D3.309 - Basophil Activation Test Detects Rocuronium Allergy During the Post-Anaphylactic Refractory Period: A PAMA Case Report

Introduction

Post-anaphylaxis mast cell anergy (PAMA) is a transient period of mast cell hyperresponsiveness after severe anaphylaxis, potentially causing false-negative early skin tests and temporary clinical non-reactivity to the culprit allergen.

Case Report (Methods)

We report the case of a 71-year-old patient referred after recurrent severe perioperative anaphylaxis. On 17 December 2024, during induction of anaesthesia for emergency surgery due to obstructive sigmoid colon carcinoma fentanyl, propofol, lidocaine, rocuronium, cefazoline was used. Immediately after induction, the patient developed severe hypotension (60/30 mmHg), severe bronchospasm, and cardiovascular collapse requiring cardiopulmonary resuscitation and epinephrine (1 mg ×3). Serum tryptase exceeded 100 µg/L.Next day, on 18 December 2024, an emergency procedure for ileus with stoma formation was performed using fentanyl, rocuronium, and midazolam without complications. On 9 January 2025, during planned definitive tumour resection, anaesthesia including rocuronium again triggered immediate severe anaphylaxis with bronchospasm and cardiovascular collapse, requiring epinephrine (1 mg ×4), hydrocortisone, and clemastine; peak tryptase again exceeded 100 µg/L.

Results

A comprehensive allergological workup was performed five days after the last anaphylaxis. Skin prick and intradermal tests to propofol, fentanyl, cefazolin, rocuronium, and lidocaine were negative. Specific IgE to chlorhexidine, ethylene oxide, latex, and α-gal were negative. Baseline serum tryptase was 6.9 µg/L, and KIT D816V mutation testing was negative.In contrast, basophil activation testing (BAT) showed a strong positive response to rocuronium (35.3% activated basophils at 333 µg/mL). One week later, repeat skin testing converted to positivity (rocuronium skin prick test and vecuronium intradermal test). Rocuronium was confirmed as the only agent administered during all procedures. Provocation test with fentanyl and propofol was negative. The patient subsequently tolerated epidural anaesthesia with levobupivacaine and general anaesthesia with fentanyl, propofol, and sevoflurane.

Conclusion

This case illustrates PAMA as a cause of transient clinical tolerance of allergen and false-negative early skin testing after severe perioperative anaphylaxis. Importantly, early BAT correctly identified the culprit drug during the refractory period, suggesting BAT as a valuable complementary diagnostic tool when skin tests are unreliable shortly after anaphylaxis.