Super-refractory status epilepticus after intoxication by quetiapine and carbamate

Abstract

Introduction: Quetiapine, an atypical antipsychotic, works through the agonism of multiple brain receptors, including dopaminergic, serotonergic, and adrenergic receptors. Compared to typical antipsychotics, quetiapine has a more favorable profile of adverse reactions. Myoclonus is infrequent. However, there have been reports of quetiapine overdose associated with generalized myoclonus. Electroencephalogram (EEG) modifications linked to the use of quetiapine are unusual. Aldicarb, commonly known as ‘chumbinho’ in Brazil, is a carbamate used as a rodenticide. Its toxicity is caused by the inhibition of acetylcholinesterase. A few reported cases of myoclonus related to its use may be due to the anticholinesterase effect causing hyperactivity. This is a case report based on retrospective analysis of the patient’s records. Case report: A 23-year-old woman was admitted after a suicide attempt by ingesting carbamate and quetiapine 36 hours after the attempt. Her initial symptoms were vomiting and sialorrhea, followed by generalized tonic-clonic seizures and coma. At admission, she was already sedated with midazolam, with her last tonic-clonic generalized seizure two hours earlier. Her pupils were myotic, with persistent tachycardia and diffuse muscular hyperexcitability – clonic movements were evoked with minimal stimuli. Brain imaging and cerebrospinal fluid analysis showed no alterations. A loading dose of 20 mg/kg of phenytoin was administered. Upon admission, an EEG showed status myoclonus. Midazolam was then titrated to 0.8 mg/kg/h, and clobazam (30 mg/day) and levetiracetam (1.500 mg/day) were added, with resolution of the status epilepticus after three days. Conclusion: Status epilepticus should be considered a possible presentation of quetiapine and carbamate intoxication.