池水 結輝

We describe the case of an unvaccinated 21-year-old Japanese male who experienced psychotic symptoms attributed to encephalopathy, known as post-acute COVID-19 syndrome (PACS). One week after his discharge following the remission of a SARS-CoV-2 infection, he experienced hyperactive delirium and unexpected movements of his limbs. As COVID-19-associated encephalopathy was suspected as a cause of the psychotic symptoms, he was admitted to the Department of Neurology. He received antiviral and steroid pulse therapy, but his psychiatric symptoms did not improve completely. Consequently, he was admitted to our psychiatric ward with a diagnosis of a primary psychotic disorder. Although he did not take psychopharmacotherapy, he gradually achieved a remission of psychiatric symptoms. At three months post-SARS-CoV-2 infection, single-photon emission computed tomography (SPECT) revealed hypoperfusion in the bilateral cerebellar dentate nuclei and occipital lobes. However, no abnormal findings were observed on fluorine-18 fluoro-deoxy-glucose positron emission tomography (18F-FDG PET) at six months after the infection. This case indicates that (1) brain perfusion SPECT can be effective for detecting functional alterations in post-acute COVID-19-associated encephalopathy, and (2) it is necessary to carefully monitor patients' progress instead of quickly diagnosing a primary psychotic disorder.

Lemborexant is a dual orexin antagonist (DORA) and is considered a safe and effective hypnotic. DORAs induce physiological sleep by blocking orexin receptors. Although the blockade of orexin signaling has triggered narcolepsy-like symptoms in rodents, there is currently no evidence of lemborexant inducing narcolepsy-like symptoms in humans. We describe the case of a 79-year-old Japanese woman with bipolar depression who experienced lemborexant-induced cataplexy and sleep attack. Her previous results on the Multiple Sleep Latency Test excluded the diagnosis of narcolepsy. She experienced narcolepsy-like symptoms on two occasions after she was administered lemborexant, in the context of hyperactive delirium, but not in a relaxed state. Her case suggests that lemborexant could trigger narcolepsy-like symptoms in patients with hyperactive delirium, even those with no history of narcolepsy. This case also emphasizes that clinicians must be very careful when they prescribe lemborexant to patients who experience hyperactive delirium.