1 - Allergy and Clinical Immunology Department, Centro Hospitalar Universitário de Lisboa Central, Lisbon, Portugal
2 - Anesthesiology Department, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal
* These authors contributed equally to this work
- Artigo, publicado na Revista Portuguesa de Alergologia e Imunologia Clínica
Introduction: Suspected hypersensitivity reactions to local anesthetics (LAs) are a common cause of referral to Allergy and Clinical Immunology Departments. Adverse drug reactions to LAs have been estimated to occur in 2.5-10% of patients, the vast majority comprising non-immune mediated reactions. True hypersensitivity immune-mediated reactions to the currently used amino amide LAs are very rare, they are estimated to contribute to less than 1% of all cases.
Case Report: An 18-year-old male patient with no relevant past medical history was referred to our Allergy and Clinical Immunology Department for evaluation of a suspected hypersensitivity reaction to LAs. On two different occasions, six months apart, the patient developed generalized tonic-clonic seizures during sleep approximately six hours after receiving LAs. Neurological evaluation, including brain computed tomography, magnetic resonance imaging and electroencephalogram, was unremarkable except for a small parietal cavernoma. He had no previous history of seizures and is currently free of events after more than two years. After consideration, the events did not suggest a hypersensitivity reaction, and a diagnosis of local anesthetic systemic toxicity (LAST) was considered likely.
Conclusion: LAST is a potentially life-threatening complication of the use of LAs. Neurological or cardiovascular symptoms after the administration of LAs, particularly when unaccompanied by typical allergic manifestations, should prompt consideration and treatment of LAST. Importantly, all physicians dealing with LAs should be aware of this potentially fatal complication and of its management. Allergy specialists, in particular, must consider this possibility in the workup of suspected allergy to LAs and when administering LAs in drug provocation tests. A multidisciplinary evaluation by allergists and anesthesiologists is warranted to manage these cases.
Palavras Chave: Drug allergy; local anesthetics; local anesthetic systemic toxicity