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

Fever is a typical non-specific thermoregulatory adaptive response of the body, resulting from the excitation of the thermoregulation center by an excess of pyrogens (thermostable high-molecular substances formed by microorganisms or tissues of the human body).

Temperature above 37°C is considered elevated. Depending on the degree of febrile reaction, there are subfebrile fever(increase in body temperature below 38 ° C), mild fever(increase in body temperature within 38–39 ° C), high fever(39–41°С) and extreme, hyperpyretic fever(increase in body temperature above 41 ° C).

According to the type of temperature curve, there are:
persistent fever- diurnal fluctuations in temperature do not exceed 1°C (typical for typhoid);
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 infections);
debilitating fever, which is a combination of laxative and abnormal fever, with daily fluctuations 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, an inverse 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);
« underwater 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 proceed in different ways. 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 relatively normal state of health of the child, 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 severe 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 a 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 blood circulation. Clinically, there is a pronounced chill, pallor of the skin, acrocyanosis, cold feet and palms, tachycardia, an increase in systolic blood pressure, an increase in the difference between axillary and rectal temperatures (up to 1 ° C and above).
It should be remembered that a moderate increase in body temperature during infectious diseases helps to mobilize the body's defenses, activates the immune system. At the same time, an extreme increase in temperature significantly worsens the general state of health, contributes to the development of a number of adverse changes in the patient's body: an increase in the tone of the sympathetic nervous system, tachycardia, and an increase in the excitability of the respiratory center. Against this background, the need of organs for oxygen increases, the main metabolism intensifies, there is a delay in the body of sodium and chlorides with the development of edema, the vessels of the skin narrow (paleness of the external integument) and internal organs; there is a spasm of precapillary sphincters. Normal blood flow is disrupted, centralization of blood circulation occurs, which ultimately leads to hypoxia of organs and tissues. Hypoxia of the myocardium, for example, entails a weakening of its contractility, hypoxia of the brain leads to its edema, impaired consciousness, convulsions. The response of internal organs and systems to an increase in body temperature in children is especially pronounced.
The symptom of an increase in body temperature is extremely "many-sided" and can occur in many diseases of various organs and be 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 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 non-specific stimuli.

Fever with SARS

In the first place among the diseases accompanied by fever, are acute respiratory viral infections (ARVI). In this case, the temperature rise 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 subfebrile temperature, accompanied by these complaints within two to three days from the onset of the disease, self-treatment with over-the-counter drugs is still possible. In other cases, you must definitely consult a doctor. Any, at first glance insignificant, symptom can be the beginning of a serious or a sign of an exacerbation of a chronic disease.
If there are "threatening" symptoms that make it possible to suspect a serious illness in a patient that requires 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, impaired consciousness, 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 disrupts heat transfer (malignant hyperthermia): temperature above 40.0 ° C; motley, "marble" skin color; despite the heat, the extremities are cold to the touch.
If temperature increase is not accompanied by a pronounced violation of the general condition, with ARVI, the temperature should be reduced to 38 ° C and higher. The desire for ARVI to normalize any temperature is not justified, as this reduces the production of immunity to this pathogen. In such a situation, measures to treat symptoms such as a runny nose, sore throat, and cough are appropriate.
It should be 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 appointment of antipyretic drugs is fundamentally necessary:
Formerly healthy children: with body temperature above 39°C and/or with muscle aches and/or headaches.
Children with a history of febrile convulsions - at a body temperature above 38.0-38.5 ° C.
Children of the first 3 months of life - at a body temperature above 38.0 ° C.

Previously, the appointment of antipyretics is also indicated for children:
with hereditary metabolic anomalies;
with convulsions in the past;
in the presence of signs of circulatory failure IIst. and more;
with respiratory failure Ist. and more;
with dehydration;
with respiratory fever;
with thymomegaly 2nd tbsp. and more;
with "white" hyperthermia.

It is necessary to take into account the arguments against the mandatory prescription 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 a certain risk, including the side effects of drugs.

The rate of temperature decrease should be 1–1.5°C in 30–60 minutes.
The duration of the use of antipyretics - 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 activity, only four commercially available drugs are optimal for treating fever in children: paracetamol, ibuprofen, naproxin, and acetylsalicylic acid (aspirin).

General recommendations for parents with fever in children
Compliance with bed rest.
Regular ventilation of the room to maintain the “comfort temperature”. - During the rise in temperature, when the patient feels chills, warming is necessary, 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.
Lowering 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 reduce only the temperature above 38.5–39°C.
Antipyretic drugs should not be taken regularly, in order to prevent a new rise in temperature.
A second dose of antipyretic should be taken only if the temperature rises again.
The duration of self-administration of an antipyretic drug, without consulting a doctor, should not exceed 2 days.
It is advisable to combine the intake of antipyretic drugs with the use of drugs for the symptomatic treatment of cough, runny nose, sore throat.
Antipyretics should not be used alone while taking antibiotics, as these drugs may mask the lack of effect of antibiotic therapy.
At elevated temperatures, you should drink plenty of fluids (3-4 liters per day).
During this period, an increased intake of food rich in vitamins should be ensured, and fatty foods should be excluded from the diet.
To relieve muscle or headaches with colds, the same medicines are used as for lowering the temperature.
The reduction of fever in children should begin with physical methods of cooling (rubbing with water at room temperature, airing the room): this is often enough to reduce it.
An antipyretic should be used only if the body temperature rises to the values indicated above 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, the ratio of benefits and risks ensures their rational use.

Paracetamol

Paracetamol(acetaminophen, tylenol, etc.) inhibits cerebral synthesis of prostaglandins to a greater extent than peripheral ones, and therefore it does not have (or has to a minimal extent) 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 an antipyretic and analgesic effect, but lacks an anti-inflammatory effect.
The usual antipyretic and analgesic dose of paracetamol is 10–15 mg/kg, which can be given 3–4 times a day.
The daily dose of paracetamol should not exceed 60 mg/kg.
The toxicity of paracetamol in children is manifested when its concentration in the blood is above 150 μg / ml. Liver disease, taking 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, pallor appear. From the end of the 1st - the 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 prolonged use, cases of nephrotoxicity (tubular necrosis), cardiotoxicity (heart attacks, ischemia), pancreatitis are described.
If, due to an overdose or cumulation, damage to the liver, kidneys occurs and the child develops nausea, vomiting, oliguria, hematuria, jaundice, hypoglycemia, he should immediately be given oral acetylcysteine at a dose of 140 mg / kg and then 70 mg / kg every 4 hours (total 17 doses).
Tips for the rational use of paracetamol for parents:
reduce the temperature only according to indications;
do not re-introduce the antipyretic in order to prevent a new rise in temperature. It should be given only after the child's body temperature has returned to the previous level;
use the recommended single dose 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 because of the danger of overlooking a bacterial infection and being late in prescribing antibacterial agents;
with the development of hyperthermia with spasm of skin vessels (cold, pale hands and feet, marbling of the skin), after the introduction of an antipyretic, you should vigorously rub the child's skin until it turns red and urgently call a doctor.
children's dosage forms of paracetamol: Panadol, Efferalgan, Kalpol, Tylenol.

Ibuprofen

The usual single dose (5 mg/kg body weight) may be increased in severe fever (up to 10 mg/kg).
Ibuprofen is one of the best true NSAIDs (i.e., drugs with antipyretic, analgesic and anti-inflammatory effects) in terms of tolerance.
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) are dose dependent. Of the rare adverse reactions, gastropathy with nausea, vomiting, enteropathy with or, bleeding, oliguria, tachycardia should be noted.

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

Folk recipes for lowering the temperature with a fever

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

bark. Pour a teaspoon of crushed bark with 300 ml of water. Boil over low heat until one glass remains. Drink on an empty stomach with honey 1 time per day. Take until the fever has passed.

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

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

Leaf infusion. It is prepared at the rate of 5-10 g of crushed raw materials per 200 ml of boiling water. Consume 1/4 cup 3-4 times a day.

Cones. Pour 25 g of cones with 2 cups of boiling water. Insist, wrapped, 2 hours, strain. Take morning and evening 50 ml 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 for 2 cups of water. The resulting volume is the daily dose, which must be taken in uniform 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 uniform doses throughout the day.

Cranberry extract has an antipyretic, anti-inflammatory, antimicrobial diuretic, tonic and refreshing effect. Cranberry syrup and puree are given as a cooling agent for febrile illnesses. Cranberry juice is prescribed for febrile patients as a refreshing and antipyretic agent.

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

As an antipyretic, it is recommended to take an infusion of black poplar buds for chronic tonsillitis, bronchitis, pneumonia, for which it is often used together with lemon and an infusion of strawberry leaves.
1. Infusion of poplar buds. 2 teaspoons of crushed raw materials are infused for 15 minutes in 200 ml (1 cup) of boiling water. The resulting infusion is taken throughout the day.
2. Tincture of poplar buds. Prepared from freshly harvested raw materials in a ratio of 1:10. Time of infusion - 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 the intake of certain medications, is called drug fever. The manifestation of LL is noted with the parallel use of antibacterial agents, and when they are canceled, a decrease in the characteristic symptoms is noted. In some cases, a similar condition can also occur with an unclear etiology, when various drugs with different properties are prescribed.

Problem Features

Drug fever occurs when certain components of drugs enter the bloodstream. And although the final pathogenesis of the disease has not been elucidated, most physicians are inclined to the cause of its occurrence 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 in different people, but on average it 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 agents, however, in different people, the manifestations of drug fever can vary significantly. The duration and strength of the manifestation of the pathological condition are different, depending on such indicators as the individual characteristics of the patient's health, the presence of parallel current diseases.

Classification and localization

There are a number of characteristic features that make it possible to identify the presence of drug fever, and the possibility of classification allows you to determine the need for 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, which 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 intake of certain medications that cause a strong body. Most often, drug fever is observed with use and prolonged use, as well as with a high susceptibility of the patient's body to the constituent components of the following drugs:

antimicrobial agents that selectively affect the microbial environment and the entire body as a whole, causing a negative reaction of the immune system;
cytotoxic drugs;
medicines used in monotherapy and with a complex effect in eliminating the manifestations of cardiovascular diseases;
drugs that affect the central nervous system, the intake of which is accompanied by a deterioration or slowdown in the main reactions of the body;
anti-inflammatory drugs;
drugs containing iodine and antihistamine components in their composition.

The listed dosage forms are most often able to cause the manifestation of symptoms of drug fever, however, other drugs, and their incorrect intake, can cause the development of this disease.

In some cases, there is a high probability of manifestation of symptoms of a negative reaction of the body even several days after the end of 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, its concentration in the blood.

The symptoms of this pathological condition include the following manifestations:

the appearance of feverish manifestations;
rise in temperature 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 the use of the drug, the degree of susceptibility to the active components.

Diagnosis of drug fever

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

Treatment

The method of therapeutic action consists in the speedy termination of the medication, which caused the manifestation of the main symptoms of drug fever. Also, with strong negative manifestations of this pathology, it is recommended, depending on the age category, the use of drugs that relieve the main symptoms.

adults

To eliminate the symptoms of drug fever in adult patients, bromocriptine is used, which helps to stabilize the condition with 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 a drug fever is detected in children, it is urgent to stop taking the drug that caused the manifestations of the pathology. If it is necessary to continue treatment, a drug is used that has a similar medicinal effect.

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

During pregnancy and lactation

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

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

Disease prevention

As a preventive measure for the occurrence of drug fever, it is necessary to test the body for the degree of susceptibility to the active substance of the drug before starting treatment based on the use of antibacterial agents.
You should also regularly carry out a supporting vitamin effect, which allows you to stop negative manifestations on the part of the body, eliminate the consequences of the negative effects of selected drugs.

Complications

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

Forecast

Usually, the prognosis of survival when a drug fever is detected is positive, however, in the absence of a therapeutic effect or its small amount, the disease is likely to become more acute, which requires not only the exclusion of the drug that caused the development of the pathology, but also the use of drugs that eliminate negative symptoms and stabilize the patient's condition.

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 (by conventional and additional laboratory methods). Fever of unknown origin can be caused by infectious and inflammatory processes, cancer, metabolic diseases, hereditary pathology, 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 extended 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 the general state of health. The occurrence of fever (> 37.2°C with axillary measurement and > 37.8 °C with oral and rectal measurements) is associated with a response, protective and adaptive reaction of the body to the disease. Fever is one of the earliest symptoms of many (not only infectious) diseases, when other clinical manifestations of the disease are not yet observed. This causes difficulties in diagnosing this condition. More extensive diagnostic testing is required to establish the causes of fever of unknown origin. The beginning of treatment, including trial, before establishing the true causes of LNG is prescribed strictly individually and is determined by a specific clinical case.

Causes and mechanism of fever development

Fever lasting less than 1 week usually accompanies various infections. A fever that lasts 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 lesions of the connective tissue. The cause of a fever of unknown origin may be an atypical form of a common disease; in some cases, the cause of an increase in temperature remains unclear.

The mechanism for increasing body temperature in diseases accompanied by fever is as follows: exogenous pyrogens (of bacterial and non-bacterial 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 vasoconstriction of the skin. It has also been experimentally proven that various tumors (lymphoproliferative tumors, tumors of the liver, kidneys) 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 (the number of neutrophils in candidiasis, herpes).
HIV-associated (HIV infection in combination with toxoplasmosis, cytomegalovirus, histoplasmosis, mycobacteriosis, cryptococcosis).

According to the level of increase, body temperature is distinguished:

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 the fever can be:

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

According to the nature of changes in the temperature curve over time, fevers are distinguished:

constant - for several days there is a high (~ 39 ° C) body temperature with daily fluctuations within 1 ° C (typhus, lobar pneumonia, etc.);
laxative - during the day the temperature ranges from 1 to 2 ° C, but does not reach normal levels (with 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);
return - a period of temperature increase (up to 39-40 ° C) is replaced by a period of subfebrile or normal temperature (relapsing fever);
wavy - manifested in a gradual (day by day) increase and a similar gradual decrease in temperature (lymphogranulomatosis, brucellosis);
incorrect - there are no patterns of daily temperature fluctuations (rheumatism, pneumonia, influenza, oncological diseases);
perverted - morning temperature readings are higher than evening ones (tuberculosis, viral infections, sepsis).

Symptoms of a fever of unknown origin

The main (sometimes the only) clinical symptom of a fever of unknown origin is a rise in body temperature. For a long time, fever can 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 in making a diagnosis of fever of unknown origin:

the patient's body temperature is 38°C or higher;
fever (or periodic rises in temperature) are observed for 3 weeks or more;
the diagnosis was not determined after examinations by conventional methods.

Fever patients are difficult to diagnose. Diagnosis of the causes of fever includes:

general analysis of blood and urine, coagulogram;
biochemical blood test (sugar, ALT, AST, CRP, sialic acids, total protein and protein fractions);
aspirin test;
three-hour thermometry;
Mantoux reaction;
radiography of the lungs (detection of tuberculosis, sarcoidosis, lymphoma, lymphogranulomatosis);
Echocardiography (excluding 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 along with conventional laboratory tests. For this purpose, the following are assigned:

microbiological examination of urine, blood, swab from the nasopharynx (allows you to identify the causative agent of infection), a blood test for intrauterine infections;
isolation of a viral culture from the secrets of the body, its DNA, viral antibody titers (allows you to diagnose cytomegalovirus, toxoplasmosis, herpes, Epstein-Barr virus);
detection of antibodies to HIV (enzyme-linked immunosorbent complex method, Western blot test);
examination under a microscope of a thick blood smear (to exclude malaria);
blood test for antinuclear factor, LE cells (to exclude systemic lupus erythematosus);
bone marrow puncture (to exclude leukemia, lymphoma);
computed tomography of the abdominal cavity (exclusion of tumor processes in the kidneys and pelvis);
skeletal scintigraphy (detection of metastases) and densitometry (determination of bone density) in osteomyelitis, malignant tumors;
study of the gastrointestinal tract by the method of radiation diagnostics, endoscopy and biopsy (with inflammatory processes, tumors in the intestines);
carrying out serological reactions, including reactions of indirect hemagglutination with the intestinal group (with 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, an anamnesis can be repeated, laboratory tests, which at the first stage could be erroneous or incorrectly assessed.

Treatment of fever of unknown origin

In the event that the patient's condition with fever is stable, in most cases treatment should be withheld. Trial treatment for a febrile patient (tuberculostatic drugs for suspected tuberculosis, heparin for suspected deep vein thrombophlebitis, pulmonary embolism, bone-fixing antibiotics for suspected osteomyelitis) is sometimes discussed. The appointment of glucocorticoid hormones as a trial treatment is justified when the effect of their use can help in the diagnosis (if subacute thyroiditis is suspected, Still's disease, polymyalgia rheumatica).

It is extremely important in the treatment of patients with fever to have information about the possible previous use of drugs. The reaction to medication in 3-5% of cases may 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, the drug should be discontinued and the patient monitored. If the fever disappears within a few days, the cause is considered to be clarified, and if the elevated body temperature persists (within 1 week after discontinuation of 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 in diseases of the gastrointestinal tract (cimetidine, metoclopramide, laxatives, which include phenolphthalein);
cardiovascular drugs (heparin, alpha-methyldopa, hydralazine, quinidine, captopril, procainamide, hydrochlorothiazide);
drugs acting on the central nervous system (phenobarbital, carbamazepine, haloperidol, chlorpromazine thioridazine);
cytotoxic drugs (bleomycin, procarbazine, asparaginase);
other drugs (antihistamines, iodine, 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 reaction of the body either to endotoxins entering the blood when its own microflora dies, or to endogenous pyrogens released during the destruction of primarily 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 provided 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 provide physiological fluctuations in human body temperature, can be disturbed by various exogenous or endogenous factors (infection, intoxication, tumor, etc.). At the same time, pyrogens formed during inflammation primarily affect activated leukocytes, which synthesize IL-1 (as well as IL-6, TNF and other biologically active substances), stimulating 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 into 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.

Change in body temperature over time distinguish the following types of fever:

Constant- body temperature is usually high (about 39 ° C), lasts 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 in 1-3 days of a normal and hyperthermic state (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 temperature increase up to 39-40 ° C and periods of normal or subfebrile temperature (with relapsing fever).
wavy- with a gradual increase from day to day and the same gradual decrease (with Hodgkin's disease, brucellosis, etc.).
wrong fever- without a definite pattern in the daily fluctuation (with rheumatism, pneumonia, influenza, oncological diseases).
perverted fever- morning temperature is higher than evening temperature (with tuberculosis, viral diseases, sepsis).

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

Fever is, as it were, a significant manifestation of the disease or its combination with such nonspecific symptoms as weakness, sweating, irritability 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 it is necessary, observing tact, to measure the temperature in the presence of medical workers simultaneously in both axillary fossae and even in the rectum.
Fever is combined with non-specific, sometimes very pronounced acute phase reactions (increased ESR, fibrinogen content, changes in the structure of globulin fractions, etc.) in the absence of local pathology that can be detected clinically and even with instrumental examination (fluoroscopy, endoscopy, ultrasound, ECG, etc.). The results of laboratory studies exclude data in favor of any acute specific infection. In a word, the patient, as it were, “burns out” for an unknown reason.
Fever is combined both with severe nonspecific acute phase reactions and with organ changes of unknown nature (abdominal pain, hepatomegaly, arthralgia, etc.). Options for combining organ changes can be very different, while not always associated with a single mechanism of development. 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 for the initial examination of a patient with fever includes such generally accepted methods of laboratory and instrumental diagnostics as a complete blood count, urinalysis, chest X-ray, ECG and echocardiography. With their low information content and depending on the clinical manifestations of the disease, more complex methods of laboratory diagnostics are used (microbiological, serological, endoscopic with biopsy, CT, arteriography, etc.). By the way, in the structure of fever of unknown origin, 5-7% falls on the so-called medicinal fever. Therefore, if there are no obvious signs of an acute abdomen, bacterial sepsis or endocarditis, then for the period of 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 to focus the differential diagnostic search 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 in diseases caused by infection

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

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

classic infectious diseases with severe acute specific fever.

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

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

Endocarditis. In the practice of the therapist, a special place as a cause of fever of unknown origin is currently occupied by infective endocarditis, in which fever (chills) often far outstrips the physical manifestations of heart disease (murmurs, expansion of the boundaries of the heart, thromboembolism, etc.). In the risk group for infective endocarditis are drug addicts (drug injections) and people who have been injected parenterally with drugs for a long time. In this case, 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 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 - 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, mediastinum. Currently, tuberculosis is often combined with congenital and acquired immunodeficiency. Most often, tuberculosis affects the lungs, 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, peritoneal and pleural effusion.

Fever - this is a protective and adaptive mechanism of the human body, which develops as a reaction to the influence of pathogenic stimuli. Sometimes fever also manifests itself in non-infectious ailments. 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 itself?

The processes of thermoregulation in the human body determines the center of thermoregulation, which is located in a person. These processes can be disrupted exogenous or endogenous factors. Sometimes the temperature rises in case of violation of the processes of heat production and heat transfer and in the normal state of the thermoregulation center.

The main manifestation of fever is elevated body temperature. If the normal body temperature, measured in the armpit, should be 36.0-36.9, then with a fever, these figures increase. With a fever, a person experiences chills, headache, weakness, severe aching muscles.

Classification of fevers is practiced depending on various factors. Taking into account the cause of 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 differs subfebrile fever (body temperature 37-37.9 °С), febrile fever (body temperature 38-38.9 °С), pyretic or high fever (body temperature 39-40.9 °С) And hyperpyretic or excessive fever (body temperature 41 °С and more).

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

According to the assessment of body temperature and the time when they appear, it is determined constant , laxative , intermittent , returnable , undulating , wrong , perverted , hectic fever. All types of fever have features of the course. For example, hectic fever develops when there are large fluctuations in body temperature. These types of fever are manifested in 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 the Crimea. Symptoms of this disease were found in 1944. His trigger is RNA virus, which enters the body through the skin when a person is bitten by a tick.

Symptoms of hemorrhagic fever are acute: body temperature rises sharply, intoxication is noted, as well as hemorrhagic syndrome (high bleeding). The patient may be disturbed by vomiting, in the initial period there is a noticeable reddening of the face. After 2-6 days, hemorrhagic syndrome is observed, which is characterized by the appearance hemorrhagic rash on the shoulders, legs, hands.

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

Prolonged fever of unknown origin can be diagnosed if a high body temperature (above 38 degrees) keeps the patient for more than two weeks, and the reasons for this phenomenon remain unidentified. 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 erroneously. According to some experts, this type of fever is based on infection, the development of a malignant tumor, and systemic diseases of the connective tissue. Approximately at 20% cases, the cause of this type of fever, both in children and adults, remains unclear. Treatment of the disease is prescribed depending on the intensity of the fever.

yellow fever a person becomes infected from animals and people, the carriers of the pathogen are mosquitoes. The first symptoms of yellow fever appear about 3-6 days after a mosquito bite. The onset of yellow fever is acute: body temperature rises to 40 degrees, there is a severe headache and pain in the joints, back, legs. There is also a hemorrhagic component: the patient's face becomes very red and swollen. Already on the second day, a 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 lasts only a few hours. Further, the person becomes worse, as thrombohemorrhagic syndrome develops. Possible bleeding, hematemesis. 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. Vaccination is the main preventive measure. Vaccination against yellow fever is mandatory if a person travels to areas where there is an endemic situation for this disease. Over 45 endemic countries identified in Latin America And Africa where you need to get vaccinated when you leave ( Colombia, Peru, Brazil, Ecuador, Kenya and etc.)

After establishing the diagnosis, the doctor prescribes the treatment of the disease that has been diagnosed. It is important not to delay contacting a specialist for conditions that cause anxiety. Eg, white fever in children, inadequate heat transfer is manifested, so there is a danger of serious overheating of the body. In this case, the doctor should be contacted immediately to establish the causes of this condition and prescribe treatment. You need to consult a doctor if your child has post-immunization fever , that is, the temperature rise after vaccination.

If a woman shows milk fever , that is, the reaction of the body to the appearance of milk in the breast of a nursing mother, you should not wait until this condition passes by itself. This is fraught with complications, so the chest must be examined by a doctor.

Fever on the lips (as rashes are called among the people) periodically appears in people who are infected with the herpes virus. How to cure herpes completely, doctors still do not know. However, local remedies can reduce the manifestations of the disease. How to treat a fever on the lip, you should ask your doctor.