Snoring and witnessed sleep apnoea

Snoring is the vibration of the soft tissues of the upper airway during sleep. It is common (about 40% of adult men and 25% of adult women snore habitually) and mostly benign, but loud, habitual snoring with witnessed pauses, gasping and daytime sleepiness is the cardinal presentation of obstructive sleep apnoea (OSA).

Clinical relevance. Moderate to severe OSA affects an estimated 10 to 17% of men and 3 to 9% of women in middle age and is under-diagnosed. It is an independent risk factor for resistant hypertension, atrial fibrillation, stroke, coronary disease, type 2 diabetes, non-alcoholic fatty liver disease and sleepiness-related collisions (a 2 to 3 fold higher crash risk). Treated, it improves blood pressure, sleepiness, mood and quality of life.

Classification.

• Primary (simple) snoring: noise without apnoeas, hypopnoeas, hypoxaemia or sleepiness.
• Upper airway resistance syndrome: snoring with arousals and sleepiness, without frank apnoeas.
• Obstructive sleep apnoea: AHI of 5 events/hour or more with symptoms, or 15 events/hour or more regardless of symptoms. Mild 5 to 15, moderate 15 to 30, severe over 30.
• Overlap syndrome: OSA with COPD.
• Obesity hypoventilation syndrome: BMI over 30, awake PaCO2 over 6.0 kPa and sleep-disordered breathing, after other causes of hypoventilation are excluded.

Mechanism. Pharyngeal collapsibility is determined by:

• anatomy (fat deposition around the pharynx, neck circumference, craniofacial structure, tonsillar size, tongue volume)
• loss of muscle tone in sleep (especially REM and supine)
• ventilatory control instability
• a low arousal threshold
• rostral fluid shift overnight (heart failure, renal disease, peripheral oedema)

Obstruction produces hypoxia, hypercapnia and arousal, which drive sympathetic activation, oxidative stress, endothelial dysfunction and insulin resistance.

History.

• Snoring pattern: loudness, position dependence, nightly or occasional, effect on partner, new onset after weight gain or after starting sedatives or alcohol.
• Witnessed apnoeas, gasping, choking, restless sleep, nocturia (2 or more times), night sweats, dry mouth, morning headache, reflux.
• Daytime: sleepiness, unrefreshing sleep, falling asleep driving, concentration, mood, libido, erectile dysfunction.
• Comorbid disease: hypertension (especially resistant), atrial fibrillation, heart failure, stroke, diabetes, hypothyroidism, acromegaly, polycystic ovary syndrome, Down syndrome, neuromuscular disease.
• Nasal obstruction, allergic rhinitis, tonsillar disease, previous head and neck surgery.
• Medicines and substances: alcohol, benzodiazepines, opioids, zolpidem, muscle relaxants, testosterone, and smoking.
• Risk tools: Epworth Sleepiness Scale (over 10 abnormal); STOP-BANG (snoring, tiredness, observed apnoea, high blood pressure, BMI over 35, age over 50, neck circumference over 40 cm, male sex).
• A STOP-BANG score of 5 to 8 gives a high probability of moderate to severe OSA, 3 to 4 intermediate, 0 to 2 low.

Examination.

• BMI, neck circumference, waist circumference, blood pressure.
• Oropharynx: Mallampati class (III or IV is high risk), tonsil size (grades 1 to 4), uvula and soft palate bulk, tongue size, retrognathia or micrognathia, overjet.
• Nose: septal deviation, turbinate hypertrophy, polyps, valve collapse.
• Neck: goitre, masses.
• Cardiovascular and respiratory: heart failure signs, pulmonary hypertension, hypoventilation signs (plethora, oedema, raised JVP).
• Endocrine: hypothyroid or acromegalic features.

Red flags.

• Sleepiness while driving or a collision or near miss; safety-critical occupation (driver, pilot, machine operator).
• Daytime hypoxia or hypercapnia, cor pulmonale, polycythaemia, or bicarbonate of 27 mmol/L or more.
• Resistant hypertension, nocturnal arrhythmia, unexplained pulmonary hypertension.
• Unilateral tonsil enlargement, neck mass, hoarseness, dysphagia, weight loss (neoplasm).
• Neuromuscular disease or bulbar symptoms.
• Pre-operative patient needing sedation or major surgery.
• Pregnancy with hypertension.

• Primary snoring.
• Obstructive sleep apnoea (the leading consideration), upper airway resistance syndrome, obesity hypoventilation syndrome, overlap syndrome.
• Central sleep apnoea or Cheyne-Stokes breathing (heart failure, opioids, stroke).
• Nasal causes: septal deviation, rhinitis, polyps, adenoid tissue (young adults), nasal valve collapse.
• Pharyngeal and laryngeal: tonsillar hypertrophy, tongue base tumour, lymphoma, laryngomalacia (rare in adults), vocal cord dysfunction.
• Endocrine: hypothyroidism, acromegaly, Cushing syndrome.
• Other causes of witnessed night events: REM sleep behaviour disorder, nocturnal seizures, periodic limb movements, nocturnal reflux, sleep-related laryngospasm, panic attacks.
• Causes of daytime sleepiness that coexist: insufficient sleep, narcolepsy, medicines, depression.

1. Pre-test probability: STOP-BANG and Epworth; do not test those with simple snoring and no risk features, who need only advice.
2. Baseline: BMI, blood pressure, venous bicarbonate (27 mmol/L or more triggers a daytime blood gas), full blood count, thyroid stimulating hormone, fasting glucose or glycated haemoglobin, lipids, electrocardiogram. Echocardiogram if heart failure, pulmonary hypertension or atrial fibrillation is suspected.
3. Home respiratory polygraphy for suspected uncomplicated OSA (a rise of 4% or more in the oxygen desaturation index correlates with an AHI of 15 or more); report the AHI, oxygen desaturation index, nadir saturation, time under 90% and central event proportion.
4. Attended polysomnography when polygraphy is negative or non-diagnostic with high suspicion, for suspected central apnoea, hypoventilation or neuromuscular disease, significant cardiopulmonary disease, parasomnia, or where narcolepsy is suspected.
5. Awake and sleep gas assessment (transcutaneous carbon dioxide) when hypoventilation is suspected.
6. Upper airway assessment: nasendoscopy and, in selected patients, drug-induced sleep endoscopy to define the level of collapse before surgery or hypoglossal nerve stimulation; lateral cephalometry for jaw surgery planning.
7. Assess comorbidity: blood pressure review, atrial fibrillation screening, liver enzymes, glycaemic status.
8. Occupation and driving assessment, and sleepiness severity.

Limits. The AHI does not capture the severity of hypoxic burden or symptoms. Polygraphy has no sleep staging and misses short events or arousals. STOP-BANG has high sensitivity but low specificity (many false positives at a score of 3 to 4). The AHI is position and stage dependent, and a supine REM-predominant pattern can be underestimated on a single night.

All patients.

• Weight reduction: aim for 10% or more of body weight; the AHI falls by roughly 25 to 30% for a 10% loss.
• Avoid alcohol within 4 hours of sleep and avoid sedatives.
• Stop smoking: nicotine patch 21 mg/24 hours for 6 weeks, 14 mg for 2 weeks, 7 mg for 2 weeks.
• Or varenicline 0.5 mg daily for 3 days, 0.5 mg twice daily for 4 days, then 1 mg twice daily for 12 weeks.
• Positional therapy (side sleeping, a device that discourages supine sleep) when events occur mainly supine.
• Treat nasal obstruction: intranasal steroid (for example mometasone 100 micrograms/nostril twice daily or fluticasone 100 micrograms/nostril daily) for rhinitis; septoplasty or turbinate reduction where needed.
• Sleep hygiene: regular schedule, 7 to 9 hours.

Obstructive sleep apnoea.

• CPAP (auto-titrating, typically 4 to 20 cmH2O) is first line for moderate to severe disease, and for mild disease with symptoms or cardiovascular risk. Optimise mask fit, humidification and ramp; review at 2 to 4 weeks and 3 months; adherence target at least 4 hours/night on at least 70% of nights; residual AHI under 5 events/hour.
• Mandibular advancement device for mild to moderate OSA, simple snoring, or CPAP intolerance; check for temporomandibular joint disease and dental suitability; review for bite change.
• Surgery in selected cases: tonsillectomy for large tonsils, maxillomandibular advancement for craniofacial deficiency, nasal surgery to improve CPAP tolerance, hypoglossal nerve stimulation in selected patients (BMI under 35, AHI 15 to 65, no complete concentric collapse at the soft palate).
• Weight-loss pharmacotherapy: tirzepatide, started 2.5 mg subcutaneously weekly for 4 weeks and increased by 2.5 mg every 4 weeks to a maintenance 10 mg or 15 mg weekly, is effective in moderate to severe OSA with obesity (AHI reductions up to about 50 to 60%).
• Bariatric surgery for BMI of 35 or more with comorbidity.
• Wakefulness drugs for residual sleepiness despite adherent CPAP, after other causes are excluded: modafinil 100 mg each morning, increased to 200 mg (maximum 400 mg).
• Or solriamfetol 37.5 mg once daily, increased after 3 days to 75 mg and then to a maximum of 150 mg.

Central sleep apnoea and hypoventilation. Optimise heart failure; avoid adaptive servo-ventilation when ejection fraction is 45% or less; non-invasive ventilation with bilevel support for obesity hypoventilation syndrome (IPAP 14 to 20 cmH2O, EPAP 4 to 8 cmH2O, with a back-up rate) in specialist units.

Monitoring. Blood pressure at 3 months (CPAP lowers 24 hour mean blood pressure by about 2 to 3 mmHg, with larger falls in resistant hypertension); annual weight and symptom review; download CPAP data; repeat sleep study after 10% weight change or substantial surgery.

Referral and escalation. Sleep medicine service for: moderate to severe symptoms, safety-critical occupation, hypoventilation, suspected central or complex apnoea, cardiovascular comorbidity, or treatment failure. ENT for anatomical obstruction. Endocrine for acromegaly or thyroid disease. Anaesthetic review before surgery.

Admission or disposition. Most patients are looked after in the outpatient setting. Admit when there is acute hypercapnic respiratory failure, cor pulmonale or decompensated heart failure.

Safety netting. Do not drive when sleepy; stop and rest if drowsy; the licensing authority must be told if sleepiness persists, and driving can resume after symptom control is confirmed. Avoid alcohol and sedatives. Report new daytime breathlessness, ankle swelling, chest pain, palpitations, headache with confusion or any collision. Bring CPAP to hospital for any admission or procedure.

Special groups.

• Pregnancy: CPAP is safe and treatment reduces hypertensive disease risk; limit weight gain.
• Peri-operative patients: continue CPAP; minimise opioids and benzodiazepines; extended monitoring in recovery.
• Professional drivers: more intensive follow-up with objective adherence data.
• Older adults: avoid sedative-hypnotics; consider a lower threshold for testing in nocturnal arrhythmia.
• Women: may present with insomnia, fatigue, depression and morning headache rather than loud snoring; the threshold for testing should be lower in these groups.