Anhydremia

ANHYDREMIA (from the Greek a- negative part, hydor-water and haima-blood), thickening of blood, a condition opposite to hydremia - dilution of blood. In normal conditions, the water content in blood fluctuates only within very insignificant limits, since blood is capable of self-regulation. The basis of such self-regulation lies in both osmotic phenomena and the tendency of blood, as a liquid colloid, to persistently retain a certain amount of water. Fluctuations in this respect are therefore usually equalized very quickly, both when blood loses water and when excessive amounts of fluids are introduced into the body. Conditions for the development of anhydremia exist whenever the body loses more or less significant amounts of water, as for example in cholera - especially if replenishment of losses from outside is at the same time limited - or when for a certain period of time insufficient fluid is introduced into the body, for example in dry eating - the so-called "Schroth" method of treatment. A. is also possible with profuse sweating, although the results obtained in experiments are not identical, apparently depending on individual fluctuations in the amount of tissue fluids. In case of abundant blood loss, A. is possible only if the tissues have previously been depleted of water*, because usually after the body loses water, fluid from the tissues immediately begins to enter the vessels and A. does not develop, but transient hydremia. The consequences of A. are determined not only by the amount of fluid lost, but to an even greater extent by the speed of the losses. - In cholera, the blood becomes thick, almost tar-like, which creates great difficulties for the work of the heart; blood movement slows down, metabolism and gas exchange decreases and is disrupted. This leads to self-poisoning by metabolic products retained in the body. - At autopsy, A. is expressed in the decrease of tissue moisture, especially of the serous sheets of the pleura, peritoneum, complete absence of the fluid normally present in these body cavities or strong thickening of the latter to the consistency of mucus (see Cholera).