What is obstructive sleep apnoea?

Obstructive sleep apnoea occurs when, during sleeping, your throat walls relax and/or your tongue flops back to block the upper section of the airway. This can lead to a temporary stopping of breathing, known as apnoea. This can cause an interruption in sleep, as your breathing can stop from between a few seconds to about a minute. When your brain registers that you have stopped breathing, a wake-up signal is sent and you begin to breathe again. Apnoeas can occur many times through the night, often without you noticing, but causing you to feel tired the next day.

Causes

Obstructive sleep apnoea happens when your throat muscles relax during sleep. These muscles support your soft palate, uvula, tonsils, tongue and the throat walls. As the throat muscles relax, your airway can become narrow and even close completely, causing reduced breathing. When you are not breathing properly, not as much oxygen is carried around your body. Your brain senses this and wakes you briefly to allow you to reopen your airway. These interruptions may be happening all night long, between 5-30 times or more an hour, without you knowing. This disrupts your sleep patterns and can cause you to feel tired and irritable during the day.

Palate

The roof of the mouth, composed of bone in the front (the hard palate) and a softer tissue at the back (the soft palate).

Tonsils

Small masses of lymphoid tissue located at the back of the mouth and on either side of the back part of the tongue.

Uvula

The small part of the palate that hangs from the back roof of the mouth, above the tongue.

Risk factors

Some risk factors of obstructive sleep apnoea can include:

Obesity or excessive weight

Being obese or carrying too much weight can lead to the formation of fat around your upper airway that can contribute to obstruction of your breathing.

Genetic considerations

Some people have an increased risk of obstructive sleep apnoea due to their anatomy. If your family members have obstructive sleep apnoea, or you are born with a narrow throat or large tonsils, you have an increased risk. Other risk factors include the shape of your facial bone, the size of your throat muscles and having a thicker neck. If you are a male, you are twice as likely to have obstructive sleep apnoea. The risk for females increases if you are overweight or have gone through menopause. The risk of sleep apnoea also increases with age in both sexes.

Illnesses

Some illnesses, including nasal congestion or obstruction, having a large goitre, or reduced thyroid hormone production (hypothyroidism) can increase the risk of obstructive sleep apnoea.

Alcohol, sedatives and tranquilisers

Using these substances can cause the throat muscles to relax, particularly if they are taken before you sleep.

Smoking

Smoking can increase inflammation and fluid retention in your upper airway. If you smoke, you are three times more likely to have obstructive sleep apnoea than people who do not.

Goitre

A visible swelling in the neck or larynx caused by an enlarged thyroid gland.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Tonsils

Small masses of lymphoid tissue located at the back of the mouth and on either side of the back part of the tongue.

Types

The severity of obstructive sleep apnoea is categorised by how often your breathing stops while you sleep. These types include:

  • Normal - fewer than five interruptions per hour;
  • Mild sleep apnoea - anywhere between 5-15 interruptions per hour;
  • Moderate sleep apnoea - anywhere between 15-30 interruptions per hour, and;
  • Severe sleep apnoea - greater than 30 interruptions per hour.

Signs and symptoms

As obstructive sleep apnoea occurs while you are sleeping, you may not know that you have the condition. Some associated signs that you or others may notice can include:

  • Sleepiness during the day, fatigue or tiredness;
  • Irritability or mood changes;
  • Poor concentration;
  • Reduced sex drive or impotence;
  • Frequent toilet breaks during the night;
  • Loud snoring and silence cycles;
  • Episodes of stopped breathing during sleep (apnoeas) witnessed by others, and;
  • Morning headache.

Obstructive sleep apnoea.During obstructive sleep apnoea, breathing temporarily stops as the upper section of the airway is blocked. 

Fatigue

A state of exhaustion and weakness.

Methods for diagnosis

A diagnosis of obstructive sleep apnoea requires the identification of repetitive apnoeas (stopping of breathing) and the presence of symptoms indicating broken sleep; this commonly includes excessive daytime sleepiness. Your doctor may use a questionnaire such as the 'Epworth sleepiness scale' to assess your level of tiredness and advise whether you are safe to drive a car or work with heavy machinery. You may also be referred to a sleep specialist, who can perform overnight monitoring tests to evaluate your signs and symptoms. Some tests to detect obstructive sleep apnoea can include:

Nocturnal polysomnography

This test involves you being connected to equipment to monitor your heart rate, blood oxygen levels, lung and brain activity and breathing patterns. This test is done while you sleep and can identify any problems. This test is normally performed in a special sleep laboratory.

Person lying in bed undergoing nocturnal polysomnography.Nocturnal polysomnography. 

Home sleep test

This test is similar to nocturnal polysomnography, but is slightly simpler and can be done at home. This test often involves measuring the rate of your heart, blood oxygen level, breathing patterns and airflow. During obstructive sleep apnoea, the results will show a drop in oxygen levels and then later, a rise in oxygen levels when you awaken. If abnormal results are found, you may not need to undergo any further testing and your doctor can prescribe a treatment method. Sometimes you may also be required to take a nocturnal polysomnography test to confirm the diagnosis. To rule out that you do not have a throat or nose blockage, your doctor may refer you to an ear, nose and throat specialist (otolaryngologist).

Types of treatment

In milder cases of obstructive sleep apnoea, lifestyles changes including losing weight, cutting down on alcohol or quitting smoking may help improve your condition. In more severe cases, there are many different types of treatment available. These can include:

Making lifestyle changes, such as exercising and losing weight, can help improve obstructive sleep apnoea. 

Continuous positive airway pressure 

The continuous positive airway pressure (CPAP) device helps to keep your airways open while you sleep by providing slightly more air pressure than your normal surroundings. It does this by feeding air through a mask into your mouth and nose. A different type of device, called a bi-level positive airway pressure (BPAP), can provide slightly more pressure when you breathe in and slightly less pressure when you breathe out.

Oral appliances

These appliances are inserted in your mouth before you sleep and can reduce snoring and mild cases of obstructive sleep apnoea. They work by bringing your jaw forward and opening your throat to help you breathe easier.

Surgery

If lifestyle changes and less invasive devices do not improve your obstructive sleep apnoea, surgery may be performed. The main goal of these surgeries is to increase the size of the airway through your throat and nose. Some procedures can include:

Tissue removal

When large tonsils may be contributing to obstructive sleep apnoea, the tonsils can be removed in a procedure called a tonsillectomy. Another procedure involves removing the tonsils and uvula tissue, and tightening the soft palate. This procedure is known as uvulopalatopharyngoplasty (UPPP).

Jaw repositioning

This procedure involves your jaw being moved slightly forward from your other facial bones. This increases the space behind the soft palate and tongue, lessening the chance of a breathing obstruction. An orthodontist and oral surgeon are generally required to perform this procedure called maxillomandibular advancement.

Implants

This procedure is used for patients who cannot tolerate a continuous positive airway pressure (CPAP) device. It involves the surgical insertion of plastic rods into the soft palate to relieve obstructive sleep apnoea.

Forming a new air passageway (tracheostomy)

This procedure can be performed if you have not responded to any other treatment and have severe, life-threatening sleep apnoea. This procedure involves the insertion of a metal or plastic tube into your neck for you to breathe through while you sleep. This tube is covered during the day and when you are breathing normally.

Palate

The roof of the mouth, composed of bone in the front (the hard palate) and a softer tissue at the back (the soft palate).

Tonsils

Small masses of lymphoid tissue located at the back of the mouth and on either side of the back part of the tongue.

Uvula

The small part of the palate that hangs from the back roof of the mouth, above the tongue.

Potential complications

Obstructive sleep apnoea can be considered a serious medical condition. One serious complication it can cause is high blood pressure (hypertension). This is due to the sudden drop in oxygen levels in the blood, which puts increased strain on the cardiovascular system. Low oxygen levels in the blood caused by obstructive sleep apnoea can also damage the heart tissue and may cause cardiac rhythm abnormalities such as atrial fibrillation. Other complications associated with obstructive sleep apnoea include fatigue during the day and increased risk of airway problems with general anaesthesia

Cardiovascular

Relating to the heart and blood vessels.

Fatigue

A state of exhaustion and weakness.

General anaesthesia

The delivery of medication that is given to a person to put them to sleep while having an operation or medical procedure. Afterwards, the person regains consciousness and usually has no memory of the procedure.

Prognosis

If you are diagnosed with obstructive sleep apnoea, there are various treatments to help lower or completely remove the symptoms of the condition. These can include lifestyle changes, the use of devices such as the continuous positive airway pressure (CPAP), or an oral appliance. If these treatments do not ease or stop obstructive sleep apnoea, several surgical options are available.

Prevention

To help prevent obstructive sleep apnoea, some lifestyle changes can be made. These may include maintaining a healthy body weight, quitting smoking and reducing your intake of alcohol and sedatives before you sleep.