Obstructive Sleep Apnoea
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Direct answer
Loud snoring, witnessed apnoeas, unrefreshing sleep and excessive daytime sleepiness in an obese, thick-necked patient — this is obstructive sleep apnoea (OSA), recurrent collapse of the pharyngeal airway during sleep producing apnoeas and hypopnoeas that fragment sleep and desaturate the patient. Polysomnography confirms it with an apnoea-hypopnoea index of five or more per hour with symptoms — mild 5 to 15, moderate 15 to 30, severe above 30. Continuous positive airway pressure (CPAP) at night is the first-line treatment, with weight loss central to long-term control.
What you must remember
- Diagnosis: polysomnography remains the standard; an apnoea-hypopnoea index of at least 5 with symptoms, or at least 15 regardless of symptoms, defines OSA — mild 5 to 15, moderate above 15 up to 30, severe above 30 events per hour; home sleep apnoea testing suits uncomplicated high-probability patients.
- STOP-BANG scores Snoring, Tiredness, Observed apnoeas, Pressure, Body mass index above 35, Age above 50, Neck above 40 cm and male Gender; three or more marks high risk.
- Risk factors and contributors: obesity (the strongest), male sex, menopause, macroglossia and retrognathia, acromegaly, hypothyroidism, adenotonsillar hypertrophy in children, alcohol and sedatives at night, and supine sleeping.
- Consequences of untreated OSA: systemic and pulmonary hypertension, cor pulmonale, atrial fibrillation, stroke and myocardial infarction, insulin resistance, daytime somnolence with road accidents, and overlap with obesity-hypoventilation when daytime hypercapnia appears.
- Treatment ladder: weight reduction and positional therapy; CPAP titrated to abolish apnoeas — first-line for moderate-to-severe disease that relieves sleepiness; mandibular advancement devices for mild disease or CPAP intolerance; adenotonsillectomy first-line in children with adenotonsillar hypertrophy; uvulopalatopharyngoplasty for selected anatomical phenotypes; tracheostomy is a last resort.
- Avoid evening alcohol and sedatives; screen for hypothyroidism and acromegaly; counsel commercial drivers on fitness; switch to bilevel therapy when hypercapnia supervenes.
- Distinguish OSA from central sleep apnoea and Cheyne-Stokes respiration of heart failure — on the polysomnogram, respiratory effort persists in OSA and is absent in central events.
From a sleepy driver to a titrated machine
A 48-year-old obese bus driver is referred after his wife watched him stop breathing at night; he snores loudly, wakes unrefreshed and dozes at traffic lights. Screen him with STOP-BANG — he scores five, high risk. Confirm with polysomnography (home testing serves uncomplicated high-probability cases): an apnoea-hypopnoea index of at least 5 with symptoms, or 15 regardless, defines the disease, and his index of 42 grades it severe. Read the tracing for effort as well as events, because the classification question lives there: in OSA the airway occludes while respiratory effort continues, whereas central apnoea lacks both, often as the Cheyne-Stokes pattern of heart failure. Audit the contributors — obesity strongest, male sex, menopause, macroglossia and retrognathia, acromegaly and hypothyroidism worth screening, alcohol and sedatives, supine sleeping — and lay out why treatment goes beyond comfort: hypertension, cor pulmonale, atrial fibrillation, stroke, insulin resistance and road accidents, with obesity-hypoventilation overlapping once daytime hypercapnia appears (bilevel replaces CPAP). The ladder runs weight reduction and positional therapy; CPAP first-line for moderate-to-severe disease; mandibular advancement devices for mild disease or CPAP intolerance; adenotonsillectomy first-line in the child; uvulopalatopharyngoplasty for selected anatomies; tracheostomy the last resort. Counsel him on evening alcohol, driving fitness and weight loss.
Where students slip
The obstructive-versus-central question is the classic: effort present against a collapsed airway in OSA, effort absent in central events — the Cheyne-Stokes stem of heart failure is answered by that distinction. The index construct is misquoted: 5 with symptoms or 15 without, with severity bands at 15 and 30. Simple snoring is over-treated as disease, while witnessed apnoeas with sleepiness in an obese patient are under-studied — the "next step" is the sleep study, not reassurance.
Frequently asked questions
What apnoea-hypopnoea index defines OSA?
Five or more events per hour with symptoms, or 15 or more without symptoms; above 30 events per hour grades as severe disease.
What does STOP-BANG screen for?
High pretest probability of OSA using snoring, tiredness, observed apnoeas, pressure, body mass index above 35, age above 50, neck above 40 cm and male gender — three or more flags risk.
What is the first-line treatment?
Nocturnal continuous positive airway pressure splinting the pharynx, combined with weight loss; mandibular advancement devices serve mild cases or the CPAP-intolerant.
How does OSA differ from central sleep apnoea?
OSA has ongoing respiratory effort against a collapsed airway, while central apnoea lacks both airflow and effort — commonly Cheyne-Stokes breathing in heart failure.
Why must OSA be treated beyond symptom relief?
Because untreated disease drives systemic and pulmonary hypertension, atrial fibrillation, stroke, insulin resistance and daytime accidents.
What is the first-line treatment in a child?
Adenotonsillectomy for adenotonsillar hypertrophy, with CPAP reserved for residual disease or non-surgical candidates.