Def: recurrent episodes of hypersomnia with cognitive and/or behavioral changes
Very rare, prevalence 1-5 per million
Male predominance
Resolves in median 13-14 yrs, may persist for decades
Episodes
Hallmark: discrete attacks of hypersomnolence with abrupt onset over a few hrs
Last days to weeks
Pt appears sleepy, confused, apathetic or dream-like
Sleep up to 22 hrs/24 hrs
Very hard to wake, near end of bouts may just rest with eyes closed
Recur every few wks to few months
Other features
Eating disturbance: megaphagia once considered core, not universal, some have anorexia
Hypersexuality
Irritability, aggression, personality change
Anxiety, mood disturbance, rarely psychosis
Derealization and depersonalization
Difficulty with communication or executive function
Autonomic: flushing, sweating, temperature dysregulation, inappropriate tachy or brady
Headache
Dx criteria (ICSD-3, all required)
- ≥2 recurrent episodes of excessive sleepiness and sleep duration, each lasting 2 days to 5 wks
- Episodes usually >1/yr and at least once every 18 months
- Normal alertness, cognition, behavior and mood between episodes
- During episodes ≥1 of: cognitive dysfunction, altered perception, eating d/o (megaphagia or anorexia), disinhibited behavior
- Not better explained by another sleep, medical, neuro or psych d/o (esp bipolar) or drugs/meds
Sleep, memory and mood may be affected between episodes despite ICSD-3 criteria
Workup
No diagnostic test, workup focuses on excluding mimics
PSG to rule out other sleep d/o, usually unremarkable in KLS
EEG to rule out epilepsy, generalized slowing in up to 70% during a bout
Brain imaging to rule out structural causes, normal in KLS
Pathophysiology
Unknown
More common in Ashkenazi Jewish population
Family hx in 5%, suggests genetic role
Triggers: infection or fever, suggests inflammatory or autoimmune mechanism
Differential dx
- Psych dz, esp bipolar d/o (major ddx)
- Meds or illicit drugs
- Migraine with brainstem aura
- Bilateral temporal lobe lesions (Klüver-Bucy syndrome)
- Intracranial mass
- Metabolic encephalopathy: urea cycle defects, mitochondrial dz
- Lyme dz
Treatment
No tx consistently helpful during episodes
Stimulants during episodes generally not effective
Treat associated sx: anxiety, psychosis, headache
Anecdotal response to antiepileptics: carbamazepine, lamotrigine, valproate
Lithium has strongest evidence (open label study)
AASM 2021: conditional rec for lithium in KLS
Counseling and psych support for pts and families
- Oxford Handbook of Sleep Medicine 2022