|Narcolepsy and Other Hypersomnias
Hypersomnia is a term that refers either to an excessive quantity of daily sleep or a difficulty to stay awake during the day, or both. The most common disorders presenting with hypersomnia are:
In narcolepsy, other symptoms beside excessive daytime sleepiness are present as well and there is a tendency to falling asleep directly or extremely rapidly into Rapid Eye Movement (REM) Sleep (i.e. deep sleep, dreaming sleep). The other hypersomnias are subdivided into Idiopathic Hypersomnia (persistent sleepiness lasting more than 3 months without abnormal tendencies to enter REM sleep) and Recurrent Hypersomnia (recurrent episodes of sleepiness that are entirely reversible in between).
Narcolepsy is a chronic, neurological sleep disorder characterized by excessive daytime sleepiness, cataplexy and abnormal REM sleep. A person with narcolepsy will experience extreme fatigue and may fall asleep at odd and inappropriate times, such as during work or school. A brief nap is generally refreshing, but the sleepiness re-occur rapidly a few hours later.
Most patients also experience cataplexy, suddenly feeling paralyzed or weak in the head, legs or other body parts especially after excitement or laughing. The disorder is sometimes confused with insomnia due to its characteristic disturbed night-time sleep and with epilepsy because of unexplained sudden falls caused by cataplexy. Another difference with other hypersomnia is that with narcolepsy, when the person falls asleep, they generally experience the REM stage of sleep within 10 minutes. Normally, people don’t reach the REM stage until after 90 minutes.
Symptoms of Narcolepsy
Beside excessive daytime sleepiness, patients may have the following symptoms:
Cataplexy – a sudden weakening of the muscles, often triggered by a strong emotion. While cataplexy can manifest as something as minor as a slight slackening of the facial muscles, in extreme cases, a person may experience total collapse or even muscle paralysis. Cataplexy is a cardinal symptom as it almost always indicates that the cause of the narcolepsy is a lack of hypocretin in the brain.
Hypnagogic hallucinations – vivid, sometimes disturbing dreamlike experiences that occur while dozing, falling asleep and/or upon awakening.
Sleep paralysis - the temporary inability to talk or move when waking; it may last a few seconds to minutes.
Automatic behavior – a person continues to function or talk while being half asleep, and awakens with no memory of doing these activities.
Insomnia – Nighttime sleep is disturbed. Patients often do fall asleep rapidly but are unable to stay asleep for more than a few hours at a time. Nighttime eating and excessive dreaming with motor activity (acting out dreams, see also REM sleep Behavior Disorder) also frequently occur.
The Cause of Narcolepsy with and without Cataplexy
In most cases of narcolepsy with cataplexy (and in rare cases without cataplexy), all the symptoms are caused by the loss of approximately 70,000 brain cells producing a chemical called hypocretin, a finding made at Stanford University. Please see Center for Narcolepsy research section for more details.
In most cases of narcolepsy without cataplexy (and in rare cases with cataplexy), the cause of the symptoms is unclear and the diagnostic is purely based on the result of an abnormal sleep test called the multiple sleep latency test (MSLT) (see below).
Diagnosis of Narcolepsy
If all the common symptoms of narcolepsy are present, diagnosing the disorder is fairly straightforward. However, if sleep attacks are isolated and there is only mild or no cataplexy, making a correct diagnosis is more challenging. It requires excluding carefully insufficient sleep (sleep deprivation), disturbed nocturnal sleep, insomnia, circadian rhythm disorders, sleep-related breathing (sleep apnea) disorders and psychiatric disorders. A general medical check up excluding anemia, hypothyroidism, heart or other general medical issues is essential.
Stanford Sleep Specialists use two main tests to diagnose narcolepsy: the nocturnal polysomnogram and the multiple sleep latency test (MSLT). The polysomnogram continuously records brain waves during sleep, as well as a number of nerve and muscle functions during nighttime sleep. During the test, the narcoleptic will usually fall asleep rapidly, enter REM sleep quickly, and potentially awaken frequently during the night.
For the MSLT, a person is given 4-5 opportunities to sleep every two hours during normal wake times. The specialist uses the test to measure the extent of daytime sleepiness (how fast the patient falls asleep in each nap, also called sleep latency), and also how quickly REM sleep begins, since narcoleptics fall asleep quickly and experience REM sleep early. A positive MSLT (diagnostic for narcolepsy) is obtained when the patient did fall asleep with a mean sleep latency below 8 minutes in the naps, and had at least 2 naps where REM sleep was reached.
In addition to the above, Stanford Sleep Specialists will commonly performed a blood genetic test for narcolepsy if they suspect hypocretin deficiency called Human Leukocyte Antigen (HLA) DQB1*06:02 typing. Almost 99% of subjects where narcolepsy is caused by a lack of hypocretin are DQB1*06:02 positive, but approximately 25% of the normal US population is positive as well so a negative test is used to exclude hypocretin deficiency.
In some selected cases, especially if Human Leukocyte Antigen (HLA) DQB1*06:02 is positive but the case is unclear, a lumbar puncture may be performed, Cerebrospinal Fluid (CSF) drawn, and CSF hypocretin-1 measured. If CSF hypocretin-1 is below 110 pg/ml, the diagnosis is consistent with narcolepsy caused by hypocretin deficiency. This particular test was first developed at Stanford and is the most definitive test for narcolepsy. Other radiological, genetic or biochemical tests may also be ordered in selected cases.
Sleep specialists normally treat narcolepsy with a combination of behavioral changes (primarily scheduling nocturnal sleep and naps) and medications, tailoring the treatment based on the potential cause(s) of the condition, individual symptoms and response to treatments. Changes in work or lifestyle can be helpful. The Narcolepsy Network provides patient education and support.
Treatment duration varies and could require frequent adjustment of medications to get the best response, though complete control of symptoms is rarely achievable. Medications used to treat narcolepsy include antidepressants, stimulants, ADHD medications and sodium oxybate.
Diagnosing Idiopathic Hypersomnia
Beside Excessive Daytime Sleepiness, symptoms of Idiopathic Hypersomnia may include:
• Excessive daily sleep: Sleeping 10 hours or more every day.
• Sleep drunkenness: Extreme sleep inertia, difficulties waking up with alarm clocks, feeling groggy for long period of times.
A person must display symptoms of hypersomnia for at least 3 months, and the disorder should have a significant impact on the person’s life to be diagnosed with hypersomnia. If symptoms occur due to medication or a medical disorder, then the person won’t be diagnosed with hypersomnia.
Making a diagnosis of Idiopathic Hypersomnia requires excluding carefully other causes of daytime sleepiness such as insufficient sleep (sleep deprivation), disturbed nocturnal sleep, insomnia, circadian rhythm disorders, sleep-related breathing (sleep apnea) disorders or medical issues. A general medical check up excluding anemia, hypothyroidism, heart or other general medical issues is essential. Excluding a psychiatric condition such as depression or generalized anxiety disorder may be difficult and is needed, requiring therapeutic trials.
Stanford Sleep Specialists use nocturnal polysomnography followed by the multiple sleep latency test (MSLT). The polysomnogram continuously records brain waves during sleep, as well as a number of nerve and muscle functions during nighttime sleep. During the test, patients with Idiopathic Hypersomnia will usually fall asleep rapidly, and will often sleep for long periods of time with a high amount of slow wave sleep. The test is important to eliminate disturbed sleep and sleep apnea as the cause or a contributor of the symptoms. In the MSLT, a person is given 4-5 opportunities to sleep every two hours during normal wake times. The specialist uses the test to measure the extent of daytime sleepiness (how fast the patient falls asleep in each nap, also called sleep latency), and also how quickly REM sleep begins. A positive MSLT (diagnostic for Idiopathic) is obtained when the patient did fall asleep with a mean sleep latency below 8 minutes in the naps, and had not more than 1 nap where REM sleep was reached (otherwise the patient may be diagnosed as narcolepsy).
In rare cases, biochemical or medical test may also be ordered.
The Cause of Idiopathic Hypersomnia
There is almost no research in the area of Idiopathic Hypersomnia. Most likely, Idiopathic Hypersomnia is not a “disease” but a combination of symptoms with many causes. In some cases, sleepiness may be due to a brain abnormality of unknown cause; for example, some subjects with Idiopathic hypersomnia have been shown to have low levels of Histamine in the Cerebrospinal fluid; others may have low grade unknown infections (starting after a flu like illness) or brain damage. In some of these cases, the brain imbalance is observed in association with other psychiatric conditions such as anxiety, depression or psychosis.
In other cases, the symptoms are complicated by a very abnormal and irregular sleep schedule and exposure to light. Sedative or stimulant medications taken in excess or at the wrong time can also complicate the issue. The concurrence of sleep apnea (sometimes adequately treated with Positive Pressure Therapy ) or other sleep disorders such as circadian disturbances is also a complicating factor.
Treating Idiopathic Hypersomnia
Treatment is based on the symptoms displayed and on a careful analysis of their most probable cause(s). Analysis of currently prescribed medications is always needed. Regularizing of nighttime and daytime sleep through behavioral interventions is a typical first step. Treating coexisting circadian abnormalities (light therapy, melatonin, etc) or sleep apnea (PAP therapy) may also be needed. The sleep specialist may then prescribe medications to help manage symptoms, and will also recommend continued changes in behavior, such as avoiding night work and activities that delay bed time, as well as changes to the diet and exercise routines. This may also include avoiding alcohol and caffeine. Medications may include stimulants such as modafinil or amphetamine-like compounds, ADHD medications, antidepressants and sedatives. In case amphetamine like stimulants are prescribed, tolerance and dependence should be carefully monitored as a possible complication. The Narcolepsy Network provides patient education and support for patients with Idiopathic Hypersomnia.
Recurrent Hypersomnia is characterized by recurrent, reversible episodes of hypersomnia often associated with other symptoms that typically occurs weeks or months apart. During episodes, sufferers experience extreme sleepiness and have big sleep requirements, sometimes sleeping as much as 16 to 20 hours a day. Two types of recurrent Hypersomnia are recognized, Kleine Levin Syndrome, and Menstrual-related Hypersomnia. Menstrual-related Hypersomnia is extremely rare. In this case, hypersomnia reoccurs periodically for one week generally around menses. The use of contraceptive hormonotherapy is usually efficacious.
Kleine Levin Syndrome
Kleine-Levin Syndrome is a rare sleep disorder that most commonly affects teens. People with this neurological disorder experience recurring periods of excessive sleep with behavioral changes. Onset of episodes is often abrupt, and sometimes preceded by flu-like symptoms. Episodes usually last 1-3 weeks. When an episode begins, the patient becomes drowsy and sleeps for most of the day and night, waking only to eat or use the bathroom. When awake but in episode, he or she frequently seems “out of it” and irritable. Childlike behaviors, sexual deshinibition, megaphagia may be observed. They also experience confusion, disorientation, and a complete lack of energy and emotion. People with recent onset Kleine-Levin Syndrome cannot attend school, work or care for themselves during episodes; most are bedridden, tired and uncommunicative. Offset of episodes is also often abrupt, and may be associated with a brief bout of insomnia.
Teenage boys account for most cases of Kleine-Levin Syndrome. In some instances, those suffering from Kleine-Levin Syndrome can go weeks, months or even years without displaying any symptoms, then have a sudden reoccurrence. The cause of Kleine-Levin Syndrome is still unknown, but the disorder generally resolves slowly over years. Episodes become less frequent and severe, to resolve in early adulthood.
Diagnosing Kleine-Levin Syndrome
Diagnosing Kleine-Levin Syndrome is admittedly a challenge but can be a relief for a family in search of answers. Because its primary symptom, hypersomnia, is common to a number of disorders, the process by which we diagnose Kleine-Levin Syndrome is one of exclusion – ruling out other conditions that share symptoms. As a result, potential Kleine-Levin Syndrome patients often will undergo a lot of tests in various specialties: for metabolic problems including diabetes, metabolic encephalopathies and hypothyroidism; an MRI to rule out a lesion, tumor or inflammation as the cause; even for multiple sclerosis, which has aspects that can mimic the symptoms of Kleine-Levin Syndrome.
The symptoms of Kleine-Levin Syndrome – somnolence, hyperphagia and withdrawal – can mimic those of severe depression, sometimes followed by a brief period of high, manic energy that could lead to a misdiagnosis of bipolar disorder. Because of all these variables, all other possibilities need to be ruled out, and the symptoms must still fit with those commonly observed in Kleine-Levin Syndrome patients.
Treating Kleine-Levin Syndrome
There is no specific, definitive treatment to cure or control Kleine-Levin Syndrome. Some aspects of the disease can be managed with medication, such as stimulants to combat the EDS, but this is most effective only once the episodes have already decreased in severity. In some cases, doctors have used lithium and carbamazepine, normally used to treat bipolar disorder, to prevent or shorten episodes. Beyond that, there really isn’t much to do to control Kleine-Levin Syndrome, other than being as aware as possible of the effects of Kleine-Levin Syndrome, how to recognize episodes and to have sufficient support from family and friends.