SN7 SHORT NOTE 5M

Describe Investigation of Perioperative Anaphylaxis in detail.

General Surgery · Final Professional

WHY Investigate

After a suspected perioperative anaphylaxis, it is essential to confirm the reaction and identify the culprit, because the patient will need future anaesthetics and must avoid the trigger — an unidentified allergen risks a fatal repeat reaction.

Tryptase & Referral

Mast-cell tryptase is released in anaphylaxis, so serial (timed) tryptase samples are taken — during/soon after the reaction, a few hours later, and a baseline — and a rise and fall confirms an anaphylactic (mast-cell) reaction. The patient is then referred to a specialist allergy/immunology clinic for skin testing (and other tests) against the drugs given, to identify the culprit and safe alternatives. The event, drugs and results are clearly documented and the patient warned/given an alert.

CLINICAL PEARL

After anaesthetic anaphylaxis: take serial tryptase (a rise then fall confirms it) and refer for allergy skin testing to identify the culprit drug and safe alternatives — then document and warn the patient. Muscle relaxants, antibiotics, chlorhexidine and latex are the usual suspects.

Practical Timing & Communication

The value of tryptase depends on timing the samples correctly, because the level rises soon after the reaction and then falls back towards the patient’s baseline over hours, so a sample taken during or shortly after the event, a further sample a few hours later and a baseline sample taken later or from records together demonstrate the characteristic rise and fall. Equally important is clear communication: the suspected reaction, the drugs given and the results are documented, the patient is informed and, once the culprit is identified by allergy testing, given written information and an alert to carry, so that every future anaesthetist can avoid the trigger and choose a safe alternative.

CLINICAL PEARL

Two actions define the follow-up of anaesthetic anaphylaxis: serial tryptase to prove it was a mast-cell reaction, and allergy referral for skin testing to name the culprit and a safe alternative — then document and warn the patient.

In Brief

In short, prove it with timed tryptase and name the culprit with skin testing, then make sure the patient carries that warning forward.

Neuromuscular blockers are the commonest trigger under anaesthesia.

KEY POINT

Key points TO remember

Investigate perioperative anaphylaxis to confirm it & identify the culprit (future safety).
Serial timed tryptase samples — a rise and fall confirms a mast-cell (anaphylactic) reaction.
Refer to allergy/immunology for skin testing against the drugs given (culprit + safe alternatives).
Document the event/drugs/results; warn the patient / give an alert.

EXAM TIP

Sources: Morgan & Mikhail’s Clinical Anesthesiology; Miller’s Anesthesia; Ajay Yadav’s Short Textbook of Anaesthesia.

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