Signs of high fever

The type of high fever (fever) is an important characteristic of any disease. Fever is distinguished by duration. Acute fever lasts up to 2 weeks, subacute - up to 6 weeks, the duration of the chronic can be more than 6 weeks. The degree of increase in body temperature is:

• subfebrile - up to 38 ° С;
• moderate - up to 39 ° С;
• febrile - up to 41 ° С;
• Hyperpyretic - over 41 ° С.

The type of fever is an important characteristic of any disease. By the nature of fluctuations in the temperature curve, the following types of fevers occur:

• a constant fever in which the temperature increase to 39-40 ° C is maintained at the same level for several days or weeks, and the daily fluctuations do not exceed one degree;
• intermittent fever, which is characterized by temperature fluctuations of not less than 1 ° C, and the temperature can reach normal limits;
• remittent fever, in which daily changes in body temperature may be similar to intermittent fever, but unlike the latter, the temperature does not decrease to normal values;
• hectic fever, which is accompanied by a rise in temperature above 40 ° C and its rapid decrease to subfebrile figures;
• atypical fever, in which an increase in body temperature from high to moderately high values occurs without a certain pattern.

Several factors influence the temperature change during the day. The decisive factor is the amount of pyrogen and the sensitivity of the thermoregulatory center to them. In addition, the state of the heat transfer system, the trophic innervation system, is important. An important role is played by the process of the formation of substances - uncouplers of oxidative phosphorylation, as well as a stock of energy material - adipose tissue in the body.

It is known that the temperature of the child's body is not the same in different places of her measurement. Immediately after birth, the temperature in the rectum fluctuates within 36.6-38.1 "C, the first day - 36.5-37.4 ° C, on the second day - 36.9-37.4 ° C. The temperature range remains more or less constant, with slight deviations in the direction of decrease or increase.In the armpit, compared with the rectum, the temperature is less by 0.3-0.6 ° C, and in the mouth - by 0.2-0.3 ° C .

In newborns, thermoregulation is not sufficiently formed, especially the mechanisms of heat transfer are underdeveloped. As a consequence, they easily overheat and supercool.

With some infectious diseases, birth trauma, surgical interventions in newborns and children of the first year of life, a hyperthermic syndrome may develop, manifested by a sharp increase in temperature accompanied by convulsions and CNS disorders that pose a serious danger to life. Hyperthermal syndrome in children of the first year of life is not a true increase in temperature, because the mechanisms of thermoregulation at this age are not sufficiently developed, as a result of which the growth of heat production against the background of intoxication is observed. Hyperthermic syndrome in newborns can occur with infectious neurotoxicosis, metabolic acidosis, brain microcirculation disorders, brain edema and other conditions that have a damaging effect on the hypothalamic center of thermoregulation.

A rapid increase in temperature in a child is associated with a high rate of metabolic processes in the child's body.

In children of the first months of life, the insufficient level of maturation of the cerebral cortex, its protective and regulating function, causes an increased impact of any physical factor on the body.

One of the most formidable complications of fever is febrile convulsions. The average population risk of febrile seizures is 3% and increases with a history of mother febrile seizures in childhood. The temperature at which convulsions appear, in most cases fluctuates from 38.5 ° C to 41 ° C (average 39.3 ° C). Seizures occur more often in the first 12-24 hours after a fever, usually at fever height.

Febrile convulsions account for 85% of all convulsive syndromes in children. Children 17-23 months are more susceptible to convulsions. In 15% of cases, febrile convulsions are noted before the age of 4 years. The periods of maximum probability of febrile convulsions occur at the 4-5th, 7th-8th, 11th-12th months of the child's life. Most often, febrile convulsions occur in children against ischemic-hypoxic encephalopathy.

The appearance of febrile seizures is due to intracerebral hyperosmolarity and edematous syndrome. Hyperthermia and developing hypoxia contribute to disruption of energy metabolism, metabolism of phospholipids in the brain tissue, activation of LPO processes, stimulation of prostaglandin F2 synthesis, which causes spasm of the cerebral vessels and along with prostaglandin E1 affects the thermoregulatory center. Hence, there is a need to use antiprostaglandin drugs as a pathogenetic treatment for febrile seizures.

At a high temperature, a vegetative imbalance develops, manifested by sympathetic activation. An increase in the tone of the sympathetic part of the autonomic nervous system causes the heart rate to increase by 8-10 strokes with an increase in body temperature by 1 ° C. Spasm of peripheral vessels, observed in the initial stage of fever, leads to an increase in blood pressure. The predominance of excitation of the sympathetic or parasympathetic parts of the autonomic nervous system in different stages of fever causes a decrease in the secretory activity of all digestive glands, motor disorders of the stomach and intestines, and changes in the tone of the intestine.

High temperature affects the central nervous system. There can be both oppression and activation of higher nervous activity. In the clinical picture, headache, drowsiness, apathy, hyperesthesia are noted. Young children may have delusions, hallucinations.

The feverish process is able to influence respiratory function by increasing the respiratory rate. For each 1 ° C above 37 ° C, the number of respiratory movements is more by 4 breaths per minute, and the number of heartbeats by 20 beats.

Despite this, the supply of oxygen no longer provides for increasing tissue needs, and in the end, relative hypoxia develops. The degree of hyperthermia at which these disorders occur is very variable. Most often it corresponds to body temperature equal to 39-40 ° C, but depends on the individual characteristics of the child's body. The younger the child, the heavier the period of the baby's birth (especially if there are already concurrent injuries), the earlier decompensation develops.

In febrile states, a negative nitrogen balance is often found-an increase in the excretion of nitrogenous metabolic products in the urine. The causes of this - intoxication with increased protein catabolism and starvation, caused by a decrease in appetite and deterioration of digestibility of food. The predominance of catabolic processes over anabolic is also associated with the action of endogenous pyrogens, IL-1 and TNF-alpha. These cytokines are also responsible for reducing lipoprotein kinase activity and blocking neolipogenesis in adipose tissue. Changes in the carbohydrate process occur mainly due to the activation of the hypothalamic-pituitary-adrenal system. In the liver, glycogenolysis processes are activated, glycogen stores are reduced, and hyperglycemia is noted in the blood.

High temperature is often accompanied by a change in water-electrolyte metabolism. At stage I, the increase in renal blood flow is accompanied by an increase in diuresis. At the II stage diuresis decreases, water retention occurs. In connection with increased secretion of aldosterone, the elimination of sodium ions from the body is limited, and accordingly, less chloride ions are released. At the III stage of fever diuresis again increases, and the secretion of water, sodium and chloride ions by sweat glands increases.

Each increase in temperature should be considered from the prognostic positions.

If heat production corresponds to heat transfer, the child has a favorable, so-called "pink" fever. It got its name because of the coloration of the patient's skin. The skin is moderately hyperemic, warm, moist to the touch. The child's behavior in this case practically does not change.

If the patient feels cold against the background of hyperthermia, the chills, his skin are pale, with a cyanotic shade of the nail lodges and lips, the limbs are cold, and the rise in body temperature progresses, it is a "pale" fever. It is accompanied by tachycardia, shortness of breath, cramps are possible.

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