Risk Factors and Causes of Sleep Apnea.

In normal circumstances, the muscles of the throat around the windpipe keep the airway stiff and open to facilitate proper breathing. And when you sleep these throat muscles are in a more relaxed state but yet keep the windpipe open allowing you to breathe normally.

These muscles support the soft palate, the uvula, the tonsils and the tongue. In sleep apnea, this system fails due to certain reasons and is the main cause of sleep apnea. Causes of different types of sleep apnea are discussed below.

Causes of Obstructive Sleep Apnea.

Persons with obstructive sleep apnea (OSA) often have a low muscle tone and the airway is often narrower than normal and may get repetitively blocked or narrowed during sleep due to the following reasons and risk factors.

Image showing how you get obstructive sleep apnea.

• Males are more prone to develop this type of apnea.
• This sleep apnea is seen more in Blacks, Hispanics and Pacific islanders.

• Enlarged tonsils and adenoids (spongy tissue situated at the back of the nasal cavity and above the roof of the oral cavity).
• An enlarged tongue can fall backwards when you sleep and obstruct airflow through the windpipe.
• A deviated nasal septum which can narrow the nasal airway obstructing airflow.
• Swelling of the nasal filters called turbinates can also obstruct airflow.
• Being obese or overweight causes extra soft tissue to be deposited around the windpipe narrowing it and obstructing airflow.
• A long or floppy palate or uvula can fall backwards when you sleep and obstruct the windpipe.
• The bony structure of the jaw and neck may be such so as decrease the size of the airway in the mouth and throat area. The lower jaw may be structurally and abnormally longer than the upper jaw. Craniofacial deformities such as developed in Marfan’s syndrome and Down syndrome can increase your risk of sleep apnea.
• Similarly, having deformities of the spine such as scoliosis increases your risk of developing sleep apnea.
• Advanced age (above 65 years) causes limitations in the neurotransmission of brain signals which keep the airway stiff during sleep. This can cause collapse of the airway and obstruct breathing.
• Smoking increases risks of obstructive sleep apnea
• People with sleep apnea often have a family history of it.
• Certain endocrinal disorders such as hypothyroidism and acromegaly increase your risk of developing sleep apnea.

When there is obstruction to airflow during breathing, there is a greater effort to breathe and take in air through the narrowed airway passage. This causes loud snoring. Secondly, due to less intake of oxygen because of restricted breathing, oxygen levels in the blood falls. When this fall is excessive, the brain is triggered to awaken you up, This happens repetitively during the night depriving of your deep sleep. When you awaken,  the throat muscles are tightened and the airway is opened allowing you breathe in freely and increase oxygen levels in the blood. This often happens with a choking sound. These frequent drops in oxygen levels cause release of stress hormones which can cause blood pressure and heart complications.

Causes of Central Sleep Apnea.

Central sleep apnea (CSA) is much less common than obstructive sleep apnea and snoring is less commonly seen. As mentioned in types of apnea,  CSA occurs due to failure of the brain to send signals to the breathing muscles to help breathing when the oxygen levels in the blood have dropped dangerously. In CSA, apnea last for more than 20 seconds causing severe drop in oxygen levels in the blood. CSA is also associated with change in heart rate, low blood oxygen levels and generally, more relaxation of body muscles (Hypotonia).

This type of sleep apnea is commonly seen in infants (especially premature infants) because of a less developed respiratory center in the brain.

It is also seen in males and in people above the age of 65 years.

It is also seen in adults with

• heart disease such as congestive cardiac failure,
• cerebrovascular disease,
• neurological disease such as encephalitis and stroke affecting the brain stem,
• in persons with brain stem or spinal injury
• Arthritis and degenerative diseases of the cervical spine and base of the skull,
• in congenital diseases.
• It can occur in places of high altitude
• and  also due to certain medications such as narcotic pain killers

CSA is seen in people with heart and lung disease because the carbon dioxide levels in the blood are higher than normal and the brain is accustomed to these high carbon dioxide and low oxygen levels and fails to respond as it should normally do.

Related posts:

1. Apnea and Sleep Apnea – A Dangerous Sleep Disorder.
2. Sleep Apnea Symptoms and Signs.
3. How is Sleep Apnea Diagnosed.
4. Surgery Treatment for Obstructive Sleep Apnea.
5. Sleep Apnea Equipment – Oral and Dental Devices.
6. Effects and Complications of Sleep Apnea.
7. UPPP – Sleep Apnea Surgery.
8. CPAP Machine for Sleep Apnea.