Dengue fever. What is a fever? Symptoms, treatment and consequences of mouse fever Duration of acute fever

Fever I Fever (febris, pyrexia)

a typical thermoregulatory protective-adaptive body response to the effects of pyrogenic substances, expressed by a temporary restructuring of heat exchange to maintain a higher than normal heat content and body temperature.

L. is based on the peculiar reaction of the hypothalamic centers of thermoregulation in various diseases to the action of pyrogenic substances (pyrogens). The entry of exogenous (for example, bacterial) pyrogens causes the appearance in the blood of secondary (endogenous) pyrogenic substances, which are characterized by bacterial thermal stability. Endogenous are formed in the body by granulocytes and macrophages when they come into contact with bacterial pyrogens or products of aseptic inflammation.

In infectious L., pyrogens are microbial products, products of metabolism and decay of microorganisms. Bacterial pyrogens are strong stress agents, and their introduction into the body causes a stress (hormonal) reaction, accompanied by neutrophilic leukocytosis. This reaction, developed during evolution, is nonspecific to many infectious diseases. Non-infectious L. can be caused by plant, animal, or industrial poisons; it is possible with allergic reactions, parenteral administration of protein, aseptic inflammation, tissue necrosis caused by circulatory disorders, tumors, neuroses, vegetative-vascular dystonia. They penetrate into the site of inflammation or tissue, which produces leukocyte pyrogen. An increase in body temperature without the participation of pyrogens is observed during emotional stress; some researchers view this reaction as a fever-like state of mixed origin.

An increase in body temperature during L. is carried out by the mechanisms of physical and chemical thermoregulation (thermoregulation). An increase in heat production occurs mainly due to muscle tremors (see Chills), and a limitation of heat transfer occurs as a result of spasm of peripheral blood vessels and decreased sweating. Normally, these thermoregulatory reactions develop during cooling. Their activation during L. is determined by the action of pyrogen on the neurons of the medial preoptic region of the anterior hypothalamus. With L., before the body temperature rises, there is a change in the sensitivity thresholds of the thermoregulation center to the temperature afferent signals entering it. cold-sensitive neurons in the medial preoptic area increases, and heat-sensitive neurons decrease. An increase in body temperature during L. differs from overheating of the body (Overheating of the body) in that it develops regardless of fluctuations in ambient temperature, and the degree of this increase is actively regulated by the body. When the body overheats, it increases only after the maximum tension of the physiological mechanisms of heat transfer turns out to be insufficient to remove heat into the environment at the same rate as its formation in the body.

Fever goes through three stages in its development ( rice. 1 ): in the first stage - there is an increase in body temperature; in the second stage - the temperature remains at high levels; in the third stage the temperature decreases. In the first stage of L., there is a limitation of heat transfer, as indicated by a narrowing of the blood vessels of the skin and, in connection with this, a limitation of blood flow, a decrease in skin temperature, and a decrease or cessation of sweating. At the same time, it increases and increases. Usually these phenomena are accompanied by general malaise, chills, nagging muscle pain, and headache. With the cessation of the rise in body temperature and the transition of heat to the second stage, it increases and is balanced with heat production at a new level. in the skin becomes intense, the pallor of the skin gives way to hyperemia, the skin temperature rises. The feeling of cold passes and intensifies. The third stage is characterized by the predominance of heat transfer by heat production. The skin continues to expand and sweating increases.

Based on the degree of increase in body temperature, subfebrile (from 37° to 38°), moderate (from 38° to 39°), high (from 39° to 41°) and excessive, or hyperpyretic, fever (over 41°) are distinguished. In typical cases of acute infectious diseases, the most favorable form is moderate fever with daily temperature fluctuations within 1°.

Based on the types of temperature curves, the following main types of fever are distinguished: constant, remitting (laxative), intermittent (intermittent), perverted, hectic (depleting) and irregular. With constant L., elevated body temperature lasts for several days or weeks with daily fluctuations within 1° ( rice. 2, a ). Such L. is characteristic, for example, of lobar pneumonia and typhus. In remitting L., which is observed in purulent diseases (for example, exudative pleurisy, lung abscess), temperature fluctuations during the day reach 2°C or more ( rice. 2, b ). Intermittent fever is characterized by alternating periods of normal body temperature and elevated ones; in this case, it is possible as sharp, for example with malaria ( rice. 2 in ), relapsing fever (relapsing L.), and gradual, for example, with brucellosis (undulating L.), an increase and decrease in body temperature ( rice. 2, g, d ). With perverted L., morning body temperature is higher than evening. This type of L. can sometimes occur with severe tuberculosis and prolonged forms of sepsis. With hectic L. ( rice. 2, e ) changes in body temperature are 3-4° and occur 2-3 times a day; this is typical for severe forms of tuberculosis and sepsis. With incorrect L. ( rice. 2, f ) there is no certain pattern in daily fluctuations in body temperature; occurs most often in rheumatism, pneumonia, influenza, dysentery.

Types of L. during illness can alternate or change from one to another. The intensity of the feverish reaction may vary depending on the functional state of the central nervous system. at the time of exposure to pyrogens. The duration of each stage is determined by many factors, in particular the dose of pyrogen, the time of its action, disorders that have arisen in the body under the influence of a pathogenic agent, etc. L. can end with a sudden and rapid drop in body temperature to normal and even below () or a gradual slow decrease body temperature (). The most severe toxic forms of some infectious diseases, as well as in the elderly, weakened people, and young children, often occur almost without L. or even with hypothermia, which is an unfavorable prognostic sign.

With L., a change in metabolism occurs (protein breakdown increases), sometimes disruption of the activity of the central nervous system, cardiovascular and respiratory systems, and gastrointestinal tract occurs. At altitude, delirium and subsequent loss of consciousness are sometimes observed. These phenomena are not directly related to the nervous mechanism of L. development; they reflect the features of intoxication and pathogenesis of the disease.

An increase in body temperature during L. is accompanied by an increase in heart rate. This does not occur in all febrile illnesses. So, with typhoid fever it is noted. The effect of increased body temperature on heart rhythm is weakened by other pathogenetic factors of the disease. An increase in heart rate, directly proportional to the increase in body temperature, is observed in L. caused by low-toxic pyrogens.

Breathing becomes more frequent as body temperature rises. The degree of increased breathing is subject to significant fluctuations and is not always proportional to the increase in body temperature. Increased breathing is mostly combined with a decrease in its depth.

With L., the digestive organs are disrupted (decreased digestion and absorption of food). Patients are coated, have dry mouth, and are sharply reduced. The secretory activity of the submandibular glands, stomach and pancreas is weakened. The motor activity of the gastrointestinal tract is characterized by dystonia with a predominance of increased tone and a tendency to spastic contractions, especially in the pyloric region. As a result of decreased opening of the pylorus, the rate of evacuation of food from the stomach slows down. The formation of bile decreases somewhat, but it increases.

Kidney activity during L. is not noticeably impaired. The increase in diuresis at the beginning of L. is explained by the redistribution of blood and an increase in its quantity in the kidneys. Water retention in tissues at altitude is often accompanied by a decrease in diuresis and an increase in urine concentration. There is an increase in the barrier and antitoxic function of the liver, urea formation and an increase in fibrinogen production. The phagocytic activity of leukocytes and fixed macrophages increases, as well as the intensity of antibody production. The production and release of corticosteroids by the pituitary gland, which have a desensitizing and anti-inflammatory effect, is enhanced.

Metabolic disorders depend more on the development of the underlying disease than on an increase in body temperature. Strengthening the immune system and mobilizing humoral mediators help increase the body’s protective functions against infection and the inflammatory process. creates less favorable conditions in the body for the proliferation of many pathogenic viruses and bacteria. In this regard, the main focus should be on eliminating the disease that caused L. The question of the use of antipyretics is decided by the doctor in each specific case, depending on the nature of the disease, the age of the patient, his premorbid condition and individual characteristics.

Treatment tactics with L. of infectious and non-infectious origin is the same in relation to the overriding importance of therapy for the underlying disease, but it differs fundamentally in the indications for symptomatic antipyretic therapy. The differences are determined by the fact that non-infectious L. is often a pathological phenomenon, the elimination of which in many cases is advisable, while infectious L., as a rule, serves as an adequate protective reaction of the body to the introduction of a pathogen. Elimination of infectious L., achieved with the help of antipyretics, is accompanied by a decrease in phagocytosis and other immune reactions, which leads to an increase in the duration of inflammatory infectious processes and the wedge period. manifestations of illness (for example, cough, runny nose), incl. and such, in addition to L., manifestations of infectious intoxication as general and muscle weakness, lack of appetite, exhaustion, . Therefore, in case of infectious L., the prescription of symptomatic therapy requires the doctor to clearly justify its need, determined individually.

In acute infectious diseases, the indication for symptomatic treatment of L. is an increase in body temperature to 38°C or more in patients with bleeding, hemoptysis, mitral stenosis, circulatory failure of II-III degree, decompensated diabetes mellitus, in pregnant women, or an increase to 40°C or more in previously healthy individuals, including children, especially if an inadequate rise in temperature is suspected due to an infectious lesion of the central nervous system. with thermoregulation disorder. Subjectively bad fever in patients is not always a sufficient justification for the use of drugs to reduce body temperature. In many cases, even with significant hyperthermia (40°-41°) in adults, you can limit yourself to non-medicinal methods of increasing heat transfer that improve the patient’s well-being: ventilating the room where it is located, eliminating excess underwear and warm bed linen, wiping the body with a damp towel, drinking small portions ( absorbed almost in the oral cavity) cool water. At the same time, one must monitor changes in breathing and; in case of pronounced deviations (in older people they are possible when body temperature rises to 38-38.5°), it should be used. Since L. is often combined with aches in the joints and muscles, headache, preference is given to antipyretics from the group of non-narcotic analgesics, especially analgin (for adults - up to 1 G appointment). For low-grade infectious fever, symptomatic treatment is not performed.

For non-infectious L., symptomatic therapy is carried out in the same cases as for infectious L., and in addition, if the patient has poor tolerance to increases in body temperature, even if it does not reach febrile values. However, in the latter case, the doctor must compare the expected effectiveness of treatment with the possible adverse effects of the use of drugs, especially if it is long-term. It should be taken into account that antipyretic drugs from the group of non-narcotic analgesics are practically ineffective for non-infectious L..

In some pathological conditions, such as thyrotoxic crisis, malignant hyperthermia (see Hyperthermic syndrome), the appearance of significant L. requires emergency treatment measures. An increase in body temperature to febrile levels in patients with thyrotoxicosis (both against the background of an infectious disease and without it) may be one of the symptoms of a developing thyrotoxic crisis, in which the patient must be urgently hospitalized, providing emergency care.

Bibliography: Veselkin P.N. Fever, M., 1963, bibliogr.; aka. Fever, BME, vol. 13, p. 217, M., 1980, bibliogr.; Multi-volume guide to pathological physiology, ed. N.N. Sirotinina, vol. 2, p. 203, M., 1966; man, ed. R. Schmidt and G. Tevs, . from English, vol. 4, p. 18, M., 1986.

a protective-adaptive reaction of the body that occurs in response to the action of pathogenic stimuli and is expressed in the restructuring of thermoregulation to maintain a higher than normal level of heat content and body temperature.

Nutritional fever(f. alimentaria) - L. in infants, caused by inadequate food composition (usually insufficient amount

Atypical fever(f. atypica) - A., occurring in a form that is not typical for this disease.

Wave-like fever(f. undulans; L. undulating) - L., characterized by alternating periods of increase and decrease in body temperature over several days.

Fever is high- L., at which the body temperature is in the range from 39 to 41°.

Hectic fever(f. hectica; synonym: L. debilitating, L. debilitating) - L., characterized by very large (3-5°) rises and rapid declines in body temperature, repeated 2-3 times a day; observed, for example, in sepsis.

Hyperpyretic fever(f. hyperpyretica; syn. L. excessive) - L. with body temperature above 41°.

Purulent-resorptive fever(f. purulentoresorptiva; synonym: L. wound, L. toxic-resorptive,) - L. caused by the absorption of toxic products from the focus of purulent inflammation.

Perverted fever(f. inversa) - L., in which the morning body temperature is higher than the evening.

Debilitating fever(f. hectica) - see Hectic fever .

Fever is intermittent(f. intermittens) - see Intermittent fever .

Infectious fever(f. infectiva) - L. that occurs during an infectious disease and is caused by the impact on the body of metabolic products or decay of pathogens, as well as endogenous pyrogens formed during the infectious process.

Debilitating fever(f. ictalis) - see Hectic fever .

Milk fever(f. lactea) - L., which occurs during acute stagnation of milk in the mammary gland.

Non-infectious fever(f. non infectiva) - L. not associated with an infectious process, for example, caused by aseptic tissue damage, irritation of certain receptor zones, or the introduction of pyrogenic substances into the body.

Fever is wrong(f. irregularis) - L. without any pattern in the alternation of periods of increase and decrease in body temperature.

Intermittent fever(f. intermittens; synonym L. intermittent) - L., characterized by alternating periods of elevated body temperature with periods of normal or reduced temperature during the day.

Relieving fever(obsolete) - see Remitting fever .

Constant fever(f. continua) - L., in which daily fluctuations in body temperature do not exceed 1°; observed, for example, with typhus, lobar pneumonia.

Wound fever(f. vulneralis) - see Purulent-resorptive fever .

Remitting fever(f. remittens: synonym L. laxative - outdated) - L. with daily fluctuations in body temperature within 1-1.5 ° without decreasing to normal levels.

Recurrent fever(f. recidiva) - L., characterized by repeated rises in the patient’s body temperature after it has decreased for several days to normal values.

Salt fever- L., developing with uncompensated retention of sodium chloride in the body; observed, for example, in infants with malnutrition.

Low-grade fever(f. subfebrilis) - L., in which the body temperature does not rise above 38°.

Toxic-resorptive fever(f. toxicoresorptiva) - see Purulent-resorptive fever .

Moderate fever- L., at which the body temperature is in the range from 38 to 39°.

Undulating fever(f. undulans) -

1) see Wavy fever;

Definition of the concept

Fever is an increase in body temperature as a result of changes in the thermoregulatory center of the hypothalamus. It is a protective-adaptive reaction of the body that occurs in response to the action of pathogenic stimuli.

Hyperthermia should be distinguished from fever - an increase in temperature when the process of thermoregulation of the body is not impaired, and the increased body temperature is caused by changes in external conditions, for example, overheating of the body. The body temperature during infectious fever usually does not exceed 41 0 C, in contrast to hyperthermia, in which it is above 41 0 C.

Temperatures up to 37 °C are considered normal. Body temperature is not a constant value. The temperature value depends on: time of day(maximum daily fluctuations are from 37.2 °C at 6 a.m. to 37.7 °C at 4 p.m.). Night workers may have the opposite relationship. The difference between morning and evening temperatures in healthy people does not exceed 1 0 C); motor activity(rest and sleep help lower the temperature. Immediately after eating, a slight increase in body temperature is also observed. Significant physical stress can cause an increase in temperature by 1 degree); phases of the menstrual cycleamong women With a normal temperature cycle, the morning vaginal temperature curve has a characteristic two-phase shape. The first phase (follicular) is characterized by low temperature (up to 36.7 degrees), lasts about 14 days and is associated with the action of estrogens. The second phase (ovulation) is manifested by a higher temperature (up to 37.5 degrees), lasts about 12-14 days and is caused by the action of progesterone. Then, before menstruation, the temperature drops and the next follicular phase begins. The absence of a decrease in temperature may indicate fertilization. It is characteristic that morning temperature measured in the axillary region, in the oral cavity or rectum gives similar curves.

Normal body temperature in the armpit:36.3-36.9 0 C, in the oral cavity:36.8-37.3 0, in the rectum:37.3-37.7 0 C.

Causes

The causes of fever are many and varied:

1. Diseases that directly damage the thermoregulation centers of the brain (tumors, intracerebral hemorrhages or thrombosis, heat stroke).

3. Mechanical injury (crumbling).

4. Neoplasms (Hodgkin's disease, lymphoma, leukemia, kidney carcinoma, hepatoma).

5. Acute metabolic disorders (thyroid crisis, adrenal crisis).

6. Granulomatous diseases (sarcoidosis, Crohn's disease).

7. Immune disorders (connective tissue diseases, drug allergies, serum sickness).

8. Acute vascular disorders (thrombosis, infarctions of the lung, myocardium, brain).

9. Disturbance of hematopoiesis (acute hemolysis).

10. Under the influence of medications (neuroleptic malignant syndrome).

Mechanisms of occurrence and development (pathogenesis)

Human body temperature is a balance between the formation of heat in the body (as a product of all metabolic processes in the body) and the release of heat through the surface of the body, especially the skin (up to 90-95%), as well as through the lungs, feces and urine. These processors are regulated by the hypothalamus, which acts like a thermostat. In conditions that cause an increase in temperature, the hypothalamus commands the sympathetic nervous system to vasodilate the blood vessels of the skin, increasing sweating, which increases heat transfer. When the temperature drops, the hypothalamus gives the command to retain heat by constricting the blood vessels of the skin and muscle tremors.

Endogenous pyrogen - a low-molecular protein produced by blood monocytes and macrophages of the tissues of the liver, spleen, lungs, and peritoneum. In some tumor diseases - lymphoma, monocytic leukemia, kidney cancer (hypernephroma) - autonomous production of endogenous pyrogen occurs and, therefore, fever is present in the clinical picture. Endogenous pyrogen, after being released from the cells, acts on the thermosensitive neurons of the preoptic region of the hypothalamus, where the synthesis of prostaglandin E1, E2 and cAMP is induced with the participation of serotonin. These biologically active compounds, on the one hand, cause an intensification of heat production by restructuring the hypothalamus to maintain the body temperature at a higher level, and on the other hand, they affect the vasomotor center, causing a narrowing of peripheral vessels and a decrease in heat transfer, which generally leads to fever. The increase in heat production occurs due to an increase in the intensity of metabolism, mainly in muscle tissue.

In some cases, stimulation of the hypothalamus may be caused not by pyrogens, but by dysfunction of the endocrine system (thyrotoxicosis, pheochromocytoma) or the autonomic nervous system (neurocirculatory dystonia, neuroses), or the influence of certain medications (drug fever).

The most common causes of drug fever are penicillins and cephalosporins, sulfonamides, nitrofurans, isoniazid, salicylates, methyluracil, procainamide, antihistamines, allopurinol, barbiturates, intravenous infusions of calcium chloride or glucose, etc.

Fever of central origin is caused by direct irritation of the thermal center of the hypothalamus as a result of acute cerebrovascular accident, tumor, or traumatic brain injury.

Thus, an increase in body temperature may be due to the activation of the system of exopyrogens and endopyrogens (infections, inflammation, pyrogenic substances of tumors) or other reasons without the participation of pyrogens at all.

Since the degree of increase in body temperature is controlled by the “hypothalamic thermostat,” even in children (with their immature nervous system) fever rarely exceeds 41 0 C. In addition, the degree of increase in temperature largely depends on the condition of the patient’s body: for the same disease It may be different for different individuals. For example, with pneumonia in young people, the temperature reaches 40 0 ​​C and higher, but in old age and in exhausted people such a significant rise in temperature does not occur; sometimes it doesn’t even exceed the norm.

Clinical picture (symptoms and syndromes)

Fever is considered acute", if it lasts no more than 2 weeks, the fever is called " chronic» with a duration of more than 2 weeks.

In addition, during the course of a fever, a distinction is made between a period of increasing temperature, a period of peak fever, and a period of decreasing temperature. Temperature reduction occurs in different ways. A gradual, step-like decrease in temperature over 2-4 days with minor evening rises is called lysis. The sudden, rapid end of fever with a drop in temperature to normal within 24 hours is called crisis. As a rule, a rapid drop in temperature is accompanied by profuse sweat. This phenomenon was given special significance before the era of antibiotics, since it symbolized the beginning of a period of recovery.

Increased body temperature from 37 to 38 0 C is called low-grade fever. Moderately elevated body temperature from 38 to 39 0 C is called febrile fever. High body temperature from 39 to 41 0 C is called pyretic fever. Excessively high body temperature (over 41 0 C) is hyperpyretic fever. This temperature in itself can be life-threatening.

There are 6 main types of fever and 2 forms of fever.

It should be noted that our predecessors attached great importance to temperature curves when diagnosing diseases, but in our time, all these classical types of fever are of little help in the work, since antibiotics, antipyretics and steroid drugs change not only the nature of the temperature curve, but also the entire clinical picture diseases.

Type of fever

1. Constant or persistent fever. There is a constantly elevated body temperature and during the day the difference between morning and evening temperatures does not exceed 1 0 C. It is believed that such an increase in body temperature is characteristic of lobar pneumonia, typhoid fever, and viral infections (for example, influenza).

2. Relieving fever (remitting). There is a constantly elevated body temperature, but daily temperature fluctuations exceed 1 0 C. A similar increase in body temperature occurs with tuberculosis, purulent diseases (for example, with a pelvic abscess, empyema of the gallbladder, wound infection), as well as with malignant neoplasms.

By the way, fever with sharp fluctuations in body temperature (the range between morning and evening body temperature is more than 1°C), accompanied in most cases by chills, is usually called septic(see also intermittent fever, hectic fever).

3. Intermittent fever (intermittent). Daily fluctuations, as in relapsing-remitting conditions, exceed 1 0 C, but here the morning minimum is within normal limits. Moreover, elevated body temperature appears periodically, at approximately equal intervals (most often around noon or at night) for several hours. Intermittent fever is especially characteristic of malaria, and is also observed with cytomegalovirus infection, infectious mononucleosis, and purulent infections (eg, cholangitis).

4. Wasting fever (hectic). In the morning, as with intermittent, normal or even decreased body temperature is observed, but daily temperature fluctuations reach 3-5 0 C and are often accompanied by debilitating sweats. Such an increase in body temperature is characteristic of active pulmonary tuberculosis and septic diseases.

5. Reverse or perverted fever differs in that the morning body temperature is higher than the evening one, although from time to time the usual slight evening increase in temperature still occurs. Reverse fever occurs with tuberculosis (more often), sepsis, and brucellosis.

6. Irregular or irregular fever manifests itself as an alternation of different types of fever and is accompanied by varied and irregular daily fluctuations. Abnormal fever occurs with rheumatism, endocarditis, sepsis, and tuberculosis.

Form of fever

1. Undulating fever characterized by a gradual rise in temperature over a certain period of time (persistent or remitting fever for several days), followed by a gradual decrease in temperature and more or less long periods of normal temperature, which gives the impression of a series of waves. The exact mechanism of this unusual fever is unknown. Often observed in brucellosis and lymphogranulomatosis.

2. Relapsing fever (recurrent) characterized by alternating periods of fever with periods of normal temperature. In its most typical form it occurs in relapsing fever and malaria.

One-day, or ephemeral fever: elevated body temperature is observed for several hours and does not recur. Occurs with mild infections, overheating in the sun, after a blood transfusion, and sometimes after intravenous administration of drugs.

Daily repetition of attacks - chills, fever, drop in temperature - in malaria is called daily fever.

Three-day fever is the repetition of attacks of malaria every other day.

Quadrennial fever is a recurrence of attacks of malaria after 2 fever-free days.

Five-day paroxysmal fever (synonyms: Werner-His disease, trench or trench fever, paroxysmal rickettsiosis) is an acute infectious disease caused by rickettsia, carried by lice, and typically occurs in a paroxysmal form with repeated four- or five-day attacks of fever separated by several days remission, or in typhoid form with multi-day continuous fever.

Symptoms accompanying fever

Fever is characterized not only by an increase in body temperature. Fever is accompanied by increased heart rate and breathing; blood pressure often decreases; patients complain of a feeling of heat, thirst, headache; the amount of urine excreted decreases. Fever increases metabolism, and since along with this appetite is reduced, patients with long-term fevers often lose weight. Feverish patients note: myalgia, arthralgia, drowsiness. Most of them have chills and chilliness. With tremendous chills and severe fever, piloerection (“goose bumps”) and trembling occur, and the patient’s teeth chatter. Activation of heat loss mechanisms leads to sweating. Abnormalities in mental status, including delirium and seizures, are more common in very young, very old, or debilitated patients.

1. Tachycardia(cardiopalmus). The relationship between body temperature and pulse deserves great attention, since, other things being equal, it is quite constant. Typically, with an increase in body temperature by 1°C, the heart rate increases by at least 8-12 beats per minute. If at a body temperature of 36 0 C the pulse is, for example, 70 beats per minute, then a body temperature of 38 0 C will be accompanied by an increase in heart rate to 90 beats per minute. The discrepancy between high body temperature and pulse rate in one direction or the other is always subject to analysis, since in some diseases this is an important recognition sign (for example, fever in typhoid fever, on the contrary, is characterized by relative bradycardia).

2. Sweating. Sweating is one of the mechanisms of heat transfer. Profuse sweating occurs as the temperature drops; when the temperature rises, on the contrary, the skin is usually hot and dry. Sweating is not observed in all cases of fever; it is characteristic of purulent infection, infective endocarditis and some other diseases.

4. Herpes. Fever is often accompanied by the appearance of a herpetic rash, which is not surprising: 80-90% of the population is infected with the herpes virus, although clinical manifestations of the disease are observed in 1% of the population; activation of the herpes virus occurs at the time of decreased immunity. Moreover, when talking about fever, ordinary people often mean herpes by this word. With some types of fever, herpetic rash occurs so often that its appearance is considered one of the diagnostic signs of the disease, for example, lobar pneumococcal pneumonia, meningococcal meningitis.

5. Febrile seizuresOgi. Seizures with fever occur in 5% of children aged 6 months to 5 years. The likelihood of developing a convulsive syndrome during fever depends not so much on the absolute level of increase in body temperature, but on the speed of its rise. Typically, febrile seizures last no more than 15 minutes (average 2-5 minutes). In many cases, cramps occur early in the development of fever and usually go away on their own.

Convulsive syndrome can be associated with fever if:

the child’s age does not exceed 5 years;

there are no diseases that can cause seizures (for example, meningitis);

no seizures were observed in the absence of fever.

First of all, in a child with febrile seizures, you should think about meningitis (lumbar puncture is indicated if the clinical picture is appropriate). To exclude spasmophilia in infants, calcium levels are assessed. If convulsions lasted more than 15 minutes, it is advisable to perform electroencephalography to exclude epilepsy.

6. Change in urine test. With kidney disease, leukocytes, casts, and bacteria can be found in the urine.

Diagnostics

In the case of acute fever, it is desirable, on the one hand, to avoid unnecessary diagnostic tests and unnecessary therapy for diseases that can result in spontaneous recovery. On the other hand, it must be remembered that under the guise of a banal respiratory infection, a serious pathology may be hidden (for example, diphtheria, endemic infections, zoonoses, etc.), which must be recognized as early as possible. If an increase in temperature is accompanied by characteristic complaints and/or objective symptoms, then this allows one to immediately navigate the diagnosis of the patient.

The clinical picture should be carefully assessed. They study in detail the anamnesis, life history of the patient, his travels, and heredity. Next, a detailed functional examination of the patient is carried out, repeating it. Laboratory tests are performed, including a clinical blood test with the necessary detail (plasmocytes, toxic granules, etc.), as well as examination of pathological fluid (pleural, joint fluid). Other tests: ESR, general urine analysis, determination of functional activity of the liver, blood cultures for sterility, urine, sputum and feces (for microflora). Special research methods include x-rays, MRI, CT (to detect abscesses), radionuclide studies. If non-invasive research methods do not allow a diagnosis to be made, a biopsy of organ tissue is performed; bone marrow puncture is advisable in patients with anemia.

But often, especially on the first day of the disease, it is impossible to determine the cause of the fever. Then the basis for decision making becomes the patient's health status before the onset fevers and disease dynamics.

1. Acute fever against the background of complete health

If fever occurs against a background of complete health, especially in a young or middle-aged person, in most cases one can assume an acute respiratory viral infection (ARVI) with spontaneous recovery within 5-10 days. When diagnosing ARVI, it should be taken into account that with infectious fever, catarrhal symptoms of varying degrees of severity are always observed. In most cases, no tests (other than daily temperature measurements) are required. When re-examined after 2-3 days, the following situations are possible: improved health, decreased temperature. The appearance of new signs, such as skin rashes, plaque in the throat, wheezing in the lungs, jaundice, etc., which will lead to a specific diagnosis and treatment. Deterioration/no change. In some patients, the temperature remains quite high or their general condition worsens. In these situations, repeated, more in-depth questioning and additional research are required to search for diseases with exo- or endogenous pyrogens: infections (including focal ones), inflammatory or tumor processes.

2. Acute fever with a changed background

If the temperature rises against the background of an existing pathology or the patient’s serious condition, the possibility of self-healing is low. An examination is immediately prescribed (the diagnostic minimum includes general blood and urine tests, chest x-ray). Such patients are also subject to more regular, often daily monitoring, during which indications for hospitalization are determined. Main options: Patient with a chronic disease. Fever may be associated primarily with a simple exacerbation of the disease if it is of an infectious-inflammatory nature, for example, bronchitis, cholecystitis, pyelonephritis, rheumatism, etc. In these cases, targeted additional examination is indicated. Patients with reduced immunological reactivity. For example, those suffering from oncohematological diseases, HIV infection, or receiving glucocorticosteroids (prednisolone more than 20 mg/day) or immunosuppressants for any reason. The appearance of fever may be due to the development of an opportunistic infection. Patients who have recently undergone invasive diagnostic tests or therapeutic procedures. Fever may reflect the development of infectious complications after examination/treatment (abscess, thrombophlebitis, bacterial endocarditis). There is also an increased risk of infection among drug addicts who inject drugs intravenously.

3. Acute fever in patients over 60 years of age

Acute fever in the elderly and senile age is always a serious situation, because due to a decrease in functional reserves, acute disorders can quickly develop under the influence of fever in such patients, for example, delirium, cardiac and respiratory failure, and dehydration. Therefore, such patients require immediate laboratory and instrumental examination and determination of indications for hospitalization. One more important circumstance should be taken into account: at this age, clinical manifestations may be asymptomatic and atypical. In most cases, fever in old age has an infectious etiology. The main causes of infectious and inflammatory processes in old age: Acute pneumonia is the most common cause of fever in old age (50-70% of cases). Fever, even with extensive pneumonia, may be low, auscultatory signs of pneumonia may not be expressed, and general symptoms (weakness, shortness of breath) will be in the foreground. Therefore, for any unclear fever, an X-ray of the lungs is indicated - this is the law ( pneumonia is the old man's friend). When making a diagnosis, the presence of intoxication syndrome (fever, weakness, sweating, cephalalgia), disorders of broncho-drainage function, auscultatory and radiological changes are taken into account. The differential diagnosis includes the possibility of pulmonary tuberculosis, which is often encountered in geriatric practice. Pyelonephritis is usually manifested by fever, dysuria and lower back pain; a general urine test reveals bacteriuria and leukocyturia; Ultrasound reveals changes in the collecting system. The diagnosis is confirmed by bacteriological examination of urine. The occurrence of pyelonephritis is most likely in the presence of risk factors: female gender, bladder catheterization, urinary tract obstruction (urolithiasis, prostate adenoma). Acute cholecystitis can be suspected when fever and chills are combined, pain in the right hypochondrium, jaundice, especially in patients with already known chronic gallbladder disease.

Other, less common causes of fever in old and senile age include herpes zoster, erysipelas, meningoencephalitis, gout, polymyalgia rheumatica and, of course, ARVI, especially during the epidemic period.

4. Prolonged fever of unknown origin

The conclusion “fever of unknown origin” is valid in cases where an increase in body temperature above 38°C lasts more than 2 weeks, and the cause of the fever remains unclear after routine studies. In the International Classification of Diseases, 10th revision, fever of unknown origin has its code R50 in the “Symptoms and Signs” section, which is quite reasonable, since it is hardly advisable to elevate the symptom to a nosological form. According to many clinicians, the ability to understand the causes of prolonged fever of unknown origin is the touchstone of a doctor’s diagnostic abilities. However, in some cases it is completely impossible to identify difficult-to-diagnose diseases. Among febrile patients who were initially diagnosed with “fever of unknown origin,” cases that have not been fully deciphered account, according to various authors, from 5 to 21% of such patients. Diagnosis of fever of unknown origin should begin with an assessment of the social, epidemiological and clinical characteristics of the patient. To avoid mistakes, you need to get answers to 2 questions: What kind of person is this patient (social status, profession, psychological portrait)? Why did the disease manifest itself now (or why did it take this form)?

1. A thorough medical history is of paramount importance. It is necessary to collect all available information about the patient: information about previous diseases (especially tuberculosis and heart valve defects), surgical interventions, taking any medications, working and living conditions (travel, personal hobbies, contact with animals).

2. Conduct a careful physical examination and perform routine tests (complete blood count, complete urinalysis, biochemical blood test, Wassermann test, ECG, chest x-ray), including blood and urine cultures.

3. Think about the possible causes of fever of unknown origin in a particular patient and study the list of diseases manifested by prolonged fever (see list). According to various authors, the basis of long-term fever of unknown origin in 70% is the “big three”: 1. infections - 35%, 2. malignant tumors - 20%, 3. systemic connective tissue diseases - 15%. Another 15-20% are due to other diseases, and in approximately 10-15% of cases the cause of fever of unknown origin remains unknown.

4. Form a diagnostic hypothesis. Based on the data obtained, it is necessary to try to find a “leading thread” and, in accordance with the accepted hypothesis, prescribe certain additional studies. It must be remembered that for any diagnostic problem (including fever of unknown origin), first of all you need to look for common and frequently occurring diseases, and not some rare and exotic diseases.

5. If you get confused, go back to the beginning. If the formed diagnostic hypothesis turns out to be untenable or new assumptions arise about the causes of fever of unknown origin, it is very important to re-question the patient and examine him, and re-examine the medical documentation. Conduct additional laboratory tests (routine) and form a new diagnostic hypothesis.

5. Long-term low-grade fever

Subfebrile body temperature is understood to mean its fluctuations from 37 to 38°C. Prolonged low-grade fever occupies a special place in therapeutic practice. Patients whose long-term low-grade fever is the dominant complaint are encountered quite often at appointments. To find out the cause of low-grade fever, such patients are subjected to various studies, they are given various diagnoses and (often unnecessary) treatment is prescribed.

In 70-80% of cases, prolonged low-grade fever occurs in young women with symptoms of asthenia. This is explained by the physiological characteristics of the female body, the ease of infection of the urogenital system, as well as the high frequency of psycho-vegetative disorders. It must be taken into account that prolonged low-grade fever is much less likely to be a manifestation of any organic disease, in contrast to prolonged fever with a temperature above 38°C. In most cases, prolonged low-grade fever reflects banal autonomic dysfunction. Conventionally, the causes of prolonged low-grade fever can be divided into two large groups: infectious and non-infectious.

Infectious subfebrile condition. Low-grade fever always raises suspicion of an infectious disease. Tuberculosis. If you have an unclear low-grade fever, you must first rule out tuberculosis. In most cases this is not easy to do. From the anamnesis, the following are essential: the presence of direct and prolonged contact with a patient with any form of tuberculosis. The most significant is being in the same place with a patient with an open form of tuberculosis: an office, apartment, stairwell or entrance of the house where the patient with bacterial excretion lives, as well as a group of nearby houses united by a common yard. A history of previous tuberculosis (regardless of location) or the presence of residual changes in the lungs (presumably of tuberculosis etiology), previously detected during preventive fluorography. Any disease with ineffective treatment within the last three months. Complaints (symptoms) suspicious for tuberculosis include: the presence of a general intoxication syndrome - prolonged low-grade fever, general unmotivated weakness, fatigue, sweating, loss of appetite, weight loss. If pulmonary tuberculosis is suspected, chronic cough (lasting more than 3 weeks), hemoptysis, shortness of breath, chest pain. If extrapulmonary tuberculosis is suspected, complaints about dysfunction of the affected organ, without signs of recovery during therapy. Focal infection. Many authors believe that prolonged low-grade fever may be due to the existence of chronic foci of infection. However, in most cases, chronic foci of infection (dental granuloma, sinusitis, tonsillitis, cholecystitis, prostatitis, adnexitis, etc.), as a rule, are not accompanied by an increase in temperature and do not cause changes in the peripheral blood. It is possible to prove the causal role of a focus of chronic infection only in the case when sanitation of the focus (for example, tonsillectomy) leads to the rapid disappearance of a previously existing low-grade fever. A constant sign of chronic toxoplasmosis in 90% of patients is low-grade fever. In chronic brucellosis, the predominant type of fever is also low-grade fever. Acute rheumatic fever (a systemic inflammatory disease of connective tissue involving the heart and joints in the pathological process, caused by beta-hemolytic streptococcus of group A and occurring in genetically predisposed people) often occurs only with low-grade body temperature (especially with the II degree of activity of the rheumatic process). Low-grade fever may appear after an infectious disease (“fever tail”), as a reflection of post-viral asthenia syndrome. In this case, low-grade fever is benign in nature, is not accompanied by changes in tests and usually goes away on its own within 2 months (sometimes the “temperature tail” can last up to 6 months). But in the case of typhoid fever, prolonged low-grade fever that occurs after a decrease in high body temperature is a sign of incomplete recovery and is accompanied by persistent adynamia, undiminished hepato-splenomegaly and persistent aneosinophilia.

6. Traveler's fever

The most dangerous diseases: malaria (South Africa; Central, South-West and Southeast Asia; Central and South America), typhoid fever, Japanese encephalitis (Japan, China, India, South and North Korea, Vietnam, Far East and Primorsky Krai Russia), meningococcal infection (incidence is common in all countries, especially high in some African countries (Chad, Upper Volta, Nigeria, Sudan), where it is 40-50 times higher than in Europe), melioidosis (South-East Asia, areas of the Caribbean Sea and Northern Australia), amoebic liver abscess (the prevalence of amebiasis is Central and South America, southern Africa, Europe and North America, the Caucasus and the Central Asian republics of the former USSR), HIV infection.

Possible causes: cholangitis, infective endocarditis, acute pneumonia, Legionnaires' disease, histoplasmosis (widespread in Africa and America, found in Europe and Asia, isolated cases described in Russia), yellow fever (South America (Bolivia, Brazil, Colombia, Peru , Ecuador, etc.), Africa (Angola, Guinea, Guinea-Bissau, Zambia, Kenya, Nigeria, Senegal, Somalia, Sudan, Sierra Leone, Ethiopia, etc.), Lyme disease (tick-borne borreliosis), Dengue fever (central and South Asia (Azerbaijan, Armenia, Afghanistan, Bangladesh, Georgia, Iran, India, Kazakhstan, Pakistan, Turkmenistan, Tajikistan, Uzbekistan), Southeast Asia (Brunei, Indochina, Indonesia, Singapore, Thailand, Philippines), Oceania, Africa , Caribbean Sea (Bahamas, Guadeloupe, Haiti, Cuba, Jamaica). Not found in Russia (only imported cases), Rift Valley fever, Lassa fever (Africa (Nigeria, Sierra Leone, Liberia, Ivory Coast, Guinea, Mozambique , Senegal, etc.)), Ross River fever, Rocky Mountain spotted fever (USA, Canada, Mexico, Panama, Colombia, Brazil), sleeping sickness (African trypanosomiasis), schistosomiasis (Africa, South America, Southeast Asia), leishmaniasis (Central America (Guatemala, Honduras, Mexico, Nicaragua, Panama), South America, Central and South Asia (Azerbaijan, Armenia, Afghanistan, Bangladesh, Georgia, Iran, India, Kazakhstan, Pakistan, Turkmenistan, Tajikistan, Uzbekistan), South -Western Asia (United Arab Emirates, Bahrain, Israel, Iraq, Jordan, Cyprus, Kuwait, Syria, Turkey, etc.), Africa (Kenya, Uganda, Chad, Somalia, Sudan, Ethiopia, etc.), Marseilles fever ( Countries of the Mediterranean and Caspian basins, some countries of Central and Southern Africa, the southern coast of Crimea and the Black Sea coast of the Caucasus), Pappataci fever (Tropical and subtropical countries, the Caucasus and Central Asian republics of the former USSR), Tsutsugamushi fever (Japan, East and Southeast Asia, Primorsky and Khabarovsk Territories of Russia), North Asian tick-borne rickettsiosis (tick-borne typhus - Siberia and the Far East of Russia, some areas of Northern Kazakhstan, Mongolia, Armenia), relapsing fever (endemic tick-borne - Central Africa, USA, Central Asia, the Caucasus and the Central Asian republics of the former USSR, severe acute respiratory syndrome (Southeast Asia - Indonesia, Philippines, Singapore, Thailand, Vietnam, China and Canada).

Mandatory tests in case of fever upon returning from a trip abroad include:

General blood analysis

Examination of a thick drop and smear of blood (malaria)

Blood culture (infectious endocarditis, typhoid fever, etc.)

Urinalysis and urine culture

Biochemical blood test (liver tests, etc.)

Wasserman reaction

Chest X-ray

Stool microscopy and stool culture.

7. Hospital fever

Hospital (nosocomial) fever, which occurs during the patient's stay in the hospital, is observed in approximately 10-30% of patients, and every third of them dies. Hospital fever aggravates the course of the underlying disease and increases mortality by 4 times compared to patients suffering from the same pathology not complicated by fever. The clinical condition of a particular patient dictates the scope of the initial examination and the principles of treatment of fever. The following main clinical conditions are possible, accompanied by hospital fever. Non-infectious fever: caused by acute diseases of internal organs (acute myocardial infarction and Dressler's syndrome, acute pancreatitis, perforated gastric ulcer, mesenteric (mesenteric) ischemia and intestinal infarction, acute deep vein thrombophlebitis, thyrotoxic crisis, etc.); associated with medical interventions: hemodialysis, bronchoscopy, blood transfusion, drug fever, postoperative non-infectious fever. Infectious fever: pneumonia, urinary tract infection (urosepsis), sepsis due to catheterization, wound postoperative infection, sinusitis, endocarditis, pericarditis, aneurysm of fungal origin (mycotic aneurysm), disseminated candidiasis, cholecystitis, intra-abdominal abscesses, bacterial translocation of the intestine, meningitis, etc.

8. Fever simulation

A false increase in temperature may depend on the thermometer itself when it does not correspond to the standard, which is extremely rare. Fake fever is more common.

Simulation is possible both for the purpose of depicting a febrile state (for example, by rubbing the reservoir of a mercury thermometer or preheating it), and for the purpose of hiding the temperature (when the patient holds the thermometer so that it does not heat up). According to various publications, the percentage of febrile state simulation is insignificant and ranges from 2 to 6 percent of the total number of patients with elevated body temperature.

Fake fever is suspected in the following cases:

• the skin feels normal to the touch and there are no symptoms accompanying fever, such as tachycardia, redness of the skin;
• the temperature is too high (from 41 0 C and above) or daily temperature fluctuations are atypical.

If feigning a fever is expected, it is recommended to do the following:

Compare the data obtained with determining body temperature by touch and with other manifestations of fever, in particular, with pulse rate.

In the presence of a medical professional and using different thermometers, measure the temperature in both armpits and always in rectum.

Measure the temperature of freshly released urine.

All measures should be explained to the patient by the need to clarify the nature of the temperature, without offending him with suspicion of simulation, especially since it may not be confirmed.

Under fever of unknown origin(LNG) refers to clinical cases characterized by a persistent (more than 3 weeks) increase in body temperature above 38°C, which is the main or even the only symptom, while the causes of the disease remain unclear, despite intensive examination (conventional and additional laboratory techniques). Fevers of unknown origin can be caused by infectious and inflammatory processes, cancer, metabolic diseases, hereditary pathology, and systemic connective tissue diseases. The diagnostic task is to identify the cause of the increase in body temperature and establish an accurate diagnosis. For this purpose, an extensive and comprehensive examination of the patient is carried out.

ICD-10

R50 Fever of unknown origin

General information

Under fever of unknown origin(LNG) refers to clinical cases characterized by a persistent (more than 3 weeks) increase in body temperature above 38°C, which is the main or even the only symptom, while the causes of the disease remain unclear, despite intensive examination (conventional and additional laboratory techniques).

Thermoregulation of the body is carried out reflexively and is an indicator of general health. The occurrence of fever (> 37.2°C for axillary measurements and > 37.8°C for oral and rectal measurements) is associated with the body’s response, protective and adaptive reaction to the disease. Fever is one of the earliest symptoms of many (not only infectious) diseases, when other clinical manifestations of the disease have not yet been observed. This causes difficulties in diagnosing this condition. To establish the causes of fever of unknown origin, a more extensive diagnostic examination is required. The start of treatment, including trial treatment, before the true causes of LNG are established, is prescribed strictly individually and is determined by a specific clinical case.

Causes and mechanism of development of fever

Fever lasting less than 1 week usually accompanies various infections. Fever lasting more than 1 week is most likely due to some serious illness. In 90% of cases, fever is caused by various infections, malignant neoplasms and systemic connective tissue lesions. The cause of fever of unknown origin may be an atypical form of a common disease; in some cases, the cause of the increase in temperature remains unclear.

The mechanism for increasing body temperature in diseases accompanied by fever is as follows: exogenous pyrogens (bacterial and non-bacterial in nature) affect the thermoregulation center in the hypothalamus through endogenous (leukocyte, secondary) pyrogen - a low molecular weight protein produced in the body. Endogenous pyrogen affects the thermosensitive neurons of the hypothalamus, leading to a sharp increase in heat production in the muscles, which is manifested by chills and a decrease in heat transfer due to the narrowing of skin blood vessels. It has also been experimentally proven that various tumors (lymphoproliferative tumors, liver tumors, kidney tumors) can themselves produce endogenous pyrogen. Violations of thermoregulation can sometimes be observed with damage to the central nervous system: hemorrhages, hypothalamic syndrome, organic brain lesions.

Classification of fever of unknown origin

There are several variants of the course of fever of unknown origin:

• classic (previously known and new diseases (Lyme disease, chronic fatigue syndrome);
• nosocomial (fever appears in patients admitted to the hospital and receiving intensive care, 2 or more days after hospitalization);
• neutropenic (number of neutrophils, candidiasis, herpes).
• HIV-associated (HIV infection in combination with toxoplasmosis, cytomegalovirus, histoplasmosis, mycobacteriosis, cryptococcosis).

Body temperature is classified according to the level of increase:

• subfebrile (from 37 to 37.9 °C),
• febrile (from 38 to 38.9 °C),
• pyretic (high, from 39 to 40.9 ° C),
• hyperpyretic (excessive, from 41°C and above).

The duration of fever can be:

• acute - up to 15 days,
• subacute - 16-45 days,
• chronic – more than 45 days.

Based on the nature of changes in the temperature curve over time, fevers are distinguished:

• constant - high (~ 39°C) body temperature is observed for several days with daily fluctuations within 1°C (typhus, lobar pneumonia, etc.);
• laxative – during the day the temperature fluctuates from 1 to 2°C, but does not reach normal levels (for purulent diseases);
• intermittent – ​​with alternating periods (1-3 days) of normal and very high body temperature (malaria);
• hectic – there are significant (more than 3°C) daily or at intervals of several hours temperature changes with sharp changes (septic conditions);
• relapsing - a period of increased temperature (up to 39-40°C) is replaced by a period of subfebrile or normal temperature (relapsing fever);
• wavy - manifested in a gradual (from day to day) increase and a similar gradual decrease in temperature (lymphogranulomatosis, brucellosis);
• incorrect - there is no pattern of daily temperature fluctuations (rheumatism, pneumonia, influenza, cancer);
• perverted - morning temperature readings are higher than evening ones (tuberculosis, viral infections, sepsis).

Symptoms of fever of unknown origin

The main (sometimes the only) clinical symptom of fever of unknown origin is a rise in body temperature. For a long time, fever may be asymptomatic or accompanied by chills, excessive sweating, heart pain, and suffocation.

Diagnosis of fever of unknown origin

The following criteria must be strictly observed when diagnosing fever of unknown origin:

• The patient's body temperature is 38°C or higher;
• fever (or periodic rises in temperature) has been observed for 3 weeks or more;
• The diagnosis has not been determined after examinations using generally accepted methods.

Patients with fever are difficult to diagnose. Diagnosis of the causes of fever includes:

• general blood and urine analysis, coagulogram;
• biochemical blood test (sugar, ALT, AST, CRP, sialic acids, total protein and protein fractions);
• aspirin test;
• three-hour thermometry;
• Mantoux reaction;
• X-ray of the lungs (detection of tuberculosis, sarcoidosis, lymphoma, lymphogranulomatosis);
• Echocardiography (exclusion of myxoma, endocarditis);
• Ultrasound of the abdominal cavity and kidneys;
• consultation with a gynecologist, neurologist, ENT doctor.

To identify the true causes of fever, additional studies are used simultaneously with generally accepted laboratory tests. For this purpose the following are appointed:

• microbiological examination of urine, blood, nasopharyngeal swab (allows to identify the causative agent of infection), blood test for intrauterine infections;
• isolation of a viral culture from body secretions, its DNA, titers of viral antibodies (allows you to diagnose cytomegalovirus, toxoplasmosis, herpes, Epstein-Barr virus);
• detection of antibodies to HIV (enzyme-linked immunosorbent complex method, Western blot test);
• microscopic examination of a thick blood smear (to rule out malaria);
• blood test for antinuclear factor, LE cells (to exclude systemic lupus erythematosus);
• performing a bone marrow puncture (to exclude leukemia, lymphoma);
• computed tomography of the abdominal organs (exclusion of tumor processes in the kidneys and pelvis);
• skeletal scintigraphy (detection of metastases) and densitometry (determination of bone tissue density) for osteomyelitis, malignant tumors;
• examination of the gastrointestinal tract using radiation diagnostics, endoscopy and biopsy (for inflammatory processes, tumors in the intestine);
• carrying out serological reactions, including indirect hemagglutination reactions with the intestinal group (for salmonellosis, brucellosis, Lyme disease, typhoid);
• collection of data on allergic reactions to drugs (if a drug disease is suspected);
• study of family history in terms of the presence of hereditary diseases (for example, familial Mediterranean fever).

To make a correct diagnosis of fever, anamnesis and laboratory tests can be repeated, which at the first stage could have been erroneous or incorrectly assessed.

Treatment of fever of unknown origin

If the patient's fever is stable, treatment should be withheld in most cases. Sometimes the issue of conducting a trial treatment for a patient with fever is discussed (tuberculostatic drugs for suspected tuberculosis, heparin for suspected deep vein thrombophlebitis, pulmonary embolism; antibiotics fixed in bone tissue for suspected osteomyelitis). The prescription of glucocorticoid hormones as a trial treatment is justified in cases where the effect of their use can help in diagnosis (if subacute thyroiditis, Still's disease, polymyalgia rheumatica is suspected).

It is extremely important when treating patients with fever to have information about possible previous medication use. The reaction to taking medications in 3-5% of cases can be manifested by an increase in body temperature, and be the only or main clinical symptom of hypersensitivity to drugs. Drug fever may not appear immediately, but after a certain period of time after taking the drug, and is no different from fevers of other origins. If drug fever is suspected, discontinuation of this drug and monitoring of the patient is required. If the fever disappears within a few days, the cause is considered clarified, and if the elevated body temperature persists (within 1 week after stopping the medication), the medicinal nature of the fever is not confirmed.

There are different groups of drugs that can cause drug fever:

• antimicrobials (most antibiotics: penicillins, tetracyclines, cephalosporins, nitrofurans, etc., sulfonamides);
• anti-inflammatory drugs (ibuprofen, acetylsalicylic acid);
• medicines used for gastrointestinal diseases (cimetidine, metoclopramide, laxatives containing phenolphthalein);
• cardiovascular drugs (heparin, alpha-methyldopa, hydralazine, quinidine, captopril, procainamide, hydrochlorothiazide);
• drugs acting on the central nervous system (phenobarbital, carbamazepine, haloperidol, chlorpromazine thioridazine);
• cytostatic drugs (bleomycin, procarbazine, asparaginase);
• other drugs (antihistamines, iodide, allopurinol, levamisole, amphotericin B).

A pathological condition accompanied by a rise in temperature and a deterioration in certain health indicators, resulting from taking certain medications, is called drug fever. The manifestation of LL is observed with the parallel use of antibacterial agents, and when they are discontinued, a decrease in characteristic symptoms is observed. In some cases, a similar condition may occur with an unclear etiology, when different drugs with different properties are prescribed.

Features of the problem

Drug fever occurs when certain drug components enter the bloodstream. And although the final pathogenesis of the disease is not clear, most doctors are inclined to believe that the cause of its occurrence is in autoimmune processes occurring in the body under the influence of certain components. The period of occurrence of manifestations of this condition can vary significantly from person to person, but on average ranges from several hours from the moment of taking the drug to several days.

The symptoms of this condition are most pronounced when taking angioplasty drugs, but the manifestations of drug fever can vary significantly from person to person. The duration and strength of manifestation of the pathological condition are different and depend on indicators such as the individual health characteristics of the patient and the presence of concurrent current diseases.

Classification and localization

There are a number of characteristic signs that allow us to identify the presence of drug fever, and the possibility of classification allows us to determine the need to use a specific drug regimen that will be most effective in a particular case.

The localization of this condition is usually standard and is characterized by the manifestation of specific symptoms in the form of a rise in temperature, the appearance of a feeling of heat and a feverish state; they appear on the surface of the skin, which can cause and.

Causes

The reasons that provoke the formation of drug fever and the manifestation of symptoms of this condition include the use of certain medications that cause a strong reaction in the body. Most often, drug fever occurs during use and prolonged use, as well as when the patient’s body is highly susceptible to the constituent components of the following medications:

• antimicrobial agents that act selectively on the microbial environment and on the entire body as a whole, causing a negative reaction of the immune system;
• cytostatic drugs;
• medicines used in monotherapy and with complex effects in eliminating the manifestations of cardiovascular diseases;
• medications that affect the central nervous system, the use of which is accompanied by a deterioration or slowdown in the body’s basic reactions;
• anti-inflammatory drugs;
• medications containing iodine and antihistamine components.

The listed dosage forms are most often capable of causing symptoms of drug fever, however, other medications and their improper use can cause the development of this disease.

In some cases, there is a high probability of symptoms of a negative reaction of the body even several days after the end of taking the drug.

Symptoms and manifestations

Since drug fever occurs as a result of taking certain medications, the manifestations and characteristic symptoms may vary slightly depending on the body’s reaction to the irritant in the form of the active component of the drug and its concentration in the blood.

The symptoms of this pathological condition include the following manifestations:

• the appearance of febrile manifestations;
• temperature rise to 39-40°C;
• the appearance of rashes and rashes on the skin;

The degree of manifestation of drug fever depends on the duration of use of the drug, the degree of susceptibility to the active components.

Diagnosis of drug fever

Detection of pathology is accompanied by an external examination of the skin, measurement of body temperature, as well as passing the necessary tests. With their help, you can obtain information about the current disease, the stage of the inflammatory process occurring in the body.

Treatment

The method of therapeutic intervention consists of promptly stopping the medication that caused the manifestation of the main symptoms of drug fever. Also, in case of strong negative manifestations of this pathology, depending on the age category, it is recommended to use medications that relieve the main symptoms.

Adults

To eliminate the symptoms of drug fever in adult patients, bromocriptine is used, which helps stabilize the condition and neutralizes the symptoms of this condition. The malignant course of the pathology is also eliminated by the use of corticosteroids.

Children and newborns

If drug fever is detected in children, it is necessary to urgently stop taking the drug that caused the manifestations of the pathology. If it is necessary to continue treatment, a drug that has a similar medicinal effect is used.

However, due to the increased sensitivity of the child’s body, the necessary treatment should be carried out under constant medical supervision to prevent possible side effects and negative consequences of the treatment.

During pregnancy and lactation

The therapeutic effect during pregnancy and breastfeeding consists of stopping the ongoing treatment with an antibacterial drug, and, if necessary, replacing it with a drug with a similar effect, which will ensure a pronounced positive result. Many note the possibility of quickly eliminating the consequences of taking a drug that caused manifestations of drug fever during pregnancy when using corticosteroids.

However, due to their increased impact on the body of a pregnant woman, treatment should be monitored in order to promptly make the necessary adjustments to the dosage of the drug and the duration of its use to eliminate possible side effects.

Disease prevention

• To prevent the occurrence of drug fever, before starting treatment based on the use of antibacterial agents, the body should be tested for the degree of susceptibility to the active substance of the drug.
• You should also regularly carry out supportive vitamin treatment, which allows you to stop negative manifestations from the body and eliminate the consequences of the negative effects of selected medications.

Complications

If the treatment is insufficient or completely absent, drug fever may transition into its malignant course, which is accompanied by an increase in current symptoms, the occurrence of additional negative manifestations in the form of a persistent increase in temperature, which is difficult to correct, and the appearance of rashes with itching and burning.

Forecast

Typically, the prognosis for survival when drug fever is detected is positive, but in the absence of therapeutic effects or its small amount, the disease is likely to transition to a more acute form, which requires not only the exclusion of the drug that caused the development of the pathology, but also the use of drugs that will eliminate negative symptoms and stabilize the condition sick.

What it is?

A typical nonspecific protective-adaptive reaction of the body to the effects of pyrogenic (temperature reaction-causing) substances, characterized by a temporary restructuring of heat exchange to maintain a higher than normal body temperature. The entry of exogenous (bacterial, etc.) pyrogens into the body causes the appearance of secondary (endogenous) pyrogenic substances in the blood, which are formed by granulocytes and macrophages upon contact with exogenous pyrogens or products of aseptic inflammation.

In infectious fever, the primary (exogenous) pyrogens are toxins secreted by microbes, products of metabolism and decay of microorganisms. Bacterial pyrogens are strong stress agents; their entry into the body causes a stress (hormonal) reaction, accompanied by neutrophilic leukocytosis. This reaction is a nonspecific symptom of many infectious diseases.

Non-infectious fever can be caused by animal, plant or industrial poisons; fever of this type is observed in allergic reactions, aseptic inflammation, parenteral administration of protein, tissue necrosis associated with circulatory disorders, tumors, etc. Leukocytes that produce leukocyte pyrogen penetrate into the site of tissue damage or inflammation.

An increase in body temperature during fever is carried out by the mechanisms of physical and chemical thermoregulation. An increase in heat production occurs mainly due to muscle tremors, and a limitation of heat transfer occurs as a result of spasm of peripheral blood vessels and a decrease in sweating. Normally, these thermoregulatory reactions develop during cooling.

Fever is characterized not only by an increase in temperature, it is also accompanied by an increase in pulse and respiration, a decrease in blood pressure, general symptoms of intoxication (headache, feeling hot, etc.), a decrease in urination, and an increase in metabolism due to increased catabolic processes.

Depending on the degree of increase in body temperature, the following types of fevers are distinguished:

• subfebrile - body temperature up to 38°C;
• weak - body temperature up to 38.5°C;
• moderate (febrile) - body temperature up to 39°C;
• high (pyretic) - body temperature up to 41°C;
• excessive (hyperpyretic) - body temperature above 41°C.

Hyperpyretic fever is accompanied by severe nervous symptoms and is life-threatening, especially in children.

The main types of fevers, distinguished by the nature of daily temperature fluctuations:

Persistent fever- long-term stable increase in body temperature, the difference between morning and evening temperatures does not exceed 1°C. Characteristic of lobar pneumonia, stage II of typhoid fever.

Relapsing fever- significant daily fluctuations in body temperature within 1.5-2°C, while the temperature does not drop to normal; observed in purulent diseases, tuberculosis, focal pneumonia, stage III of typhoid fever.

Intermittent fever- a rapid, significant increase in temperature, which lasts for several hours, and then is replaced by a rapid drop to normal values; observed in malaria.

Hectic (debilitating) fever- large daily fluctuations in body temperature (up to 3-5°C), while temperature rises with a rapid decline can be repeated several times during the day; typical for severe pulmonary tuberculosis, suppuration, sepsis.

Perverted Fever- change in the circadian rhythm with higher temperature rises in the morning and a decrease in the evening; can be observed with sepsis, tuberculosis, brucellosis.

Wrong fever- temperature fluctuations during the day without a specific pattern; may occur with rheumatism, sepsis, endocarditis, etc.

Relapsing fever- alternating periods of increased temperature with periods of normal temperature, which last several days; characteristic of relapsing fever.

Ephemeral fever- an increase in body temperature is observed for several hours, after which it does not recur; occurs with mild infections, overheating in the sun, after a blood transfusion, etc.