Fever with temperature: types of fevers and measurement of body temperature. Fever - high body temperature

Fever is a typical nonspecific thermoregulatory adaptive reaction of the body that occurs as a result of excitation of the thermoregulation center by an excess of pyrogens (thermostable high-molecular substances formed by microorganisms or tissues of the human body).

Temperatures above 37°C are considered elevated. Depending on the degree of febrile reaction, there are low-grade fever(increase in body temperature below 38°C), moderate fever(increase in body temperature within 38–39°C), high fever(39–41°C) and extreme, hyperpyretic fever(increased body temperature above 41°C).

Based on the type of temperature curve, the following are distinguished:
persistent fever- daily temperature fluctuations do not exceed 1°C (typical for typhus);
laxative fever- daily fluctuations of more than 1°C (viral, bacterial infections);
wrong, or atypical fever, - high or moderately high body temperature, daily fluctuations are different and irregular (the most common type of fever in any infection);
debilitating fever, which is a combination of laxative and irregular fever, with daily variations in body temperature exceeding 2–3°C;
intermittent fever- short-term periods of high temperature are combined with periods of apyrexia, normal body temperature during the day (purulent infections, tuberculosis, rheumatism); usually in the morning the body temperature is normal, but in the evening there is a significant increase in it; with rheumatoid arthritis, Wissler-Fanconi subsepsis, the opposite relationship is observed (inverse type);
relapsing fever- characterized by alternation of febrile attacks (2–7 days) with periods of apyrexia (1–2 days) (malaria, relapsing fever, periodic illness, diffuse connective tissue diseases and other immunopathology);
« sea fever" - a term proposed by Professor A. A. Kisel, who meant by it daily fluctuations in body temperature of more than 1 ° C, although the maximum body temperature is normal or subfebrile. At that time, this condition was often regarded as tuberculosis intoxication.

Fever in children

With the same level of hyperthermia in children, fever can occur differently. In children, there are “white” and “pink” fevers. If heat transfer corresponds to heat production, this indicates an adequate course of fever and is clinically manifested by the child’s relatively normal state of health, pink or moderately hyperemic skin color, moist and warm to the touch (“pink” fever). The absence of sweating in a child with pink skin and fever should be alarming in terms of suspicion of expressed due to vomiting and tachypnea.
In the case of “white” fever with increased heat production, heat transfer is inadequate due to impaired peripheral circulation; the course of such fever is prognostically unfavorable. The leading pathogenetic link of “white” fever is excessive hypercatecholaminemia, which leads to the appearance of clinical signs of centralization of the blood circulation. Clinically, severe chills, pallor of the skin, acrocyanosis, cold feet and palms, tachycardia, increased systolic blood pressure, and an increase in the difference between the axillary and rectal temperature (up to 1°C and above) are noted.
It should be remembered that a moderate increase in body temperature during infectious diseases helps to mobilize the body's defenses and activates the immune system. At the same time, an extreme increase in temperature significantly worsens general well-being and contributes to the development of a number of unfavorable changes in the patient’s body: increased tone of the sympathetic nervous system, tachycardia, increased excitability of the respiratory center. Against this background, the organs’ need for oxygen increases, basal metabolism intensifies, sodium and chlorides are retained in the body with the development of edema, blood vessels in the skin (pallor of the external integument) and internal organs narrow; spasm of the precapillary sphincters occurs. Normal blood flow is disrupted, centralization of blood circulation occurs, which ultimately leads to hypoxia of organs and tissues. Myocardial hypoxia, for example, entails a weakening of its contractility, brain hypoxia leads to swelling, impaired consciousness, and convulsions. The response of internal organs and systems to an increase in body temperature in children is especially pronounced.
The symptom of increased body temperature is extremely “many-faced” and can occur in many diseases of various organs and is based on an infectious, non-infectious, as well as psychogenic nature.
If in adults a febrile reaction primarily occurs during infectious processes: viral infections, bacterial infections, fungal (mycotic) infections, then in children hyperthermia quite often does not have an infectious nature (overheating, psycho-emotional stress, allergic reactions, teething, etc. ). Unlike adults, children, especially young children, are much more likely to react with an increase in temperature to any nonspecific stimuli.

Fever with ARVI

In first place among diseases accompanied by fever are acute respiratory viral infections (ARVI). In this case, the rise in temperature is preceded by hypothermia, and the fever is accompanied by other characteristic complaints indicating a pathological process in the bronchopulmonary system and nasopharynx (rhinitis, sore throat, cough, shortness of breath, chest pain when breathing). With low-grade fever, accompanied by these complaints within two to three days from the onset of the disease, self-medication with over-the-counter medications is still possible. In other cases, you must definitely consult a doctor. Any seemingly insignificant symptom can be the beginning of a serious one or a sign of an exacerbation of a chronic disease.
If “threatening” symptoms occur, allowing one to suspect a serious illness in the patient, requiring mandatory referral of patients to a doctor, the following is noted: an increase in temperature above 39°C, accompanied by severe pain, shortness of breath, disturbance of consciousness, and convulsions; duration of temperature above 38°C in a patient with symptoms of acute respiratory disease for 3–5 days; temperature over 37.5°C, persisting for more than 2 weeks.
Elevated temperature poses a particular threat if it is accompanied by a spasm of skin vessels that interferes with heat transfer (malignant hyperthermia): temperature above 40.0°C; variegated, “marbled” skin color; despite the heat, the limbs are cold to the touch.
If temperature increase is not accompanied by a pronounced violation of the general condition; in case of ARVI, the temperature should be reduced to 38°C or higher. The desire to normalize any temperature during ARVI is not justified, since this reduces the development of immunity to this pathogen. In such a situation, measures to treat symptoms such as runny nose, sore throat, and cough are advisable.
It should be especially emphasized that over-the-counter antipyretics, due to their mechanism of action, do not reduce a slightly elevated temperature of -37.2–37.3 ° C.

In children with ARVI, the prescription of antipyretic drugs is fundamentally necessary:
Previously healthy children: with body temperature above 39°C, and/or with muscle aches, and/or with headache.
For children with a history of febrile convulsions - at a body temperature above 38.0–38.5°C.
For children in the first 3 months of life - at a body temperature above 38.0°C.

Previous use of antipyretics is also indicated for children:
with hereditary metabolic abnormalities;
with a history of seizures;
in the presence of signs of circulatory failure II stage. and more;
with respiratory failure Ist. and more;
with dehydration;
with respiratory fever;
with thymomegaly stage 2. and more;
with “white” hyperthermia.

It is necessary to take into account the arguments against the mandatory use of antipyretics for any rise in temperature:
fever can serve as the only diagnostic indicator of the disease;
antipyretic therapy obscures the clinical picture of the disease, providing a sense of false security;
feverish reaction - protective, enhancing the immune response;
Antipyretic therapy also carries certain risks, including side effects of the drugs.

The rate of temperature decrease should be 1–1.5°C in 30–60 minutes.
The duration of use of antipyretics is no more than 3 days, analgesics - up to 5 days.

In children at risk, drug therapy with antipyretic drugs should be started. Although many drugs have antipyretic effects, only four commercially available drugs are optimal for the treatment of fever in children: paracetamol, ibuprofen, naproxin and acetylsalicylic acid (aspirin).

General recommendations for parents with fever in children
Maintaining bed rest.
Regular ventilation of the room to maintain a “comfort temperature”. - During the period of rising temperature, when the patient feels chills, it is necessary to warm up, lie down under a warm blanket.
At the height of the temperature, after it has stopped rising, cooling brings a subjective feeling of relief, so you can open up and/or wipe yourself with water at room temperature.
Reducing the temperature is aimed at improving the general well-being of the patient and does not affect the cause of the disease.
It is advisable to only reduce the temperature above 38.5–39°C.
Antipyretic medications should not be taken regularly in order to prevent a new rise in temperature.
A repeat dose of the antipyretic should be taken only if the temperature rises again.
The duration of self-use of an antipyretic drug, without consulting a doctor, should not exceed 2 days.
It is advisable to combine the use of antipyretic drugs with the use of drugs for the symptomatic treatment of cough, runny nose, and sore throat.
You should not use antipyretic drugs on your own while taking antibiotics, as these drugs can mask the lack of effect of antibacterial therapy.
At elevated temperatures, you should drink plenty of fluids (3–4 liters per day).
During this period, you should ensure an increased intake of food rich in vitamins and exclude fatty foods from the diet.
To relieve muscle pain or headaches due to colds, the same medications are used as to reduce fever.
Reducing fever in children should begin with physical cooling methods (wiping with water at room temperature, ventilating the room): this is often sufficient to reduce it.
An antipyretic should only be used if the body temperature rises to the above values or if chills and/or trembling occur.
The most reliable and safe antipyretic drugs for children are paracetamol and ibuprofen in children's dosage forms.

Knowledge of the pharmacological properties of these drugs and the balance between benefits and risks ensures their rational use.

Paracetamol

Paracetamol(acetaminophen, Tylenol, etc.) inhibits cerebral synthesis of prostaglandins to a greater extent than peripheral synthesis, and therefore it does not have (or has a minimal degree of) an antiplatelet effect (i.e. does not impair platelet function), does not cause or increase bleeding. The minimal peripheral effect of paracetamol creates another important advantage over other NSAIDs: paracetamol does not reduce diuresis, which is a very important advantage in febrile young children with a tendency to cerebral edema, toxicosis, and convulsions. It has antipyretic and analgesic effects, but lacks anti-inflammatory effects.
The usual antipyretic and analgesic dose of paracetamol is 10–15 mg/kg and can be given 3–4 times daily.
The daily dose of paracetamol should not exceed 60 mg/kg.
The toxicity of paracetamol in children occurs when its concentration in the blood is above 150 mcg/ml. Liver disease, intake of activators of hepatic oxidases (and in adults, alcohol) increases the toxicity of paracetamol. The toxic effects of paracetamol are due to its hepatotoxicity. In the first hours, nausea, vomiting, and pallor appear. From the end of the 1st - beginning of the 2nd day, there are no clinical symptoms, but an increase in transaminases begins. From the 3rd day, jaundice, coagulopathy, encephalopathy, increased transaminases and bilirubin, tremor, hypoglycemia, acute renal failure, and myocardial damage develop.
With long-term use, cases of nephrotoxicity (tubular necrosis), cardiotoxicity (heart attacks, ischemia), and pancreatitis have been described.
If, due to an overdose or accumulation, damage to the liver or kidneys occurs and the child develops nausea, vomiting, oliguria, hematouria, jaundice, hypoglycemia, he should immediately be given acetylcysteine orally at a dose of 140 mg/kg and then 70 mg/kg every 4 hours (total 17 doses).
Tips for rational use of paracetamol for parents:
reduce temperature only when indicated;
do not re-introduce antipyretics to prevent a new rise in temperature. It should be given only after the child’s body temperature has returned to its previous level;
use the recommended single dosage of paracetamol (10–15 mg/kg), in no case exceed the daily dose (60 mg/kg);
do not give paracetamol without consulting a doctor for more than 3 days due to the risk of a bacterial infection and being late in prescribing antibacterial agents;
If hyperthermia develops with spasm of skin vessels (cold, pale hands and feet, marbling of the skin), after administering an antipyretic, you should vigorously rub the child’s skin until it turns red and immediately call a doctor.
children's dosage forms of paracetamol: Panadol, Efferalgan, Calpol, Tylenol.

Ibuprofen

The usual single dose (5 mg/kg body weight) can be increased in case of severe fever (up to 10 mg/kg).
Ibuprofen is one of the best true NSAIDs (i.e., drugs that have antipyretic, analgesic and anti-inflammatory effects) in terms of tolerability.
The daily dose should not exceed 25–30 mg/kg. In acute overdose, the minimum toxic dose is approximately 100 mg/kg. Symptoms (nausea, abdominal pain, confusion, lethargy, headache, visual disturbances, metabolic acidosis) depend on the dose. Among the rare adverse reactions, it is necessary to note gastropathy with nausea, vomiting, enteropathy with or, bleeding, oliguria, tachycardia.

A. P. Viktorov, State Pharmacological Center, Ministry of Health of Ukraine

Traditional recipes for reducing temperature during fever

Used for fever, has a vasodilating effect.
Decoction: a tablespoon of crushed leaves in a glass of water. Boil for 20 minutes, leave for 1 hour, strain. Take 1/3 cup 3 times a day.

Bark. Pour a teaspoon of crushed bark into 300 ml of water. Boil over low heat until one cup remains. Drink on an empty stomach with honey once a day. Take until the fever goes away.

The flowers have a pronounced diaphoretic and antipyretic effect, which is associated with the presence of the glycoside sambunigrin in them. An infusion of black elderberry flowers is prepared at the rate of 5 g (1-2 tablespoons) of raw material per 200 liters of water. Take 1/3 cup 2-3 times a day.

Parsley. Pass 2.5 kg of parsley through a meat grinder and squeeze out the juice. Pour 150 g of vodka into this juice and mix. Take 100 ml twice a day on an empty stomach (morning and before bedtime). The next day in the morning drink another 100 ml. After this, the fever usually stops.

Infusion of leaves. Prepared at the rate of 5-10 g of crushed raw materials per 200 ml of boiling water. Drink 1/4 cup 3-4 times a day.

Cones. Pour 25 g of cones with 2 cups of boiling water. Leave, covered, for 2 hours, strain. Take 50 ml morning and evening for three days. The medicine is taken while lying in bed, warm.

Infusion or decoction of fruits, leaves or stems. Prepared at the rate of 2-4 tablespoons of crushed raw materials per 2 glasses of water. The resulting volume is the daily dose, which must be taken in equal portions.

Infusion of flowers. 2-3 tablespoons of raw materials are poured with one and a half glasses of water. The resulting volume of infusion is used in even doses throughout the day.

Cranberry extract has antipyretic, anti-inflammatory, antimicrobial, diuretic, tonic and refreshing effects. Cranberry syrup and puree are given as coolants for febrile illnesses. Cranberry juice is prescribed to feverish patients as a refreshing and antipyretic.

Lemon juice along with an infusion of strawberry leaves is recommended for feverish patients, especially children.

As an antipyretic, it is recommended to take an infusion of black poplar buds for chronic tonsillitis, bronchitis, and pneumonia, for which it is often used together with lemon and infusion of strawberry leaves.
1. Infusion of poplar buds. 2 teaspoons of crushed raw materials are infused for 15 minutes in 200 ml (1 glass) of boiling water. Take the resulting infusion throughout the day.
2. Tincture of poplar buds. Prepared from freshly harvested raw materials in a ratio of 1:10. Infusion time is 7-10 days. Take 20-50 drops 3-4 times a day.

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.

Prevention of disease

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.

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

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, typhus);
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).

Fever- one of the oldest protective and adaptive mechanisms of the body, arising in response to the action of pathogenic stimuli, mainly microbes with pyrogenic properties. Fever can also occur in non-infectious diseases due to the body’s reaction either to endotoxins entering the blood during the death of its own microflora, or to endogenous pyrogens released during the destruction primarily of leukocytes, other normal and pathologically altered tissues during septic inflammation, as well as autoimmune and metabolic disorders.

Development mechanism

Thermoregulation in the human body is ensured by a thermoregulatory center located in the hypothalamus, through a complex system of control over the processes of heat production and heat transfer. The balance between these two processes, which ensure physiological fluctuations in human body temperature, can be disrupted by various exo- or endogenous factors (infection, intoxication, tumor, etc.). In this case, pyrogens formed during inflammation primarily affect activated leukocytes, which synthesize IL-1 (as well as IL-6, TNF and other biologically active substances), which stimulates the formation of PGE 2, under the influence of which the activity of the thermoregulation center changes.

Heat production is influenced by the endocrine system (in particular, body temperature rises with hyperthyroidism) and the diencephalon (body temperature rises with encephalitis, hemorrhage in the ventricles of the brain). An increase in body temperature can temporarily occur when the balance between the processes of heat production and heat transfer is disturbed in the normal functional state of the thermoregulation center of the hypothalamus.

A number of fever classifications .

Depending on the cause of occurrence, infectious and non-infectious fever are distinguished.

According to the degree of increase in body temperature: subfebrile (37-37.9 °C), febrile (38-38.9 °C), pyretic or high (39-40.9 °C) and hyperpyretic or excessive (41 °C and above ).

According to the duration of fever: acute - up to 15 days, subacute - 16-45 days, chronic - over 45 days.

By changes in body temperature over time The following types of fever are distinguished::

Constant- body temperature is usually high (about 39 °C), lasting for several days with daily fluctuations within 1 °C (with lobar pneumonia, typhus, etc.).
Laxative- with daily fluctuations from 1 to 2 °C, but not reaching the normal level (with purulent diseases).
Intermittent- alternation after 1-3 days of normal and hyperthermic states (characteristic of malaria).
Hectic- significant (over 3 °C) daily or at intervals of several hours temperature fluctuations with a sharp drop and rise (in septic conditions).
Returnable- with periods of increased temperature up to 39-40 ° C and periods of normal or subfebrile temperature (with relapsing fever).
wavy- with a gradual increase day by day and the same gradual decrease (with lymphogranulomatosis, brucellosis, etc.).
Wrong fever- without a specific pattern in daily fluctuations (with rheumatism, pneumonia, influenza, cancer).
Kinky Fever- morning temperature is higher than evening temperature (with tuberculosis, viral diseases, sepsis).

Based on combination with other symptoms of the disease, the following forms of fever are distinguished:

Fever is a significant manifestation of the disease or its combination with such nonspecific symptoms as weakness, sweating, increased excitability in the absence of inflammatory acute phase shifts in the blood and local signs of the disease. In such cases, it is necessary to make sure that there is no simulation of fever, for which you should, with tact, measure the temperature simultaneously in both armpits and even in the rectum in the presence of medical workers.
Fever is combined with nonspecific, sometimes very pronounced acute-phase reactions (increased ESR, fibrinogen content, changes in the structure of globulin fractions, etc.) in the absence of local pathology, detected clinically and even with instrumental examination (fluoroscopy, endoscopy, ultrasound, ECG, etc.) . The results of laboratory tests exclude evidence in favor of any acute specific infection. In a word, the patient seems to “burn out” for an unknown reason.
Fever is combined with both pronounced nonspecific acute phase reactions and organ changes of unknown nature (abdominal pain, hepatomegaly, arthralgia, etc.). Options for combining organ changes can be very different, although they are not always connected by a single development mechanism. In these cases, to establish the nature of the pathological process, one should resort to more informative laboratory, functional-morphological and instrumental research methods.

The scheme of initial examination of a patient with fever includes such generally accepted methods of laboratory and instrumental diagnostics as a general blood test, urine test, chest X-ray, ECG and Echo CG. When their information content is low and depending on the clinical manifestations of the disease, more complex laboratory diagnostic methods are used (microbiological, serological, endoscopic with biopsy, CT, arteriography, etc.). By the way, in the structure of fever of unknown origin, 5-7% is accounted for by the so-called drug fever. Therefore, if there are no obvious signs of acute abdomen, bacterial sepsis or endocarditis, then during the examination it is advisable to refrain from using antibacterial and other drugs that tend to cause a pyrogenic reaction.

Differential diagnosis

The variety of nosological forms manifested by hyperthermia for a long time makes it difficult to formulate reliable principles of differential diagnosis. Taking into account the prevalence of diseases with severe fever, it is recommended that the differential diagnostic search be focused primarily on three groups of diseases: infections, neoplasms and diffuse connective tissue diseases, which account for 90% of all cases of fever of unknown origin.

Fever due to illnesses caused by infection

The most common causes of fever for which patients consult a general practitioner are:

infectious and inflammatory diseases of internal organs (heart, lungs, kidneys, liver, intestines, etc.);

classical infectious diseases with severe acute specific fever.

Infectious and inflammatory diseases of internal organs. All infectious and inflammatory diseases of internal organs and nonspecific purulent-septic processes (subphrenic abscess, liver and kidney abscesses, cholangitis, etc.) occur with fever of varying degrees.

This section discusses those that are most often encountered in the medical practice of a doctor and can manifest themselves for a long time only as fever of unknown origin.

Endocarditis. In the practice of a therapist, infective endocarditis currently occupies a special place as a cause of fever of unknown origin, in which fever (chills) often far outstrips the physical manifestations of heart disease (murmurs, enlargement of the borders of the heart, thromboembolism, etc.). At risk for infective endocarditis are drug addicts (injecting drugs) and people who have been administered parenteral medications for a long time. The right side of the heart is usually affected. According to a number of researchers, it is difficult to identify the causative agent of the disease: bacteremia, often intermittent, in almost 90% of patients requires 6-fold blood cultures. It should be borne in mind that in patients with a defect in the immune status, fungi can be the cause of endocarditis.

Treatment is antibacterial drugs after determining the sensitivity of the pathogen to them.

Tuberculosis. Fever is often the only manifestation of tuberculosis of the lymph nodes, liver, kidneys, adrenal glands, pericardium, peritoneum, mesentery, and mediastinum. Currently, tuberculosis is often combined with congenital and acquired immunodeficiency. The lungs are most often affected by tuberculosis, and the x-ray method is one of the most informative. Reliable bacteriological research method. Mycobacterium tuberculosis can be isolated not only from sputum, but also from urine, gastric juice, cerebrospinal fluid, and from peritoneal and pleural effusion.

Fever is a protective-adaptive mechanism of the human body that develops as a reaction to the influence of pathogenic stimuli. Sometimes fever also occurs with non-infectious illnesses. This is how the body reacts to the action of endotoxins, endogenous pyrogens, which are released when they are destroyed, a septic inflammatory process occurs, and metabolic disorders and autoimmune processes are also observed.

How does fever manifest?

The processes of thermoregulation in the human body are determined by the thermoregulation center, which is located in the person. These processes may be disrupted exogenous or endogenous factors. Sometimes the temperature rises in the event of a disturbance in the processes of heat production and heat transfer and in the normal state of the thermoregulation center.

The main manifestations of fever are increased body temperature. If normal body temperature, measured in the armpit, should be 36.0-36.9, then with fever these indicators increase. With a fever, a person experiences chills, headache, weakness, and severe muscle aches.

Classification of fevers is practiced depending on various factors. Taking into account the reason for the development of this condition, it is determined infectious And non-infectious fever.

Taking into account the level of increase in body temperature, the patient varies low-grade fever fever (body temperature 37-37.9 °C), febrile fever (body temperature 38-38.9 °C), pyretic or high fever (body temperature 39-40.9 °C) And hyperpyretic or excessive fever (body temperature 41 °C and more).

Depending on the duration of this condition, it varies acute , subacute And chronic fever.

According to the assessment of body temperature indicators and the time when they appear, it is determined constant , laxative , intermittent , returnable , wavy , wrong , perverted , hectic fever. All types of fever have peculiarities of their course. For example, hectic fever develops with strong fluctuations in body temperature. These types of fever appear with the development of certain diseases.

A number of diseases associated with fever and associated symptoms are identified.

Types of fevers

Crimean hemorrhagic fever is a viral disease that develops as a result of exposure to a pathogen transmitted by ticks. Crimean fever was first diagnosed in Crimea. Signs of this disease were discovered in 1944. Its causative agent is RNA virus, which enters the body through the skin when a person is bitten by a tick.

Symptoms of hemorrhagic fever manifest themselves acutely: body temperature rises sharply, intoxication is noted, as well as hemorrhagic syndrome (high level of bleeding). The patient may be bothered by vomiting, and in the initial period there is noticeable redness of the face. After 2-6 days, hemorrhagic syndrome is observed, which is characterized by the appearance hemorrhagic rash on the shoulders, feet, hands.

If hemorrhagic fever with renal syndrome develops, then the acute onset of fever is combined with symptoms of intoxication and serious kidney damage. As a consequence, hemorrhagic renal fever leads to kidney damage and liver failure. There is bleeding from the gums, nosebleeds, and the person may lose consciousness. Viral diseases associated with hemorrhagic syndrome, are also dangerous because a person may develop bleeding in the stomach and intestines. Development of complications ( sepsis , pulmonary edema , pneumonia ) and improper treatment can be fatal. Therefore, prevention of infection is important: immediately after a tick bite, you need to consult a specialist. Far Eastern hemorrhagic fever is a serious disease that requires urgent treatment.

Prolonged fever of unknown origin can be diagnosed if the body temperature is high (above 38 degrees) lasts for more than two weeks in the patient, and the reasons for this phenomenon remain unknown. At the same time, a comprehensive examination was carried out and all diagnostic standards were taken into account. A very important point is the differential diagnosis of fever of unknown origin, since sometimes this diagnosis can be made incorrectly. According to some experts, this type of fever is based on infection, the development of a malignant tumor, and systemic connective tissue diseases. Approximately at 20% In cases of this type of fever, both in children and adults, the cause remains unclear. Treatment of the disease is prescribed depending on the intensity of the fever.

Yellow fever humans become infected from animals and people; the pathogen is transmitted by mosquitoes. The first symptoms of yellow fever appear approximately 3-6 days after a mosquito bite. The onset of yellow fever is acute: body temperature rises to 40 degrees, severe headache and pain in the joints, back, and legs appear. There is also a hemorrhagic component: the patient’s face becomes very red and swollen. Already on the second day the person suffers from severe vomiting, nausea and thirst. Around the fifth day, a period of remission begins when the person begins to feel better. But this improvement only lasts a few hours. Then the person becomes worse, as thrombohemorrhagic syndrome develops. Bleeding and bloody vomiting are possible. The disease is fraught with the development of serious complications - sepsis , pneumonia , myocarditis . Treatment of this disease consists of symptomatic therapy and prevention of further progression of the disease. The main preventive measures are vaccination. Vaccination against yellow fever is mandatory if a person travels to areas where this disease is endemic. More than 45 endemic countries have been identified in Latin America And Africa, when traveling to which it is necessary to get vaccinated ( Colombia, Peru, Brazil, Ecuador, Kenya and etc.)

After making a diagnosis, the doctor prescribes treatment for the disease that has been diagnosed. It is important not to delay contacting a specialist for conditions that cause anxiety. Eg, white fever Children exhibit inadequate heat transfer, so there is a danger of serious overheating of the body. In this case, you should consult a doctor immediately to determine the causes of this condition and prescribe treatment. You should consult your doctor if your child has post-immunization fever , that is, an increase in temperature after vaccinations.

If a woman exhibits milk fever , that is, the body’s reaction to the appearance of milk in the breasts of a nursing mother, you should not wait until this condition goes away on its own. This is fraught with complications, so the breast must be examined by a doctor.

Fever on the lips (as people call rashes) periodically appears in people who are infected with the herpes virus. Doctors still don’t know how to cure herpes completely. However, local remedies can reduce the manifestations of the disease. How to treat lip fever is worth asking your doctor.