Stroke is associated with obstructive sleep apnea.Obstructive sleep apnea is associated with problems in daytime functioning, such as daytime sleepiness, motor vehicle crashes, psychological problems, decreased cognitive functioning, and reduced quality of life. Other associated problems include cerebrovascular diseases (hypertension, coronary artery disease, and stroke) and diabetes. These problems could be, at least in part, caused by risk factors of OSA. Central sleep apnea
In pure central sleep apnea or Cheyne–Stokes respiration, the brains respiratory control centers are imbalanced during sleep. Blood levels of carbon dioxide, and the neurological feedback mechanism that monitors them, do not react quickly enough to maintain an even respiratory rate, with the entire system cycling between apnea and tachypnea, even during wakefulness. The sleeper stops breathing and then starts again. There is no effort made to breathe during the pause in breathing: there are no chest movements and no struggling. After the episode of apnea, breathing may be faster (tachypnea) for a period of time, a compensatory mechanism to blow off retained waste gases and absorb more oxygen. While sleeping, a normal individual is "at rest" as far as cardiovascular workload is concerned. Breathing is regular in a healthy person during sleep, and oxygen levels and carbon dioxide levels in the bloodstream stay fairly constant. Any sudden drop in oxygen or excess of carbon dioxide (even if tiny) strongly stimulates the brains respiratory centers to breathe. In any person, hypoxia and hypercapnia have certain common effects on the body.
Prognosis
Death could occur from untreated OSA due to lack of oxygen to the body.There is increasing evidence that sleep apnea may lead to liver function impairment, particularly fatty liver diseases (see steatosis).It has been revealed that people with OSA show tissue loss in brain regions that help store memory, thus linking OSA with memory loss. Using magnetic resonance imaging (MRI), the scientists discovered that people with sleep apnea have mammillary bodies that are about 20% smaller, particularly on the left side. One of the key investigators hypothesized that repeated drops in oxygen lead to the brain injury.The immediate effects of central sleep apnea on the body depend on how long the failure to breathe endures. At worst, central sleep apnea may cause sudden death. Short of death, drops in blood oxygen may trigger seizures, even in the absence of epilepsy. In people with epilepsy, the hypoxia caused by apnea may trigger seizures that had previously been well controlled by medications. In other words, a seizure disorder may become unstable in the presence of sleep apnea. In adults with coronary artery disease, a severe drop in blood oxygen level can cause angina, arrhythmias, or heart attacks (myocardial infarction). Longstanding recurrent episodes of apnea, over months and years, may cause an increase in carbon dioxide levels that can change the pH of the blood enough to cause a respiratory acidosis. Epidemiology
The Wisconsin Sleep Cohort Study estimated in 1993 that roughly one in every 15 Americans was affected by at least moderate sleep apnea.