Obstructive sleep apnea

Obstructive sleep apnea (OSA) is the most common type of sleep apnea and is characterised by repeated episodes of complete or partial obstructions of the upper airway during sleep, despite the effort to breathe, and is usually associated with a reduction in blood oxygen saturation. In the Obstructive Sleep Apnea-Hypopnea Syndrome, the episodes of decreased breathing are called “hypopnea” and its definition requires a ≥30% drop in flow for 10 seconds or longer, associated with ≥3% oxygen desaturation. The episodes of breathing cessations are called “apneas” (literally, “without breath”) and to be defined, a ≥90% drop in flow for 10 seconds or longer must be assessed and associated with ≥3% oxygen desaturation, or an arousal. Obstructive sleep apnea (OSA) is the most common type of sleep apnea and is characterised by repeated episodes of complete or partial obstructions of the upper airway during sleep, despite the effort to breathe, and is usually associated with a reduction in blood oxygen saturation. In the Obstructive Sleep Apnea-Hypopnea Syndrome, the episodes of decreased breathing are called “hypopnea” and its definition requires a ≥30% drop in flow for 10 seconds or longer, associated with ≥3% oxygen desaturation. The episodes of breathing cessations are called “apneas” (literally, “without breath”) and to be defined, a ≥90% drop in flow for 10 seconds or longer must be assessed and associated with ≥3% oxygen desaturation, or an arousal. In the third edition of the International Classification of Sleep Disorders (ICSD-3), Obstructive Sleep Apnea is classified amongst the Sleep Related Breathing Disorders and is divided in two categories, namely adult OSA and pediatric OSA. Obstructive Sleep Apnea is differentiated from Central Sleep Apnea (CSA) which is characterized by changes in the respiratory cycle during sleep but without the effort to breath during the apnea. The respiratory effort must then be assessed in order to correctly classify the apnea as obstructive given the specificity of the diaphragmatic activity in this condition: the inspiratory effort is continued or increased through the entire episode of absent airflow. When hypopneas are present alongside apneas, the term Obstructive Sleep Apnea-Hypopnea is used and when it is associated with daytime sleepiness and other daytime symptoms, it is called Obstructive Sleep Apnea-Hypopnea Syndrome. To be categorized as Obstructive, the hypopnea must meet one or more of the following symptoms: (1) snoring during the event, (2) increased oronasal flow flattening, and/or (3) thoraco-abdominal paradoxical respiration during the event If none of them are present during the event, it is categorized as central hypopnea. Individuals with OSA are rarely aware of difficulty breathing, even upon awakening. It is often recognized as a problem by others who observe the individual during episodes or is suspected because of its effects on the body. OSA is commonly accompanied with snoring. The terms obstructive sleep apnea syndrome or obstructive sleep apnea–hypopnea syndrome are used to refer to OSA when it is associated with symptoms during the daytime (e.g. excessive daytime sleepiness, decreased cognitive functions). Symptoms may be present for years or even decades without identification, during which time the individual may become conditioned to the daytime sleepiness and fatigue associated with significant levels of sleep disturbance. Individuals who generally sleep alone are often unaware of the condition, without a regular bed-partner to notice and make them aware of the signs. As the muscle tone of the body ordinarily relaxes during sleep, and the airway at the throat is composed of walls of soft tissue, which can collapse, it is not surprising that breathing can be obstructed during sleep. Although a minor degree of OSA is considered to be within the bounds of normal sleep, and many individuals experience episodes of OSA at some point in life, a small percentage of people have chronic, severe OSA. Many people experience episodes of OSA for only a short period. This can be the result of an upper respiratory infection that causes nasal congestion, along with swelling of the throat, or tonsillitis that temporarily produces very enlarged tonsils. The Epstein-Barr virus, for example, is known to be able to dramatically increase the size of lymphoid tissue during acute infection, and OSA is fairly common in acute cases of severe infectious mononucleosis. Temporary spells of OSA syndrome may also occur in individuals who are under the influence of a drug (such as alcohol) that may relax their body tone excessively and interfere with normal arousal from sleep mechanisms. Common symptoms of OSA include unexplained daytime sleepiness, restless sleep, and loud snoring (with periods of silence followed by gasps). Less common symptoms are morning headaches; insomnia; trouble concentrating; mood changes such as irritability, anxiety and depression; forgetfulness; increased heart rate and/or blood pressure; decreased sex drive; unexplained weight gain; increased urination and/or nocturia; frequent heartburn or gastroesophageal reflux disease; and heavy night sweats. Whereas the vast majority of patients with obstructive sleep apnea exhibit snoring, a minority (20-25%) of patients with central sleep apnea do not snore. The hallmark symptom of OSA syndrome in adults is excessive daytime sleepiness. Typically, an adult or adolescent with severe long-standing OSA will fall asleep for very brief periods in the course of usual daytime activities if given any opportunity to sit or rest. This behavior may be quite dramatic, sometimes occurring during conversations with others at social gatherings. The hypoxia (absence of oxygen supply) related to OSA may cause changes in the neurons of the hippocampus and the right frontal cortex. Research using neuro-imaging revealed evidence of hippocampal atrophy in people suffering from OSA. They found that OSA can cause problems in mentally manipulating non-verbal information, in executive functions and working memory. This repeated brain hypoxia is also considered to be a cause of Alzheimer's disease. Diagnosis of obstructive sleep apnea is significantly more common among people in relationships, who are alerted to their condition by being informed by their sleeping partner since individuals with obstructive sleep apnea are often unaware of the condition. There is a stigma associated with loud snoring, and it is not considered a feminine trait. Consequently, females are less likely to be told by their partners that they snore, or to admit it to themselves or doctors. Furthermore, CPAP (Continuous Positive Airway Pressure) machines are also perceived negatively by females, and less likely to be utilized to their full extent in this group.