1347 Nocturnal Behaviors in Primary Angiitis of the Central Nervous System (PACNS): Sleepwalking or Seizures?

Abstract Introduction Nocturnal events characterized by complex motor behaviors, vocalizations, and altered awareness are commonly attributed to NREM parasomnias which include behaviors such as sleepwalking and night terrors. However, these presentations can closely mimic epilepsy, particularly frontal lobe epilepsy (FLE), due to overlap in semiology. This clinical overlap can cause diagnostic confusion and frequently leads to misdiagnosis. Report of case(s) Herein, we present this case of a 62-year-old male patient with a history of presumed Primary Angiitis of the Central Nervous System (PACNS) who presented to our sleep clinic with abnormal nocturnal behavior. The patient’s initial presentation in 2015 included dysphagia and dysarthria. Brain MRI at that time revealed intermittent left frontal lobe T2/FLAIR hyperintensities, and cerebral angiography demonstrated beading and distal areas of stenosis corresponding to the region of hyperintensity. Based on these findings, a diagnosis of presumed PACNS was made, and the patient has remained on chronic immunosuppression since 2015. The patient reported a longstanding history of sleepwalking, previously occurring every 6 months however now increasing in frequency to every 6- 8 weeks. He described episodes in which he awoke in a different part of his home, such as the living room, and discovered that he had moved household items during the night, with no recollection of these events. He was referred to Neurology to evaluate for underlying seizure activity. Conclusion Our case highlights the diagnostic challenges in distinguishing NREM parasomnias from nocturnal seizures, particularly in patients with underlying neurological disorders such as PACNS. Misdiagnosis of seizure activity as benign NREM parasomnias can delay appropriate diagnosis and management of seizures; and vice versa, misdiagnosing parasomnias as epilepsy can lead to unnecessary antiseizure therapy and side effects. Physicians should maintain a high index of suspicion for seizure activity in patients with abnormal nocturnal events who have underlying neurological disease as early recognition and accurate diagnosis are crucial to effective treatment and improve quality of life. Support (if any)