Obstructive Sleep Apnea

Obstructive sleep apnea is a common sleep-related breathing disorder. It leads to intermittent breathing pauses during sleep despite continuous involuntary breathing effort. This happens due to the relaxation of throat muscles, which block air through the upper airway. It subsequently leads to oxygen desaturation and arousal from sleep, causing severe sleep disturbances in individuals.

The main reason for the development of obstructive sleep apnea is the extra relaxation of throat muscles, causing narrowing of airway passages at the level of tongue or soft palate. People usually have to wake up several times from sleep to open their throat muscles for air entry. Shortness of breath can wake you up, but it will rapidly correct itself with one or two deep breaths. You might produce a snorting, choking, or gasping sound. In children, it usually occurs due to enlarged tonsils or adenoids. Whereas obesity, old age, and male sex are the primary causative associations in adults. 

There are clear signs and symptoms related to sleep apnea that are present insidiously, and it may take many years before a patient is referred for a clinical evaluation. These include:

• Excessive daytime fatigue
• Sleepiness
• Loud snoring
• Dry Mouth
• Sore throat
• Bedwetting (usually in children and old age)
• Mental health issues (e.g., depression & anxiety)
• Hypertension
• Headaches
• Memory problems
• Decreased cognitive functioning
• Sexual problems
• Gastroesophageal reflux disease (GERD)
• Heart problems
• Eye problems
• Relationship issues

In the past, about 4% male population and 2% female population have been reported with obstructive sleep apnea in the United States.  However, its prevalence has increased, with recent numbers indicating as high as 14% and 5% prevalence in males and females, respectively. Additionally, it is more common in ethnic populations, including Hispanics, Blacks, and Asians. The risk of developing this disorder increases with age, and after 50 years of age, prevalence between men and women becomes equal.

The risk factors of sleep apnea can be divided into structural and non-structural/anatomical categories. The structural risk factors include:

• Undersized lower jaw
• Mandibular deformities
• Adenoid hypertrophy
• Tonsillar hypertrophy
• Down syndrome
• Prader Willi syndrome
• Hyoid bone deformities

The non-anatomical risk factors are:

• Genetics
• Advancing age
• Obesity
• Male gender
• Smoking
• Sedative Medications
• Awkward sleeping positions
• Abnormal Snoring

Some medical conditions are also linked to sleep apnea, including:

• Stroke
• Asthma
• Nasal congestion
• Thyroid problems
• Metabolic syndromes (e.g., diabetes)
• Neurological disorders (e.g., myasthenia gravis)

The doctor carries out a physical exam for the diagnosis of sleep apnea. The exam includes assessing risk factors, such as obesity, loud snoring, daytime fatigue or sleepiness, neck circumference measurement (usually greater than 17cm in male adults), hypertension, diabetes, etc. In most cases, the physical exam is typical in individuals, and more invasive testing is required to establish a definitive diagnosis.

Polysomnography (PSG) is the standard gold test to diagnose sleep apnea in patients. It is performed overnight to detect any disturbances in patients’ sleeping patterns. The following things are evaluated during the test:

• Sleep stages are monitored in patients with the help of an electroencephalogram.
• Eye movements are recorded via electrooculogram.
• The movement of chest and leg muscles is measured via an electromyogram.
• Heart rhythm is checked via electrocardiogram (EKG).
• Breathing movements via oral and nasal routes are analyzed via temperature and pressure sensors and pulse oximetry.

The interpretation of results is according to the American Academy of Sleep Medicine standards. The apnea-hypopnea index that equals the number of obstructive events experienced by a patient per hour is used to document the severity of the disease. In adults following criteria is used to categorize the severity of the problem:

• Apnea-hypopnea index of 5-14.9/hour=Mild obstructive sleep apnea
• Apnea-hypopnea index of 15-29.9/hour=Moderate obstructive sleep apnea
• Apnea-hypopnea index greater than 30/hour=Severe obstructive sleep apnea

In children, different criteria are followed that is:

• Apnea-hypopnea index of 1-4.9/hour=Mild obstructive sleep apnea
• Apnea-hypopnea index of 5-9.9/hour=Moderate obstructive sleep apnea
• Apnea-hypopnea index greater than 10/hour=Severe obstructive sleep apnea

For adolescents aged between 13-17 years, either one of the criteria is appropriate to use depending on the specific clinical scenario.

These conditions share somewhat similar characteristics with obstructive sleep apnea:

• Asthma
• Obstructive/restrictive pulmonary disease
• Depression
• Insomnia
• Narcolepsy
• Hypothyroidism
• GERD
• Periodic limb movement disorder

Invasive treatment is usually reserved for moderate to severe insomnia. Continuous positive airway pressure (CPAP) is the most effective treatment modality to reverse the signs and symptoms in patients. Other treatment modalities, such as oral appliances, somnoplasty, and advanced mandibular splints, can be recommended for patients who are not compliant with CPAP.

Medication is generally not required in sleep apnea patients. However, in patients with residual daytime sleepiness despite CPAP therapy, the FDA has approved the use of Modafinil.

Any anatomical defects in oral and nasal cavities should be corrected as they can be the primary cause of sleep apnea. In children, tonsillectomy and adenectomy are routinely performed to overcome sleep apnea. Additionally, sometimes uvulopalatopharyngoplasty (UPPP) is also carried out in conjugation with other surgical procedures.

The following lifestyle changes can prevent the occurrence of sleep apnea:

• Weight reduction
• Exercise
• Giving up smoking
• Sleeping on your side
• Not resting on your back
• Nasal decongestants
• Avoiding sedative medications