(Primary hypersomnia)

Very rare. Onset before the age of 25 years. There are two types that differ from narcolepsy by lack of episodes of catatonia:

-        primary hypersomnia with increase in sleep duration, where the nocturnal sleep duration is greater than 10 hours. Prevalence: 1/10,000 to 1/25,000. Sleep is restful and of good quality but there is excessive daytime sleepiness with long and non-invigorating sleep episodes followed by a difficult awakening ("sleep drunkenness")

-        primary hypersomnia without increase in the duration of sleep. Prevalence 1/11,000 to 1/100.000. The duration of night sleep is normal but there are unintended daytime naps of  variable duration and invigorating followed by a normal awakening.

Some patients show signs of dysautonomia: orthostatic syncope, Raynaud's phenomenon, migraines, disorders of the temperature regulation.

Treatment: modafinil (inhibits neuronal reuptake of norepinephrine and dopamine and CYP2C9), or methylphenidate or amphetamines.

Differential diagnosis: narcolepsy and Kleine-Levin syndrome (see these terms).

Anesthetic implications:

maintain the daily treatment until operating day ; increased risk of awareness ? Postanesthetic intensive monitoring. Risk of delayed awakening after IV general anesthesia based on propofol (reduced metabolism by the inhibition of CYP2C9 by modafinil).

References :

-        Aflaki S, Hu S, Kamel RA, Chung F, Singh M.
Case report of a patient with idiopathic hypersomnia and a family history of malignant hyperthermia undergoing general anesthesia: an on overview of the anesthetic considerations.
A&A Case Reports 2017; 8: 238-41.

Updated: May 2017