2. Case report
A 77-year-old patient was admitted for a left ureteroileoplasty. During anesthetic induction, he presented hypotension after mechanical ventilation treated with epinephrine from which he recovered, and when receiving prophylactic antibiotic therapy with 2 grams of amoxicillin/clavulanic acid (AC) intravenously he developed diffuse urticaria with bronchospasm, followed by cardiac arrest within 2 minutes. Cardiopulmonary resuscitation was successful, and the patient required 6 mg of intravenous epinephrine, external electric shock, 11 puffs of salbutamol and 100 mg of hydrocortisone. Serum biomarkers were obtained and elevated tryptase and histamine levels confirmed mast cells and possibly basophils activation and degranulation during anaphylaxis (Table I ). The surgical procedure was not performed, and the patient was transferred to the intensive care unit for recovery and monitoring. Allergy to amoxicillin or clavulanic acid was suspected. On day 3 after the event, he developed pneumonia and 1 g of oral amoxicillin/clavulanic acid was administered without symptoms. As the prescribing error was quickly identified, no additional doses were administered, and the antibiotic therapy was replaced by levofloxacin. The patient was informed of the prescribing error.
The allergology consultation carried out four weeks later revealed that the patient had been taking amoxicillin (3 grams/day for 4 days), which had been well tolerated one month before the event, due to urinary tract infection. Skin prick tests (SPTs) and intradermal skin tests (IDTs) for amoxicillin, amoxicillin/clavulanic acid, cefazolin, piperacillin-tazobactam and cefotaxime; SPT for latex and basophil activation tests (BATs) (expression of CD63/CD203c by flow cytometry) for amoxicillin, amoxicillin/clavulanic acid, cefazolin, piperacillin-tazobactam and cefotaxime were performed. The results confirmed an IgE-mediated allergy to amoxicillin (Table II ): IDTs and BATs were positive for amoxicillin and amoxicillin/clavulanic acid and negative to all other drugs. A challenge with 3000 mg of piperacillin-tazobactam was negative.
Amoxicillin and clavulanic acid were considered responsible for the per-operative anaphylactic shock, and the diagnosis of post-anaphylactic mast cell anergy was proposed to explain the absence of clinical reaction to the reintroduction of 1 gram of amoxicillin/clavulanic acid on day 3 after anaphylaxis.