Type of fever: morning temperature is higher than evening temperature. Types, types of fevers and the course of febrile syndrome. For systemic vasculitis

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 disturbed, and the increased body temperature is caused by a change 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 is 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) manifests itself more high 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 body temperature at a higher temperature. high level, and on the other hand, they affect the vasomotor center, causing 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 autonomic nervous system(neurocirculatory dystonia, neuroses), 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 alternation various types 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, seizures 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 methods studies 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 in the background full 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 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 picture)? 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 seen 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 in recent years 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 Chronic toxoplasmosis in 90% of patients has 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 South-East Asia; Central and South America), typhoid fever, Japanese encephalitis (Japan, China, India, South and North Korea, Vietnam, the Far East and Primorsky Krai of 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, the Caribbean and Northern Australia), amoebic liver abscess (prevalence of amebiasis - Central and South America, southern Africa, Europe And North America, Caucasus and 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, the Caribbean (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-West Asia ( United Arab Emirates, Bahrain, Israel, Iraq, Jordan, Cyprus, Kuwait, Syria, Turkey, etc.), Africa (Kenya, Uganda, Chad, Somalia, Sudan, Ethiopia, etc.), Marseilles fever (Mediterranean and Caspian countries 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 Russia), North Asian tick-borne rickettsiosis (tick-borne typhus - Siberia and the Russian Far East, some areas 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 return from foreign trip 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 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 feverish state (for example, by rubbing a reservoir 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.

According to the degree of increase, the temperature is distinguished: subfebrile - 37-38 °C, febrile - 38-39 °C, hyperpyretic - above 39 °C.

Regarding the course of development of fever, three periods are distinguished in the temperature curve:

A) the initial stage or period of temperature increase. In some diseases this period is very short and measured in hours, usually accompanied by chills, in others it extends over a more or less long period, for several days;

B) the stage of the height of fever. The peak of the temperature curve lasts from several hours to many days and even weeks;

B) stage of temperature decrease. In some diseases, the temperature decreases quickly within a few hours - a critical drop in temperature or crisis, in others - gradually over several days - a lytic drop or lysis.

Based on the nature of temperature fluctuations, the following types of fever are distinguished:

1) constant fever is characterized by the fact that during the day the difference between morning and evening temperatures does not exceed 1 ° C, while a high temperature is noted;

2) laxative fever gives daily temperature fluctuations within 2 ° C, with the morning minimum above 37 ° C. With a relieving fever, a rise in temperature is accompanied by chills, a decrease in temperature is accompanied by sweating;

3) intermittent fever is characterized by a sudden increase in temperature to 39 ° C or higher, and after a few hours the temperature drops to normal numbers. The rise in temperature is repeated every 1-2 or 3 days. This type of fever is characteristic of malaria;

4) heptic fever is characterized by an increase in temperature by 2-4 °C in the evening and a drop to normal or lower in the morning. This drop in temperature is accompanied by severe weakness with profuse sweating. Observed in sepsis, severe forms of tuberculosis;

5) the reverse type of fever is different in that the morning temperature is higher than the evening temperature. Occurs in pulmonary tuberculosis;

6) irregular fever is accompanied by varied and irregular daily fluctuations. Occurs with rheumatism, flu, etc.;

7) relapsing fever is characterized by alternating periods of fever with fever-free periods. A rise in temperature to 40 °C or more is followed by a drop after a few days to normal, which lasts for several days, and then the temperature curve repeats. This type of fever is characteristic of relapsing fever;

8) undulating fever is characterized by a gradual increase in temperature over several days and a gradual decrease to normal. Then there is a new increase followed by a decrease in temperature. This temperature occurs with lymphogranulomatosis and brucellosis.

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

Subfebrile temperature - 37–38 °C:

a) low-grade fever - 37–37.5 °C;

b) low-grade fever - 37.5–38 °C;

Moderate fever - 38–39 ° C;

High fever - 39–40 ° C;

Very high fever - over 40 ° C;

Hyperpyretic - 41–42 °C, it is accompanied by severe nervous phenomena and is itself life-threatening.

Fluctuations in body temperature throughout the day and throughout the febrile period are of great importance for diagnosis.

In this regard, there are main types of fever:

Persistent fever – the temperature stays high for a long time. During the day, the difference between morning and evening temperatures does not exceed 1 °C; characteristic of lobar pneumonia, stage II of typhoid fever;

Remitting (remitting) fever – high temperature, daily temperature fluctuations exceed 1–2 °C, with a morning minimum above 37 °C; characteristic of tuberculosis, purulent diseases, focal pneumonia, in Stage III typhoid fever;

Wasting (hectic) fever - characterized by large (3–4 °C) daily temperature fluctuations, which alternate with a drop to normal or below, which is accompanied by debilitating sweats; typical for severe pulmonary tuberculosis, suppuration, sepsis;

Intermittent (intermittent) fever - short-term increases in temperature to high numbers strictly alternate with periods (1-2 days) of normal temperature; observed in malaria;

Undulating (undulating) fever - it is characterized by periodic increases in temperature, and then a decrease in the level to normal numbers. Such “waves” follow one another for a long time; characteristic of brucellosis, lymphogranulomatosis;

Relapsing fever is a strict alternation of periods of high temperature with fever-free periods. At the same time, the temperature rises and falls very quickly. The febrile and non-febrile phases last for several days each. Characteristic of relapsing fever;

Reverse type of fever - morning temperature is higher than evening temperature; sometimes observed in sepsis, tuberculosis, brucellosis;

Irregular fever – characterized by varied and irregular daily fluctuations; often observed in rheumatism, endocarditis, sepsis, tuberculosis. This fever is also called atypical (irregular).

It should be noted that types of fever during illness can alternate or transform into one another. The intensity of the febrile 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. Fever can end with a sudden and rapid drop in body temperature to normal or even lower (crisis) or a gradual slow decrease body temperature (lysis). The most severe toxic forms of some infectious diseases, as well as infectious diseases in the elderly, weakened people, and young children often occur with almost no fever or even hypothermia, which is an unfavorable prognostic sign.