# Obstructive Sleep Apnoea

> Obstructive sleep apnoea with snoring, apnoeic episodes, Epworth score, polysomnography, CPAP and surgery for MBBS ENT exams.

- Canonical URL: https://prepelephant.com/topics/mbbs/ent/obstructive-sleep-apnoea
- Exam / course: MBBS · Subject: ENT
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Obstructive Sleep Apnoea", PrepElephant, https://prepelephant.com/topics/mbbs/ent/obstructive-sleep-apnoea

## Direct answer

Obstructive sleep apnoea (OSA) is repeated collapse of the pharyngeal airway during sleep, producing apnoeas and hypopnoeas that fragment sleep and drop oxygen saturation. The patient, usually middle-aged and overweight, snores loudly, has witnessed pauses in breathing and falls asleep easily by day. Diagnosis is confirmed by polysomnography, graded by the apnoea-hypopnoea index, and treated first with weight loss and continuous positive airway pressure (CPAP), with surgery reserved for selected anatomical obstruction.

## What you must remember

- **Mechanism:** during sleep the pharyngeal dilator muscles relax, and a narrowed airway — from obesity, macroglossia, large tonsils and adenoids, retrognathia or nasal obstruction — collapses repeatedly.
- **Clinical features:** loud habitual snoring, witnessed apnoeic pauses, restless sleep, excessive daytime sleepiness, morning headache and dry mouth, irritability and poor concentration; the Epworth sleepiness scale quantifies sleepiness.
- **Examination:** body mass index and neck circumference, nasal patency, tonsil size, tongue position and any retrognathia; in children, adenotonsillar hypertrophy dominates the picture.
- **Diagnosis:** polysomnography (sleep study) records sleep stages, airflow, respiratory effort, oxygen saturation and heart rate; an apnoea-hypopnoea index above five events per hour with symptoms defines the disease, graded as mild, moderate or severe.
- **Consequences of untreated OSA:** systemic hypertension, increased cardiovascular and cerebrovascular risk, type 2 diabetes association, daytime accidents and reduced quality of life.
- **Management ladder:** weight reduction, alcohol and sedative avoidance, positional therapy; CPAP as the gold standard for moderate to severe disease; mandibular advancement appliances for mild cases with dental fit; and surgical options — adenotonsillectomy in children, septoplasty or other nasal surgery to aid therapy, uvulopalatopharyngoplasty in selected adults, and tracheostomy as the definitive bypass in extreme cases.
- **Follow-up:** symptom review, adherence to CPAP and repeat assessment after significant weight change; anaesthesia in OSA patients carries higher airway risk and needs planning.

## Common confusion

Simple snoring without apnoeas, somnolence or desaturation is not OSA, though it may share the same anatomy. Also distinguish obstructive from central sleep apnoea: in the obstructive type, respiratory effort continues against a closed airway, whereas in central apnoea both effort and airflow cease — a distinction the sleep study traces and one that changes treatment entirely.

## Exam-focused takeaway

For theory, define OSA, list risk factors and clinical features, describe the polysomnographic diagnosis with the apnoea-hypopnoea index, and give the management ladder from lifestyle measures through CPAP to site-directed surgery. In viva, expect the Epworth scale, why adenotonsillectomy helps children and why CPAP, not surgery, is first line for most adults. In the posting, take a snoring history from the spouse — the witnessed apnoea account often makes the diagnosis before any test.

## Frequently asked questions

### How is obstructive sleep apnoea defined?

Recurrent upper airway collapse during sleep causing apnoeas and hypopnoeas with arousals and desaturation, an apnoea-hypopnoea index above five per hour with typical symptoms.

### What is the Epworth sleepiness scale?

A short questionnaire scoring the tendency to doze in eight situations, used to grade excessive daytime sleepiness and monitor response to treatment.

### What is the first-line treatment for moderate to severe OSA?

Weight loss wherever applicable plus CPAP therapy at night, which splints the airway open and reverses apnoeas and desaturation.

### Which operation most helps children with OSA?

Adenotonsillectomy, because adenoid and tonsillar hypertrophy is the dominant cause in children.

### What is the role of uvulopalatopharyngoplasty?

It enlarges the oropharyngeal airway by resecting redundant palatal and tonsillar tissue in carefully selected adults with palatal-level obstruction, after a sleep study.

### Why must OSA be treated rather than ignored?

Untreated OSA worsens systemic hypertension and cardiovascular risk, impairs daytime function and driving safety, and degrades overall quality of life.