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Primary Hypersomnia Clinical Presentation

  • Author: Adrian Preda, MD; Chief Editor: Iqbal Ahmed, MBBS, FRCPsych(UK)  more...
Updated: Jan 09, 2015


The diagnostic criteria of idiopathic hypersomnia in ICSD-2, in addition to the clinical criteria, which are similar to DSM-5 criteria, include 1 or more of the following polysomnographic features[2] :

  • A sleep period that is normal or prolonged in duration
  • A sleep latency of less than 10 minutes
  • Normal REM sleep latency
  • A sleep latency of less than 10 minutes on the Multiple Sleep Latency Test
  • Fewer than 2 sleep-onset REM periods

Additional characteristics

The most typical referral is for the polysymptomatic form of primary hypersomnia and is characterized by the following[5, 21] :

  • Excessive daytime sleepiness leading to prolonged naps that are not refreshing
  • Nocturnal sleep of long duration (as much as 12h 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.

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 might develop automatic behavior, during which they act in a semicontrolled fashion. (During automatic behavior episodes, these patients may endanger themselves through risk of injury.)

In patients with the recurrent form (i.e., 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 Examination

The patient may appear overtired or even fall asleep in the physician’s office. The rest of the physical examination, however, will not reveal any particular features suggesting a diagnosis of hypersomnolence.

The physical examination goal is to exclude alternate diagnoses. A diagnosis of obstructive sleep apnea rather than hypersomnolence should be considered for a patient presenting with hypersomnia associated with central obesity, micrognathia or retrognathia, macroglossia, crowded oropharynx, nasal obstruction, and tonsillar enlargement.

An underlying rheumatologic disease, such as active rheumatoid arthritis or osteoarthritis, may cause daytime hyperoxia and sleepiness associated with poor nighttime sleep due to pain. Prior head trauma sequela or a current brain tumor can leave their specific mark on the neurologic examination.

Specific findings may suggest a degenerative neurologic condition (e.g., Parkinson or Huntington disease), endocrine dysfunction (e.g., hypothyroidism), viral and bacterial infections (e.g., hypersomnia secondary to viral encephalitis), pulmonary disease with secondary sleep-related breathing difficulties (e.g., chronic bronchitis) or musculoskeletal disorders (e.g., rheumatoid arthritis, fibromyalgia).

An overweight patient with primary hypersomnia should be assessed for underlying endocrine problems and sleep apnea.

If psychomotor retardation or agitation is noted, mental disorders with secondary sleep disturbance need to be ruled out before making a diagnosis of hypersomnolence.

Mental status examination

Major depressive disorder commonly presents with decreased energy and tiredness and atypical depression presents with hypersomnia. Similarly, speech that is soft in quality, with a decreased rate of production and an increased latency of answers, might indicate excessive tiredness, but it may also indicate depression.

Mood might be “down," tired,” or even “depressed,” with mood congruent and a decreased range of affect. If this is the case, the meaning of the words needs to be carefully qualified. Is it that the patient has depression (ie, major depressive disorder) or is it that he/she feels down as a reaction to oversleeping and decreased ability to function?

Thought processes should be coherent and goal directed. While suicidal ideation is not typical for hypersomnolence, because of the overlap between sleeping and affective disorders, standard questioning about the presence of suicidal and homicidal ideation is recommended.

Insight and judgment are most times good. Mild cognitive changes in the domains of attention, concentration and short-term memory are occasionally present, but most often the cognitive examination should not reveal any significant deficits.

Recurrent hypersomnia

On the neurologic examination, patients with Klein-Levin syndrome may present with a number of nonspecific findings including nystagmus, dysarthria, and generalized hyperreflexia.

For secondary Kleine-Levin syndrome, patients tend to be older and have more frequent and longer episodes, but they present with clinical symptoms and treatment responses similar to those of primary cases.[11]

Contributor Information and Disclosures

Adrian Preda, MD Professor of Clinical Psychiatry and Human Behavior, Director of Residency Program in Psychiatry, Vice-Chair, Department of Psychiatry and Human Behavior, University of California, Irvine, School of Medicine

Adrian Preda, MD is a member of the following medical societies: American Association for the Advancement of Science, American Psychiatric Association, International College of Neuropsychopharmacology, International Congress of Schizophrenia Research, Schizophrenia International Research Society, Society of Biological Psychiatry

Disclosure: Nothing to disclose.

Chief Editor

Iqbal Ahmed, MBBS, FRCPsych(UK) Faculty, Department of Psychiatry, Tripler Army Medical Center; Clinical Professor of Psychiatry, Uniformed Services University of the Health Sciences; Clinical Professor of Psychiatry, Clinical Professor of Geriatric Medicine, University of Hawaii, John A Burns School of Medicine

Iqbal Ahmed, MBBS, FRCPsych(UK) is a member of the following medical societies: Academy of Psychosomatic Medicine, American Neuropsychiatric Association, American Society of Clinical Psychopharmacology, Royal College of Psychiatrists, American Association for Geriatric Psychiatry, American Psychiatric Association

Disclosure: Nothing to disclose.


Jennifer S Morse, MD Associate Medical Director, Optum Health

Jennifer S Morse, MD is a member of the following medical societies: Academy of Psychosomatic Medicine, Aerospace Medical Association, and American Psychiatric Association

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

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Primary hypersomnia. Polysomnographic study demonstrates apnea (absence of carbon dioxide fluctuation indicating no flow), chest wall paradox, abrupt increase in tidal volume at the end of apnea, and oxygen desaturation. All of these features are consistent with obstructive sleep apnea.
Primary hypersomnia. In contrast to obstructive sleep apnea, mixed apnea shows absence of respiratory efforts in the first segment of the apnea.
Primary hypersomnia. Periodic limb movements show intermittent leg electromyogram activity accompanied by electroencephalogram arousals.
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