Central sleep apnea (CSA) is a disorder that affects breathing during sleep. It is distinct from obstructive sleep apnea (OSA), which is much more common and well-known.
CSA is often tied to an underlying health condition, and if it is left unaddressed, it may affect overall health by causing fragmented sleep, daytime drowsiness, thinking problems, moodiness, and fatigue.
While there can be overlap with the causes, symptoms, and treatments of obstructive sleep apnea, central sleep apnea is a distinct disorder, and it is important to understand central sleep apnea in its own right.
What Is Central Sleep Apnea?
Central sleep apnea is a condition defined by pauses in breathing due to a lack of respiratory effort during sleep. Unlike obstructive sleep apnea, the pauses in breathing throughout the night are due to the lack of respiratory muscles activating or the brain failing to ask the respiratory muscles to activate.
To breathe in, our brain sends a signal to the diaphragm and the muscles of our rib cage to contract. The contraction of the diaphragm and rib cage muscles produces an inhalation. In central sleep apnea, there is typically a lack of communication from the brain to these muscles.
It is important to note that a few central apneas per night is considered normal. We often “forget to breathe” briefly as we drift off to sleep or after waking up.
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How Is Central Sleep Apnea Different From Obstructive Sleep Apnea?
In obstructive sleep apnea, a person makes a notable effort to breathe, but the airway in the back of the throat is blocked. The blockage in the back of the throat causes an obstruction to our windpipe, which leads to sleep fragmentation and a disturbed oxygen balance in the body.
In central sleep apnea, the problem isn’t a blocked airway. Instead, pauses in breathing occur because the brain and the muscles that control breathing aren’t functioning properly. As a result, there is no normal respiratory effort, which is in clear contrast to OSA.
While OSA and CSA are separate conditions, they can arise at the same time in what is known as mixed sleep apnea. In addition, treatment of OSA with continuous positive airway pressure (CPAP), can induce central sleep apnea, and this is called treatment-emergent central sleep apnea.
How Common Is Central Sleep Apnea?
While the exact number of people with central sleep apnea is unknown, it is estimated that about .9% of people over 40 in the United States have the condition. Though it affects both men and women, it occurs more often in men of greater than 65 years old. People who have a heart condition, use narcotics, suffer from a stroke, live in high altitudes, or use CPAP are at greater risk for central sleep apnea.
What Are the Different Types of Central Sleep Apnea?
Central sleep apnea is divided into two categories, and each of the categories has its subtypes.
The first category we will walk you through is the hypoventilation type. In this type of central sleep apnea, the brain fails to effectively send signals to the respiratory muscle to initiate breathing. Often, carbon dioxide builds up in these cases. Hypoventilation-type of central sleep apnea includes the following subtypes:
- Narcotic-Induced Central Sleep Apnea: In this type of central sleep apnea, the use of narcotics, such as opioids, diminishes the brain’s ability to properly initiate and regulate breathing.
- Central Sleep Apnea Related to a Medical Condition: This type of central sleep apnea often occurs as a result of a stroke, tumor, or trauma affecting the brain. Typically, the brain stem, a part of the brain that helps control breathing, is affected.
- Congenital Central Hypoventilation Syndrome (CCHS): CCHS is a very rare genetic condition that most often affects newborns or very young children. There is a lack of signal to breathe during wakefulness and sleep
- Central Sleep Apnea Due to Neuromuscular Disease: Typically seen in amyotrophic lateral sclerosis (ALS) or multiple sclerosis, central sleep apnea emerges due to extreme weakness in the respiratory muscles.
The second category of central sleep apnea involves hyperventilation (breathing deep breaths and quickly), followed by pauses in breathing. This type of central sleep apnea occurs because of aberrant pacing and control of respiration. Hyperventilation-type of central sleep apnea includes the following subtypes:
- Cheyne-Stokes Breathing: Cheynes-Stokes breathing is a unique type of central sleep apnea commonly found in people with heart conditions. The most common heart conditions associated with Cheynes-Stokes breathing include heart failure and atrial fibrillation. The pattern of breaths is distinct from all other types of central sleep apneas listed, and includes an oscillation of small and large breaths followed by long pauses of breathing.
- Altitude-Induced Periodic Breathing: This form of central sleep apnea can occur shortly after a person has ascended in altitude, such as above 8,000 feet, where the air has a lower concentration of oxygen. As a response, a person’s breathing becomes faster and larger. During sleep, this may cause pauses in breath.
- Treatment-Emergent Central Sleep Apnea: Formerly known as complex sleep apnea, this is a type of central sleep apnea that starts to occur after someone begins continuous positive airway pressure (CPAP) treatment for OSA. In most cases, this version of CSA resolves on its own.
- Idiopathic Central Sleep Apnea: Idiopathic means that it does not have a clear cause, so this version of CSA occurs without a readily identifiable explanation.
What Are the Symptoms of Central Sleep Apnea?
Most people with central sleep apnea present with disturbed sleep, such as excessive daytime sleepiness, fragmented sleep, waking up feeling unrefreshed, or having morning headaches. As you can imagine, these symptoms are quite non-specific, and one should seek a healthcare professional for further evaluation if these symptoms are present.
In some cases, central sleep apnea can present because a bed partner notices quiet pauses in breathing. In contrast to OSA, snoring is not a common symptom for central sleep apnea.
How Is Central Sleep Apnea Diagnosed?
A definitive diagnosis of CSA is made using an in-lab polysomnography, which is a detailed sleep study that measures breathing, respiratory effort, electrocardiogram, heart rate, oxygen, eye movement activity, muscle activity, and electrical activity of the brain during an overnight stay in a sleep clinic.
Because central sleep apnea can be tied to several health problems, a healthcare provider may also recommend other tests, such as a brain scan or an echocardiogram of the heart to determine the underlying cause.
Anyone who has noticed potential symptoms of central sleep apnea should speak with a doctor who can review their situation and determine if any diagnostic testing is appropriate.
What Is the Treatment for Central Sleep Apnea?
The key to treating central sleep apnea is addressing any underlying health issues that are causing the condition. The type of treatment for central sleep apnea depends on the category and subtype of central sleep apnea. For example, steps may be taken to mitigate congestive heart failure. Those on opioids or other respiratory-depression medications may gradually reduce and taper off the medications. If at high altitude, the individual can trek back to sea level. In many cases, focusing on the coexisting problem can relieve or eliminate abnormal breathing during sleep.
For many patients with central sleep apnea, the use of CPAP or BiPAP machines can decrease cessations in respiration. Supplemental oxygen may be used in a similar way.
In 2017, the Food and Drug Administration (FDA) approved an implantable device that stimulates breathing-related muscles as a treatment for CSA. This treatment has shown promise in improving breathing and sleep quality in some research studies.
Depending on a person’s situation, a combination of treatments (10) may be used in order to best address their symptoms. A healthcare provider with a specialty in sleep medicine would be best to review the benefits and side effects of various treatment options for central sleep apnea.
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