Sleep Apnoea

Overview

Sleep apnoea is a sleep-related breathing disorder characterised by repeated pauses in breathing or periods of shallow breathing during sleep. These episodes can last from a few seconds to several minutes and occur multiple times a night, often accompanied by snorting or choking sounds as normal breathing resumes.

The most common type, obstructive sleep apnoea (OSA), involves a physical blockage of the airway. Central sleep apnoea (CSA), less common, results from a failure of the brain to send the appropriate signals to the muscles that control breathing.

Signs and Symptoms

The symptoms of sleep apnoea include loud snoring, episodes of breathing cessation witnessed by others, abrupt awakenings accompanied by gasping or choking, morning headache, daytime sleepiness, difficulty concentrating, and irritability. Some individuals might be asymptomatic or have subtle manifestations such as treatment-resistant hypertension and cardiac arrhythmias.

Risk Factors

Several factors increase the risk of developing sleep apnoea:

• Obstructive Sleep Apnoea (OSA): Obesity, male gender, age over 40, large neck circumference, enlarged tonsils, endocrine disorders like hypothyroidism, and lifestyle habits such as smoking or alcohol consumption.
• Central Sleep Apnoea (CSA): Older age, male gender, heart failure, atrial fibrillation, stroke, and spinal cord injury.

Diagnosis

The diagnosis of sleep apnoea often starts with a clinical evaluation and an overnight sleep study, known as polysomnography (PSG), which monitors various physiological parameters during sleep. Home sleep tests are an alternative for some patients.

The Apnoea-Hypopnea Index (AHI), which measures the number of apnoeas and hypopneas per hour of sleep, is used to classify the severity of sleep apnoea.

Treatment

Lifestyle Changes: Weight loss, avoidance of alcohol and sedatives, and changing sleep positions can be effective in mild cases.

Continuous Positive Airway Pressure (CPAP): CPAP is the most common treatment for moderate to severe OSA, using a machine that provides a constant stream of air through a mask to keep the airways open during sleep.

Oral Appliances: Custom-made devices that adjust the position of the lower jaw and tongue to keep the airway open.

Surgery: Various surgical options are available, such as uvulopalatopharyngoplasty (UPPP) and maxillomandibular advancement (MMA), aimed at removing or stiffening tissue and enlarging the airway.

Complications

Untreated sleep apnoea can lead to a range of serious health problems, including hypertension, cardiovascular disease, stroke, diabetes, and increased risk of motor vehicle accidents. The chronic lack of restorative sleep can also result in significant daytime sleepiness, mood disorders, and cognitive impairment.

Epidemiology

Sleep apnoea is a common disorder affecting approximately 1 in 10 people. It is more prevalent in men than women and its incidence increases with age and obesity.

In 2019, it was estimated that OSA affects around 936 million to 1 billion people globally between the ages of 30-69.

History

The clinical recognition of sleep apnoea has evolved significantly, with the introduction of CPAP therapy in the 1980s being a major milestone. This has led to the establishment of many sleep clinics and the development of various treatment modalities to manage this condition effectively.

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Self-assessment MCQs (single best answer)

What is the most common type of sleep apnoea?

Which of the following is NOT a common symptom of sleep apnoea?

What diagnostic tool is considered the gold standard for diagnosing sleep apnoea?

Which of the following lifestyle changes is NOT typically recommended for managing sleep apnoea?

What is the primary function of a CPAP machine in treating sleep apnoea?

Which of the following is a common risk factor specifically for central sleep apnoea (CSA)?

Which surgical procedure involves advancing the lower jaw to treat sleep apnoea?

Which of the following complications is NOT typically associated with untreated obstructive sleep apnoea (OSA)?

Which of the following devices is often used as an alternative to CPAP for mild to moderate obstructive sleep apnoea?

What is the Apnoea-Hypopnea Index (AHI) used to measure?