Repeated temporary interruption of breathing during sleep
- Most common in children and in adults between the ages of 40 and 60
- More common in males
- Being overweight, drinking alcohol, and smoking are risk factors
- Genetics is not a significant factor
In sleep apnoea, breathing stops during sleep for at least 10 seconds at least five times an hour. Mild sleep apnoea causes few symptoms, but severe sleep apnoea may lead to low oxygen levels, which can cause serious symptoms. Sleep apnoea is more common in people who smoke, drink alcohol, or are overweight. It may occur at high altitudes.
What are the types?
Sleep apnoea can be divided into two types: obstructive sleep apnoea (OSA), which is common and due to blockage of the airway, and central sleep apnoea, which is rare and caused by a problem with the nerves that control breathing. In some cases, a mixture of both types of sleep apnoea occurs.
Obstructive sleep apnoea
This condition mainly affects men aged between 40 and 60. OSA occurs when the air passages in the upper respiratory tract become obstructed during sleep. Most commonly, obstruction is caused by the soft tissue of the pharynx relaxing and blocking the flow of air. The obstruction prevents breathing until the low levels of oxygen in the blood cause a person to respond by waking up and taking a deep, snorting breath. Being overweight (particularly around the neck area) or having a large tongue or a small mouth can also cause or contribute to the obstruction. In children, enlarged tonsils (see Tonsillitis) or enlarged adenoids are the most common causes of obstruction that can lead to OSA.
What are the symptoms?
The symptoms of OSA develop gradually, and it may be a partner or another member of your family who first notices your disturbed sleep. Central sleep apnoea may develop suddenly, depending on the cause. Symptoms of both types may include:
Restless, unrefreshing sleep.
Poor memory and concentration.
Headache in the morning.
Change in personality.
In men, erectile dysfunction.
Frequent passing of urine at night.
In severe cases, daytime sleepiness may result in accidents, such as when driving. Taking sleeping drugs and drinking alcohol may aggravate the symptoms. Left untreated, complications may develop, such as an irregular heartbeat (see Arrhythmias) and pulmonary hypertension. There is also an increased risk of high blood pressure developing (see Hypertension). Severe sleep apnoea may eventually be life-threatening.
How is it diagnosed?
If your doctor suspects that you have sleep apnoea, he or she will examine your nose and throat to look for an obvious cause of obstruction to your breathing. You may also have an endoscopy of the nose and throat and X-rays or CT scanning of the head and neck. To confirm the diagnosis and assess the severity of sleep apnoea, you may be asked to undergo sleep studies.
What is the treatment?
If you have mild OSA, you should avoid sleeping drugs and alcohol. If you are overweight, losing weight often helps. You should also try to sleep on your side or elevate the head of the bed, which may relieve the symptoms. If it is caused by high altitudes, sleep apnoea should disappear when you acclimatize or return to lower altitudes.
The first choice of treatment for OSA is usually positive pressure ventilation. In this procedure, air is steadily pumped through a tightly-fitting nasal mask. The increased air pressure keeps the airways open so that breathing is easier. The treatment is easy to use, but some people may find the mask uncomfortable and difficult to tolerate. If positive pressure ventilation is not effective, surgery to reconstruct the soft palate may be considered. If OSA is caused by enlarged tonsils or adenoids, surgery may be necessary to remove them (see Tonsillectomy and adenoidectomy).
Treatment for OSA is usually successful. Central sleep apnoea is more difficult to treat because, in most cases, the underlying causes are less likely to be reversible.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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