A Case of Anaphylaxis in Which a Basophil Activation Test Was Used to Identify the Suspected Agent

A 9-year-old boy (height 133 cm; weight 32 kg; body mass index 18.0 kg/m²) was scheduled for intensive restorative dental treatment and extractions under general anesthesia due to an exaggerated gag reflex. After application of standard anesthetic monitors, anesthesia was induced slowly with sevoflurane (1–7%), oxygen (2 L/min), and nitrous oxide (4 L/min), along with appropriate intravenous weight-based doses of atropine (0.3 mg) and fentanyl (50 μg). After inducing muscle relaxation with rocuronium (20 mg), nasotracheal intubation was performed using a size 5.5 endotracheal tube, and anesthesia was maintained with sevoflurane (2%). Following administration of intravenous flomoxef sodium (1 g), an oxacephem for antibiotic coverage and local anesthesia using 2.7 mL of 2% lidocaine (54 mg) with 1:80,000 epinephrine (0.034 mg), a rubber dam sheet was placed to isolate the operative site. During dental treatment, the patient developed profound hypotension (minimum blood pressure 48/17 mm Hg), tachycardia (maximum heart rate 137 bpm), and cutaneous (upper extremity edema) and gastrointestinal (a 300-mL discharge of secretions from the previously placed orogastric tube) signs suggestive of an allergic reaction, although other cutaneous and oral signs, such as erythema, urticaria, and intraoral edema, were not observed. He was clinically diagnosed with anaphylaxis, intravenous boluses of epinephrine (initial dose 50 μg; subsequent doses 25 μg × 6 times; total dose 200 μg) were administered, and his vital signs then stabilized. Further dental treatment under general anesthesia was deferred at that time, and a subsequent blood test revealed elevated β-tryptase levels.

The patient's parents did not consent to a skin-prick test; therefore, a basophil activation test (BAT) was performed to identify the offending anaphylactic agent. All probable allergens, including the anesthetic drugs and surgical materials used, were tested. The BAT results were strongly positive for the rubber dam sheet (Figure), indicating that latex was the most probable cause of anaphylaxis. Approximately 9 months later, the dental treatment was successfully performed under general anesthesia using latex-free materials.

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DISCUSSION

Both in vitro and in vivo tests are used to identify the causative agents of anaphylaxis. In vitro tests include the measurement of specific immunoglobulin E levels; however, these tests are limited by their lack of versatility because only specific antigens can be tested.^1,2 In vivo tests include the skin prick and intradermal tests.^1,2 While skin tests are sensitive and effective for identifying potential allergens, they are painful for patients and carry an inherent but low risk of inducing anaphylaxis.³ As such, the BAT has become increasingly popular in recent years for identifying causative anaphylactic agents.^2,4–10 The BAT has demonstrated a high diagnostic accuracy, with a sensitivity of 91.7% and specificity of 100% for rocuronium,⁴ and a sensitivity of 88% and specificity of 100% for sugammadex,⁵ 2 of the most common agents used during anesthesia induction and reversal, respectively. Therefore, the BAT is useful for identifying potential anaphylactic agents during general anesthesia. Moreover, the BAT is considered more versatile than specific immunoglobulin E antibody tests and can theoretically be used to test any potential allergen.⁶ In this case, the test was performed using the rubber dam sheet as a potential antigen.

CONCLUSION

Although the causative agent of anaphylaxis cannot always be identified with the BAT alone, it is safer than skin tests^2,4–7,9,10 and can identify causative agents with an accuracy comparable with that of skin tests.⁶ Therefore, the BAT is expected to be a useful tool alongside standard skin tests for detecting anaphylactic agents.