From Big Medical Encyclopedia

DEHYDRATION OF THE ORGANISM (synonym: negative water balance, dehydration, hydropenia, gipogidriya, ex-icos) — reduction of the general water content in an organism when its losses exceed receipt and education.

On the mechanism of development of O. of the lake it can be caused by excess removal of water at its insufficient compensation, loss of water owing to primary loss of sodium, restriction or the termination of reception of water.

The organism can lose a significant amount of water through intestines (at a diarrhea, intestinal fistula, effect of laxatives), a stomach (at plentiful vomiting), kidneys (a polyuria at not sugar and a diabetes mellitus, a hyperparathyreosis, nek-ry diseases of kidneys, action of diuretic), skin (the strengthened sweating), lungs (at increase in volume of ventilation in the conditions of dryness of air), as a result of blood loss, the expiration of exudate (at extensive burns, wounds). During the performance of physical activity the greatest loss of water with then is observed in conditions overheatings of an organism (see). At rise on high mountains the increased loss of water is promoted by the strengthened release of sweat owing to an exercise stress and its bystry evaporation; at height a lot of water is lost also through lungs in connection with increase of volume of ventilation and dryness of air. The loss of water connected with a long glycoprival diet can be O.'s cause of the lake.

The excess loss of water (without polyuria) which is not corresponding to its reduced consumption arises owing to primary increase of excretion of sodium with urine at insufficiency of mineralokortikoidny function of bark of adrenal glands. At these states vomiting and a diarrhea strengthen O. of the lake. The negative balance of sodium and O. of the lake are observed at a hypodynamia. The lake of the lake arises also owing to insufficient water consumption, extreme degree to-rogo is xerophagia, or its full deprivation. Water starvation and O. the island are possible at the weakened patients or who are in unconsciousness at seriously ill patients of children, at psychogenic loss of feeling thirst (see), and also at natural disasters. At the person at deficit of drinking water appetite is lost and there comes the complete starvation. Animals at deprivation of water in 2 — 3 days refuse a dry feed, preferring a complete starvation.

Lakes of the lake — one of the menacing states, at Krom are deeply broken many fiziol, functions. The lake, inevitable at O., reduction of volume of blood is partially compensated by the lowered release of sodium and water kidneys under action Aldosteronum (see) and vasopressin (see). The lake leads the accruing O. to development angidremiya (see), at a cut the volume of the circulating blood decreases and increases it viscosity (see), blood pressure decreases and the threat appears collapse (see). Reactive narrowing of many peripheral vessels and restriction in in them a blood-groove reduce filtering in balls of kidneys and diuresis (see) that conducts to azotemias (see) and to acidosis (see). Due to the reduction of secretion of sialadens and glands went. - kish. a path digestion is broken. Disturbance of a water balance in tissue of a brain and the accruing intoxication cause disorder of functions of a nervous system (spasms, coma).

At O. of the lake water content in skin, a bone tissue, lungs, intestines, muscles considerably decreases. About a half of the lost liquid usually is the share of extracellular water and about a half — on intracellular. Depletion of cells water considerably breaks their functions. If at an overhydratation of cells the ability lost by mitochondrions to use oxygen is recovered after normalization of osmotic pressure in cells, then at heavy O. the lake is disturbance is irreversible; deep disorder of metabolism of cells can cause loss of potassium and the phenomenon hypopotassemias (see).

Morphologically at O. the lake observes flabbiness of fabrics, heavy trophic disorders of skin (develop at long xerophagia). Signs of a reduction of sinusoid of a liver, sinus network of a spleen, a capillary network of lungs, decrease in a blood-groove in system of microcirculation (see), a zapus-tevaniye of many renal balls, atrophic changes and the centers of destruction in a liver, kidneys, sialadens are found, went. - kish. path.

Clinically The lake of the lake is shown by reduction of the weight (weight) of a body, strong thirst, loss of appetite, nausea. The mucous membrane of an oral cavity, a conjunctiva dry. There is a hoarseness. Skin becomes flabby, wrinkled, loses elasticity, a fold of skin of a stomach is long does not smooth out. Blood and intraocular pressure decrease, pulse is speeded up and weakened. The diuresis decreases. Weakness increases, there is a headache, dizziness, instability of gait, coordination of movements is broken. An animal force, attention weakens, working capacity decreases. There are complaints to a pricking in muscles, paresthesia. Sometimes body temperature increases. During the weighting the wedge, pictures occurs further reduction of body weight; eyeballs sink down, features are pointed, sight and hearing weaken, swallowing is sharply complicated; the circulatory unefficiency accrues; thrombosis of vessels is possible (see. Thrombosis ); the urination becomes painful, the diuresis progressively decreases up to anuries (see). The mentality is broken. At heavy O. of the lake the feeling of thirst can be lost.

For judgment of existence and O.'s weight of the lake it is necessary to control body weight daily. It is important to define also precisely amount of the emitted urine and the consumed liquid with drink and food depending on age, sex and a somatotype. During the calculation it is necessary to consider that loss of water by sweating and with expired air at adults makes in days apprx. 15 ml/kg and increases for 13% at temperature increase of the environment by each degree. As O.'s indicators of the lake can serve also increase gematokritny number (see) and strengthening of anions of chlorine in plasma (see. Hyperchloremia ).

O.'s degree of the lake and a way of its correction depend not only on the volume of the lost water, but also on a condition of water and electrolytic balance. Osmotic pressure in fluid mediums of an organism makes apprx. 285 mosm/l whereas the osmotic pressure of various liquids lost at patol, states, is very diverse. As a result of blood loss, the expiration of exudate, wound separated isotonic liquid is lost and cells are dehydrated. Reduction of volume of intravascular liquid leads to movement of a part of water from an interstitium in vessels and hyponatremias (see). Loss of sodium and related water is observed at insufficiency of adrenal glands. Angidremiya and a hyponatremia is accompanied by hypoosmolarity of plasma. In such conditions the overhydratation of cells develops. Excess introduction by the patient with O. of the lake of water or hypoosmotic liquid threatens with water poisoning (see. Water salt metabolism ). The polyuria with excessive loss of sodium is possible at badly controlled use natriuretic diuretic or at defeat of distal departments of nephron.

In a wedge, practice should deal with rather bigger loss of water, than electrolytes more often. The liquids lost at a diarrhea, intestinal fistulas, vomiting, the strengthened sweating, gipoosmolyarna; the water emitted through a respiratory organs is completely deprived of electrolytes. Osmotic concentration of urine exceeds osmotic concentration of plasma more often. The lake of the lake owing to a diarrhea, vomiting, excessive release of sweat, evaporation of water at a hyperventilation, water starvation and xerophagia is followed by hyper osmolarity of extracellular liquid and dehydration of cells.

Dehydration of an organism with hyper osmolarity of extracellular liquid (blood plasma) and dehydration of cells accompanies not diabetes mellitus. Disturbance of secretion of vasopressin or hyposensitivity of renal tubules cause allocation of a large amount of gipoosmotichny urine therefore blood is condensed and its osmotic concentration increases (to 295 we wash! л). The lake of the lake with dehydration of cells at a giperparati-eoza is also caused polyuria (see) with low osmotic concentration of urine. Parathormone suppresses a reabsorption of water, the hypercalcemia reduces sensitivity of tubules to vasopressin. The polyuria at a diabetes mellitus is caused by high osmotic concentration of primary urine at the expense of the increased content in it of glucose, sodium. Osmotic concentration of blood at a diabetes mellitus, despite loss of sodium, is increased for the account hyperglycemia (see). The lake of the lake with extracellular and intracellular loss of water can develop at use of osmotic diuretics.

At relative rest and moderate ambient temperature of people can live without water within a week. In a heat this term is reduced to 3 days. O.'s signs of the lake clearly are noticeable at loss of water in the quantity approximately equal to 5% of body weight. At loss of water in the quantity equal — 8% of body weight (or apprx. 1/3 extracellular waters), the lake expressed to O. is observed; the loss of water making 10 — 20% of body weight is life-threatening.

Compensation of loss of water is made taking into account possible loss or excess of electrolytes, avoiding artificial shifts of osmotic concentration and ionic composition of plasma. At loss of hypoosmotic liquid often happens to compensate enough its drink waters; in need of bystry intervention solution of glucose, than solution of salt is better to enter parenterally 5%. If the patient has no considerable electrolytic shifts and is not broken acid-base equilibrium (see), at O.'s treatment islands use the solutions which are most coming on structure to a blood plasma. The threat of a collapse at O. of the lake does necessary urgent recovery of volume of blood.

Dehydration of an organism at children

the hydra Inherent to a children's organism lability and instability of regulation of a water salt metabolism causes the high frequency of dehydration at various diseases.

Wedge, O.'s manifestations by the lake are absent if loss of water makes less than 5% of body weight of the child; at losses of water, equal 10% of body weight, all symptoms of dehydration clearly are expressed; at loss of the water making 15% of body weight there comes heavy O. of the lake.

O.'s frequency of the lake at various diseases of children of early age is explained with tension of a water salt metabolism at the limited range of the protective and adaptive reactions of neuroendocrinal system directed to economy of water; lack of feeling of thirst at small children; considerable (in comparison with adults) loss of water through skin and lungs owing to rather bigger body surface falling on a weight unit of a body at children; inability of kidneys to provide economy of water and salts at a condition of dehydration; adrenal insufficiency, edges often accompanies diseases.

At children preferential extracellular liquid is lost, the edge is not compensated by movement of water from cells since at newborns and children of early age the volume of extracellular liquid exceeds this volume at adults, at to-rykh more water contains in cells. In this regard at children very much the angidremiya and a hypovolemia early develops: the volume of the circulating blood decreases more than for 30%, the speed of a blood-groove in fabrics considerably decreases, the minute volume of the blood which is thrown out by heart decreases, the arteriovenous difference in saturation of blood oxygen accrues. Thus, the circulatory unefficiency with a hypoxia of congestive type develops that is followed by sharp disturbance of energy balance and oppression of functions of c. N of page up to coma (see).

Depending on the changes of indicators of exchange of water and electrolytes characterizing a condition of extracellular liquid at children types of dehydration can meet hypertensive (water scarce), isotonic and hypotonic (soledefitsitny). The hypertensive type meets most often at diseases of the period of a neonatality, the exception makes adrenogenital syndrome (see), at Krom loss of sodium and chlorine is more considerable, than loss of water. It must be kept in mind that the lose of weight of a body on 3 — the 5th days of life, not exceeding 10% initial (i.e. at the birth), shall not inspire alarms, it should be considered as fiziol, dehydration of a transition period. However more considerable loss of water demands correction. The hypertensive type O. of the lake can develop at children of chest age at artificial feeding by the concentrated milk mixes that in the absence of feeling of thirst and limited ability of kidneys to removal of excess of salt can lead the lake to O.

At children of chest and early age the main reason of O. of the lake should be considered went. - kish. diseases, intestinal infections, to-rye most often are followed by isotonic type O. of the lake.

Hypotonic dehydration can be observed at the children suffering from a mucoviscidosis, at Krom there is a loss of electrolytes with then and secrets of others exocrine glands. Diseases of kidneys (nephrite with loss of salts or a long diet with restriction of water and salt), and also not diabetes mellitus, feverish states are the reasons of hypotonic dehydration at children of more advanced age at inf. diseases.

Types O. of the lake can be defined at least at a half of patients on a wedge, to these (tab.), but the most reliable indicators receive at a laboratory research of such indicators as Gematokritny number, concentration of sodium, potassium or the general osmotic concentration of a blood plasma, the central venous pressure.

O.'s treatment by the lake at children is carried out by administration of liquids, infusion of solutions of glucose and salts (regidratation). The main task of rehydration therapy — to recover the available deficit of water and salts and to provide the daily need for them. Regidratation is carried out under control of a condition of the sick child and datas of laboratory (the loudspeaker of venous pressure, an indicator of a hematocrit, average size of an hour diuresis, specific density of urine). The choice of volume of water loading is considered correct if the size of a hematocrit and average size of an hour diuresis meet age standard, the central venous pressure is not higher than 80 mm w.g. and it is not lower than 20 mm w.g., fluctuations of specific density of urine — within 1,010 — 1,015. Correction of disturbances of electrolytic exchange at hypotonic or hypertensive types of dehydration should be carried out under control of dynamics of concentration of electrolytes in a blood plasma.

Table. Some clinical laboratory indicators at various types of dehydration at children of early age

Bibliography: Babayevo And. X., Serebryakov E. P. and With e f e r about in and R. I. A water salt metabolism at the person and animals at action of factors of an arid zone, Ashgabat, 1979; Veltishchev Yu. E. Water salt metabolism of the child, M., 1967; Danilov N. V. Physiological bases of the drinking mode, M., 1956; P and-p and I am a N A. V. and Tsybulkin E. K. Acute toxicoses at early children's age, L., 1979; The Guide to pathological physiology, under the editorship of. A. A. Bogomoltsa, t. 2, page 259, M. — L., 1937; Rug. An acid-base state and electrolytic balance, the lane with English, M., 1978, bibliogr.; Soboleva A. D. Reaction of cells and fabrics to dehydration, Novosibirsk, 1975.

Ya. A. Lazarisl. A. Serebrovskaya; Yu. E. Veltishchev (ped.).