Adult Snoring and Obstructive Sleep Apnea

1

What is the difference between snoring and obstructive sleep apnea (OSA)? What about sleep-disordered breathing (SDB) and upper airway resistance syndrome (UARS)?

Snoring is simply noisy breathing during sleep that occurs due to the vibration of lax tissue in the upper airway. SDB is characterized by snoring along with symptoms suggestive of OSA, including daytime somnolence and snoring. Sleep-disordered breathing exists along a continuum of severity. UARS represents the mildest form of SDB and is characterized by a normal apnea-hypopnea index (AHI) with an elevated respiratory disturbance index (RDI), indicative of respiratory events that fragment sleep quality but are not severe enough to cause oxygen desaturation. OSA, the most severe form of SDB, affects quality of life and is potentially life-threatening. In adults, OSA is defined by an AHI of greater than five events per hour during sleep, as revealed by polysomnography. OSA is caused by upper airway tissue collapse resulting in airway obstruction.

2

How common is snoring? What about sleep apnea?

Snoring is very common across the population. Based on self-report questionnaires and questionnaires, 40% of middle-aged men and 28% of middle-aged women snore. This increased to as high as 84% and 73%, respectively, in the seventh decade of life. It is estimated that as many as 3% to 7% of men and 2% to 5% of women have OSA. It has been shown that the prevalence is even higher in obese, senior, postmenopausal, and minority populations. The risk of OSA is higher when a person has a close relative (parent, child, or sibling) with OSA.

3

What causes snoring and OSA?

Snoring is caused by variations in airflow across dynamic portions of the upper airway, which results in the vibration of soft tissues. Most commonly, it occurs in the areas of the uvula, soft palate, tonsillar pillars, and/or pharyngeal walls. Occasionally, it may also occur at the base of the tongue or the epiglottis. OSA occurs secondary to collapse at the anatomic levels mentioned above, with airway collapse that is significant enough to not only result in vibratory snoring but also affect airflow and disruption in oxygen saturation. Obesity often contributes to snoring and apnea due to increased weight of the neck tissues; increased fat in the parapharyngeal space, which narrows the pharynx; redundancy in the soft palate; and fullness in the tongue base.

4

What is obstructive sleep apnea (OSA)?

OSA refers to a collection of conditions and syndromes that have periods of apnea , a temporary cessation of breathing (defined as intermittent cessation of airflow during sleep that lasts 10 seconds or longer), and/or hypopneas (defined as a partial reduction in airflow that results in oxygen desaturation) as key occurrences. It was initially described in the early 1800s. One of the first accounts was written by Charles Dickens in 1837 and titled The Posthumous Papers of the Pickwick Club . Subsequently, William Osler coined the term “pickwickian” in 1918 to describe the obese, hypersomnolent patient. The pathogenesis and pathophysiology of OSA have been extensively studied. During sleep, the upper airway is occluded, resulting in an episode of obstructive apnea. As a result, the patient experiences brief arousal from sleep. With the return of breathing, the patient typically returns to sleep quickly. This sequence is repeated many times.

5

What are the subclassifications of sleep apnea?

Over the years, various sleep apnea syndromes have been described and classified into three main types: central, obstructive, and mixed . Central sleep apnea refers to apneas notable for cessation of airflow due to cessation of breathing effort . Obstructive sleep apnea (OSA) refers to apnea due primarily to the collapse of the upper airway during sleep. Mixed apnea refers to apnea with both central and obstructive characteristics. Of the three main types of apneas, OSA is the most common and has received the most scientific interest and study.

6

What are common symptoms of obstructive sleep apnea?

Snoring, restless sleep, witnessed episodes of choking or gasping for air while sleeping, excessive daytime somnolence, morning headaches, nocturia, changes in mood (depression, irritability, anxiety, aggression), poor concentration, memory loss, night sweats, and bruxism.

7

What medical comorbidities can predispose patients to sleep apnea?

• Obesity: Obesity is very common in patients with OSA. Although being overweight is not necessary for OSA, truncal obesity predisposes patients to sleep apnea. In patients with a small airway diameter at baseline, even modest weight gain can cause OSA.

• Hypothyroidism: There appears to be a link between hypothyroidism and OSA beyond increased BMI alone. It is thought that mucoprotein and hyaluronic acid deposition in the upper airway may be related to increased airway compression. Treating underlying hypothyroidism often improves sleep apnea, independent of weight change or pulmonary function.

• Acromegaly: Tongue enlargement and skeletal changes, including increased head size, can also impact the airway and predispose patients to OSA.

• Gastroesophageal reflux disease (GERD): GERD is commonly present alongside OSA. Changing intrathoracic pressures and obesity predispose patients to reflux, and the inflammation caused by untreated GERD has been shown to worsen sleep apnea.

• Polycystic ovarian syndrome: Hormone dysregulation in PCOS can lead to increased frequency of apneic episodes in women with an anatomic predisposition for pharyngeal collapse. Hormonal changes associated with postmenopausal women have also been shown to cause a higher incidence of OSA.