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Primary Hypersomnias

Checked: 23-08-2022 by katy baetjer Next Review: 23-08-2024

Overview

Hypersomnolence describes excessive daytime sleepiness. Frequently this is a secondary condition (e.g. nocturnal insomnia, obstructive sleep apnoea, depression or drug side effects).

However, there are a number of primary (or central) hypersomnias as described below:

Narcolepsy

Narcolepsy is a rare, lifelong autoimmune neurological disorder that causes an inability to regulate sleep-wake cycles resulting in a crossover of sleep and wake features, most typically somnolence during the day in spite of adequate overnight sleep.

Symptoms:

Excessive daytime sleepiness (sleep intruding into wake)
Sleep attacks – sudden onset sleeping episodes, usually without warning.
Cataplexy may be present in some cases and is the most specific symptom of narcolepsy. This is the sudden, temporary loss of muscle control causing either weakness or collapse but with preserved consciousness and may occur in response to emotional stimuli such as laughter or surprise. (REM atonia occurring from wakefulness)
Disturbed nocturnal sleep (wake intruding into sleep)
Sleep paralysis – the temporary inability to move after waking (REM atonia continuing into wakefulness)
Sleep related hallucinations – either when falling asleep (hypnogogic hallucinations) or waking up (hypnopompic hallucinations) – REM phenomena occurring during light sleep or wakefulness.

Idiopathic Hypersomnia

This is a descriptive diagnosis for people with clinically significant daytime somnolence, causing impairment in day-to-day life, where there is no underlying medical, psychiatric, primary sleep disorder, or medicine/drug related cause.

It generally becomes apparent during adolescence and can be effectively treated with long term wakefulness promoting agents.

Who to refer

Primary hypersomnia (narcolepsy or idiopathic hypersomnia) is rare and secondary causes should be considered and managed before considering referral.

Adult patients (aged 18 years and over) can be referred as detailed in the Services section below.

Paediatric patients (aged under 18 years) -please consider the following service for advice: The neuropsychiatry team have established a drop-in consultation service for all local and community colleagues that occurs on the 1st Tuesday of each month at 15:00 p.m. They are happy to discuss patients aged under 18 who are being considered for referral in this forum. If a clinician would like to attend the drop in to discuss a patient then they can contact the team on 01173428168 or email them at paediatric.neuropsy@uhbw.nhs.uk

What to do before referral

Consider and address causes of secondary hypersomnias including:

medical, psychiatric and pharmacological causes e.g. depression, drug side effects from any CNS depressants.

other sleep disorders such as insomnia, obstructive sleep apnoea and sleep deprivation.

Management advice in primary care

Once possible secondary causes have been excluded or addressed then assessment of suspected primary hypersomnia should take place in secondary care.

The following measures may also be helpful:

Lifestyle measures

Sleep hygiene
Planned naps during the day

Driving advice

The DVLA advice on Excessive sleepiness may be helpful. There is also link to a patient leaflet 'Tiredness can kill'

Pharmacological treatments

As per BNSSG Formulary, pharmacological treatments for Narcolepsy and Idiopathic Hypersomnia can only be initiated in secondary care.

Services

Neuropsychiatry Sleep Disorders clinic - NBT

Resources

NBT Sleep Disorders Clinic webpage

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