Date amended:
External
Statements of Principles
Current RMA Instruments
Reasonable Hypothesis SOP
11 of 2022
Balance of Probabilities SOP
12 of 2022
Changes from previous Instruments

ICD Coding
  • ICD-9-CM Codes: 347
  • CD-10-AM Codes: G47.4
Brief description

This is a sleep disorder characterised by attacks of daytime sleepiness.  Other manifestations that are present to a variable extent are cataplexy (sudden, transient emotionally-triggered loss of muscle tone and weakness), sleep paralysis (inability to move for 1 or 2 minutes immediately after waking), and hypnagogic hallucinations (hallucinations occurring during the transition from wakefulness to sleep). 

Confirming the diagnosisIs 

This is a complicated diagnosis.  The diagnosis may be suspected based on history and examination, but confirmation requires formal sleep studies (both polysomnography (clinic or home based) and a multiple sleep latency test) and an opinion from a qualified sleep physician.

Additional diagnoses that may be covered by SOP (further information required)
  • Cataplexy
Conditions excluded from SOP
  • Chronic daytime sleepiness from any other cause
  • Sleep apnoea*
  • Sleepiness/narcolepsy due to drugs or other medical conditions

* another SOP applies

Clinical onset

Onset is most commonly in the teens or early 20s.  The condition typically presents with daytime sleepiness +/- manifestations of the other symptoms described above.  Symptoms tend to worsen over a period of months to years after initial onset and then stabilise.

Clinical worsening

The only SOP worsening factor is for inability to obtain appropriate clinical management.  Management consists of both non-pharmacolocial measures (e.g. appropriate sleep schedules and naps, psychological support) and pharmacological therapy with agents that promote wakefulness and alertness.  The condition is typically lifelong and does not tend to worsen with age.