Narcolepsy is characterized by the classic tetrad of EDS, cataplexy, hypnagogic hallucinations, and sleep paralysis. However, this tetrad is seen only rarely in children. Narcolepsy is frequently unrecognized. EDS is the primary symptom of narcolepsy and must be present for at least 3 months to justify the diagnosis. In persons with narcolepsy, severe EDS leads to involuntary somnolence during activities that normally engage attention, such as driving, eating, or talking. Sleepiness in narcolepsy may be severe and constant, with paroxysms during which patients may fall asleep without warning (ie, sleep attacks).
Patients with narcolepsy tend to take short and refreshing naps during the day. Their daytime naps may be accompanied by dreams. Patients with narcolepsy have trouble sleeping at night. Obesity is another common feature of narcolepsy. The combination of narcolepsy and obesity may promote the development of OSA.
The DSM-5 defines narcolepsy as recurrent episodes of irrepressible need to sleep, lapsing into sleep, or napping occurring within the same day. These must have been occurring at least three times per week over the past 3 months. At least one of the following must also be present:
Episodes of cataplexy occurring at least a few times per month
Hypocretin deficiency
REM sleep latency ≤ 15 minutes, or a mean sleep latency ≤ 8 minutes and two or more sleep-onset REM periods
The AASM's International Classification of Sleep Disorders, third edition, reclassified narcolepsy into two types. Narcolepsy type 1 is distinguished by sleepiness plus cataplexy and a positive MSLT result or sleepiness plus hypocretin deficiency.
Narcolepsy type 2 requires sleepiness and a positive MSLT and the absence of type 1 markers. Hypersomnia and/or MSLT findings must not be better explained by another sleep, neurologic, mental, or medical condition or by medicine or substance use.
Sleep studies are an essential part of the evaluation of patients with possible narcolepsy. The combination of overnight polysomnography followed by MSLT can provide strongly suggestive evidence of narcolepsy while excluding other sleep disorders. HLA typing may provide collateral data but is more useful for excluding the diagnosis by documenting that the patient does not have either DQB1*0602 or DQA1*0602.
Treatment of narcolepsy has both nonpharmacologic and pharmacologic components. In addition to a regular sleep schedule (usually 7.5-8 hours of sleep per night) and, in some cases, scheduled naps during the day, the following nonpharmacologic measures are also important:
Providing emotional support and career or vocational counseling to patients and parents
Assisting with documentation for special academic needs, insurance, disability forms, and attaining a driver's license
Questioning patients about high-risk behaviors, such as alcohol and drug use, which may exacerbate symptoms
Inquiring about depression, family conflict, and other psychosocial problems
Pharmacologic treatment of narcolepsy involves the use of central nervous system stimulants, such as methylphenidate; modafinil; dextroamphetamine sulfate; methamphetamine; and amphetamine; or solriamfetol, a dopamine/norepinephrine reuptake inhibitor.
According to practice parameters for the treatment of narcolepsy from the AASM, modafinil is effective for treatment of EDS due to narcolepsy. The approved recommended dose of modafinil is 200 mg given once daily, but higher doses and split-dose regimens have been investigated.
Read more clinical information about narcolepsy.
This Fast Five Quiz was excerpted and adapted from the Medscape Drugs & Diseases articles Insomnia, Obstructive Sleep Apnea, Narcolepsy, Restless Legs Syndrome, and REM Sleep Behavior Disorder.
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Cite this: Helmi L. Lutsep, Zab Mosenifar, Stephen Soreff. Fast Five Quiz: Sleep Disorders - Medscape - Aug 03, 2020.
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