Hypersomnia (abnormal sleepiness)

Hypersomnia (pathological sleepiness) can complicate the course of many diseases, mainly of the nervous system, and manifests itself as both permanent and paroxysmal (periodic) hypersomnia.

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Main causes of hypersomnia

1. Narcolepsy.
2. Idiopathic hypersomnia.
3. Sleep apnea syndrome.
4. Kleine-Levin syndrome.
5. Organic damage to the upper parts of the brainstem and diencephalon (traumatic brain injury, space-occupying lesions, encephalitis, progressive hydrocephalus, etc.).
6. For mental illnesses (depression, dysthymia).
7. After infectious diseases.
8. For night pain and frequent night attacks (eg, hypnogenic paroxysmal dystonia, periodic limb movements, restless legs syndrome).
9. Delayed sleep phase syndrome.
10. Psychogenic (stress-related, in neurotic disorders).
11. Somatic diseases.
12. Iatrogenic hypersomnia.

Narcolepsy

Pathological sleepiness in narcolepsy is characterized by irresistible attacks of sleep that occur in an inappropriate situation. Attacks are triggered by a monotonous environment, meetings, prolonged sitting, etc. The frequency of attacks varies from isolated to several hundred per day. The average duration of an attack is 10-30 minutes. During an attack, the patient can be awakened, but this is not always easy. The detailed picture of narcolepsy includes five main manifestations: in addition to attacks of daytime sleepiness (hypersomnia), cataplexy (short-term generalized or partial attacks of loss of tone and strength without impairment of consciousness) are also characteristic; hypnagogic hallucinations that appear episodically when falling asleep; cataplexy of awakening and falling asleep ("sleep paralysis") and disturbances of night sleep.

A polygraphic sleep study reveals an early onset of the REM sleep phase (characteristic reduction in the latent period of REM sleep), frequent awakenings, reduction of delta sleep and other characteristic disturbances in its structure.

Idiopathic hypersomnia

Idiopathic hypersomnia is characterized by prolonged nocturnal sleep combined with abnormal daytime sleepiness; it differs from narcolepsy by the absence of cataplexy, hypnagogic hallucinations, and sleep paralysis.

The diagnosis is one of exclusion; polysomnography shows prolonged nocturnal sleep without evidence of other sleep pathology. MTLS shows shortened sleep latency without the appearance of REM sleep. Treatment is similar to that for narcolepsy, except for anticataplectic drugs.

Sleep apnea syndrome (Pickwickian syndrome)

Snoring and excessive daytime sleepiness are the most typical external manifestations of the "sleep apnea" syndrome. Unlike physiological pauses in breathing during sleep, pathological pauses in breathing during sleep occur more frequently (more than 5 per hour) and last longer (more than 10 seconds), and the sleep itself is characterized by a typical restless nature with frequent awakenings. Sleep apnea is accompanied by other characteristic signs: loud snoring, increased daytime sleepiness, hypnagogic hallucinations, nocturnal enuresis, morning headaches, arterial hypertension, excess weight, decreased libido, personality changes, decreased intelligence.

There are central, obstructive and mixed apneas.

Causes of central apnea: organic lesions of the brain stem (amyotrophic lateral sclerosis, syringobulbia, primary alveolar hypoventilation or "Ondine's curse syndrome", etc.) and peripheral paresis of the respiratory muscles (Guillain-Barré syndrome and other severe polyneuropathies).

Obstructive sleep apnea is most common: tonsil hypertrophy, swelling and inflammatory infiltration; anatomical abnormalities of the lower jaw; obesity; Prader-Willi syndrome; enlarged tongue or uvula in Down syndrome, hypothyroidism or acromegaly; weakness of the pharyngeal dilator (myotonic dystrophy, muscular dystrophies, medulla oblongata lesions, amyotrophic lateral sclerosis); pharyngeal tumor; skull base abnormalities (Arnold-Chiari syndrome, Klippel-Feil syndrome, achondroplasia); dyspnea in Shy-Drager syndrome and familial dysautonomia. Mixed apneas are the most common. Sleep apnea is a risk factor for sudden death.

The best diagnostic method is nocturnal polysomnography, which allows for objective recording and measurement of apnea, as well as associated hypoxemia (decreased blood oxygen saturation).

Kleine-Levin syndrome

The disease manifests itself in attacks of periodic drowsiness with an increased feeling of hunger (gluttony) and psychopathological disorders (confusion, anxiety, psychomotor agitation, hallucinations, hypersexuality). The duration of an attack is from several days to several weeks. Forced awakening can provoke pronounced aggressive behavior. The disease debuts without an apparent cause mainly in puberty and affects almost exclusively males.

Organic lesion of the upper parts of the brainstem and diencephalon

Economo's epidemic encephalitis in the acute phase is often accompanied by pathological drowsiness ("ophthalmoplegic hypersomnia"). Traumatic brain injury is another possible cause of hypersomnia. Minor drowsiness is possible in the acute stage and during the recovery period of almost any infection; it is sometimes noted after mild traumatic brain injury. Acute cerebrovascular accidents, as well as brain tumors, can be accompanied by prolonged hypersomnic states. Hypersomnic syndromes differ from coma in their relative arousability: external influences make it possible to bring the patient out of hibernation and achieve a more or less adequate response to verbal stimuli. Clarification of the nature of the organic lesion is achieved by using, in addition to clinical examination, neuroimaging methods and lumbar puncture, if the latter is not associated with the risk of dislocation of the brain stem.

Hypersomnia is sometimes observed in multiple sclerosis, Wernicke's encephalopathy, and African sleeping sickness.

Among the degenerative diseases that are sometimes accompanied by hypersomnia, the most common are Alzheimer's disease, Parkinson's disease, and multiple system atrophy.

Mental illnesses

Mental illnesses, especially those of endogenous origin, can sometimes be accompanied by increased sleepiness. Depression (for example, in seasonal affective disorders) is manifested by decreased activity and sleepiness. The onset of schizophrenia in adolescence is often characterized by an increased need for daytime sleep.

Infectious diseases

Infectious diseases, especially in the convalescence stage, are accompanied by increased drowsiness in the picture of an asthenic state.

Night pain and other pathological conditions that interrupt night sleep

Night pain of somatogenic or neurogenic origin, as well as frequent night attacks (for example, frequent attacks of hypnogenic paroxysmal dystonia), periodic limb movements during sleep or restless legs syndrome, causing fragmentation of night sleep, can lead to compensatory daytime sleepiness and cause a decrease in performance and adaptation.

Delayed sleep phase syndrome

This syndrome, like some other similar syndromes, is caused by a disruption of the circadian rhythm and is characterized by complaints of extremely difficult awakening, requiring a long time, and excessive morning sleepiness. However, these patients do not have evening sleepiness and go to bed late at night.

Psychogenic hypersomnia

"Hysterical hibernation" (according to outdated terminology) may manifest itself as episode(s) of hibernation lasting many hours or many days in response to acute emotional stress. A behavioral picture of sleep is observed (the patient appears to be asleep and cannot be awakened by external stimuli), but the EEG records a clear a-rhythm with a pronounced orienting reaction to external stimuli.

Somatic diseases

Hypersomnia may occur in such somatic diseases as liver failure, renal failure, respiratory failure, electrolyte disturbances of various origins, heart failure, severe anemia, endocrine disorders (hypothyroidism, acromegaly, diabetes mellitus, hypoglycemia, hyperglycemia).

Iatrogenic hypersomnia

Hypersomnia of iatrogenic origin is often encountered in neurological practice. It is caused by benzodiazepines, nonbenzodiazepine hypnotics (phenobarbital, zolpidem), sedative antidepressants, neuroleptics, antihistamines, narcotic analgesics, beta-blockers.

So-called physiological hypersomnia is observed with sleep deprivation associated with lifestyle and disruption of the usual sleep-wake cycle.

Catamenial hypersomnia associated with the menstrual cycle has also been described.

Among the intoxications that cause hypersomnia, alcohol abuse is the most common.

Diagnostic studies for pathological sleepiness

Electropolygraphy of wakefulness and night sleep with respiration recording; clinical assessment of somatic, mental and neurological status; if necessary - CT and MRI, cerebrospinal fluid examination (rare).

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