亜酸化窒素吸入鎮静時に心因性非てんかん発作を生じたと考えられた1例

抄録

  We herein report a case of psychogenic non-epileptic seizures during dental treatment under inhalation sedation in a patient with a dental phobia.

  A 21-year-old woman with epilepsy, panic disorder, and autism spectrum disorder underwent nitrous oxide inhalation sedation for dental treatment because of a dental phobia. Unlike previous visits, she did not speak on the day of treatment. Sedation was induced by the inhalation of 100% oxygen followed by 20% nitrous oxide. Immediately after treatment, the patient did not react to verbal stimulation and exhibited convulsions of the eyelids and arms. We suspected that an epileptic seizure had occurred and started an intravenous drip of 250 mg of phenytoin. However, the convulsions did not cease, and we therefore administered 5 mg of diazepam. The convulsions ceased thereafter, but the patient still did not respond to verbal stimulation. During the arm drop test, the patient’s arm moved to avoid her face. She gradually recovered consciousness and became able to talk. However, the convulsions recurred, and her consciousness level decreased. Phenytoin was restarted and the convulsions gradually ceased, but the patient remained unresponsive ; she was therefore transported to a high care unit. Her consciousness level subsequently recovered, and she was discharged from the hospital the next day.

  We initially believed that the convulsions and loss of consciousness had been caused by an epileptic seizure. However, phenytoin and diazepam were ineffective, and her arm avoided her face when it was dropped ; thus, we also considered the possibility of a psychogenic non-epileptic seizure. Dental treatment in a lightly sedative state might cause psychogenic non-epileptic seizures in patients with increased stress.

  Even in patients with epilepsy, the accurate diagnosis of seizures is important to ensure that appropriate measures are taken.