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ICSD-2 Hypersomnias

III. Hypersomnias of Central Origin

• Narcolepsy with Cataplexy

• Narcolepsy Without Cataplexy

• Narcolepsy Due to Medical Condition Without Cataplexy

• Narcolepsy Due to Medical Condition With Cataplexy

• Narcolepsy, Unspecified

• Recurrent Hypersomnia

• Idiopathic Hypersomnia With Long Sleep Time

• Idiopathic Hypersomnia Without Long Sleep Time

• Behaviorally induced Insufficient Sleep Syndrome

• Hypersomnia Due to Medical Condition

• Hypersomnia Due to Drug or Substance (Abuse)

• Hypersomnia Due to Alcohol Use

• Hypersomnia Due to Drug or Substance (Medications)

• Hypersomnia Not Due to Substance or Known Physiological Condition

• Physiological (Organic) Hypersomnia, Unspecified

Testing for Hypersomnias

• Mean sleep latency < 8 minutes is considered diagnostic of sleepiness on MSLT

– Stopped using: < 5 min: sleepiness; 5-10 min: grey zone, indeterminate; > 10 min: normal

• Proper testing conditions for MSLT

– Free of drugs that influence sleep for at least 15 days (or at least 5 times the half-life of the drug and the longest acting active metabolite)

– Sleep wake schedule standardized for at least 7 days before the testing (and documented by sleep log or actigraphy)

– Nocturnal PSG on the night immediately preceding the MSLT to rule out other sleep disorders, and TST at least 6 hrs (but may need more)

– Clinically significant SRBD or PLMS may be present, and if so, should be treated prior to making any of these diagnoses

• Mean Sleep Latency

– 3.1 +/- 2.0 min narcolepsy

– 6.2 +/- 3.0 min idiopathic hypersomnia

– 10.5 +/- 4.6 min healthy controls

– < 8 min in up to 30% of healthy people

• SOREMPs

– More specific for narcolepsy than MSL

– Also seen in 2% healthy controls, SDB

Narcolepsy with Cataplexy

• Diagnostic Criteria

– EDS almost daily for at least 3 months

– Definite cataplexy (sudden, transient loss of muscle tone triggered by emotions, bilateral, brief (<2 min), consciousness preserved, at least at the beginning)

– Diagnosis should be confirmed by

• PSG and MSLT

– MSL <= 8 min AND >=2 SOREMPs

• Or CSF hypocretin levels <= 110 pg/mL

• Classic symptoms: EDS, cataplexy, hypnagogic hallucinations, sleep paralysis

– Also get automatic behaviors

– 50% have nocturnal sleep disruption (mostly maintenance insomnia)

– Typically report sleep as refreshing, but EDS returns 2-3 hrs after nocturnal sleep or naps

• Increased risk for RBD

• Related to increased BMI and may result in OSA

• HLA DQB1*0602 seen in almost all patient with narcolepsy, but also in 12-38% of the general population

• Onset typically 15-25 yrs old. EDS typically first symptom; cataplexy rarely precedes EDS and can occur many years later

• Caused by loss of hypothalamic neurons containing hypocretin

• PSG typically reveals SL < 10 min and a SOREMP (25-50%). Often increased stage 1 and arousals

Narcolepsy Without Cataplexy

• Diagnostic Criteria

– EDS almost daily for at least 3 months

– Typical cataplexy is not present, although doubtful or atypical cataplexy episodes may be present

– Diagnosis MUST be confirmed by PSG and MSLT

• MSL <= 8 min AND >=2 SOREMPs

– CSF hypocretin levels are typically normal but may be low

• 10-20% have decreased CSF hypocretin-1 levels

• In patients with normal hypocretin levels, the cause of narcolepsy without cataplexy is unknown, although 1 autopsy study reported a decrease in # of hypocretin cells, but not as low as narcolepsy with cataplexy

Narcolepsy Due to Medical Condition

Diagnostic Criteria

• EDS almost daily for at least 3 months

• One of the following:

– Definite cataplexy

– If not definite cataplexy, PSG & MSLT must be performed

• PSG reveals adequate sleep (at least 6 hrs)

• MSLT MSL < 8min and 2 or more SOREMPs

• CSF hypocretin-1 levels < 110pg/mL (provided pt is not comatose)

• Significant underlying medical or neurological condition

Narcolepsy with cataplexy:

– lesions of the hypothalamus

• tumors

• Strokes

• Sarcoidosis

– paraneoplastic encephalitis (anti-Ma2 antibodies)

– Nieman-Pick type C disease,

– Coffin Lowry Disease

Narcolepsy without cataplexy

– head trauma

– multiple sclerosis

– myotonic dystrophy

– Prader-Will Syndrome

– Parkinson's

– multi-system atrophy

Recurrent Hypersomnia

• Diagnostic Criteria

– Recurrent EDS of 2 days to 4 weeks in duration

– Episodes recur at least once per year

– Normal alertness, cognitive function and behavior between attacks

• May sleep 16-18 hrs per day during episodes

• There are 2 well characterized subtypes:

– Kleine-Levin Syndrome

• Recurrent episodes are associated with behavioral abnormalities including binge-eating, hypersexuality, irritability, aggression, and cognitive abnormalities such as feelings of unreality, confusion, and hallucinations

– Menstrual related Hypersomnia

• Occurs within the first months of menarche

• Episodes generally last 1 week and rapidly resolve with menses

• OCPs generally lead to prolonged remission

Idiopathic Hypersomnia With Long Sleep Time

• Diagnostic Criteria

– EDS almost daily for at least 3 months

– Patient has prolonged nocturnal sleep time (>10 hrs) documented by interview, actigraphy or sleep logs. Waking up is laborious

– PSG excludes other causes of EDS

– PSG demonstrates short SOL and major sleep period > 10 hrs

– MSLT demonstrates MSL < 8 min and < 2 SOREMPs

Idiopathic Hypersomnia Without Long Sleep Time

– Same except Sleep time 6-10 hrs

• Head trauma should not considered to be the cause of sleepiness

• Naps are typically unrefreshing

• Sleep drunkenness is common

• Autonomic nervous system abnormalities are common including:

– migrainous headaches

– orthostatic hypotension

– Raynaud’s phenomenon

• PSG generally demonstrates normal sleep of prolonged duration; SWS may be increased

• Brain imaging should be performed to rule structural lesions

• Psychiatric evaluation should be considered

Behaviorally induced Insufficient Sleep Syndrome

• Diagnostic Criteria

– EDS almost daily for at least 3 months

– Habitual sleep episode by history, sleep log or actigraphy is less than expected for age adjusted normative data

– Will typically sleep longer when not confined to their habitual sleep schedule (i.e. weekends)

– PSG not required (but if done) demonstrates SOL < 10 min & SE > 90%

– MSLT not required but may show MSL < 8 min with or without multiple SOREMPs

– Generally recommend to increase sleep time prior to PSG or MSLT

• if sxs resolve with increased sleep, diagnosis is confirmed

• The chronic sleep deprivation is voluntary but unintentional – typically not recognized by the patient

• Common in adolescence due to increased sleep need compared to adults but there is social pressure to sleep less

Hypersomnia Due to Medical Condition

• Diagnostic Criteria

– EDS almost daily for at least 3 months

– Presence of medical or neurological disorder to account for sxs

– If MSLT is performed, MSL < 8 min and no more than 1 SOREMP

– Parkinson's disease, head trauma, Prader-Willi Syndrome, myotonic dystrophy, lesions of the hypothalamus or brainstem (tumors, stroke, encephalitis)

– Medical causes include

• endocrine disorders (hypothyroidism, adrenal insufficiency)

• hepatic encephalopathy

• renal insufficiency

• pancreatic insufficiency

– Toxins include methylchloride, trichloroethylene and organic solvents

Other Hypersomnias

• Hypersomnia Due to Drug or Substance (Abuse)

• Hypersomnia Due to Alcohol Use

• Hypersomnia Due to Drug or Substance (Medications)

• Hypersomnia Not Due to Substance or Known Physiological Condition

• Physiological (Organic) Hypersomnia, Unspecified

Diagnosis	MSL	SOREMPs	Comments
Narcolepsy (all types)	<= 8 min	2 or more	Naps often refreshing
Recurrent Hypersomnia	???	???	Normal between episodes
Idiopathic Hypersomnia	<= 8 min	< 2	Naps are unrefreshing
Behaviorally induced Insufficient Sleep Syndrome	<= 8 min	Variable	Symptoms improve with increasing TST MSLT results if performed (not needed)

Reference:

The International Classification of Sleep Disorders, Second Edition. The American Academy of Sleep Medicine Press, 2005. Can be purchased at the AASM store online!