Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episodes are termed "apneas" with complete or near-complete cessation of breathing, or "hypopneas" when the reduction in breathing is partial. In either case, a fall in blood oxygen saturation, a disruption in sleep, or both may result. A high frequency of apneas or hypopneas during sleep may interfere with restorative sleep, which – in combination with disturbances in blood oxygenation – is thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime (e.g. excessive daytime sleepiness, decreased cognitive function).Most individuals with OSA are unaware of disturbances in breathing while sleeping, even after awakening. A bed partner or family member may observe an individual snoring or appear to stop breathing, gasp, or choke while sleeping. Individuals who live or sleep alone are often unaware of the condition. Symptoms may be present for years or even decades without identification, during which time the individual may become conditioned to the daytime sleepiness, headaches and fatigue associated with significant levels of sleep disturbance. Obstructive sleep apnea has been associated with neurocognitive morbidity, as well as a link between snoring and neurocognitive disorders.
People are usually split up into low and high risk for bleeding/blood clotting groups (based on their age, their medical history, their blood counts and their lifestyles), low risk individuals are usually treated with aspirin, whereas those at high risk are given hydroxycarbamide and/or other treatments that reduce platelet count (such as interferon-α and anagrelide). Agents
Hydroxycarbamide, interferon-α and anagrelide can lower the platelet count. Low-dose aspirin is used to reduce the risk of blood clot formation unless the platelet count is very high, where there is a risk of bleeding from the disease, and hence this measure would be counter-productive as aspirin-use increases the risk of bleeding.The PT1 study compared hydroxyurea plus aspirin to anagrelide plus aspirin as initial therapy for ET. Hydroxyurea treated patients had a lower incidence of arterial thrombosis, lower incidence of severe bleeding and lower incidence of transformation to myelofibrosis, but the risk of venous thrombosis was higher with hydroxycarbamide than with anagrelide. It is unknown whether the results are applicable to all ET patients. In people with symptomatic ET and extremely high platelet counts (exceeding 1 million), plateletpheresis can be used to remove platelets from the blood to reduce the risk of thrombosis. Prognosis
Essential thrombocythemia is sometimes described as a slowly progressive disorder with long asymptomatic periods punctuated by thrombotic or hemorrhagic events. However, well-documented medical regimens can reduce and control the number of platelets, which reduces the risk of these thrombotic or hemorrhagic events.