Sleep Apnea: Causes, Symptoms, Diagnosis and Treatment
What is sleep apnea: A simple definition
Sleep apnea is a chronic sleep disorder which is characterized by interruption of breathing during sleep. Breathing interruptions can be of two types:
- Apnea. Total blockage of airflow for 10 or more seconds due to the relaxation of the muscles and soft tissues of the throat.
- Hypopnea. Results in partially blocked airway reducing the airflow by greater than 50% for 10 seconds or more.
As a result, in sleep apnea patients, the breathing either stops completely or becomes shallow for around 10-20 seconds. These pauses in breathing can be as numerous as 20 to 30 times per hour.
Types of Sleep Apnea
Though there are various types of sleep apnea, all types are characterized by interrupted breathing leading to decreased oxygen inhalation. This results in the reduction of blood oxygen levels which acts as a trigger for the brain to reinitiate the breathing mechanism. The patient gasps, and the breathing starts, until the next breathing pause happens. This process is repeated multiple times during sleep.
Obstructive Sleep Apnea Syndrome
Obstructive Sleep Apnea (OSA) syndrome is the most common of all types of sleep apnea, and is caused due to an obstruction or blockage in the upper respiratory tract. OSA syndrome is often accompanied by snoring or loud noise which occurs when an individual with airflow obstruction tries to breathe and air passes through the blockage.
Though more common in overweight individuals, OSA syndrome can occur in anyone including small children with enlarged tonsils which may block the upper airway (throat) causing apnea and Hypopnea episodes.
Obstructive Sleep Apnea Syndrome may be aggravated by ingestion of alcohol, tranquilizers or sleeping pills.
The severity of OSA syndrome, in some patients, can be agrivated when they sleep in a supine position (on their backs) as compared to lateral position (on their sides). Such patients are said to suffer from Positional Sleep Apnea.
Central Sleep Apnea
Central sleep apnea is a less common form of sleep apnea. It is characterized by interruption in breathing due to a lack of respiratory effort. In central sleep apnea there is a malfunctioning of the neurological control centers, leading to failure to provide a signal for the respiratory muscles to breathe.
As a result the individual misses one or more breathing cycles. Because the airways are not blocked in central sleep apnea, the patient does not snore. Central sleep apnea occurs more frequently in patients who are ill and are hospitalized.
Complex Sleep Apnea (Mixed Sleep Apnea)
Brief episodes of central sleep apnea develop in some individuals suffering from longstanding and severe obstructive sleep apnea syndrome. Such type is known as complex sleep apnea or mixed sleep apnea.
Causes of Sleep Apnea
All muscles of our body have a tendency to relax when we are asleep. This is true for muscles of the upper airway also; still they are open enough so that airflow can naturally happen during sleep. However, airflow blockage may occur due to number of factors including:
- Obese and overweight individuals. Overweight individuals have a greater tendency to develop sleep apnea as the weight gain in such individuals may lead to an increased soft tissue in the throat area making it harder for the upper airway muscles to keep it open during sleep.
- Enlarged tonsils and adenoids. This can also lead to the blockage of the upper airway.
- Structural abnormalities. Abnormalities of the upper airway such as deviated nasal septum, which causes an obstructed and narrowed airway, can also lead to sleep apnea episodes.
- Airway blockage. Airway may also be blocked temporarily by nasal congestion leading to apnea episodes.
- Airway constriction. Constriction in the airway resulting due to asthma may also cause narrowing of airways which may result in episodes of apnea.
Signs and Symptoms of Sleep Apnea
The most common symptoms of sleep apnea are:
- Loud snoring. Episodes of loud snoring during sleep which may be heard by family members.
- Choking and gasping. During sleep, choking and gasping are common episodes among individuals suffering from sleep apnea.
- Excessive daytime sleepiness. The most common symptom of sleep apnea is waking up un refreshed and feeling sleepy or drowsy in the morning and throughout the day, also known as excessive daytime sleepiness (EDS). There is a tendency to fall asleep while driving, working, reading or even while watching TV.
- Morning headaches. Sufferers may develop morning headaches which are difficult to treat.
Symptoms of forgetfulness, irritability, lack of concentration, depression and mood swings may also occur in patients suffering from sleep apnea.
Long term side effects or complications of sleep apnea
Sleep apnea is a serious medial disorder which can lead to various dangerous complications, especially if left untreated. Some of the major problems or dangers arising from untreated sleep apnea are:
- Cardiovascular complications. Individuals suffering from sleep apnea have two to three times greater risk of developing hypertension (high blood pressure). In patients with an underlying heart disease, the episodes of apnea and Hypopnea may cause sudden death due to heart attack. Presence of sleep apnea also increases the episodes of bradycardia due to sudden interruption in breathing.
- Neurological complications. There is an increased risk of stroke and brain damage in patients suffering from sleep apnea. Sleep apnea also causes morning headaches which are very difficult to treat.
- Psychological complications. Patients with sleep apnea often suffer from insomnia and depression. They experience symptoms of daytime fatigue, dry mouth, night sweats, nightmares, chest pain and frequent episodes of memory loss. Dementia may also develop due to brain cell damage caused by low oxygen levels.
Sleep apnea is also linked to the development of diabetes and metabolic syndrome.
Diagnosis of Sleep Apnea
The condition of sleep apnea often remains undiagnosed. A physician records the complete case history and performs a complete physical exam including a check up of the upper respiratory tract for any abnormality.
The diagnosis of sleep apnea is confirmed by a sleep study or polysomnography which is monitoring of your sleep cycles and stages during sleep. Polysomnography can be conducted at a sleep center or at home.
Sleep apnea test at a sleep center
During a sleep study, measurement of your sleep cycles and stages are done by recording various parameters such as heart rate, brain waves, eye movements, blood oxygen levels, amount of inflow and outflow of lung air during breathing, electrical activity of muscles, breathing rate etc.
This recording is done by placing various electrodes and monitors on different areas of your body. A trained health care practitioner observes you during the study, measuring the various parameters.
Home sleep apnea test
Home sleep apnea tests can be done by portable sleep study devices that are meant to used at home to diagnose sleep apnea. Such devices are available at a sleep center and usually you can call trained personnel to come to your house and set up the device.
The home sleep apnea test is a simplified test which is designed to measure your heart rate, oxygen level of blood and patterns of airflow and breathing. Sleep apnea sufferers will show a drop in blood oxygen level during episodes of apnea.
Before performing the test, no sleep medications should be taken. Alcoholic and caffeinated beverages should also be avoided before hand.
A sleep study measures the apnea and hypopnea episodes during sleep. The results of a sleep study are reported by the AHI or Apnea-Hypopnea Index also known as the RDI or Respiratory Disturbance Index.
An Apnea-Hypopnea Index demonstrates the severity of sleep apnea by measuring the total number of episodes of apnea and hypopnea that occur per hour of sleep during a sleep study. These episodes of apnea and hypopnea must last for at least 10 seconds and are usually associated with reduced blood oxygen levels.
Categorizing the severity of sleep apnea based on AHI
- Mild sleep apnea. An AHI score between 5 and 15 is classified as mild sleep apnea.
- Moderate sleep apnea. And AHI score between 15 and 30 is classified as moderate sleep apnea.
- Severe sleep apnea. An AHI score of more than 30 is classified as severe sleep apnea.
An AHI score of less than 5 is usually regarded as normal.
Treatment Options for Sleep Apnea
There are various treatment options available to treat sleep apnea. Some of which include sleep apnea devices, breathing machines, surgery, and various lifestyle modifications such as throat exercises, losing weight, etc.
Sleep apnea devices or aids
There are various types of sleep apnea devices available which are recommended to treat patients with mild sleep apnea.
- Dental appliance. A dental appliance such as a mouthpiece or mouthguard is the most common form of treatment for individuals suffering from mild sleep apnea. It is designed to keep the upper airways open during sleep by adjusting the lower jaw and tongue.
- Cervical pillow. Another solution for sleep apnea can be a cervical pillow which is an orthopedic pillow designed for maintaining a correct position of the body while lying in bed. It helps by keeping the airways open during sleep.
- Chin strap. Another device which helps people with sleep apnea is a chin strap. A chin strap is designed such that the jaw is held in a specific position which allows for the upper airways to remain open during sleep.
- Jaw supporter. As effective solution to sleep apnea, a jaw supporter works by keeping the jaw closed firmly, thus keeping the airways open during sleep.
Sleep apnea breathing machines
The most common breathing machine used to treat moderate and severe sleep apnea is the CPAP (Continuous Positive Airway Pressure) machine. This machine has a mask which is fitted over your nose and mouth. Air pressure, adjusted for each individual patient, is blown through the CPAP mask into the throat. Thus, the airways are not blocked or narrowed during sleep. This maintains blood oxygen at normal levels.
In a BiPAP (bilevel positive airway pressure) machine the air delivered through the mask is at higher pressure during inhalation and at lower pressure during exhalation. This makes the machine more adaptable to users with central sleep apnea problems.
Supplemental oxygen may be used as a therapy to treat cases of central sleep apnea.
Sleep apnea surgery options
Some sleep apnea patients may benefit from surgical interventions. Various types of surgical procedures may be performed depending on the cause of sleep apnea.
- Uvulopalatopharyngoplasty procedure. Throat surgery such as Uvulopalatopharyngoplasty (UPPP) is done to remove the excess tissue in the throat which may be causing blocking or narrowing in the throat. The tissues from the back of the throat may also be removed by laser surgery or laser assisted uvulopalatoplasty.
- Pillar procedure. A minor surgery, pillar procedure is done to treat cases of mild to moderate sleep apnea. In this procedure small polyester rods are placed surgically in the soft palate to stiffen it and reduce its relaxation.
In children surgery may be done to remove the enlarged tonsils as they may be a major cause of blockage or narrowing of the airway.
Alternative treatment of sleep apnea
Apart from the treatment discussed above, various alternative treatment options may be used to treat sleep apnea. These include natural cures in the form of various lifestyle modifications such as losing excess weight, avoidance of alcoholic beverages and sleeping pills, refrain from eating heavy meals at night and sleeping on your side and abdomen.
Certain home remedies are also recommended which may help in relieving the symptoms of sleep apnea to some extent. Some of these are the use of eucalyptus oil to ease nasal congestion, eating walnuts to enhance breathing and use of herb valerian as a natural sleep aid. The nature’s rite sleep apnea relief is a herbal medicine which works by increasing both the levels of respiration and sleep in sleep apnea patients.
Some researchers claim that performing certain throat exercises which are meant to strengthen the throat are helpful in relieving the symptoms of sleep apnea.
Positional therapy for sleep apnea
As already mentioned, sleep apnea symptoms can be relieved by sleeping on your side or on abdomen.
Sleep Apnea Statistics
Have you ever wondered how many people have sleep apnea or how common sleep apnea is? Here is the answer:
More than 12-18 million American adults are estimated to suffer from sleep apnea. It is more common in men than in women. The incidence of sleep apnea is increased in pregnant and menopausal women.
Overweight adults are more prone to develop sleep apnea as are those adults who are over 40 years of age.
Sleep apnea may occur in those children who have enlarged tonsils causing airway blockage.
Life expectancy of patients suffering from sleep apnea, if left untreated, is greatly reduced mainly due to the cardiovascular and neurological complications associated with the disorder. Adopting an appropriate treatment plan may greatly improve the quality of life and reduce the development of life threatening complications in sleep apnea patients.