Fever and its treatment. For systemic vasculitis

Fever- increased body temperature, which occurs as a protective-adaptive reaction in infectious and many other diseases, or as a manifestation of thermoregulation disorders in nervous or nervous pathologies endocrine system. Accompanied by a violation of certain body functions, it is additional load on the respiratory and circulatory systems.

For fever the basal metabolism is increased, the breakdown of proteins increases (and therefore the excretion of nitrogen in the urine increases), the frequency of respiration and heart contractions increases; confusion of consciousness is possible. However, the dysfunctions and metabolism observed during fever are often determined not by the fever itself, but by the underlying disease.

Depending on the cause distinguish between infectious and non-infectious fever. The latter is observed in case of poisoning with various poisons (plant, animal, industrial, etc.), with idiosyncrasy, allergic reactions(for example, with parenteral protein administration) and diseases ( bronchial asthma), malignant tumors, aseptic inflammation, necrosis and autolysis. As a manifestation of disorders of body temperature regulation, non-infectious fever is observed in diseases of the brain, thyrotoxicosis, and ovarian dysfunction.

The mechanism of occurrence of infectious and non-infectious fever is similar. It consists of irritation nerve centers thermoregulation by substances (so-called pyrogens) of exogenous nature (decomposition products of microbes, toxins) or formed in the body ( immune complexes, pyrogens produced in leukocytes). There are three stages of the febrile reaction. The first stage - an increase in temperature - is the result of an increase in heat production with a decrease in heat transfer, which is caused by a reflex spasm of skin vessels. In this case, pale skin and chills are often noted. Then heat transfer begins to increase due to the dilation of blood vessels, and in the second stage of fever, when the temperature is kept at elevated level(the height of fever), both heat production and heat transfer are increased. Pale skin gives way to hyperemia (redness), skin temperature rises, and the patient experiences a feeling of heat. The third stage of fever - a decrease in temperature - occurs due to a further increase in heat transfer, incl. due to profuse sweating and significant additional vasodilation, which can lead to collapse. Such a course is often observed during a sharp, so-called critical, decrease in temperature, or crisis. If the decrease in temperature occurs gradually over many hours or several days (lytic decrease, or lysis), then the threat of collapse, as a rule, is absent.

For some diseases(eg malaria) fever is cyclical in nature: three stages of fever are repeated at certain intervals when the temperature remains normal. Based on the degree of increase in body temperature, subfebrile (from 37° to 38°), moderate (from 38° to 39°), high (from 39° to 41°) and excessive, or hyperpyretic, fever (over 41°) are distinguished.

In typical cases of acute infectious diseases the most favorable form is moderate fever with daily temperature fluctuations within 1°.

Hyperpyrexia is dangerous due to profound disruption of vital functions, and the absence of fever indicates a decrease in the body’s reactivity.

How to treat a fever?

You can take paracetamol and aspirin in moderate doses, as indicated in the instructions for these drugs, for no longer than 3 days in a row, with a glass of water. big amount water.

Be careful with aspirin! It increases the risk of hemorrhages and bleeding with influenza.

If the temperature is high, then make an exception for medicinal plants that help reduce the temperature. Additionally, non-drug procedures can be performed:

1. You can bring down the temperature by rubbing the body with vodka or vinegar, half diluted with water. Undress during the procedure, and do not dress immediately afterwards. Rubbing should be done frequently, as water dries quickly on a hot body.

2. Don't dress too lightly and at the same time don't bundle up. In the first case, chills occur, and in the second, overheating. Wrapping up a feverish patient is like wrapping a blanket around a hot house.

3. Open a window in the room or use an air conditioner or fan. Cool air helps eliminate the heat emanating from your body.

4. High temperature causes thirst. The fact that you sweat and breathe rapidly contributes to the loss of fluid that needs to be replenished. To reduce your temperature, drink raspberry tea, lime color and honey, cranberry or lingonberry juice. Recipes for diaphoretic tea are given below.

5. You can put a compress of vinegar water on your head. In this case, the heat will be tolerated much easier.

6. A good antipyretic. Mix the juice of 1 onion with the juice of 1 apple and 1 tablespoon of honey. Take 3 times daily.

Increased body temperature that is not caused by changes in the hypothalamus is usually called hyperthermia. Many patients use the term “fever” very loosely, often implying a feeling of being warm, cold, or sweating without actually taking their temperature.

Symptoms are primarily due to the condition causing the fever, although the fever itself may cause discomfort.

Pathogenesis of fever

The goal of the body's thermoregulation system is normally to ensure that the actual internal body temperature remains at a set level of about 37 °C (with daily fluctuations). In contrast to passive hyperthermia, during fever the mechanisms of thermoregulation are preserved and when exposed to the pyrogenic factor, the set point of temperature homeostasis increases. In this regard, thermoregulation mechanisms begin to maintain an increased temperature (green line). Clinically, this becomes noticeable during an increase in body temperature. Since the actual body temperature does not correspond to the increased set point, the body reduces heat loss due to decreased cutaneous blood flow, resulting in cooling of the skin (cold sensation). In addition, heat production is also increased due to shaking (tremor). This continues until the actual temperature level (red line) approaches the new set point (plateau). When the set point for temperature homeostasis decreases, body temperature drops because the actual level is now too high. Accordingly, the skin bleeds, the person feels hot and sweats profusely.

Fever is especially characteristic of infections as a manifestation of the reaction acute phase, in which pyrogens are the cause of the change in the set point. Exogenous pyrogens are structural elements pathogen, and the most active of them are lipopolysaccharide complexes (endotoxins) gram-negative bacteria. These pathogens, or pyrogens, are opsonized and phagocytosed by macrophages, such as Kupffer cells in the liver. Macrophages secrete many cytokines, including endogenous pyrogenic interleukin, interferon, tumor necrosis factors TNF-α (cachectin) and TNF-β (lymphotoxin), macrophage inflammatory protein MIP-1 and many others. These cytokines (with a molecular weight of approximately 15-30 kDa) are thought to reach the circumventricular regions of the brain, which do not have a blood-brain barrier. Cytokines can therefore cause temperature response in these organs or in the nearby preoptic zone and in the vascular organ of the lamina terminalis through prostaglandin PGE2. In this case, antipyretic drugs (antipyretics) are effective.

For example, acetylsalicylic acid inhibits enzymes that convert arachidonic acid in PGE2.

Considering that after intravenous injection lipopolysaccharides, the above-mentioned cytokines are released only 30 minutes after the onset of fever, and with subdiaphragmatic vagotomy their release is delayed, it should be thought that exogenous pyrogens activate the preoptic region and the vascular organ of the terminal lamina also through afferent fibers from abdominal cavity. Perhaps the signaling substances secreted by Kupffer cells of the liver activate the afferent fibers closest to them vagus nerve, which transmit the pyrogenic signal through the solitary nucleus to groups of noradrenergic neurons of types A1 and A2. They, in turn, transmit a signal from the ventricular noradrenergic pathway to the thermoregulatory neurons of the preoptic area and the vascular organ of the lamina terminalis. Norepinephrine released there causes the formation of PGE2, and through it, fever. This usually causes the release of ADH (V 1 -receptor effect), α-melanocyte-stimulating hormone (α-MSH) and corticotropin-releasing hormone (CRH; corticoliberin), preventing the development of fever by negative feedback due to the release of endogenous antipyretics.

Due to an increase in body temperature, heart rate increases (by 8-12 beats/min per degree) and energy metabolism increases, resulting in fatigue, aching joints and headache, the phase lengthens slowly wave sleep(which performs a restorative function for the brain), and, under certain circumstances, disturbances of consciousness, sensory disturbances (delirium febrile) and convulsions occur. The role of fever is to counteract infection. Elevated temperature inhibits the replication of some pathogens and kills others. In addition, the plasma concentration of metals necessary for bacterial reproduction, such as iron, zinc and copper, decreases. In addition, cells affected by viruses are destroyed, which slows down the replication of viruses. Therefore, exogenous antipyretics should only be used if the fever is accompanied by seizures (usually in infants and young children) or is so high (> 39°C) that seizures are feared.

During a 24-hour period, body temperature varies from the most low levels early morning to highest late afternoon. The maximum change is approximately 0.6 °C.

Body temperature is determined by the balance between heat production by tissues, especially the liver and muscles, and heat loss in the periphery. Typically, the thermoregulatory center of the hypothalamus maintains core temperature between 37° and 38°C. Fever results from the hypothalamic control point being elevated, causing vasoconstriction and shunting blood away from the periphery to reduce heat loss; Sometimes shivering occurs, which increases heat production. These processes continue until the temperature of the blood washing the hypothalamus reaches a new point. Rebooting the hypothalamus point downward (for example, with antipyretic drugs) provokes heat loss through sweating and vasodilation. The ability to generate fever is reduced in certain patients (eg, alcoholics, very old people, very young people).

Pyrogens are those substances that cause fever. External pyrogens are ordinary microbes or their products. The best studied lipopolysaccharides of gram-negative bacteria (commonly called endotoxins) and the toxin Staphylococcus aureus which causes toxic shock. External pyrogens usually cause fever by producing the release of endogenous pyrogens, which raise the hypothalamic point. Prostaglandin E 2 synthesis plays a critical role.

Consequences of fever. Although many patients worry that the fever itself can be harmful, minor increases temperatures caused by most acute illnesses are well tolerated by healthy adults. However, excessive temperature rise (usually >41°C) can be dangerous. This increase is more typical of severe hyperthermia caused by environment, but sometimes results from exposure to illegal drugs (eg, cocaine, phencyclidine), anesthetics, or antipsychotics. At this temperature, protein denaturation occurs and inflammatory cytokines are released, which activate the inflammatory cascade. The result is cellular dysfunction, leading to malfunction and ultimately failure of most organs; the coagulation cascade is also activated, leading to disseminated intravascular coagulation.

Because fever can increase, the basal metabolic rate at temperatures above 37°C increases by approximately 10-12% for every 1°C, fever can produce physiological stress in adults with pre-existing cardiac or pulmonary insufficiency. Fever may also worsen mental status in patients with dementia.

Fever in healthy children can cause febrile seizures.

Causes of fever

Many disorders can cause fever. Broadly speaking, they are classified as:

• infectious (most common);
• neoplastic;
• inflammatory (including rheumatic, non-rheumatic and drug-related).

The cause is acute (i.e., with a duration<4 дней) лихорадки у взрослых чаще всего инфекционная. Когда у пациентов появляется лихорадка из-за неинфекционной причины, лихорадка является почти всегда хронической или рецидивирующей. Кроме того, изолированная острая лихорадка у пациентов с установленными воспалительным или неопластическим процессами с большой вероятностью является инфекционной. У здоровых людей острая лихорадка вряд ли будет первоначальным проявлением хронического заболевания.

Infectious causes. Virtually all infectious diseases can cause fever. But in general, the most likely reasons are:

• upper and lower respiratory tract infections;
• gastrointestinal infections;
• infections urinary tract;
• skin infections.

Most acute respiratory and gastrointestinal infections are viral.

Certain patient and environmental factors also determine which causes are most likely.

Patient factors include health status, age, occupation, and risk factors (eg, hospitalization, recent invasive procedures, presence of intravenous or urinary catheters, use of mechanical ventilation).

External factors are those that place patients at high risk of contracting certain diseases - for example, through infectious contacts, local outbreaks, disease vectors (eg, mosquitoes, ticks), shared objects, food, water, or geographic location (eg, living in endemic area or recent travel there).

Some reasons based on these factors are predominant.

Two main questions are important in the initial assessment of acute fever:

• Identify any local symptoms (eg headache, cough). These signs help narrow down the range of possible causes. The localizing sign may be part of the patient's chief complaint or be identified only by specific issues.
• Determining whether the patient is seriously or chronically ill (especially if such an illness has not been identified). Many causes of fever in healthy people are self-limiting, and many (for viral infections) are difficult to diagnose accurately. Limiting tests to the severely or chronically ill may help avoid many expensive, unnecessary and often fruitless searches.

Story. The history of present illness should include the level and duration of fever and the method used to measure the temperature. Severe, shaking, teeth-chattering chills (not just a feeling of cold) suggest fever due to infection. Pain is an important clue to the possible cause of the disease; The patient should be asked about pain in the ears, head, neck, teeth, throat, chest, abdomen, side, rectum, muscles and joints.

Other local symptoms include nasal congestion and/or discharge, cough, diarrhea, and urinary symptoms (urinary frequency, incontinence, dysuria). The presence of the rash (including its nature, location, and timing of the rash's onset in relation to other features) and enlarged lymph nodes may aid in diagnosis. The patient's contacts must be identified.

Review of systems should exclude symptoms of chronic illness, including recurrent fevers, night sweats, and weight loss.

Previous medical history should include the following:

• recent surgeries;
• known medical conditions that predispose to infection (eg, HIV infection, diabetes, cancer, organ transplantation, sickle cell anemia, heart valve disease - especially if there is a prosthetic valve);
• other known disorders that predispose to fever (eg, rheumatologic disorders, systemic lupus erythematosus, gout, sarcoidosis, hyperthyroidism, cancer).

Questions to ask about recent travel include inquiring about travel location, time since return, specific location (e.g., off-the-beaten-path, urban only), pre-travel vaccinations, and use of malaria preventive medications (if required) .

All patients should be asked about the possibility of exposure (eg, through suspicious food or water, insect bites, contact with animals, or unprotected sex).

Vaccination history, especially against hepatitis A and B and against organisms that cause meningitis, influenza, or pneumococcal disease, should also be reviewed.

The drug use history should include specific questions about the following:

• drugs known to cause fever;
• drugs that predispose to an increased risk of infection (eg, corticosteroids, anti-TNF drugs, chemotherapy and anti-rejection (eg, transplant) drugs, other immunosuppressants);
• illegal use of injectable drugs (predisposing to endocarditis, hepatitis, septic pulmonary embolism and skin and soft tissue infections).

Physical examination. The physical examination begins with confirmation of fever. Fever is most accurately diagnosed by measuring rectal temperature.

Temperature in oral cavity usually about 0.6°C lower and can be even lower for many reasons, such as recent ingestion of a cold drink, mouth breathing, hyperventilation, and inappropriate measurement time (mercury thermometers require up to several minutes). Measuring tympanic membrane temperature with an infrared sensor is less accurate than rectal temperature. Monitoring skin temperature using temperature-sensitive crystals fused into plastic strips placed on the forehead is not productive for detecting increases in core temperature.

Other vital signs are assessed if tachypnea, tachycardia, or hypotension is present.

For patients with local symptoms, examination continues as described in this Guide. For patients with fever without local symptoms, a complete examination is necessary because clues to diagnosis may lie in any organ system.

The patient's general appearance should be taken into account, including any weakness, lethargy, confusion, cachexia, and depression.

The entire skin should be inspected for rash, especially petechial or hemorrhagic rash and any lesions or areas of erythema or blisters that suggest skin or soft tissue infection. The axillae and areas of the internal epicondyle of the humerus and groin should be examined for adenopathy. In hospitalized patients, the presence of any intravenous, internal (NGT), urinary catheters, and any other tubes inserted into the body should be noted. If the patient has recently had surgery, the surgical sites should be carefully examined.

When examining the head and neck, you need to pay attention to the following:

• eardrums: inspection for infection;
• sinuses (frontal and maxillary): percussion;
• temporal arteries: palpation for tenderness;
• nose: examination for congestion and discharge (clean or with pus);
• eyes: examination for conjunctivitis or jaundice;
• fundus: examination for Roth spots (suggesting infective endocarditis);
• Oropharynx and gums: inspect for inflammation or ulceration (including any candidiasis that suggests decreased immunity);
• neck: tilt to detect discomfort, stiffness, or both, indicating meningism, and palpate for adenopathy.

The lungs are examined for abnormal sounds or signs of consolidation, and the heart is listened for murmurs (suggesting possible endocarditis).

The abdomen is palpated for hepatosplenomegaly and tenderness (suggesting infection).

Percussion is performed along the lateral surfaces to identify pain in the kidney area (which suggests pyelonephritis). A pelvic examination is performed in women to check for cervical pathology or adnexal tenderness; A genital examination is performed on men to check for urination and local tenderness.

The rectum is inspected for tenderness and swelling, suggesting a perirectal abscess (which may be occult in immunocompromised patients).

All major joints are examined for swelling, erythema, and tenderness (suggesting joint infection or rheumatologic disorder). The hands and feet are examined for signs of endocarditis, including hemorrhages from splinters under the nails, painful erythematous subcutaneous nodules on the tips of the fingers (Osler's nodes), and nontender hemorrhagic spots on the soles of the feet (Janeway lesions).

Danger signals. The following phenomena should be given special attention:

• change mental state,
• headache, neck stiffness, or both,
• petechial rash,
• hypotension,
• dyspnea,
• significant tachycardia or tachypnea,
• temperature >40 °C or<35 °С,
• recent travel to an area where malaria is endemic,
• recent use of immunosuppressants.

Interpretation of results. The degree of fever is usually not related to the cause of the infection. The fever pattern, once thought to be significant, is not.

The likelihood of severe illness is considered. If severe illness is suspected, immediate and rapid testing and often hospitalization are necessary.

Danger signals strongly suggest severe impairment. Headache, neck stiffness, and a petechial, or purpuric, rash suggest meningitis. Tachycardia (below the normal increase usually seen with fever) and tachypnea, with or without hypotension or changes in mental status, suggest sepsis. Malaria should be suspected in patients who have recently been to an endemic area.

Decreased immunity, whether due to a known cause, the use of immunosuppressive drugs, or suspected by physical examination (eg, weight loss, oral candidiasis), is also a concern, as are other known chronic diseases, intravenous drug use, and heart murmurs.

The elderly, especially those living in nursing homes, are at particular risk.

Local findings identified by history or physical examination are assessed and interpreted. Other suggestive symptoms are generalized adenopathy and rash.

Generalized adenopathy may occur in older children and young adults with acute mononucleosis; usually accompanied by significant pharyngitis, malaise, and hepatosplenomegaly. Primary HIV infection or secondary syphilis should be suspected in patients with generalized adenopathy, sometimes accompanied by arthralgias, rash, or both. HIV infection develops 2–6 weeks after infection (although patients may not always report unprotected sex or other risk factors). Secondary syphilis is usually preceded by chancroid with systemic symptoms developing 4-10 weeks later.

Fever and rash have many reasons to be related to infection or drug use. Petechial, or purpuric, rashes should be given special attention; it suggests possible meningococcemia, Rocky Mountain spotted fever (especially if the palms or soles of the feet are affected), and, less commonly, some viral infections(eg dengue fever, hemorrhagic fevers). Other suggestive skin lesions include the classic erythema migrans of Lyme disease, lesions of Stevens-Johnson syndrome, and painful erythema of cellulitis and other bacterial soft tissue infections. Possibility of deferred hypersensitivity to the drug (even after long periods of use) must be taken into account.

If there are no localized findings, healthy individuals with an acute fever and only nonspecific symptoms (eg, malaise, generalized pain) are likely to have a self-limited viral illness unless there is a history of exposure (including new, unprotected sexual contact) to a vector. illness or exposure to an endemic area (including recent travel).

Drug-related fever (with or without rash) is a diagnosis of exclusion and often requires a decision to discontinue the drug. The difficulty is that if antibiotics are the cause, then the disease being treated may also cause the fever. Sometimes the clue is that fever and rash begin after clinical improvement in the infection and without worsening or reappearance of underlying symptoms (eg, a patient being treated for pneumonia reappears with fever without cough, shortness of breath, or hypoxia).

Carrying out analyzes. The analysis depends on whether there are local phenomena.

If there are local phenomena, tests are carried out in accordance with clinical hypotheses and symptoms. This applies to the following situations:

• mononucleosis or HIV infection - serological analysis;
• Rocky Mountain spotted fever - biopsy of skin lesions to confirm the diagnosis (serological analysis in the acute period is useless);
• bacterial or fungal infection - blood cultures to diagnose possible bloodstream infections;
• meningitis - immediate lumbar puncture and IV dexamethasone and antibiotics (CT scan of the head should be done before lumbar puncture if patients are at risk for cerebral herniation syndrome; IV dexamethasone and antibiotics should be given immediately after blood cultures are taken for culture and before CT head tomography);
• specific tests are based on evidence of possible exposure (eg contacts, vectors or exposure to endemic areas): testing for these diseases, especially peripheral blood smear for malaria.

If there are no local findings in otherwise healthy patients and severe disease is not suspected, patients can usually be observed at home without testing. For most, symptoms disappear quickly; and the few who develop bothersome or localized symptoms should be re-examined and tested based on new findings.

If a patient is suspected of having a severe illness, but there are no local phenomena, tests are necessary. Patients with danger signs suggestive of sepsis require culture (urine and blood), chest x-ray, and evaluation of metabolic abnormalities with measurement of serum electrolytes, glucose, BUN, creatinine, lactate, and liver enzymes. Typically, a complete blood count is done, but the sensitivity and specificity for diagnosing a severe bacterial infection is low. However, the white blood cell count is prognostically important in immunocompromised patients (a low count may be associated with a poor prognosis).

Patients with significant abnormalities may need testing even if they do not have any local findings and do not appear severely ill. Because of the risk and devastating effects of endocarditis, intravenous drug users typically are admitted to the hospital for serial blood cultures and often echocardiography when febrile. Patients taking immunosuppressants require a complete blood count; if neutropenia is present, begin testing and obtain a chest x-ray, as well as cultures of blood, sputum, urine, stool, and any suspicious discharge from skin lesions.

Elderly patients with fever often require testing.

Treatment of fever

In certain cases, anti-infective therapy is prescribed; Empiric anti-infective therapy is required if severe infection is suspected.

Whether fever due to infection should be treated with antipyretics is controversial. Experimental evidence, but not clinical studies, suggests that fever increases host defenses.

Fever may need to be treated in certain patients at particular risk, including adults with heart or lung failure or dementia. Drugs that inhibit brain oxygenase are effective in reducing fever:

• acetaminophen 650-1000 mg orally every 6 hours;
• ibuprofen 400-600 mg orally every 6 hours

The daily dose of acetaminophen should not exceed 4 g to avoid toxicity; Patients should be asked not to concomitantly take non-prescription cold and flu products that contain acetaminophen. Other nonsteroidal anti-inflammatory drugs (eg, aspirin, naproxen) are also effective antipyretics. Salicylates should not be used to treat fever in children with viral illnesses because such use has been associated with Reye's syndrome.

If temperature >41°C, other body cooling measures (eg, cool water evaporative cooling, cooling blankets) should also be used.

Basics of Geriatrics

In frail older adults, the infection is less likely to cause a fever, and even if the infection raises the temperature, it may be lower than a normal fever. Likewise, other signs of inflammation, such as focal pain, may be less obvious. Often a change in mental status or a decrease in daily functioning may be the only initial manifestations pneumonia or urinary tract infection.

Despite less severe illness, older people with fever are significantly more likely to develop severe illness. bacterial disease compared to younger people. For younger adults, the cause is usually respiratory infection or urinary tract infection, and in the elderly, infections of the skin and soft tissues are among the main causes.

Focal phenomena are assessed as in younger patients. But unlike younger patients, older patients will likely require urinalysis, urine culture, and x-rays. Blood cultures should be done to rule out sepsis; if septicemia is suspected or vital signs are abnormal, patients should be hospitalized.

Fever is a protective-adaptive mechanism of the body that occurs in response to the action of pathogenic stimuli. During this process, an increase in body temperature is observed.

Fever may occur due to infectious or non-infectious infectious diseases.

Causes

Fever may occur due to heatstroke, dehydration, injury, and also as an allergic reaction to medications.

Symptoms

Symptoms of fever are caused by the action of pyrogen substances that enter the body from the outside or are formed inside it. Exogenous pyrogens include microorganisms, their toxins and waste products. The main source of endogenous pyrogens are cells of the immune system and granulocytes (a subgroup of white blood cells).

In addition to increased body temperature, fever may cause:

• Redness of the facial skin;
• Headache;
• Trembling;
• Aching bones;
• Intense sweating;
• Thirst, poor appetite;
• Rapid breathing;
• Manifestations of unreasonable euphoria or confusion;
• In children, fever may be accompanied by irritability, crying, and feeding problems.

Other dangerous symptoms fevers: rash, cramps, abdominal pain, pain and swelling in the joints.

The symptoms of fever depend on the type and cause.

Diagnostics

To diagnose fever, methods of measuring human body temperature are used (in armpit, in the oral cavity, in the rectum). The temperature curve is diagnostically significant - a graph of rises and falls in temperature during the day. Temperature fluctuations can vary significantly depending on the cause.

To diagnose the disease that caused the fever, a detailed medical history is collected and a thorough examination is performed (general and biochemical analysis blood, urine analysis, stool analysis, radiography, ultrasound, ECG and others necessary research). Held dynamic observation for the appearance of new symptoms accompanying fever.

Types of disease

Depending on the degree of temperature increase, there are the following types fever:

• Subfibrality (37-37.9°C)
• Moderate (38-39.9 °C)
• High (40-40.9 °C)
• Hyperpyretic (from 41°C)

Based on the nature of temperature fluctuations, fever is divided into the following types:
Constant fever. High temperature for a long time. The temperature difference in the morning and evening is no more than 1°C.

Relieving fever (remitting). High temperature, morning low above 37°C. Daily temperature fluctuations are more than 1-2°C.

• Wasting fever (hectic). Large daily temperature fluctuations (3-4 °C), which alternate with a decrease in temperature to normal levels and below. Accompanied by severe sweating.
• Intermittent fever (intermittent). Short-term increases in temperature to high performance alternate with periods normal temperature
• Reverse type fever - morning temperature is higher than evening temperature.
• Wrong fever(atypical) - varied and irregular daily fluctuations.

Fever is classified according to its form:

• Undulating fever (undulating). Periodic increases in temperature, and then a decrease to normal indicators During a long time.
• Relapsing fever - strict rapid alternation of periods high temperature with fever-free periods.

Patient Actions

An increase in body temperature requires contacting a doctor to determine the cause.

If children have a fever accompanied by seizures, remove any objects near him that could injure him, make sure he is breathing freely, and call a doctor.

An increase in temperature in a pregnant woman, as well as symptoms accompanying fever, require immediate consultation with a doctor: swelling and pain in the joints, rash, severe headache, ear pain, cough with yellowish or greenish sputum, confusion, dry mouth, abdominal pain , vomit, extreme thirst, strong pain sore throat, painful urination.

Treatment

Treatment at home is aimed at replenishing the water-salt balance, maintaining vitality body, control over body temperature.

At temperatures above 38 °C, antipyretic drugs are prescribed. It is prohibited to use aspirin to reduce body temperature in children; it is recommended to use it in age dosages, or .

Treatment is prescribed depending on the results of a medical examination and the cause of the fever.

Complications

High body temperature or prolonged signs of fever can cause seizures, dehydration, and hallucinations.
Fever caused by severe infections can lead to death. Fever can also be life-threatening in people with mild immune system, cancer patients, elderly people, newborns, people with autoimmune diseases.

Prevention

Prevention of fever is the prevention of diseases and conditions that accompany it.

Under fever unknown origin (LNG) are understood 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). Fever of unknown origin can be caused by infectious and inflammatory processes, oncological diseases, metabolic diseases, hereditary pathology, systemic diseases connective tissue. The diagnostic task is to identify the cause of increased body temperature and establish accurate diagnosis. For this purpose, an extensive and comprehensive examination of the patient is carried out.

ICD-10

R50 Fever of unknown origin

General information

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

Thermoregulation of the body is carried out reflexively and is an indicator general condition 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 most early symptoms many (not only infectious) diseases, when others have not yet been observed clinical manifestations diseases. This causes difficulties in diagnosis this state. To establish the causes of fever of unknown origin, more extensive research is required. diagnostic examination. Start of treatment, including trial treatment, until the true reasons LNG is prescribed strictly individually and is determined by 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 various infections, malignant neoplasms and systemic lesions connective tissue. Fever of unknown origin may be caused by atypical form common illness, in some cases the reason for 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 sharp increase heat production in the muscles, which is manifested by chills and decreased heat transfer due to narrowing of skin blood vessels. It has also been experimentally proven that various tumors(lymphoproliferative tumors, liver, 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 lesions brain.

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, and 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, 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 simultaneously with generally accepted laboratory tests apply additional research. 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 puncture bone marrow(to exclude leukemia, lymphoma);
• computed tomography of the abdominal organs (exception tumor processes in the kidneys and pelvis);
• skeletal scintigraphy (detection of metastases) and densitometry (determination of density bone tissue) with osteomyelitis, malignant formations;
• examination of the gastrointestinal tract using radiology diagnostics, endoscopy and biopsy (if inflammatory processes, tumors in the intestines);
• carrying out serological reactions, including indirect hemagglutination reactions with intestinal group(for salmonellosis, brucellosis, Lyme disease, typhus);
• collection of data on allergic reactions to medications(if a drug-induced disease is suspected);
• study of family history in terms of the presence hereditary diseases(eg familial Mediterranean fever).

To make a correct diagnosis of fever, anamnesis may be repeated, laboratory research, which at the first stage could be 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 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 is required. this drug and patient monitoring. If the fever disappears within a few days, the cause is considered clarified, and if it persists elevated temperature body (within 1 week after discontinuation of the medication) medicinal nature fever is not confirmed.

Exist various groups 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).