syncope

—syncopic /sin kop"ik/, syncopal, adj.

/sing"keuh pee', sin"-/, n.

1. Gram. the contraction of a word by omitting one or more sounds from the middle, as in the reduction of never to ne'er.

2. Pathol. brief loss of consciousness associated with transient cerebral anemia, as in heart block, sudden lowering of the blood pressure, etc.; fainting.

[1350-1400; ME < LL syncope < Gk synkopé a cutting short, equiv. to syn- SYN- + kop- (s. of kóptein to cut) + -e fem. n. suffix]

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Effect of temporary impairment of blood circulation to a part of the body.

It is often used as a synonym for fainting, which is loss of consciousness due to inadequate blood flow to the brain. Paleness, nausea, sweating, and then pupil dilation, yawning, deep rapid breathing, and rapid heartbeat usually precede it. It lasts from under a minute to several minutes and may be followed by headache, confusion, and a weak feeling. The cause may be physical (e.g., heart failure, low blood sugar) or emotional (e.g., fear, anxiety). Abnormal vagus or autonomic nerve response can cause fainting (without preceding symptoms) triggered by ordinary activities such as urination, swallowing, coughing, or standing up or by pressure on the pulse point in the neck. Local syncope is coldness and numbness in a small area, especially the fingers, from diminished blood flow.

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▪ medical disorder

      effect of temporary impairment of blood circulation to a part of the body. The term is most often used as a synonym for fainting, which is caused by insufficient blood flow to the brain as a result of a fall in blood pressure.

      Fainting tends to be preceded first by paleness, nausea, and sweating and then by dilatation of the pupils, yawning, deeper and more rapid breathing, and a rapid heartbeat. The faint usually lasts from a fraction of a minute to several minutes and may be followed by headache, confusion, nervousness, and a feeling of weakness. It is usually prompted by fear, anxiety, or pain.

      Carotid sinus syncope, sometimes called the tight-collar syndrome, also causes brief unconsciousness from impaired blood flow to the brain. Unlike the ordinary faint, this syncope is not preceded by pallor, nausea, and sweating. (The carotid sinus is a widened portion of the carotid artery where there are nerve endings sensitive to pressure; when they are stimulated, the heart is slowed, blood vessels dilate, and blood pressure consequently falls, causing, in turn, reduction in blood flow to the brain.) Pressure on the carotid sinuses by a tight collar, by turning the head to the side, in swallowing, or even in shaving the side of the neck over the carotid sinus may be sufficient to cause the syncope, or it may occur spontaneously. This syncope may be used diagnostically, since faintness upon massage of one carotid sinus may suggest a narrowed carotid or basilar artery on the opposite side of the neck.

      Syncope involving temporary unconsciousness may also be caused by any of a number of organic (physical) diseases or disorders, such as aortic stenosis, heart failure, and a low level of sugar in the blood.

      Local syncope is whitening, weakness, coldness, and numbness of a small area of the body, especially the fingers, as a result of diminished blood flow to the part. It is associated with Raynaud's disease (Raynaud syndrome).

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