FEVER

From Big Medical Encyclopedia

FEVER — one of reactions of the strengthened thermogenesis which is shown a muscular shiver and a cryesthesia; develops at healthy at adaptation to cold, and at patients as a component of feverish reaction. The lake should distinguish from the trembling connected with a hyperadrenalemia, a hypoglycemia, contagious excitation and an extrapyramidal hyperkinesia (see. Trembling ).

O.'s manifestations begin with a cryesthesia and hypersensitivity of skin to tactile and temperature stimulations. Skin becomes pale, with the expressed pilomotor reaction («goosellesh»); sweating (see) is absent; lips get a cyanochroic shade. Then there is a muscular shiver covering consistently masseters, muscles of a shoulder girdle, a back and, at last, all skeletal muscles. At development of feverish reaction (see. Fever ) the muscular shiver can have character of attacks with short intervals between them (several seconds) in the beginning, then the feeling of a shiver becomes continuous and proceeds of several minutes till several o'clock.

At healthy faces of O. arises in response to considerable heat waste (thermolysis) during the cooling of a body. At the same time, as well as in most cases at development of feverish reaction, O.'s emergence has the reflex nature and is directed to biologically reasonable strengthening of thermogenesis. Less often O. are the cornerstone patol, the processes which are initially breaking neuroendocrinal regulation of heat exchange of an organism with Wednesday. In such cases of O. and change of body temperature are not reasonable for life activity of an individual.

Strengthening of thermogenesis at O. is caused by reduction thermolyses (see) and increase heats production (see). It is established that as in cases fiziol, adaptations to cold, and at feverish reaction, the thermolysis by reduction of a blood-groove in skin (at the expense of vasoconstriction) and reduction of sweating decreases in the beginning. It leads to decrease in temperature of skin and stimulation of skin cryoreceptors. From cold receptors impulses come to back departments of a hypothalamus, from there — to a cerebral cortex, creating a cryesthesia, and in a red kernel, from to-rogo excitement is transferred to motor neurons of a spinal cord, and from them — to skeletal muscles. As a result the tone of skeletal muscles raises that promotes formation of heat, and then there are frequent (from 8 to 12 in 1 sec.) in-coordinate reductions of separate groups of muscle fibers which are shown a shiver of a body and followed by significant increase in heat production (in 5 and more times). At development of feverish reaction after O. there comes the phase of balance between thermogenetic and thermolytic processes, but on more high level of body temperature. At the strengthened thermolysis (warm integuments), thermogenesis is also activated, hl. obr. thanks to an intensification of metabolic processes. The attempt to change body temperature in this or that direction causes the corresponding thermoregulatory reactions directed to recovery of the reached thermal level in in the fever patient. So, naira., wrapping in cold sheets causes bystry decrease in temperature with the subsequent strongest O., later to-rogo body temperature increases to initial level again.

Diagnostic value The lake partially matches diagnostic value of feverish reaction. At the same time O. is more specific to development of feverish reaction at purulent inflammations, septic states, a toxaemia, malaria, a lung fever. Quite often O. is observed after various intravenous transfusions that is explained by either understerilization, or low temperature of the entered solutions; at hemotransfusion of O. can be a consequence of the reaction caused by partial incompatibility of blood of the donor with blood of the recipient.



Bibliography: Veselkin P. N. Fever, M., 1963; Pathological physiology, under the editorship of A. D. Ado and L. M. Ishimova, page 184, M., 1980; X and at l and to e And. The autonomic nervous system, Anatomy and physiology, the lane from Romanians., page 324, Bucharest, 1978.


M of X. Turyanov.

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