A 23-year-old man comes to the physician at his girlfriend's insistence. She says that the patient's frequent snoring keeps her up at night and that in the last 4 months he has twice fallen asleep while they were talking. In this same period, the patient says that he has regularly fallen asleep in the afternoon while reading or watching television but typically feels refreshed after a brief nap. When asked whether he experiences any other symptoms, the patient hesitantly reveals that he sometimes hears a voice call his name prior to falling asleep. He also reports uncharacteristic episodes of clumsiness in which he has suddenly dropped objects or fallen to his knees. Examination shows no abnormalities. Which of the following is the most likely diagnosis in this patient?

Question

A 23-year-old man comes to the physician at his girlfriend's insistence.  She says that the patient's frequent snoring keeps her up at night and that in the last 4 months he has twice fallen asleep while they were talking.  In this same period, the patient says that he has regularly fallen asleep in the afternoon while reading or watching television but typically feels refreshed after a brief nap.  When asked whether he experiences any other symptoms, the patient hesitantly reveals that he sometimes hears a voice call his name prior to falling asleep.  He also reports uncharacteristic episodes of clumsiness in which he has suddenly dropped objects or fallen to his knees.  Examination shows no abnormalities.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec160b_3b0b_e82a_9249_d3026a75a03d_MD0001_00 Narcolepsy is a chronic sleep disorder characterized by frequent, overwhelming urges to sleep. It is commonly associated with cataplexy, a sudden loss of muscle tone that occurs in response to intense (usually positive) emotions. Narcolepsy results from the depletion of hypocretin (also known as orexin)-secreting neurons in the lateral hypothalamus that are involved in maintaining wakefulness. Patients with narcolepsy experience shortened sleep latency and typically enter rapid eye movement (REM) sleep almost immediately. They commonly experience intrusions of REM sleep phenomena during sleep-wake transitions, including hypnagogic (upon falling asleep) and hypnopompic (upon awakening) hallucinations and sleep paralysis (inability to move immediately after awakening). The clinical diagnosis of narcolepsy can be confirmed by low cerebrospinal fluid levels of hypocretin-1 or shortened REM sleep latency on polysomnography. (Choice A) This patient is experiencing hypnagogic hallucinations, which are characteristic of narcolepsy. Brief psychotic disorder is diagnosed when one or more positive psychotic symptoms are present for less than a month in the absence of another medical disorder or substance use. (Choice B) Delayed sleep-wake phase disorder most often presents in adolescence and is characterized by intact duration and quality of sleep that is shifted to a later bedtime and wake time. (Choice C) Idiopathic hypersomnia is diagnosed when excessive and impairing daytime sleepiness cannot be explained by another sleep disorder. Patients with idiopathic hypersomnia have persistent daytime sleepiness rather than "sleep attacks." Unlike patients with narcolepsy, they typically do not feel refreshed after naps. (Choice D) Insufficient sleep may result in excessive daytime sleepiness, napping, and quicker REM onset, but it is not associated with cataplexy or sleep-related hallucinations. (Choice F) Obstructive sleep apnea, the most common cause of excessive daytime sleepiness, is characterized by loud snoring, gasping, and apneas during sleep. It is caused by upper airway obstruction and is not associated with cataplexy, sleep-related hallucinations, or sleep paralysis. (Choice G) Patients with REM sleep behavior disorder lose normal sleep paralysis during REM sleep and, as a result, act out the content of their dreams (eg, punching, kicking). Educational objective: Narcolepsy is a chronic sleep disorder characterized by excessive daytime sleepiness, cataplexy, and REM sleep-related phenomena (ie, hypnagogic/hypnopompic hallucinations, sleep paralysis). __________ References: Narcolepsy. (http://www.ncbi.nlm.nih.gov/pubmed/28179647) Diagnosis and management of narcolepsy. (http://www.ncbi.nlm.nih.gov/pubmed/28837992)

A 23-Year-Old Man Comes to the Physician at His Girlfriend's