Central sleep apnoea, a sleep disorder that causes abnormal respiration during sleep, is a relatively uncommon condition and has lower diagnosis rates compared to other sleep disorders. It is thought that less than 1% of the population develops this condition at some point in their lives.
Today, we are going to look at central sleep apnoea in more detail, including the common causes, symptoms and treatment options.
What is Central Sleep Apnoea?
Central sleep apnoea (CSA) is a type of sleep disorder that affects your breathing while you sleep. It is characterised by pauses in breathing during sleep which occur because the central respiratory centre in your brain doesn’t properly transmit signals to your respiratory muscles that control breathing when you sleep.
During a typical sleep cycle, your brain sends signals to your respiratory muscles to maintain normal breathing. For someone with CSA, there will be a brief lack of communication between the brain and the respiratory muscles. This will cause an interruption in your normal breathing.
When these pauses in breathing, known as apnoea, occur, your body (either your brain or your respiratory muscles) does not make an attempt to breathe. Although a small number of apnoea is normal, for example when you are transitioning between sleep stages, someone with central sleep apnoea will experience breathing interruptions multiple times an hour. They can occur either sporadically or in a cyclical pattern, with each episode typically lasting from a few seconds up to 90 seconds.
Central sleep apnoea can be a primary health condition, which means it occurs on its own or it can be a secondary health condition, which means it occurs secondary to another health condition. The majority of cases of sleep apnoea are secondary, meaning that for most people, another health condition acts as an underlying cause of CSA.
There are multiple types of central sleep apnoea:
Idiopathic Central Sleep Apnoea (Primary CSA):
This type of CSA has no obvious underlying cause. There is no obvious reason why the brain doesn’t send the correct signals to the respiratory muscles during sleep. This type of central sleep apnoea is less common than other types.
Central Sleep Apnoea with Cheyne-Stokes Respiration (CSA-CSR):
This is the most common type of CSA and is most frequently found in people with heart conditions. It is characterised by a gradual increase and then a decrease in breathing effort and airflow. The abnormal breathing observed in CSA-CSR is distinct in that it involves a pattern of small and large breaths, which are followed by longer pauses in breathing.
Central Sleep Apnoea related to a medical condition (without Cheyne-Stokes breathing):
Other medical conditions can be associated with CSA, for example there may be damage to the brain stem which causes a disruption in respiration signals. In this type of CSA, abnormal breathing will occur but not the characteristic Cheyne-Stokes respiration.
Medication or Drug-Induced Central Sleep Apnoea:
Certain types of medication, such as some medications used to treat pain or obesity, or substances, such as methadone, can reduce your brain’s ability to send messages to the respiratory muscles or to properly regulate breathing, leading to CSA.
Treatment-Emergent Central Sleep Apnoea (TE-CSA):
This type of CSA occurs as a side-effect of positive airway pressure (PAP) therapy. PAP therapy is commonly used as a treatment for obstructive sleep apnoea (OSA). In this case, the treatment of one sleep disorder can result in the person developing another sleep disorder. It is estimated that up to 15% of people who have PAP therapy develop TE-CSA. However, in many cases, this type of CSA resolves by itself, without the need for medical intervention.
Central sleep apnoea due to high altitude periodic breathing:
This is usually a short-term sleep disorder that occurs after a previously healthy person has ascended to a high altitude (usually 8,000ft above sea level or more) where there is a lower concentration of oxygen in the air. This can cause you to breathe faster and deeper and cause respiratory pauses during sleep.
What Causes Central Sleep Apnoea?
There are many possible causes of central sleep apnoea. What causes one person to develop CSA can be different to what causes another person to develop this sleep disorder.
Some of the most common causes of central sleep apnoea are:
Cardiovascular conditions
Cardiovascular conditions, including heart failure and atrial fibrillation, are the most common cause of CSA. If the heart fails to pump blood effectively around the body, this can cause changes in blood flow and oxygen levels, which can in turn affect your brain’s respiratory control centres.
Strokes or disorders of the brainstem
If you have damage to the brainstem, for example from a stroke, a neurological disorder, a brain injury or a disease, this can lead to CSA. The brainstem controls breathing and damage to this area can disrupt your body’s normal respiratory signals.
Spinal cord injuries
Individuals who have a spinal cord injury have a significantly higher risk of developing sleep-disordered breathing, including CSA. Spinal cord injury often results in impaired ventilation, including a lack of respiratory effort during sleep.
Certain medications
There are certain medications that can increase the risk of someone developing CSA or that can exacerbate the symptoms of CSA. These can include:
- Opioids.
- Benzodiazepines.
- Antidepressants.
- Anticonvulsants.
- Muscle relaxants.
- Antiplatelet medication.
As well as the possible causes listed above, certain risk factors can increase the likelihood of someone developing central sleep apnoea:
Other medical conditions
Certain medical conditions can increase the risk of developing CSA, including:
- Spinal cord injuries.
- Kidney failure.
- Excessive growth hormone production.
- Some metabolic disorders.
- Obesity.
- Hypoventilation syndrome.
Age
People over 65 years of age are more likely to be diagnosed with CSA. This could be because older people have higher incidences of other health conditions, such as cardiovascular issues and diseases of the brain, which can increase the risk of sleep apnoea. It could also be that the ageing process itself and the ageing of the brain and the respiratory muscles can increase the risk of central sleep apnoea.
Sex
Central sleep apnoea is more commonly diagnosed in men and people assigned male at birth. This could be related to testosterone levels, the differences in the breathing control centre and different upper airway anatomy.
Signs of Central Sleep Apnoea
Because the breathing pauses occur during sleep, many people do not realise they are experiencing central sleep apnoea. Instead, you may be alerted to the breathing pauses by a bed partner, or you may experience other symptoms that cause you to visit a doctor, who then identifies CSA.
Some symptoms that could indicate you have central sleep apnoea include:
- Reports of abnormal night-time breathing (e.g. from a partner).
- Waking up gasping or with shortness of breath.
- Choking or gasping during your sleep.
- Experiencing night-time chest discomfort or chest pain.
You may also experience the following symptoms which are indicative of a sleep disorder:
- Experiencing headaches in the morning.
- Difficulties waking up in the morning.
- Low alertness or difficulties concentrating.
- Reduced emotional capacity.
- Extreme daytime tiredness or fatigue with no obvious cause.
- Poor quality or non-restorative sleep.
- Feeling irritable and experiencing mood disturbances.
- Having low energy levels.
- Impaired daytime functioning.
- Excessive daytime sleepiness.
- Impaired cognitive performance.
- Slower reaction times.
- Poor attention span.
- Impaired judgement and difficulties making decisions.
- Memory difficulties.
The Impact of Central Sleep Apnoea
Central sleep apnoea can be potentially dangerous. Sudden drops in your blood oxygen levels and the disordered and interrupted sleep that some people with this condition experience can affect your health in multiple ways, such as:
- Increased cardiovascular risk, e.g. heart attacks.
- Increased risk of developing diabetes.
- Higher blood pressure.
- Increased risk of strokes.
However, because CSA is often caused by other health conditions, it could be that the increased health risks commonly associated with CSA are actually associated with the health condition that caused the CSA. For example, CSA patients with an underlying cardiovascular condition or who have obesity are more likely to develop other health conditions.
Sleep disorders can also impact your life in other ways. If the breathing pauses you experience affect the quality or length of your sleep on a long-term basis, there are multiple ways this can negatively impact you, including:
Physical health consequences:
As well as the health conditions listed above that are commonly associated with central sleep apnoea, consistently disordered sleep can affect your physical health in other ways, including:
- A weakened immune system (making you more susceptible to common illnesses).
- Increased risk of weight gain and obesity (because of a disruption to the hormones that regulate hunger and satiety).
- Increased inflammation in the body (which can result in a number of health conditions).
- Lower pain threshold.
- Digestive and gastronomic issues, including irritable bowel syndrome (IBS).
Reduced libido. - Increased sensitivity to pain.
- Impaired physical functioning (e.g. slower reaction times, a decline in coordination).
Mental health consequences:
Consistently poor sleep can impact your mental and emotional health and your cognitive functioning. For example, disordered sleep can affect your emotional regulation and exacerbate symptoms of mental health conditions.
Some ways disordered sleep can impact your mental health and cognitive functioning include:
- Increased susceptibility to stress and anxiety.
- Increased risk of developing depression or the exacerbation of depression symptoms.
- Difficulties concentrating.
- Increased emotional reactivity and difficulties with emotion regulation.
- Feeling irritable.
- Having low energy and low mood.
- Increased feelings of loneliness or isolation.
- Impaired short-term and long-term memory.
- Impaired judgement and decision-making.
- Impaired daily functioning.
- Increased social withdrawal.
- Concentration difficulties.
- Decreased productivity.
- Difficulties making decisions, including making hasty decisions or making decisions you wouldn’t usually make.
- Difficulties with problem-solving.
- Difficulties driving or operating machinery safely.
- Increased risk of accidents.
- Increased risk of mental health conditions, including schizophrenia and bipolar disorder.
- More likely to experience psychotic episodes, including mania, psychosis or paranoia.
- Increased risk of suicide.
How is Central Sleep Apnoea Diagnosed?
If you think you may have central sleep apnoea, for example if a bed partner has raised concerns about your night-time breathing or if you have any of the symptoms listed above, you should visit your GP or your primary healthcare physician.
Your doctor will likely ask about your symptoms. They may also ask you to keep a sleep diary, where you track and monitor your sleep, your sleep habits, any sleep problems you recognise and any symptoms you identify each day. You may be asked to keep a sleep diary for a specified amount of time, such as one week or one month.
They will likely also look at your medical history, to see if you have any of the health conditions commonly associated with CSA. They will likely also look at any medication you take and ask about other factors, such as whether you take any illegal substances.
Because central sleep apnoea is a potentially dangerous sleep disorder, if your doctor thinks there is any possibility you are experiencing CSA, they will likely refer you for a sleep study, also known as a polysomnography.
A polysomnography assesses your sleep and takes place overnight, usually in a sleep centre or within a specialist sleep laboratory in a hospital. To determine whether you are breathing abnormally during your sleep, the sleep technician will attach sensors to different parts of your body, including your head and chest. The sensors will monitor and record:
- Your oxygen levels and the amount of oxygen in your blood.
- Your brain waves.
- Your breathing patterns and respiratory effort.
- Your heart rate and heart rhythm.
- Your sleep stages.
- The movements of your chest and abdomen.
The sleep study will show whether apnoea is occurring, how many apnoea occur during sleep, how long each breathing pause lasts and whether they occur sporadically or in a cyclical pattern.
If the sleep study shows that you are experiencing breathing pauses during sleep, with at least five apnoea occurring per hour, your doctor will likely make a diagnosis of central sleep apnoea. Once a diagnosis has been made, your doctor may then try to identify why these pauses are occurring. This enables them to diagnose you with the correct type of central sleep apnoea and create an appropriate treatment plan.
It could also be that you have no prior indication that you have CSA and, instead, a doctor recognises signs of central sleep apnoea when assessing you for another condition. For example, because multiple sleep disorders can coexist, you may undergo a sleep study for a different sleep disorder and also receive a diagnosis of CSA.
Treatment for Central Sleep Apnoea?
There are multiple treatment options available for central sleep apnoea and your doctor will likely create an individualised treatment plan based on multiple factors including:
- The type of central sleep apnoea you are diagnosed with.
- The underlying cause of your sleep disorder.
- The severity of your symptoms.
- Any other health conditions you are diagnosed with.
- Any other medication you take.
CSA treatment plans are designed to regulate your breathing patterns during sleep. Because the majority of people with central sleep apnoea have developed secondary CSA, related to another health condition or a medication or drug they are taking, treatment plans usually focus on treating the underlying cause of your sleep disorder. In many cases, treating the underlying cause of CSA eliminates the occurrence of breathing pauses.
If it is not possible to treat the underlying cause of your central sleep apnoea, for example if you have sustained a permanent injury to your brainstem, your treatment plan will likely focus on managing your condition and minimising your symptoms.
Some treatment options designed to specifically treat abnormal breathing patterns during sleep are:
Positive airway pressure (PAP) therapy
During PAP therapy, a special machine pumps a steady stream of air into your airway to assist your breathing while you are asleep. There are multiple PAP therapy options, including:
- Continuous positive airway pressure (CPAP) – CPAP delivers a steady stream of air pressure throughout every breath.
- Bi-level positive airway pressure (BiPAP) – BiPAP offers two pressure settings, with distinct air pressure levels for inhalation and exhalation.
- Adaptive servo-ventilation (ASV) – ASV automatically adjusts the air pressure based on your breathing patterns.
Supplemental oxygen
If PAP therapy proves ineffective or if your central sleep apnoea is caused by your existing use of PAP therapy, a machine that provides supplemental oxygen into your lungs may be recommended instead. This helps to maintain consistent oxygen saturation during sleep.
Medication
Although medication is not usually the first choice of treatment, your doctor may prescribe medication if other forms of treatment have not been successful. Medication can help to stimulate your respiratory muscles.
Phrenic nerve stimulation
This is one of the newest treatment options for central sleep apnoea. The device is implanted into your chest and sends an electrical current into the phrenic nerve to stimulate the diaphragm to contract and encourage normal breathing.
Surgery
If there is a physical reason why you breathe abnormally in your sleep, it may be possible to correct this through surgery. For example, your brainstem may have an abnormality or there may be compression on your brainstem from your skull. In this situation, it may be possible to correct the physical abnormalities using surgery.
As well as formal treatment prescribed by your doctor, there are other steps you can take to reduce the occurrence of CSA episodes and reduce the impact your sleep disorder has on your life. These include:
Avoiding triggers
There are specific triggers that can increase the likelihood of you having apnoea episodes, including:
- Drinking alcohol.
- Taking drugs, specifically opioids.
- Using sedative medication.
- Travelling to high altitude.
- Being an unhealthy weight.
Avoiding these triggers can minimise the impact of CSA on your life.
Learn about your condition
Educating yourself about central sleep apnoea can help you to understand your symptoms, your triggers and your treatment options. Understanding your condition and seeking resources and support, for example from the Sleep Apnoea Trust, can make it easier to manage your condition and reduce the impact it has on your life.
What is the Difference Between Central Sleep Apnoea and Obstructive Sleep Apnoea?
Both central sleep apnoea (CSA) and obstructive sleep apnoea (OSA) are sleep disorders characterised by abnormal breathing during sleep.
However, the main difference is that while abnormal breathing in CSA occurs because of a lack of communication between the brain and the respiratory muscles, for someone with OSA, abnormal breathing occurs because of a physical blockage in your airway.
Someone with obstructive sleep apnoea will make a physical effort to breathe during sleep; however, their normal breathing will be hindered by the blockage, which could result in pauses in breathing, snoring or fragmented sleep. The blockage may occur because your throat muscles relax, blocking the airway or because your airway collapses during your sleep.
