COMMON SLEEP DISORDERS
HYPERSOMNIA
What is Hypersomnia?
Many people feel drowsy in the early afternoon and they have a desire for a quick nap, this is probably normal and different from excessive daytime sleepiness, which is a much more significant problem. Hypersomnia is defined as a disorder of excessive sleepiness as evidenced by either prolonged sleep episodes or daytime sleep episodes that occur almost daily and will cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
What is causing excessive daytime sleepiness?
The prevalence of excessive daytime sleepiness, reported by up to 30% of the adult population, is important that physicians, educators, and public policymakers approach this complaint thoughtfully and this article will discuss the etiology of hypersomnia and diagnostic approach and treatment.
*Sleep deprivation
By far, the most common cause of excessive daytime sleepiness in modern society is chronic sleep deprivation. Healthy adults can require anywhere from 4 to 10 hours of sleep. Therefore, people who need 8 hours of sleep a night but receive only 6 hours may become severely sleep-deprived and notably hyper-somnolent.
Primary hypersomnia
Excessive sleepiness for at least 1 month is not related to other mental disorders or direct physiological effects of a substance (eg, drug of abuse, medication). The prevalence of primary hypersomnia in the general population is not known but it may be found in 0.5-5% of persons and it is characterized by the following:
Excessive daytime sleepiness leads to prolonged naps that are not refreshing, nocturnal sleep of long duration (as much as 12 h or more), and sleep drunkenness. These patients do not feel refreshed following naps and, therefore, fight sleepiness as long as they are able. Patients are difficult to awaken from sleep or naps
Before a diagnosis of primary hypersomnia is considered all other causes of hypersomnia, should be excluded, so elimination of other causes of excessive daytime somnolence helps diagnose primary hypersomnia.
*Medication-induced hypersomnia
Certain agents may cause true hypersomnia. sedative-hypnotic agents, such as barbiturates, benzodiazepines, and Many medications that are occasionally prescribed for insomnia, such as tricyclic antidepressants and antihistaminic agents, may cause drowsiness.
*Other medical conditions may cause hypersomnia
Posttraumatic hypersomnia
Brain tumors
Metabolic disorders such as hypothyroidism
Seizure disorder
Hydrocephalus
Depression
What is the appropriate Diagnostic approach for hypersomnia patients?
All patients with chronic daytime sleepiness should have a thorough history, sleep history, physical exam, and neurologic exam seeking evidence of cataplexy, hypnagogic or hypnopompic hallucinations, or sleep paralysis.
1*Subjective measures of excessive daytime sleepiness can be measured by The Epworth Sleepiness scale, which is a self-administered questionnaire in which patients rate their likelihood of falling asleep in eight different life situations each situation is scored on a scale from 0 (not at all likely to fall asleep) to 3 (very likely to fall asleep). The resulting total score is between 0 and 24. Although what score constitutes abnormal sleepiness is controversial, total scores above 10 generally warrant investigation.
2*objective measures of excessive daytime sleepiness can be measured by an all-night polysomnogram(PSG) followed up with multiple sleep latency testing (MSLT) the day after.
Patients are asked to arrive at the sleep laboratory two to three hours before their regular bedtime with their usual sleeping items such as a favorite pillow, robe, slippers, toothbrush, and reading materials. A trained sleep technician will prepare the patient for the test and apply sensors to the head, face, chest, abdomen, and legs. None of these devices hurt. Most people do not find it hard to fall asleep even with all the wires attached to them. It is easy for the patient to move around or be disconnected from the sensors during the night to use the bathroom. The bedroom at the sleep laboratory has been designed to be quiet, comfortable, and homey. The sleep study equipment and the technician who monitors the patients throughout the night will be in a separate room. A light breakfast is served after the sleep study.
MSLT generally begins 1.5 to three hours after PSG. The patient is placed in a sleep-inducing environment (dark & quiet room) and is instructed to try to sleep. It consists of four or five opportunities (at 2-hour intervals throughout the day) to take a 15- to 20-minute nap.
In PSG, Patients who have narcolepsy typically demonstrate spontaneous awakenings, mildly reduced sleep efficiency, and short latency to REM. In MSLT, Patients who have narcolepsy typically fall asleep in 10 minutes or less and usually display REM sleep on at least two of the daytime naps. MSLT results must be interpreted in light of the patient's clinical symptoms and results of the preceding night's polysomnogram. Telling a patient that he or she does not have narcolepsy based on negative MSLT results is unacceptable.
In idiopathic CNS hypersomnia, the results of the all-night polysomnogram are unremarkable, and the MSLT reveals objective hypersomnia without the occurrence of REM sleep during the naps.
3-*Measurement of the concentration of orexin-A/hypocretin-1 in CSF is primarily a research tool, but it can be useful in certain clinical situations.
4*HLA testing has been studied but is NOT considered routine diagnostic testing for narcolepsy now.
5*blood testing to exclude metabolic or endocrine disorders and to exclude anemia, in addition, some genetic tests may help to direct you to the right diagnosis.
6*CT images for the brain to exclude pathological reasons for hypersomnia.
Treatment of hypersomnia
1) Pharmacologic treatment
Stimulant medications, such as modafinil (Provigil) an alpha1-agonist, have been used for several years to treat narcolepsy and hypersomnia.
Older stimulants are thought to act primarily through brainstem dopamine, nigrostriatal, and mesocorticolimbic pathways. These medications help reduce daytime sleepiness, improving the symptom in 65-85% of patients.
Cataplectic attacks usually are treated by adding a tricyclic antidepressant such as clomipramine or a selective serotonin reuptake inhibitor (SSRI), most commonly fluoxetine, while imipramine and clomipramine have been used for sleep paralysis.
2) Behavioral treatment including good sleep hygiene Most patients improve if they maintain a regular sleep schedule, usually 7.5-8 hours of sleep per night, Scheduled naps during the day also may help in addition avoiding shift work is essential.
3) Environmental treatments including safety during driving. Here are some suggestions to sleepy drivers:
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