Narcolepsy

Question 1

What is narcolepsy?

Answer 1

Disorder of regulation of consciousness and sleep

Characterised by elements of sleep intruding into wakefulness and vice versa.

Question 2

What are the classic tetrad symptoms of narcolepsy? (4)

Answer 2

• Excessive Daytime Sleepiness (EDS)
• Cataplexy
• Hypnagogic hallucinations
• Sleep paralysis

These symptoms are key indicators for diagnosing narcolepsy.

Question 3

What triggers cataplexy in narcolepsy patients?

Answer 3

Partial muscle weakness triggered by positive emotions such as excitement

It involves transient muscle weakness, often affecting the face, neck, and knees.

Question 4

What are hypnagogic hallucinations?

Answer 4

Abnormal visual/auditory perceptions on falling asleep or waking (fear threatening hallucination) in REM

Often occur in REM sleep and may follow episodes of cataplexy or sleep paralysis.

Question 5

What is sleep paralysis?

Answer 5

Brief inability to perform voluntary movement at sleep onset or awakening.

Episodes may last up to 2 minutes and can be interrupted by external stimuli.

Question 6

How long does sleep paralysis last?

Answer 6

Episodes may last up to 2 minutes in duration.

Question 7

Can sleep paralysis be interrupted by external stimuli?

Answer 7

Yes

Question 8

What percentage of narcoleptics suffer from sleep paralysis?

Answer 8

20-50% of narcoleptics suffer with sleep paralysis.

Question 9

What is the estimated prevalence of Narcolepsy Type 1 (NT1)?

Answer 9

25-50 per 100,000

Occurs equally in males and females, with an age of onset from teens to early twenties.

Question 10

What is the estimated prevalence of Narcolepsy Type 2 (NT2)?

Answer 10

20-34 per 100,000

NT2 occurs without cataplexy.

Question 11

Narcolepsy occurs in females more than males

Answer 11

No it is split equally between males and females

Question 12

Age of onset of narcolepsy

Answer 12

Age of onset: teens to early twenties.
may occur as early as 5 years of age / after 40 years of age.

Question 13

Are there genetic factors asccoaited with narcolepsy

Answer 13

Genetic factors – 1% AD inheritance
A variation of the HLA-DQB1 gene has been strongly associated with narcolepsy.

Question 14

What is a key aetiological factor in narcolepsy?

Answer 14

Hypocretin (Orexin) deficiency

Genetic factors and autoimmune responses may also play a role.

Question 15

What is the role of hypocretins in narcolepsy?

Answer 15

Promote wakefulness and suppress REM sleep

They are neurotransmitters produced by neurons in the dorsolateral hypothalamus.

Question 16

What does hypocretin help produce (3 hormones)

Answer 16

Norepinephrine
Serotonin
Dopamine

Question 17

What is the Epworth Sleepiness Scale score indicative of narcolepsy?

Answer 17

17+/24

A higher score indicates greater excessive daytime sleepiness.

Question 18

What is the Multiple Sleep Latency Test (MSLT) used for?

Answer 18

To assess sleep quality and diagnose narcolepsy

Requires a mean sleep onset latency of <8 minutes with 2 or more sleep onset REM periods.

Question 19

What is a recommended management strategy for narcolepsy? (3)

Answer 19

• Regular sleep-wake schedule
• Brief (20min) daytime naps
• Regular daytime physical activity
• Medication

Medications include Modafinil and Sodium Oxybate.

Question 20

What is the function of Modafinil in narcolepsy treatment?

Answer 20

Promotes wakefulness by preventing dopamine reuptake

It is commonly prescribed to manage excessive daytime sleepiness.

Question 21

What is the role of Sodium Oxybate in narcolepsy management?

Answer 21

Improves night-time sleep, hypothesised GABA B receptor agonist

It is used to help manage symptoms of narcolepsy.