KleineLevin

Kleine-Levin syndrome (KLS) is a rare sleep disorder defined by recurrent episodes of excessive sleep (hypersomnia) accompanied by cognitive and behavioral changes. It is sometimes called sleeping beauty syndrome.

During episodes, sleep can dominate the day for days to weeks. Patients may show confusion, disorientation, irritability, and impaired memory. Many experience hyperphagia, and some exhibit disinhibited or hypersexual behavior; between episodes, individuals are typically symptom-free.

Onset usually occurs in adolescence, with episodes often decreasing in frequency and severity over time. Remission may occur after several years, though some patients continue to have episodes into adulthood.

Etiology is unknown. The leading view implicates transient hypothalamic or thalamic dysfunction, with possible autoimmune or infectious triggers and a genetic susceptibility. Neuroimaging is typically normal, though occasional studies show functional changes during episodes.

Diagnosis is clinical and by exclusion. There is no definitive test. Criteria focus on recurrent hypersomnia episodes lasting days to weeks, preserved wakefulness between episodes, and cognitive or behavioral symptoms during episodes.

Management aims to ensure safety and symptom relief during episodes. There is no proven cure. Acute treatment may include wake-promoting agents such as modafinil or stimulant medications; sedatives for agitation; and supportive care for nutrition and hydration. In some cases, lithium or other mood stabilizers reduce relapse frequency.

KLS is extremely rare, with most reports from adolescence. The prognosis is generally favorable, as many patients experience substantial improvement or remission over time, though the course is variable.