Kleine-Levin Syndrome

Kleine-Levin syndrome, often referred to as ‘Sleeping Beauty Syndrome’, is a rare and complex neurological disorder which is characterised by recurring episodes of excessive sleep, altered behaviour and cognitive disturbances. People with Kleine-Levin syndrome (KLS) can sleep for extensive periods, often ranging from 15 to 21 hours per day, and this can continue for days, weeks or even months at a time. During these episodes, patients may also experience changes in personality, disorientation, hallucinations, and excessive eating, leading to significant disruption in their daily lives. 

KLS is extremely rare, with an estimated prevalence of 1 to 5 cases per million people. This rarity contributes to its mystery and the challenges in studying it comprehensively. The scarcity of cases and the lack of clear understanding of its pathophysiology make it a particularly challenging condition for both patients and healthcare providers.

What is Kleine-Levin Syndrome (KLS)?

Kleine-Levin syndrome (KLS) is a rare neurological disorder which is characterised by recurring periods of excessive sleepiness and altered behaviour. The key features of KLS include:

• Hyper somnolence – people with KLS experience episodes of extreme sleepiness, sleeping for 15 to 21 hours per day. These episodes can last for days, weeks or even months.
• Cognitive and behavioural changes – during episodes, patients may exhibit cognitive impairment, confusion, apathy, hallucinations and childlike behaviour. They might also show changes in mood, such as irritability or depression.
• Hyperphagia – some people may experience an increased appetite and consume large quantities of food during episodes.
• Hypersexuality – an increased libido and inappropriate sexual behaviour can be observed in some cases.
• Inter-episode periods – between episodes, people return to their normal state with no or minimal symptoms, allowing them to function normally.

KLS typically begins during adolescence and can persist for a decade or more, though it can, in some cases, also begin in childhood or adulthood. The frequency and duration of episodes can vary widely among individuals.

The exact cause of KLS is unknown, but it is believed to involve dysfunction in the hypothalamus and thalamus, areas of the brain responsible for regulating sleep, appetite and body temperature. Potential triggers include infections, head injuries and stress.

Prevalence and Demographics

The prevalence of KLS is estimated to be about 1 to 5 cases per million people. This rarity means that it is often underdiagnosed or misdiagnosed, which can contribute to uncertainty about its true prevalence. Many cases may go unreported or be mistaken for other sleep disorders or psychiatric conditions. 

KLS most commonly begins in adolescence. The typical age of onset is around 15 years old, but cases have been reported in individuals ranging from 4 to 82 years. KLS predominantly affects males. Studies suggest a male-to-female ratio of about 3:1. There does not appear to be a significant ethnic or racial element to KLS and cases have been reported globally across various ethnicities and regions.

While most cases are sporadic, there have been some instances suggesting a possible genetic link, with a few reports of KLS occurring in more than one family member.

Symptoms and Episodes

The typical symptoms experienced during KLS episodes include:

• Hypersomnia – this is the most prominent symptom; individuals with KLS can sleep for 15-20 hours a day, waking only to eat or use the bathroom.
• Cognitive disturbances – during episodes, people often experience confusion, disorientation, and an overall slowed thinking process. They may appear to be in a dream-like state or detached from reality.
• Behavioural changes – people may display unusual behaviours, such as childlike behaviour, irritability, or a lack of motivation.
• Hyperphagia – an increased appetite, particularly for sweet and high-carbohydrate foods, is common. Individuals may binge eat during their brief periods of wakefulness.
• Hypersexuality – some people may exhibit an increased libido or inappropriate sexual behaviours, although this is less common.
• Altered perception – sensory hypersensitivity, such as an increased sensitivity to noise and light, and perceptual disturbances, including hallucinations, may occur.
• Emotional changes – mood swings, depression and anxiety are frequently reported during episodes.

Causes and Triggers

The exact causes of KLS are not well understood, but several potential causes and triggers have been identified. Some evidence suggests a genetic predisposition, as KLS sometimes runs in families. There is ongoing research into specific genetic mutations that may contribute to the syndrome. 

Some other causes and triggers may include:

• Neurological abnormalities – hypothalamic dysfunction. The hypothalamus, which regulates sleep and appetite, may not function properly in individuals with KLS. Abnormalities in the thalamus, which is involved in sensory perception and regulation of motor functions, have also been implicated.
• Autoimmune response – some researchers believe that KLS may be related to an autoimmune response where the body’s immune system mistakenly attacks healthy brain tissue.
• Viral infections – there is evidence suggesting that infections, particularly viral infections, might trigger the onset of KLS in susceptible individuals. Infections like the flu or Epstein-Barr virus have been noted in some cases preceding the first episode. Many people report that their first KLS episode or subsequent episodes occur following an upper respiratory infection, such as the flu or a cold.
• Stress – high levels of stress, whether physical or emotional, can trigger episodes. Try to reduce your stress levels. You can do this by identifying the sources of stress in your life and practising stress-reducing techniques such as mindfulness and meditation, deep breathing exercises, or yoga.
• Sleep deprivation – episodes can be triggered or worsened by periods of sleep deprivation.
• Alcohol and drug use – consumption of alcohol or certain drugs might precipitate an episode.
• Hormonal changes – KLS can often begin during adolescence, suggesting that hormonal changes may play a role.
• Menstrual cycle – in females, episodes may be correlated with the menstrual cycle, indicating a hormonal trigger.

Impact on Daily Life

The impact on daily life for those affected by KLS can be profound and multifaceted, affecting both the individual and their families. 

The impact on people with KLS can include:

• Sleep patterns – individuals experience episodes of excessive sleep (hypersomnia) that can last for days, weeks or even months. During these episodes, people may sleep up to 20 hours a day, waking only to eat or use the bathroom.
• Cognitive and behavioural changes – when awake, people may experience confusion, irritability, aggression and altered behaviour. They might also experience a dream-like state, with a sense of unreality or detachment from their surroundings.
• Social and occupational challenges – maintaining employment or education is challenging due to the unpredictability and length of episodes. Social relationships can be strained as people may withdraw or behave atypically during episodes.
• Physical health – prolonged periods of inactivity and irregular eating patterns can lead to weight gain and other health issues.

Impact on family members and caregivers can include:

• Emotional and psychological strain – families often experience significant stress and anxiety due to the unpredictable nature of the syndrome. There may be feelings of helplessness and frustration in dealing with the recurring episodes.
• Financial burden – the need for constant care can lead to financial strain, particularly if a caregiver must reduce work hours or leave employment.
• Social isolation – the family might experience social isolation due to the need to stay home and care for the affected person. There can also be a lack of understanding and support from the wider community, adding to the sense of isolation.

Sleep problems often coexist with symptoms of depression or anxiety. Sleep problems can exacerbate depression or anxiety, and depression or anxiety can lead to sleep problems. Mind offers some helpful advice about how you can access support for your mental health if this is something you are struggling with.  

Lack of sleep and too much sleep are also linked to many chronic health problems, such as heart disease and diabetes.

For further reading about the link between sleep and mental health, please see our knowledge base. 

Diagnosis and Management

The diagnosis and management of KLS can be challenging due to its rarity and the overlap of symptoms with other conditions.

Diagnosis of Kleine-Levin syndrome involves:

• Clinical history – patients typically experience recurrent episodes of hypersomnia lasting days to weeks, interspersed with periods of normal sleep and behaviour. Episodes can last from a few days to several weeks and occur several times a year.
• Cognitive and behavioural symptoms – during episodes, patients may show symptoms of confusion, apathy, hallucinations and excessive eating. Some may exhibit hypersexuality or other unusual behaviours.
• Age of onset – the condition most commonly begins during adolescence.
• Exclusion of other conditions – sleep studies such as polysomnography and multiple sleep latency tests (MSLT) can be used to rule out other sleep disorders.
• Neurological examination – MRI or CT scans can be used to exclude structural brain abnormalities.
• Psychiatric evaluation – to rule out psychiatric disorders like bipolar disorder, depression or schizophrenia.
• Infections and autoimmune conditions – blood tests and lumbar puncture to exclude infections or autoimmune conditions.

Acute episode management of Klein-Levin syndrome includes:

• Supportive care – ensuring patient safety, hydration and nutrition during hypersomnia episodes. Family education and support are crucial.
• Symptomatic treatment – medications to manage specific symptoms, for example antipsychotics for hallucinations, or mood stabilisers for behavioural issues.

Long-term management can include:

• Preventive medication – some medications may reduce the frequency or severity of episodes, although their efficacy varies.
• Behavioural therapy – cognitive-behavioural therapy (CBT) to help patients cope with the impact of the disorder on their lives.
• Regular monitoring – regular follow-ups to monitor medication side effects and adjust treatment as necessary.
• Lifestyle and supportive measures – maintaining a regular sleep schedule and structured daily routine can be helpful. Patient and family education about the disorder, available treatments and support networks.
• Counselling and support groups – psychological support for patients and their families to deal with the emotional and social impact of KLS.

The long-term prognosis for KLS varies. Some patients experience a reduction in the frequency and severity of episodes over time, while others may have persistent and recurrent episodes for many years. The condition often gradually improves with age, particularly after the third decade of life.

Continued research is necessary to better understand the underlying mechanisms of KLS, identify biomarkers for diagnosis, and develop more effective treatments. Multidisciplinary care involving neurologists, sleep specialists, psychiatrists and other healthcare providers is often essential for optimal management of KLS.

Coping with KLS

Coping with KLS can be challenging for both patients and their families, but there are several strategies that can help in managing the condition, including:

• Regular monitoring – regular follow-ups with a neurologist or sleep specialist can help manage the symptoms and track the progression of the syndrome.
• Medication – although there is no cure for KLS, medications can help manage symptoms. Stimulants like modafinil or amphetamines can be used to reduce excessive sleepiness. Mood stabilisers, antidepressants or antipsychotics might be prescribed to address mood changes or behavioural issues.
• Lifestyle and coping strategies – maintaining a regular sleep schedule and creating a sleep-friendly environment can help to regulate sleep patterns to some extent.
• Structured routine – establishing a consistent daily routine can help to reduce stress and provide a sense of normalcy.
• Having a healthy well-balanced diet – balanced nutrition supports overall health and can improve energy levels.
• Exercise – regular physical activity can help boost mood and energy levels, although it should be balanced to avoid overexertion.
• Psychological and emotional support – this can include cognitive-behavioural therapy (CBT), or other forms of counselling can help patients and families cope with the emotional impact of KLS.
• Support groups – joining support groups for KLS can provide a sense of community and understanding, allowing individuals and families to share experiences and coping strategies.
• Education and advocacy – educating friends, family and colleagues about KLS can foster understanding and support. Advocating for adjustments at work or school can help manage the impact of the disorder on daily life. This might include flexible hours or rest periods.
• Crisis management – have a plan in place for managing episodes, including a list of emergency contacts and a clear outline of steps to take during an episode.
• Medical alert – consider using a medical alert bracelet or card that provides information about KLS in case of emergencies.
• Research and education – keeping up with the latest research on KLS can provide new insights into potential treatments and management strategies. Understanding the nature of KLS can empower patients and families to take an active role in managing the condition.

By combining medical treatment with lifestyle adjustments, psychological support, and proactive planning, individuals with Kleine-Levin syndrome and their families can better cope with the challenges posed by this condition. 

KLS Support UK are a small charity offering help and support to those affected by Kleine-Levin syndrome. 

NHS offers some useful information and advice on where you can access support if you have a sleep problem.