Obstructive sleep apnea is due to a blockage in the airways. Central sleep apnea is caused by a problem with the nerves that control breathing. In some cases a mixture of both types of sleep apnea may occur.
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) affects primarily men between the ages of 30 and 50. It occurs when air passage in the upper respiratory tract becomes obstructed during sleep (obstruction is caused by soft tissue of the pharynx relaxing and blocking the flow of air). It prevents breathing until low levels of oxygen in the blood cause a person to respond by waking up and taking a deep, snorting breath. Being overweight or having a small tongue or mouth can contribute to the obstruction. In children enlarged tonsils or adenoids are the most common cause of obstruction.
Most Common Symptoms:
Most folks who have obstructive sleep apnea don't remember the episodes of apnea during the night. The predominant symptoms are usually associated with excessive daytime sleepiness due to poor sleep during the night. Often, family members, especially spouses, witness the periods of apnea. Symptoms that may be observed include:
* Loud snoring
* Periods of not breathing (apnea)
* Awakening not rested in the morning
* Abnormal daytime sleepiness, including falling asleep at inappropriate times
* Morning headaches
* Recent weight gain
* Limited attention
* Memory loss
* Poor judgment
* Personality changes
Additional symptoms that may be associated with this disease:
* Hyperactive behavior, especially in children
* High blood pressure
* Automatic behavior (performing actions by rote)
* Leg swelling (if severe)
Tests that can be done:
A complete medical history taken by a health care practitioner is the most important diagnostic tool. Often, a survey that asks a series of questions about daytime sleepiness, sleep quality and bedtime habits is done.
A physical examination of the mouth, neck and throat (oropharynx) is important to detect abnormalities that may predispose.
Tests may include:
* Sleep studies
* An ECG to show arrhythmias during sleep
* An arterial blood gases to show low oxygen or elevated carbon dioxide
* Echocardiogram to evaluate the function of the heart
* Thyroid function studies
Statistics show those that don't have OSA treated die within 5 years. Plus sleep apnea increases the risk of:
-Cardiovascular disease (leading to heart failure, heart attack and stroke)
-Hypertension (high blood pressure), especially below age 60*
-Auto accidents: Sufferers of severe sleep apnea are two to three times more likely to be involved in auto accidents than the general population, mainly due to falling asleep while driving.
March 16, 1999 editorial in Annals of Internal Medicine. Also August 11, 1997 Archives of Internal Medicine article states: "If causal, the high prevalence of sleep disordered breathing could account for hypertension in a substantial number of adults in the United States." Hypertension affects one in four adult American men, most of whom have uncontrolled (untreated) high blood pressure.
Having a trach generally ends obstructive sleep apnea, it will help but not resolve central sleep apnea.
Web sites that may or may not be helpful (links valid March 2012):
Recurrence of sleep apnea syndrome following tracheostomy. A shift from obstructive to central apnea
Should I have surgery to treat obstructive sleep apnea ?
Central Sleep Apnea
Central sleep apnea(CSA) is where the region of the brain and nerves that regulate breathing do not function normally and cause breathing to be impaired or stop. It can be caused by head injury or stroke.
Central sleep apnea usually occurs in people who are seriously ill. For example, it can occur in people with a variety of severe and life-threatening lower brain stem lesions. The brainstem controls breathing. As a result, any disease or injury affecting this area may result in problems with normal breathing during sleep or when awake.
There is also a form of central sleep apnea that commonly occurs in people with congestive heart failure. The most common cause of central apnea is heart failure which causes Cheyne-Stokes breathing. In congestive heart failure, an aggressive treatment of the heart may improve the outlook.
Conditions that can cause central sleep apnea include:
* Bulbar poliomyelitis
* Encephalitis affecting the brainstem
* Neurodegenerative illnesses
* Stroke affecting the brainstem
Other causes include complications of cervical spine surgery, secondary radiation in the region of the cervical spine, severe arthritis and degenerative changes in the cervical spine or the base of the skull, or primary hypoventilation syndrome.
Tests that can be done:
* Lung and breathing studies
* All-night polygraphic sleep monitoring
* Tests to diagnose an underlying medical condition
Idiopathic Central Sleep Apnea
Idiopathic central sleep apnea (ICSA) is when the apnea is not associated with another disease. For idiopathic apnea, the outlook is usually favorable. There have been some studies done on oxygen use. The frequency of central apneas was reduced by more than 50%. Obstructive and mixed apneas were unaffected by oxygen. Oxygen effectively reduces central sleep apnea in eucapnic patients.
Jan 2006 SLEEP the official journal of the Associated Professional Sleep Societies, LLC, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society reported on another study shows an increased prevalence of atrial fibrillation (AF) among patients with idiopathic central sleep apnea in the absence of congestive heart failure. This study is the first to demonstrate a relationship between AF and CSA in the absence of congestive heart failure.
Also in Jan 2006 the American Journal of Respiratory and Critical Care Medicine reported on a study on Acetazolamide. Acetazolamide has been shown to alleviate idiopathic central sleep apnea and central apnea at high altitude. The present study shows that acetazolamide is also effective in heart failure. Acetazolamide decreased the apnea-hypopnea index in each subject, and the reduction in the apnea-hypopnea index occurred mostly because of a reduction in central apneas.
Cheyne-Stokes Respiration (CSR) is a breathing pattern characterised by rhythmic oscillation of tidal volume with regularly recurring periods of hyperpnoea, hypopnoea and apnoea. Some studies have shown CO2 inhalation reduces central sleep apnea (CSA) in patients with congestive heart failure (CHF) and idiopathic CSA. Conclusion of one study: CO2 inhalation reverses CSA but not arousals from sleep.