ICD-117A41	OBSTRUCTIVE SLEEP APNOEA (OSA) Obstructive sleep apnoea
ICD-10G47.3	Sleep apnoea
DSM-5-TRG47.33	Obstructive Sleep Apnea Hypopnea

1. Definition and nosology

Obstructive Sleep Apnea (OSA; ICD-11: 7A41; DSM-5-TR: G47.33) — recurrent complete (apnea) or partial (hypopnea) obstruction of the upper airway during sleep; daytime sleepiness, cognitive impairment, increased cardiovascular mortality.

2. History

• Gastaut H. (1965) — classic description of OSA.
• Sullivan C.E. (1981) — invented CPAP.
• AASM Practice Parameters (update).

3. Epidemiology

• In adults: approximately 13% in men, approximately 6% in women (moderate-to-severe OSA).
• Increases with age and BMI.
• Comorbidity: hypertension (50%), cardiovascular disease, stroke, atrial fibrillation, diabetes.

4. Aetiology and pathogenesis

• Anatomical — adipose tissue in the upper airway, small mandible, enlarged tonsils/adenoids.
• Genetic and family history.
• Posture — worsens in supine position.
• Alcohol, sedative — worsens.

5. Clinical features

• Waking up with loud snoring, observed apnea, or choking sensation.
• Daytime sleepiness (dangerous while driving), fatigue.
• Morning headache, dry mouth.
• Concentration, memory problems.
• Sexual dysfunction, depressive symptoms.

6. Diagnosis

6.1 Unified diagnostic criteria

Polysomnography (PSG) — AHI (Apnea-Hypopnea Index) ≥ 5/hour + symptoms; AHI ≥ 15 irrespective of symptoms.

6.2 Source-specific clarifications

• AASM Clinical Practice Guideline for Diagnostic Testing (2017).
• Home Sleep Apnea Test (HSAT) — appropriate for moderate-severe OSA.

6.3 Diagnostic algorithm

1. STOP-BANG screening (Snoring, Tiredness, Observed apnea, BP, BMI, Age, Neck, Gender).
2. Epworth Sleepiness Scale.
3. Polysomnography or HSAT.
4. Cardiovascular evaluation.

6.4 Differential diagnosis

7. Examination and assessment

• STOP-BANG, Epworth.
• Polysomnography or Home Sleep Apnea Testing.
• BMI, neck circumference.

8. Treatment

1. CPAP — Continuous Positive Airway Pressure is first-line. For moderate-severe OSA; AHI significantly reduced, mortality reduced.
2. BiPAP — in refractory cases or CPAP non-response.
3. Weight loss — mild OSA; bariatric surgery in severe obesity.
4. Mandibular advancement device (MAD) — mild-moderate OSA, CPAP non-responsive.
5. Postural therapy — supine-avoidant.
6. Surgery (UPPP, hypoglossal nerve stimulation — Inspire) — in selected cases.
7. Withdrawal from alcohol and sedatives.

Source-specific specifications

• AASM CPAP standard, MAD selective.
• NICE NG202 (OSA-COPD-overlap).

Treatment methods

1. CPAP — First-line; adherence main problem.
2. Mandibular Advancement Device (MAD) — Mild-moderate OSA; when CPAP fails.
3. Hypoglossal Nerve Stimulation (Inspire) — New surgical option; in selected cases.
4. STOP-BANG, Epworth, PSG — Screening and diagnosis.

9. Prognosis

• Cardiovascular mortality decreases with CPAP.
• Without treatment — stroke, atrial fibrillation, diabetes, increased mortality.

10. Myths and misconceptions

Myth 1: “OSA only occurs in obese people”

Evidence: Possible in normal-weight patients as well (anatomical factors).

Myth 2: “Snoring is the main sign of OSA, nothing more is needed”

Evidence: snoring alone not proof; AHI measurement required; untreated OSA high mortality and morbidity.

Myth 3: “CPAP only reduces symptoms, does not affect mortality”

Evidence: CPAP reduces cardiovascular mortality (Marin Lancet 2005).

Myth 4: “Central sleep apnea and OSA are treated the same”

Evidence: Different intervention (ASV — Adaptive Servo-Ventilation for central apnea); differentiation is critical.

11. Sources

1. WHO. ICD-11. 7A41 Obstructive sleep apnoea. 2024.
2. APA. DSM-5-TR. 2022.
3. Kapur V.K. et al. AASM Clinical Practice Guideline for Diagnostic Testing for Adult OSA. J Clin Sleep Med 2017;13(3):479–504.
4. Marin J.M. et al. Long-term cardiovascular outcomes in men with OSA-hypopnoea with or without treatment with CPAP. Lancet 2005;365(9464):1046–1053.