Central sleep apnoea: causes, symptoms, tests and treatment

Sleep apnoea means that breathing stops and starts during sleep. The NHS notes that the most common type is obstructive sleep apnoea, in which the airways become too narrow while you sleep. Central sleep apnoea is a different mechanism. Great Ormond Street Hospital (GOSH) explains that in central sleep apnoea there are pauses in breathing during which the body makes no attempt to breathe, because the brain does not send the correct signals to the muscles that control breathing.

The brainstem normally controls breathing and is very sensitive to the chemicals in the blood, particularly carbon dioxide. GOSH explains that if the level of carbon dioxide falls too low, a central apnoea occurs to allow it to rise again, which is part of how the control system works. In central sleep apnoea this control system does not work as it should.

Source note: the UK patient information used here comes from the NHS website page on sleep apnoea in general, which concentrate on obstructive disease, and from a paediatric hospital page on central sleep apnoea, which was last reviewed by the trust in 2016. Adult-specific detail on central sleep apnoea is therefore limited on this page, and an adult sleep or respiratory specialist is the right person to explain how it applies to you.

GOSH says central sleep apnoea can be caused by a number of conditions that affect the control centres for breathing in the brainstem. It describes several types.

• Apnoea of infancy or prematurity, in babies and young children, which may be caused by immaturity of the brainstem respiratory control centre or by other medical conditions.

• Central sleep apnoea due to an underlying medical condition affecting the nervous system, such as neurological conditions, craniofacial abnormalities, neuromuscular conditions or injury or abnormality of the brainstem.

• Central sleep apnoea due to an underlying condition affecting chemoreception, including congenital central hypoventilation syndrome, cardiac failure, obesity hypoventilation syndrome and Prader-Willi syndrome.

GOSH lists observed episodes of stopped breathing or abnormal breathing patterns during sleep, abrupt awakenings with shortness of breath, difficulty staying asleep, excessive daytime sleepiness, difficulty concentrating, mood changes and morning headaches. Snoring can occur but may not be as prominent as in obstructive sleep apnoea.

The NHS lists general sleep apnoea symptoms such as breathing stopping and starting, gasping, snorting or choking noises, waking up a lot and loud snoring, with daytime tiredness, poor concentration, mood swings and morning headaches. It suggests asking someone to stay with you while you sleep so they can check, and to see a GP if you have the main symptoms.

The NHS says that if a GP thinks you may have sleep apnoea they may refer you to a specialist sleep clinic, where devices check things like breathing and heartbeat overnight. This can usually be done at home, but sometimes you may need to stay in the clinic. The test shows whether you have sleep apnoea and how severe it is, based on how often breathing stops (the AHI score).

GOSH explains that sleep studies are the main method of investigating central sleep apnoea, and that a range of tests may be needed to confirm or rule out the diagnosis because breathing difficulties during sleep have many possible medical causes. For children, a sleep study is typically an overnight stay with sensors measuring breathing rate, heart rate, oxygen levels, chest wall movement, airflow and carbon dioxide, interpreted by a paediatric sleep consultant.

GOSH says treatment depends on the cause. Apnoea of prematurity or infancy may improve as the child gets older and the respiratory centre matures. Supplemental oxygen during sleep may reduce the number of pauses and lessen the effects by improving oxygen levels in the blood. Bilevel positive airway pressure (BPAP) provides extra air pressure through a mask, varying on breathing in and out, and can be set to deliver a breath if one has not occurred within a certain number of seconds. Medication may sometimes be available to stimulate breathing, and surgery may be an option if the brainstem is affected by an abnormality or compression such as in Chiari malformation.

For sleep apnoea in general, the NHS describes CPAP machines, lifestyle changes such as losing weight, stopping smoking and cutting back alcohol, and other devices, noting that CPAP is provided free on the NHS if needed. A sleep specialist will decide which treatment is appropriate for central rather than obstructive disease, as the right device and settings can differ.

The NHS says that without treatment sleep apnoea can lead to high blood pressure, a higher chance of stroke, type 2 diabetes, heart disease, depression or mood changes, difficulty concentrating and a higher chance of a serious accident caused by tiredness. It also says you may need to tell the DVLA about your sleep apnoea, and that if sleep apnoea with excessive sleepiness is confirmed you must not drive until symptoms such as feeling very tired are under control.

On the NHS, sleep apnoea is investigated through a GP referral to a sleep clinic or respiratory service, with treatment and equipment provided free if needed. Private sleep clinics offer sleep studies and consultations; if you go privately, it is important that results are shared with your GP and that any underlying cause, such as heart failure, is properly investigated and managed.