50 micrograms. Where only 1:10 000 is stocked, the IM dose becomes 5 mL — say the concentration, volume and route aloud before every injection.Doctor / Nurse
- Lie the patient flat with the legs raised — sudden death has occurred in patients sat up, stood up or walked. If breathing makes lying flat intolerable they may sit up but the legs stay raised; unconscious but breathing → recovery position with legs raised; after about 20 weeks of pregnancy → left lateral position.
- High-flow oxygen by reservoir mask at 15 L/min immediately and for as long as the emergency continues, targeting saturations of 94–98% once stability returns.
- Fluid, delivered under pressure or by hand: 500–1000 mL of crystalloid (0.9% sodium chloride or Hartmann's) rapidly in an adult, escalating to 1–2 litres and beyond if hypotension persists; 10 mL/kg boluses in a child reassessed after each. A bag hanging on a pole is not a fluid challenge; avoid colloids. Adrenaline does not substitute for fluid nor fluid for adrenaline.Doctor / Nurse
- Persisting wheeze after adrenaline = treat as acute asthma: nebulised salbutamol 5 mg (2.5 mg under 5 years), oxygen-driven, repeated as needed, adding ipratropium 500 micrograms (250 micrograms in children) for severe bronchospasm. Upper airway oedema: nebulised adrenaline 3 mg in an adult (1:1000 solution 0.5 mL/kg, maximum 5 mL, in a child) — it buys time but does not secure an airway; prepare early for a difficult airway.Doctor / Nurse
- Only after adrenaline: chlorphenamine 10 mg slow IV or IM (5 mg 6–12 years; 2.5 mg 6 months–6 years; 250 micrograms/kg under 6 months) — rapid IV injection causes hypotension. Hydrocortisone 200 mg (100 mg 6–12 years; 50 mg 6 months–6 years; 25 mg under 6 months) is unhelpful in the first hour and never a substitute for adrenaline — never let any of these delay it.Doctor / Nurse
- Refractory anaphylaxis (no improvement after two IM doses): continue IM adrenaline every 5 minutes, escalate fluid to litres, move to a low-dose titrated adrenaline infusion with continuous cardiac monitoring; glucagon 1–2 mg IV or IM every 5 minutes (children 20–30 micrograms/kg, maximum 1 mg) for the beta-blocked patient. Observe after recovery: minimum 6 hours from resolution (12 hours or longer if severe, more than one dose, hypotension, airway involvement, asthma or beta-blocker) — 10–20% of episodes are biphasic and the second phase may be worse.Doctor / NurseNot available at your setup — Infusion pump.
| Age | Adrenaline 1:1000 IM |
|---|---|
| Adult / over 12 years | 500 micrograms = 0.5 mL |
| 6–12 years | 300 micrograms = 0.3 mL |
| 6 months – 6 years | 150 micrograms = 0.15 mL |
| Under 6 months | 100–150 micrograms = 0.1–0.15 mL |
| Weight cross-check | 0.01 mg/kg, max 0.5 mg |
Refer / escalate
Call for senior help and critical care the moment there is stridor, hoarseness, inability to swallow saliva, progressive tongue or pharyngeal swelling, hypotension, reduced conscious level, or failure to improve after two doses of IM adrenaline — and refer every patient who has had anaphylaxis for specialist allergy assessment before discharge.
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