eMedicine Specialties > Psychiatry > Psychosomatic

Primary Hypersomnia

Author: Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM, Program Director, Associate Professor, Department of Internal Medicine, Divisions of Pulmonary and Critical Care Medicine, University of Manitoba; Site Director of Respiratory Medicine, St Boniface General Hospital
Contributor Information and Disclosures

Updated: Jun 29, 2007

Introduction

Background

According to the International Classification of Sleep Disorders (ICSD), idiopathic hypersomnia is defined as a disorder of presumed central nervous system (CNS) cause that is associated with excessive sleepiness consisting of prolonged sleep episodes of non–rapid eye movement (NREM) sleep. For the criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision (DSM-IV-TR) for primary hypersomnia, see DSM-IV-TR diagnostic criteria for 307.44 primary hypersomnia.

In comparison with narcolepsy, which is characterized by well-defined clinical, polysomnographic, and immunogenetic features, idiopathic hypersomnia is not well characterized. Primary hypersomnia can be classified as monosymptomatic or polysymptomatic. Isolated excessive daytime sleepiness that is not due to abnormal nocturnal awakenings characterizes the monosymptomatic form. The polysymptomatic form consists of abnormally long nocturnal sleep and signs of sleep drunkenness upon awakening.

In the literature, 3 possible subgroups of idiopathic CNS hypersomnia have been suggested, as follows:

• Subgroup I: These patients have a positive family history, and associated clinical symptoms suggest dysfunction of the autonomic nervous system. These symptoms include headache, syncope, orthostatic hypotension, and peripheral vasoconstriction (cold hands and feet).
• Subgroup II: This group includes patients who had a viral infection associated with neurological symptoms, such as Guillain-Barré syndrome, infectious mononucleosis, or atypical viral pneumonia. Even after their infectious disease resolves, these patients continue to require significantly more nocturnal sleep and continue to feel very tired. Although initially these patients are fatigued, subsequently, they have difficulty differentiating fatigue from sleepiness. To fight tiredness, these patients nap and eventually present with complaints of excessive daytime sleepiness. Analysis of cerebral spinal fluid demonstrates moderate lymphocytosis (30-50 cells/mL³ or 30-50 X 10-6/L with mild-to-moderate elevation in protein).
• Subgroup III: These patients do not have a positive family or viral infection history, and the cause of the disorder truly is idiopathic.

Recurrent primary hypersomnia

Some patients have recurrent episodes of hypersomnia, which often is associated with compulsive overeating and hypersexuality. This presentation is termed Kleine-Levin syndrome, or KLS. The periods of hypersomnia occur for days to weeks at a time but recur several times a year. In between the symptomatic periods, the patients have normal sleep requirements and do not have excessive daytime sleepiness. Some patients may develop symptoms of irritability, impulsive behavior, depersonalization, hallucinations, depression, and confusion. The etiology of this disorder is not known.

Kleine-Levin syndrome is a rare disorder with symptoms that include periodic hypersomnia, cognitive and behavioral disturbances. Mostly men (68%) are affected. The median age of onset is 15 years (range, 4-82 y; 81% during the second decade), and the syndrome may last up to 8 years. The episodes recur every 3-4 months and may last up to 10 days, but they may last longer in women. KLS may be precipitated by infections (38.2%), head trauma (9%), or alcohol consumption (5.4%). Characteristic symptoms include hypersomnia (100%), cognitive changes (96%, including a specific feeling of derealization), eating disturbances (80%), hypersexuality (43%), compulsions (29%), and depressed mood (48%). Somnolence decreased with stimulants (mainly amphetamines), while neuroleptics and antidepressants are of poor benefit. Lithium rather than carbamazepine or other antiepileptics had a higher success rate for stopping relapses. In secondary KLS, patients were older and had more frequent and longer episodes, but they hadclinical symptoms and treatment responses similar to those of primary cases.³

Pathophysiology

A definite mechanism of primary hypersomnia is not known. In experimental animal studies, destruction of the nonadrenergic neurons of the rostral third of the locus ceruleus complex has produced hypersomnia. Additionally, injury to the adrenergic neurons at the bundle of isthmus also has led to hypersomnia associated with a proportional increase of both NREM and REM sleep. These experiments have produced a state resembling idiopathic or primary hypersomnia. Evidence suggests that malfunction of the neurotransmitter dopamine occurs in narcolepsy, and a similar malfunction of the norepinephrine system may occur in idiopathic hypersomnia. A genetic basis for idiopathic hypersomnia is suggested, but the mode of inheritance has not been determined.

Hypocretin-1 (hcrt-1) and hypocretin-2 (hcrt-2) (also called orexin-A and orexin-B) are newly discovered neuropeptides processed from a common precursor and are involved in narcolepsy. Hypocretin-containing cells are located exclusively in the lateral hypothalamus, with widespread projections within the central nervous system. The role of the hypocretin system in other disorders causing excessive daytime sleepiness is more uncertain. Recently, very low cerebrospinal fluid concentrations of hypocretin-1 and hypocretin-2 in HLA DQB1*0602 were found in primary hypersomnia. Furthermore, a generalized defect in hcrt-2 transmission may be present in this disorder.

Frequency

United States

The prevalence of primary hypersomnia in the general population is not known. Excessive daytime sleepiness without a definite cause may be found in 0.5-5% of persons. Primary hypersomnia is diagnosed in 5-10% of all patients referred to the sleep laboratory for evaluation of excessive daytime sleepiness. From various studies, a ratio of the rate of idiopathic hypersomnia to narcolepsy is reported as 28.7:76.9%.

Mortality/Morbidity

The course of primary hypersomnia is chronic, with persistent symptoms of excessive daytime sleepiness occurring without resolution. This daytime sleepiness can lead to depression. Kleine-Levin syndrome begins during adolescence, and the disease process may continue for years, with spontaneous resolution during adult life.

Sex

Kleine-Levin syndrome affects males approximately 3 times more often than females.

Age

As with narcolepsy and Klein-Levin syndrome, onset of this condition is most common during adolescence and rare in people older than 30 years.

Clinical

History

• The most typical referral is for the polysymptomatic form of idiopathic hypersomnia and is characterized by the following:
• • Excessive daytime sleepiness leading to prolonged naps that are not refreshing
  • Nocturnal sleep of long duration (as much as 12 h or more)
  • 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. Episodes of automatic behavior also are present.
• Some patients complain of headaches, fainting episodes, orthostatic hypotension, and peripheral vascular complaints of Raynaud phenomenon. Rarely, hypnagogic hallucinations and sleep paralysis may be observed. During long periods of drowsiness, patients develop automatic behavior, during which they act in a semicontrolled fashion.
• In patients with the recurrent form (ie, Kleine-Levine syndrome), hypersomnia occurs for days to weeks several times a year. In between, patients do not have excessive daytime sleepiness. Some patients may develop symptoms of irritability, hypersexuality, hyperphagia, impulsive behavior, depersonalization, hallucinations, depression, and disorientation.

Physical

Upon physical examination, no particular features suggest a diagnosis of primary hypersomnia; however, physical examination findings may help exclude the alternate diagnosis of obstructive sleep apnea. Features that may suggest obstructive sleep apnea are central obesity, micrognathia or retrognathia, macroglossia, crowded oropharynx, nasal obstruction, and tonsillar enlargement.

• Upon physical examination, exclude a specific neurological disorder. An underlying rheumatological disease, such as active rheumatoid arthritis or osteoarthritis, may cause daytime hyperoxia because of poor nighttime sleep due to pain.
• Primary depression may present as hypersomnia, which may be excluded by performing a careful psychiatric evaluation.
• Patients with primary hypersomnia are at increased risk of developing a major depressive disorder (see Depression). Patients should receive a careful mental status and psychiatric evaluation for depression. Therefore, in the psychiatric evaluation, determining if any dynamic-family, work, or interpersonal issues, which may cause or contribute to the depression, is important. Clinical features of depressive disorders vary according to the severity of the illness, as follows:
• • Mild depression
    • In mild depression, a loss of interest or pleasure may be present to some degree. Social withdrawal or neglect of pleasurable activities can be present. Appetite usually is reduced, and individuals may have to force themselves to eat. These individuals also may develop a sense of worthlessness or guilt. During depressive episodes, many individuals find it hard to think, concentrate, or make decisions.
    • Patients typically complain of low mood, lack of energy and enjoyment, and poor sleep. Patients often demonstrate anxiety, phobias, and obsessive symptoms. Sleep disturbances such as difficulty in sleep initiation and sleep maintenance are common. The patient's mood may vary during the day, but the biological features occur infrequently.
  • Moderate-to-severe depression
    • In contrast, the clinical features of moderate-to-severe depression not only are more intense, but additional symptoms may be present.
    • Regarding appearance, patients who are depressed may have psychomotor changes including agitation, inability to sit still, retardation, slow speech, and slow thinking. Decreased energy, tiredness, and fatigue may occur. The patient also may appear restless and unable to relax.
    • Regarding mood, patients appear sad and depressed. The mood is described as down or depressed, which may be observed from a person's facial expressions and demeanor. Anxiety and irritability are associated features. Increased irritability and exaggerated sense of frustration over minor matters may be reported.
    • Lack of interest and enjoyment occur quite frequently, and patients stop pursuing previously enjoyed activities and loose pleasure from everyday living. Reduced energy may lead to lethargy, insufficient efforts on the patient's part, and leaving everyday tasks unfinished. Patients complain of poor concentration and poor memory. However, with effort, recall and retention usually are normal. Physical complaints also are common in patients with depressive disorders. Either new physical symptoms appear or preexisting physical disorders become more symptomatic.
    • Depressive thinking manifests as patients being pessimistic in their thinking and often having guilty thoughts. These thoughts concern both the present and the future. Patients expect the worst and foresee failure in their work, finances, and lives. These ideas of hopelessness may progress to suicide in many cases. Patients also may be concerned with their past and develop unreasonable guilt and self-blame.
    • Biological symptoms are present more commonly in severe depression. Several types of sleep disturbance may be present, and early morning awakening is quite characteristic. Patients are unable to fall asleep again. They also may develop symptoms of delay in falling asleep and waking up through the night. The other biological symptoms are loss of appetite, loss of weight, constipation, and loss of libido.
    • Other psychiatric symptoms that may develop in many patients with depressive disorders include depersonalization, obsessional symptoms, phobias, and conversion symptoms such as fugue state or loss of function of an extremity. Patients frequently report memory difficulties and suboptimal intellectual performance. Eventually, these individuals may lose the ability to function socially or occupationally.
    • Regarding delusions, patients with very severe depression usually develop delusions that intensify the nondelusional thinking disorder present in moderate depression. These patients develop delusions of worthlessness, guilt, ill health, poverty, nihilism, and persecution.
    • Hallucinations may occur. In severe depressive disorders, perceptual auditory disturbances may be present. Visual hallucinations are uncommon. Suicidal ideas may intensify, and, rarely, homicidal ideas may develop.
• DSM-IV-TR diagnostic criteria for 307.44 primary hypersomnia
• • The predominant complaint is excessive sleepiness for at least 1 month (or less if recurrent) as evidenced by either prolonged sleep episodes or daytime sleep episodes that occur almost daily.
  • The excessive sleepiness causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
  • The excessive sleepiness is not better accounted for by insomnia and does not occur exclusively during the course of another sleep disorder (eg, narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, parasomnias) and cannot be accounted for by an inadequate amount of sleep.
  • The disturbance does not occur exclusively during the course of another mental disorder.
  • The disturbance is not due to the direct physiological effects of a substance (eg, drug of abuse, medication) or a general medical condition.
  • For a diagnosis of recurrent primary hypersomnia, periods of excessive sleepiness last at least 3 days and occur several times a year for at least 2 years.

Causes

Primary hypersomnia is an idiopathic disorder. Although head injury or viral infections can cause a disorder resembling primary hypersomnia, the true causes for most cases remain unknown. No genetic, environmental, or other predisposition has been identified.

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