Review Question - QID 106599

Action	Numeric Key	Letter Key	Function Key
Choose 1	1
Choose 2	2
Choose 3	3
Choose 4	4
Choose 5	5
Submit Response			Enter
Previous Question			Left Arrow
Next Question		N	Right Arrow
Open/Close Bookmode		C
Open Image			Spacebar

Sleep Sleep Disorders Narcolepsy QID: 106599 (M1.NE.15.73)

QID 106599 (Type "106599" in App Search)

An 18-year-old man presents to his primary care physician with a complaint of excessive daytime sleepiness. He denies any substance abuse or major changes in his sleep schedule. He reports frequently dozing off during his regular daily activities. On further review of systems, he endorses falling asleep frequently with the uncomfortable sensation that there is someone in the room, even though he is alone. He also describes that from time to time, he has transient episodes of slurred speech when experiencing heartfelt laughter. Vital signs are stable, and his physical exam is unremarkable. This patient is likely deficient in a neurotransmitter produced in which part of the brain?

Type & Select Correct Answer

Type in at least one full word to see suggestions list

Thalamus

13%

48/365

Pons nucleus

29/365

Hippocampus

19%

71/365

Hypothalamus

45%

163/365

Midbrain

10%

36/365

Select Answer to see Preferred Response

Review TC In New Tab

This clinical presentation is consistent with narcolepsy, which results from the loss of the neuropeptides orexin-A and orexin-B (also known as hypocretin-1 and hypocretin-2), which are associated with wakefulness and are produced in the lateral hypothalamus.

Narcolepsy is characterized by the following pathognomonic symptoms: excessive daytime sleepiness (associated with dozing off, or so-called "sleep attacks"), hypnagogic or hypnopompic hallucinations (occurring when falling asleep or waking up, respectively), and cataplexy (emotionally triggered transient muscle weakness, in this case reflected with transient slurring of speech during laughter). Patients with narcolepsy also experience sleep paralysis, which is the complete inability to move for one or two minutes immediately after awakening.

Pagel discusses the work-up of a patient with excessive daytime sleepiness. The most common cause is obstructive sleep apnea, with an estimated 26 to 32 percent of adults at risk. Patients with excessive daytime sleepiness face a significantly increased risk of motor vehicle and work-related incidents and have generally worse health outcomes compared to patients with less daytime fatigue.

Mignot summarizes the current drug therapy used in the treatment of narcolepsy. Before treatment for narcolepsy is initiated, other diagnoses such as sleep deprivation, sleep apnea, disturbed nocturnal sleep, and psychiatric comorbidities must be ruled out. The treatment of narcolepsy involves pharmacotherapies (sodium oxybate, stimulants such as modafinil, and/or antidepressants) in addition to behavioral modifications.

Illustration A depicts the production of orexin in the hypothalamus, produced in hypothalamic neurons which then projects to other areas of the brain important for wakefulness. Video A includes a description of cataplexy, a major symptom of narcolepsy, by a patient with narcolepsy. Episodes of cataplexy can be incredibly scary, as consciousness is preserved but the patient is unable to move.

Incorrect Answers:
Answers 1-3,5: These regions of the brain are not responsible for the production of orexin-A and orexin-B, which are produced in the hypothalamus.

ILLUSTRATIONS: