A 23-year-old man with a bleeding femoral fracture is hypotensive and receives a blood transfusion. Immediately after the transfusion starts, he develops fever, chills, severe itching, dyspnoea, stridor, neck swelling, SpO2 75% and bilateral polyphonic rhonchi. EXAM TASKS Identify and justify the event causing deterioration. List the immediate measures. Provide a treatment plan. Give me the best brief answer
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Acute Anaphylactic Transfusion Reaction - Complete Management
1. IDENTIFICATION AND JUSTIFICATION
Diagnosis: Anaphylactic Transfusion Reaction (severe/grade IV)
This is NOT a simple febrile or haemolytic reaction. The clinical picture is anaphylaxis triggered by the blood transfusion, with features of angio-oedema + upper airway obstruction + lower airway bronchospasm + cardiovascular collapse + urticaria - all occurring within seconds to minutes of starting transfusion.
| Feature | This Patient | Significance |
|---|---|---|
| Fever + chills | Present | Immune activation |
| Severe itching | Present | IgE-mediated mast cell degranulation - urticaria |
| Stridor | Present | Laryngeal/supraglottic oedema - upper airway emergency |
| Neck swelling | Present | Angioedema |
| Dyspnoea + bilateral polyphonic rhonchi | Present | Bronchospasm - lower airway obstruction |
| SpO2 75% | Present | Critical hypoxaemia - life-threatening |
| Hypotension (pre-existing) | Present | Distributive + haemorrhagic shock |
| Onset: immediately after transfusion | Present | Classic anaphylaxis timing |
Pathophysiology: Anaphylaxis occurs most commonly in IgA-deficient patients who possess IgA-specific antibodies of the IgE class. Transfused IgA (present in donor plasma) cross-links these IgE antibodies on mast cells and basophils, triggering massive release of histamine, tryptase, and leukotrienes. This causes: (1) systemic vasodilation and capillary leak → hypotension; (2) laryngeal and supraglottic oedema → stridor and neck swelling; (3) bronchial smooth muscle contraction → wheezing and bronchospasm. Haptoglobin deficiency is an alternative mechanism (anti-haptoglobin IgG/IgE). - Roberts and Hedges' Clinical Procedures in Emergency Medicine, p. 607
Why not other reactions?
- Febrile non-haemolytic reaction: fever alone, NO stridor/bronchospasm/angioedema
- Haemolytic reaction: flank/back pain, haemoglobinuria, DIC - no urticaria or airway oedema
- TRALI: delayed pulmonary oedema, non-cardiogenic - no urticaria or stridor
2. IMMEDIATE MEASURES
Priority: STOP - CALL - AIRWAY - ADRENALINE
- STOP the transfusion immediately - first and non-negotiable step; do NOT resume
- Keep the IV line open with normal saline (new giving set)
- Call for help - activate resuscitation team / senior anaesthetist
- Airway assessment and positioning - sit the patient upright if tolerated; prepare for intubation
- High-flow oxygen - 15 L/min via non-rebreather mask targeting SpO2 >94%
- Epinephrine (Adrenaline) IM - first-line drug
- 1 mg/mL (1:1,000) solution, 0.5 mg IM into the anterolateral thigh
- Repeat every 5 minutes if no improvement
- If in shock with no response: IV epinephrine infusion 0.1-1 mcg/kg/min
- Aggressive IV fluid resuscitation - normal saline boluses (caution in context of ongoing haemorrhage)
- Monitor: continuous ECG, SpO2, BP, urine output
- Send blood sample back to blood bank + patient identification check
- Notify blood bank immediately - return unused blood product for investigation
3. TREATMENT PLAN
Phase 1: Immediate (0-5 minutes)
| Drug | Dose | Route | Rationale |
|---|---|---|---|
| Epinephrine | 0.5 mg (1:1,000) | IM (anterolateral thigh) | Reverses bronchospasm, oedema, hypotension - first-line |
| Oxygen | 15 L/min | Non-rebreather mask | Treat SpO2 75% |
| 0.9% NaCl | 500-1000 mL bolus | IV | Volume replacement for distributive shock |
Phase 2: Adjunct Pharmacotherapy (5-15 minutes)
| Drug | Dose | Route | Rationale |
|---|---|---|---|
| H1 antihistamine (chlorphenamine) | 10 mg | IV slow | Reduce urticaria, pruritus - adjunct only |
| H2 antihistamine (ranitidine) | 50 mg | IV | Complement H1 blockade |
| Corticosteroids (hydrocortisone) | 200 mg | IV | Prevent biphasic reaction, reduce oedema - delayed onset |
| Nebulised salbutamol | 2.5-5 mg | Inhaled | Epinephrine-resistant bronchospasm |
Critical note: Antihistamines and steroids do not act rapidly enough to treat acute anaphylaxis. Epinephrine is the only drug that works fast enough to reverse the life-threatening components. - Rosen's Emergency Medicine, p.3757
Phase 3: Airway Management
- If stridor persists or worsens despite epinephrine: early endotracheal intubation (do not delay - laryngeal oedema can progress to complete obstruction)
- Racemic epinephrine (nebulised) may help reduce supraglottic oedema as a bridge
- RSI with ketamine (maintains BP) + succinylcholine preferred in this haemodynamically unstable patient
- Have surgical airway (cricothyrotomy) kit at bedside
Phase 4: Haemorrhage Management (concurrent)
- This patient still has a bleeding femoral fracture - once airway and anaphylaxis are being controlled, orthopaedic/surgical team must address haemostasis
- Future blood transfusion (if still needed) must use washed red blood cells (plasma-depleted) or IgA-deficient blood products
- Pre-medicate with corticosteroids + antihistamines 30-60 minutes before any future transfusion
Phase 5: Investigation and Monitoring
- Serum tryptase: draw within 30 minutes - 6 hours of symptom onset (confirms anaphylaxis)
- Blood bank: ABO/Rh crossmatch verification, direct antiglobulin test
- Blood cultures (rule out septic transfusion reaction)
- FBC, U&E, LFTs, coagulation screen
- Admit to ICU/HDU for minimum 24 hours (risk of biphasic anaphylaxis)
- Allergy/immunology referral after discharge: IgA level, anti-IgA antibodies
Future Transfusion Safety
- Document reaction formally (haemovigilance reporting)
- Patient requires IgA-deficient blood products or washed cellular products for all future transfusions
- Provide medical alert bracelet
Summary mnemonic: SAEOC
- S - Stop transfusion
- A - Adrenaline (IM 0.5 mg, 1:1,000)
- E - Epinephrine infusion if shock persists + Ensure airway
- O - Oxygen + IV fluids
- C - Corticosteroids + antihistamines (adjuncts)
Sources: Roberts and Hedges' Clinical Procedures in Emergency Medicine, p. 607; Rosen's Emergency Medicine, p. 3755-3757; Goldman-Cecil Medicine, Transfusion Reactions chapter
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