Sleep apnea syndrome: diagnosis and treatment
Obstructive sleep apnea syndrome is a disorder in which normal airflow through the upper airways is interrupted. The main tool for verifying this condition is polysomnography. This comprehensive monitoring method allows for recording respiratory excursions, assessing oronasal airflow, and continuously tracking oxygen saturation levels (oximetry) throughout the entire sleep period.
The diagnosis is confirmed if the apnea index exceeds 5. This means that the patient experiences five or more episodes of breathing cessation per hour, with each such pause lasting more than 10 seconds. Examination of the hypnogram in such patients demonstrates severe distortions in sleep architecture: the normal cyclicity and sequence of stages are completely disrupted.
The therapeutic strategy is built around restoring adequate patency of the airways:
- CPAP therapy (continuous positive airway pressure method) is the most effective intervention. The device delivers an airflow under increased pressure in rhythm with spontaneous breathing, passing it through closed or narrowed pathways.
- For mild manifestations, conservative measures are used: weight loss, treatment of nasopharyngeal pathologies, and the use of special devices that prevent the tongue and lower jaw from falling back.
- Surgical treatment is indicated when conservative methods are ineffective and aims at the surgical elimination of the causes of obstruction.
Restless legs syndrome and periodic movements
Motor disorders associated with sleep are often disguised by complaints of leg discomfort. Periodic limb movement disorder is characterized by stereotyped, repetitive motor patterns lasting only 1.5–2.5 seconds. They are localized predominantly in the legs. The classic pattern includes extension of the big toe, dorsiflexion at the ankle joint, flexion at the knee, and sometimes at the hip joint.
Closely related to this condition is restless legs syndrome. Patients describe agonizing paresthesias (unpleasant sensations) in the lower extremities that occur at rest. Symptoms worsen before falling asleep. Patients complain of pulling, drawing, aching, or tingling sensations. To get rid of this discomfort, the person is forced to actively move their legs, frequently change position, pace, or walk.
Pharmacological management for both syndromes includes:
- Dopaminergic drugs (dopamine receptor agonists, levodopa).
- Benzodiazepines.
- Anticonvulsants (gabapentin, carbamazepine, clonazepam).
- Iron supplements (may be useful in certain cases).
Nocturnal cramps and bruxism
Special attention should be given to cramps associated with sleep—brief, involuntary spasmodic contractions of the calf or foot muscles. They are markedly painful, last from a few seconds to a few minutes, and inevitably lead to abrupt awakening. Elimination of triggering causes is recommended as therapy, while massage and stretching exercises for the involved muscles are effective for relieving muscle tension.
Another common phenomenon is bruxism, which manifests as teeth grinding during sleep. The pathogenesis is based on uncontrolled contraction of the masticatory muscles, accompanied by a characteristic sound. Treatment consists of eliminating the potential cause and mandatory use of dental appliances (mouth guards). They are necessary to prevent mechanical damage to the dentition and temporomandibular joints.
Briefly: answers to topical questions
What sleep phases and stages form the normal architecture on a hypnogram?
Normal sleep architecture on a hypnogram is formed by the alternation of non-REM and REM sleep phases.
The following components are distinguished:
- Non-REM sleep phase (orthodox sleep, NREM sleep) — includes stage I (state of drowsiness and light sleep), stage II (medium-depth sleep), and stage III (deepest sleep).
- REM sleep phase (paradoxical sleep, fast-wave sleep) — periodically alternates with slow-wave sleep.
Throughout the night, the phase-alternation cycles repeat 6–7 times, with the duration of non-REM sleep gradually shortening and REM sleep increasing.
Which neurological diseases require differential diagnosis with restless legs syndrome?
Differential diagnosis of restless legs syndrome is carried out with neurological diseases and conditions that act as its "mimics".
Such pathologies include:
- Polyneuropathy — damage to the peripheral nerves of the extremities (e.g., in diabetes mellitus), causing pain syndrome.
- Parkinson's disease — it is necessary to exclude the "wearing-off" phenomenon (worsening of motor symptoms due to the waning effect of antiparkinsonian drugs).
- Cramps — muscle cramps.
Symptoms can also be mimicked by venous outflow disorders.
To memorize the movements in periodic limb movement disorder, imagine a wave moving from bottom to top: big toe (extension) → ankle (dorsiflexion) → knee (flexion) → hip joint (flexion).
Class and exam questions
What apnea index value is considered diagnostically significant?
The diagnosis is established if the apnea-hypopnea index is greater than 5. This means 5 or more breathing cessations lasting over 10 seconds per hour.
How to clinically differentiate restless legs syndrome?
The key sign is that pulling, aching, or tingling sensations in the legs occur at rest, intensify before sleep, and force the patient to actively move, walk, or change position for relief.
What is the principle of CPAP therapy?
The device creates continuous positive airway pressure in the airways. Air is delivered under pressure in the rhythm of spontaneous breathing, physically expanding the narrowed sections of the airways.
What are mouth guards used for in bruxism?
Special dental mouth guards are worn during sleep to prevent tooth destruction and damage to the temporomandibular joints due to severe contraction of the masticatory muscles.
What else to study on this topic
- Polysomnography: method of recording oronasal airflow and interpreting oximetry
- Anatomical risk factors: retraction of the lower jaw and tongue during sleep
- Mechanisms of action of dopaminergic agents in restless legs syndrome
- Differential diagnosis of nocturnal cramps and other muscle spasms
- Indications for surgical treatment of obstructive sleep apnea
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Other topics in "Chapter 32. Sleep-Wake Disorders"
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