Abstract
Introduction
Dementia with Lewy bodies (DLB) can be associated with degeneration of the hypocretin system and reduced hypocretin levels. However, reports of DLB initially presenting with narcolepsy with cataplexy symptoms are sparse.
Report of Case
A 77-year-old man presents with two years of new onset hypersomnia, tremors, memory difficulties, and gait instability. Before his sleep evaluation, he was started on levetiracetam for suspected seizures and levodopa for suspected Parkinson’s disease, without improvement. During his evaluation for hypersomnia, he reported loud snoring, witnessed apneas, sleep maintenance difficulty, hypnagogic hallucinations of well-formed images, and vivid dreams with dream enactment behavior occurring almost nightly. He had witnessed episodes of cataplexy described as transient lower extremity weakness with associated bifacial weakness, inability to speak, and no loss of consciousness, self-injury, loss of bowel/bladder control, or post-event symptoms. These events completely resolved after 1-minute, occurred while sitting or standing, and were spontaneous or triggered by anger or anxiety. His Epworth Sleepiness Scale was 18 and Ullanlinna Narcolepsy Scale was 35, suggestive of narcolepsy with cataplexy. Physical examination did not reveal Parkinsonism or resting tremor. He subsequently underwent a baseline polysomnogram that showed an apnea-hypopnea index of 32.7 events/hour. During an in-laboratory titration study, he had REM sleep without atonia. A 30-minute EEG was interpreted as normal and a typical cataplexy-like event captured during continuous EEG monitoring had no ictal correlate. Despite adherence to positive airway pressure therapy, he continued to have hypersomnia, cataplexy, and visual hallucinations during transitions from wake to sleep. He was tapered off levetiracetam and levodopa with a plan for further evaluation of probable DLB.
Conclusion
Narcolepsy with cataplexy symptoms is an uncommon presentation of probable DLB as seen in this case with two core clinical features of DLB (RBD and visual hallucinations), suggesting neurodegeneration of the hypocretin system.
Evaluating a novel behavioral paradigm for visual hallucinations in Dementia with Lewy bodies