cyanosis(redirected from cyanosis retinae)
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cyanosis(sī'ənō`sĭs), bluish coloration of the skin, mucous membranes, and nailbeds, resulting from a lack of oxygenated hemoglobin in the blood. It is a symptom of many disorders, including various pulmonary and heart diseases and many congenital heart defects (see blue babyblue baby,
infant born with a congenital heart defect that causes a bluish coloration of the skin as a result of cyanosis (deoxygenated blood). The color is most noticeable around the lips and at the tips of the fingers and toes.
..... Click the link for more information. ). Cyanosis that is caused by slowed circulation through peripheral blood vessels results in a bluish tinge only on the cool portions of the body (fingertips, nose, ears). In such cases the capillary blood gives up more than normal amounts of oxygen. Although this type of cyanosis can be caused by reduced cardiac output (e.g., in congestive heart failure), the most common causes are nervous tension and exposure to cold. Another type of cyanosis results from poisoning, either by nitrates in contaminated food or water or by certain chemicals and drugs.
in medicine, a bluish violet discoloration of the skin and mucous membranes that occurs with human diseases accompanied by circulatory and respiratory disorders.
a bluish discoloration of the skin and mucous membranes. The condition ranges in coloration from gray-blue to black-blue (“cast iron”). Cyanosis is due to an increase in the concentration (more than 5 g percent) of reduced hemoglobin, which has a bluish coloration, in capillary blood. Intense cyanosis of the extremities is called acrocyanosis. A distinction is made between central cyanosis, which results from a disturbance of oxygen saturation of blood in the lungs, and peripheral cyanosis, which results from a slowing of the blood flow and from extensive oxygen extraction into the surrounding tissues. Central cyanosis is observed mainly in pulmonary diseases, congenital heart diseases, and poisonings by carbon dioxide and aniline derivatives. Peripheral cyanosis is seen in heart diseases caused by circulatory disturbances and conditions such as thrombophlebitis and Raynaud’s disease in which a local slowing of blood flow occurs. False cyanosis is caused by a change in the color of the skin itself.