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Resources for Diagnosing Narcolepsy

Understand the criteria for making a narcolepsy diagnosis and find ICD-10 codes for narcolepsy.

International Classification of Sleep Disorders, 3rd Edition (ICSD-3) Diagnostic Criteria1

Narcolepsy Type 1 (Narcolepsy With Cataplexy)

  • Daily periods of irrepressible need to sleep or daytime lapses into sleep occurring for at least three months*
  • One or both of the following:
    • Cataplexy and a mean sleep latency of ≤ 8 minutes and two or more SOREMPs on an MSLT performed according to standard techniques. A SOREMP (within 15 minutes of sleep onset) on the preceding nocturnal polysomnogram may replace one of the SOREMPs on the MSLT
    • CSF hypocretin-1 concentration, measured by immunoreactivity, is either ≤ 110 pg/mL or < 1/3 of mean values obtained in normal subjects with the same standardized assay

Narcolepsy Type 2 (Narcolepsy Without Cataplexy)

  • Daily periods of irrepressible need to sleep or daytime lapses into sleep occurring for at least three months
  • A mean sleep latency of ≤ 8 minutes and two or more SOREMPs are found on an MSLT performed according to standard techniques. A SOREMP (within 15 minutes of sleep onset) on the preceding nocturnal polysomnogram may replace one of the SOREMPs on the MSLT
  • Cataplexy is absent
  • Either CSF hypocretin-1 concentration has not been measured or CSF hypocretin-1 concentration measured by immunoreactivity is either > 110 pg/mL or > 1/3 of mean values obtained in normal subjects with the same standardized assay§
  • The hypersomnolence and/or MSLT findings are not better explained by other causes such as insufficient sleep, obstructive sleep apnea, delayed sleep phase disorder, or the effect of medication or substances or their withdrawal

*In young children, narcolepsy may sometimes present as excessively long night sleep or as resumption of previously discontinued daytime napping.

If narcolepsy type I is strongly suspected clinically but the MSLT criteria are not met, a possible strategy is to repeat the MSLT.

If cataplexy develops later, then the disorder should be reclassified as narcolepsy type 1.

§If the CSF hypocretin-1 concentration is tested at a later stage and found to be either ≤ 110 pg/mL or < 1/3 of mean values obtained in normal subjects with the same assay, then the disorder should be reclassified as narcolepsy type 1.

CSF, cerebrospinal fluid; MSLT, Multiple Sleep Latency Test; SOREMP, sleep-onset REM period.

Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Diagnostic Criteria2

Narcolepsy

  • Recurrent periods of an 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
  • The presence of at least one of the following:
    • Episodes of cataplexy, defined as either (a) or (b), occurring at least a few times per month:
      1. In individuals with long-standing disease, brief (seconds to minutes) episodes of sudden bilateral loss of muscle tone with maintained consciousness that are precipitated by laughter or joking
      2. In children or in individuals within 6 months of onset, spontaneous grimaces or jaw-opening episodes with tongue thrusting or a global hypotonia, without any obvious emotional triggers
    • Hypocretin deficiency, as measured using CSF hypocretin-1 immunoreactivity values (less than or equal to one-third of values obtained in healthy subjects tested using the same assay, or less than or equal to 110 pg/ml). Low CSF levels of hypocretin-1 must not be observed in the context of acute brain injury, inflammation, or infection
    • Nocturnal sleep polysomnography showing REM sleep latency less than or equal to 15 minutes, or a multiple sleep latency test showing a mean sleep latency less than or equal to 8 minutes and two or more SOREMPs

International Classification of Diseases, 10th Revision (ICD-10) Codes3

Narcolepsy With Cataplexy

G47.411

Narcolepsy Without Cataplexy

G47.419

  1. American Academy of Sleep Medicine. International Classification of Sleep Disorders. 3rd ed. Darien, IL: American Academy of Sleep Medicine; 2014.
  2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: American Psychiatric Association; 2013.
  3. ICD-10 Data. Sleep disorders G47-. https://www.icd10data.com/ICD10CM/Codes/G00-G99/G40-G47/G47-#G47.41. Accessed April 9, 2021.

Performance of routine tasks without awareness.

Sudden and brief loss of muscle tone, often triggered by strong emotions or certain situations. Narcolepsy with cataplexy is known as narcolepsy type 1.

Complete collapse to the ground; nearly all skeletal muscles are involved.

Only certain muscle groups are involved.

Biological clock mechanism that regulates the 24-hour cycle in the physiological processes of living beings. It is controlled in part by the SCN in the hypothalamus and is affected by the daily light-dark cycle.

Frequent awakenings and inappropriate transitions between states of sleep and wakefulness during nighttime sleep.

The inability to stay awake and alert during the day.

A neurotransmitter in the brain that supports wakefulness.

Vivid, realistic, and sometimes frightening dream-like events that occur when falling asleep.

Also known as orexin. A neuropeptide that supports wakefulness and helps suppress non-REM sleep and REM sleep.

Primary brain region for regulating the timing of sleep-wake states.

Unintentionally falling asleep due to excessive daytime sleepiness. Also known as “sleep attacks.”

Brief, unintentional lapses into sleep or loss of awareness.

A validated objective measure of the tendency to fall asleep in quiet situations.

People living with narcolepsy type 1 have low levels of hypocretin.

Narcolepsy without cataplexy; the cause of narcolepsy type 2 is unknown.

A state of sleep characterized by slower-frequency, more synchronized neuronal activity and decreased muscle tone. Deep stages help to restore the body.

A multiparameter test that monitors physiologic signals during sleep; used as a diagnostic tool in sleep medicine.

A state of sleep characterized by fast-frequency, desynchronized activity on EEG, vivid dreams, and loss of muscle tone. Normally occurs 60-90 minutes after sleep onset. Also known as “paradoxical sleep.”

Brief loss of control of voluntary muscles with retained awareness at sleep-wake transitions.

Sleep-onset REM period.

The VLPO as well as the median preoptic nucleus (MnPO) are located in the hypothalamus and contain essential neurons for promoting non-REM sleep. These neurons project to all wake-promoting regions to inhibit wakefulness and promote non-REM sleep during the night.8,11 Neurons in the extended VLPO mediate the promotion of REM sleep by inhibiting certain wake-promoting neurons that suppress REM sleep.8