Low-grade fever of unknown etiology. Prolonged low-grade fever causes

Low-grade fever body (low-grade fever, low-grade fever) – constant increase body temperature ranging from 37.1°C to 38.0°C, observed for a long time, from two weeks to several months or years.

Causes of low-grade fever

Possible causes of low-grade fever not related to the disease

1. An increase in body temperature can be caused by a decrease in heat transfer, for example, with the administration of atropine, or by an increase in heat production during overheating.
2. An increase in the formation of energy and heat production in the body, followed by low-grade fever, occurs during stress reactions and with the administration of certain medications (phenamine, muscle relaxants).
3. Functional disorders of thermoregulation can be hereditary (about 2% of healthy children are born with a body temperature above 37°C).
4. Emotional stress may lead to disruption of thermoregulation due to activation of the hypothalamus.
5. Premenstrual syndrome - an increase in body temperature is explained by an increase in the content of steroid hormones and their metabolites (ethiocholanolone, pregnane) in the blood, and is not a targeted biological reaction, but is genetically determined.
6. Pregnancy can lead to an increase in body temperature to 37.2°C - 37.3°C. Most often, body temperature becomes normal by the end of the first trimester, but in some women it may remain elevated throughout pregnancy, which is associated with an increase in progesterone production.
7. A short-term increase in body temperature may occur during intense physical activity in a hot room.

Possible causes of low-grade fever associated with the disease

All diseases leading to low-grade fever can be divided into two large groups:

I. Increase in body temperature associated with the action of pyrogens– substances that, entering the body from the outside or forming inside it, cause fever.

Don't forget about sexually transmitted infections. The widespread uncontrolled use of antibiotics in modern reality can lead to a long-term asymptomatic course of a number of diseases (for example, chlamydiasis, syphilis, etc.), when a low-grade fever is the only sign of the disease. HIV infection can also be accompanied by low-grade fever, which is possible even before positive laboratory tests appear.

The reason for the increase in body temperature to subfebrile levels during infectious processes is the product pathogenic flora specific endotoxins with weak pyrogenicity (the ability to increase human body temperature) and weak ability to cause an adequate immune response.

2. From diseases associated with changes in the body’s immune response a, low-grade fever is accompanied by rheumatism, rheumatoid arthritis, collagenosis, sarcoidosis, chronic enteritis, ulcerative colitis, post-infarction syndrome, drug allergies. The mechanism of occurrence of low-grade fever in in this case next: the synthesis of endogenous (internal) pyrogen by specific cells (monocyte-macrophage cells) is enhanced and their activity increases due to an increase in the sensitivity of the body. Also important are the processes of aseptic (in the absence of infection) melting of tissue, causing so-called resorptive fever, for example, with recurrent myocardial infarction, pulmonary infarction, hemorrhages in the body cavity and tissue, etc.

It is also possible to increase the temperature due to allergic reactions (for example, to medications, during vaccination).

3. For malignant tumors low-grade fever can be one of the earliest manifestations of the disease, sometimes 6 to 8 months ahead of its other symptoms. At the same time, the formation of immune complexes plays a role in the development of low-grade fever, which trigger immune reaction, but the earliest increase in body temperature is associated with the production of a protein with pyrogenic properties by tumor tissue. In most tumors, this protein can be detected in the blood, urine, and tumor tissue. In the absence of local manifestations malignant tumor diagnostic value has a combination of low-grade fever with specific changes in the blood. Low-grade fever is characteristic of exacerbation of chronic myeloid leukemia and lymphocytic leukemia, lymphomas and lymphosarcoma.

II. Low-grade fever that occurs without the participation of pyrogens, observed in diseases and conditions that impair the function of thermoregulation.

In case of violations endocrine system(pheochromacytoma, thyrotoxicosis, pathological menopause, etc.) low-grade fever may be a consequence of increased production of energy and heat in the body.

It is possible that there is a so-called thermoneurosis, characterized by the presence of low-grade fever, as a manifestation of a persistent disorder of heat exchange as a result of functional damage to the temperature center, which occurs with autonomic dysfunction in children, adolescents and women young. Such low-grade fever often depends on the intensity of physical and mental activity, and is often characterized by a wide range of daily temperature fluctuations (about 1°) and its normalization during night sleep.

Disturbances in thermoregulation may be a manifestation of organic pathology of the nervous system at the level of the brain stem. Also, mechanical irritation of the hypothalamus may have a certain significance in the occurrence of low-grade fever. Head injuries and endocrine changes are factors that provoke thermoregulation disorders. Cases of low-grade fever in iron deficiency anemia have been described.

Difficulty in diagnosis functional reasons low-grade fever is that approximately half of the patients have foci chronic infection.

Examination for low-grade fever

When examining patients for low-grade fever, it is necessary to exclude false low-grade fever. It is necessary to keep in mind the incorrect readings of a thermometer that does not correspond to the standard, the possibility of simulation, an artificial increase in body temperature in patients with psychopathy and hysteria caused by different ways. In the latter case, the discrepancy between temperature and pulse attracts attention.

If false low-grade fever is excluded, then it is necessary to conduct an epidemic and clinical examination of the patient. In view of the extensive list of causes of low-grade fever, it is necessary individual approach to the examination of each patient. The patient is asked not only for information about previous diseases and surgical interventions, but also living conditions and professional data. Be sure to find out hobbies, recent travel, use of any drugs or alcohol, and possible contact with animals. A detailed physical examination is required. Next, a standard laboratory examination is carried out.

1. General blood test: it is possible to increase the number of leukocytes in infectious diseases, hemolytic anemia for malignant neoplasms.
2. General urine test: for chronic infections urinary tract leukocytes and protein appear in the urine.
3. X-ray of the chest organs - will be visible specific signs lung gangrene, lung abscess, tuberculosis (if this pathology is present).
4. ECG: there may be changes characteristic of bacterial endocarditis.
5. Blood for HIV infection.
6. Blood for viral hepatitis B and C.
7. Blood for RW (syphilis).
8. Antibiotic-susceptible blood cultures are performed if sepsis is suspected.
9. Culture of antibiotic-susceptible urine should be performed for urinary tract infections.
10. Sputum culture for Mycobacterium tuberculosis.

If this examination does not help establish the diagnosis, it is necessary to perform an ultrasound examination of the organs. abdominal cavity and pelvis, donate blood for tumor markers, blood for rheumatoid factor, hormones thyroid gland(TSH, T3, T4), it is possible to use more invasive diagnostic procedures(biopsy). In some cases they can be informative CT scan and magnetic resonance imaging.

Treatment for subfibrile temperature

An increase in temperature within the subfebrile range practically does not worsen general condition patient and therefore does not require symptomatic treatment. The temperature decreases when the disease or cause that led to this condition is eliminated. For example, with adnexitis, prostatitis and other foci of chronic infection, it is necessary to antibacterial therapy. At neuropsychiatric disorders sedatives and antidepressants are used. However, it must be remembered that self-medication (especially antibacterial drugs, hormonal agents, salicylates, etc.) without finding out the cause of low-grade fever is unacceptable, since these drugs can affect the course of the disease and “lubricate” the severity specific symptoms, can cause harm to the patient, subsequently aggravate the course of the disease, and also complicate the correct diagnosis.

Why is low-grade fever dangerous?

Low-grade fever is dangerous because long time may not be noticed by the patient and is discovered by chance. But due to the fact that the symptom does not bring physical suffering to the patient, the examination, and, consequently, full treatment is postponed indefinitely. However, prolonged low-grade fever may be a symptom of such life-threatening diseases such as HIV infection, malignant neoplasms, bacterial endocarditis, etc.

Which doctors should I contact if I have a low-grade fever?

Therapist. Depending on the accompanying symptoms and the identified cause of the increase in temperature may require the help of doctors: infectious disease specialist, endocrinologist, cardiologist, otolaryngologist.

General practitioner Kletkina Yu.V.

Low-grade fever (low-grade fever)- slight (37 - 37.9’C) increase in body temperature, observed over a long period of time (from several weeks). It can be observed continuously throughout the day or occur at certain hours.

Low-grade fever is a symptom of many diseases, and therefore may be associated with different symptoms. In some cases, a persistent increase in temperature is the patient's only complaint. The most common companions of low-grade fever are increased heart rate, weakness, drowsiness, and lack of appetite.

Low-grade fever is primarily a consequence of the restructuring of thermoregulatory processes in the body. It is caused by an acceleration of metabolism or dysfunction of the thermoregulation center due to infectious, allergic or any other influences.

Low-grade fever in children, especially younger age, often has no connection with any pathology. It occurs due to the body’s thermoregulation not yet established. Children's body temperature rises after motor activity, overheating, and in infants after eating.

One of common reasons persistent low-grade fever is psychological and mental stress, as well as stress, accompanied by general poor health, dizziness, and shortness of breath.

Diagnosis and treatment

If you have persistent low-grade fever, you should consult a therapist. At the Medicenter, consultations are conducted by a highly qualified therapist with extensive experience. The doctor will quickly and reliably diagnose the cause of low-grade fever and begin treating the disease, not the symptom!

Before visiting a doctor, the patient is recommended to measure body temperature every 3 hours (excluding sleep time) and record the data for 1-2 weeks. The records must be shown to the doctor. This will help him when collecting anamnesis and drawing up individual plan examinations.

It is advisable for women not to carry out this test during menstruation, because... An increase in temperature may be one of the manifestations of premenstrual syndrome.

Due to the wide range of diseases that occur against the background of low-grade fever, diagnosing its cause presents some difficulties. Particular emphasis is placed on collecting patient complaints, as well as an initial examination. First of all, diseases of infectious etiology are excluded, such as tuberculosis, which is often asymptomatic.

In almost every case, a patient with low-grade fever needs to undergo general and biochemical analysis blood, general analysis urine, electrocardiography, and undergo chest x-ray. If signs of infection are detected, the doctor conducts a targeted search for the source of infection (virus).

If the doctor has a more clear diagnostic version, he may refer the patient for special studies (gynecological, urological, ultrasound diagnostics internal organs, blood test for hormones) or for consultation with a specialized specialist.

Diagnosis and treatment of some diseases that occur against the background of low-grade fever require hospitalization of the patient.

Treatment of low-grade fever with antipyretics is rarely practiced. The underlying cause of the disease is subject to treatment.

Important! If you suspect low-grade fever, you should not delay a visit to the doctor, because this symptom typical for many serious illnesses, in particular HIV infection.

If outpatient examinations are not possible, Medicenter doctors make house calls to all districts of St. Petersburg. Trips to the suburbs of St. Petersburg are negotiated separately.

Body temperature is one of the most important physiological parameters indicating the state of the body. We all know well from childhood that normal body temperature is +36.6 ºC, and an increase in temperature of more than +37 ºC indicates some kind of disease.

What is the reason for this condition? An increase in temperature is a reaction of the immune system to infection and inflammation. The blood is saturated with temperature-raising (pyrogenic) substances produced by pathogenic microorganisms. This in turn stimulates the body to produce its own pyrogens. Metabolism speeds up somewhat to make it easier for the immune system to fight the disease. Typically, fever is not the only symptom of the disease. For example, with colds, we feel their typical symptoms - fever, sore throat, cough, runny nose. For mild colds, body temperature can be at +37.8 ºC. And in case of severe infections, such as influenza, it rises to +39-40 ºC, and the symptoms may be accompanied by aches throughout the body and weakness.

Danger of elevated temperature

In such situations, we know very well how to behave and how to treat the disease, because diagnosing it is not difficult. We gargle, take anti-inflammatory drugs and antipyretics, if necessary, we drink antibiotics, and the disease gradually goes away. And after a few days the temperature returns to normal. Most of us have encountered this situation more than once in our lives.

However, it happens that some people experience slightly different symptoms. They find that their temperature is higher than normal, but not by much. We are talking about low-grade fever - a temperature in the range of 37-38 ºC.

Is this condition dangerous? If it does not last long - for a few days, and you can associate it with some kind of infectious disease, then no. It is enough to cure it, and the temperature will subside. But what to do if there are no visible symptoms Do you have any colds or flu?

Here you need to keep in mind that in some cases colds may have mild symptoms. Infection in the form of bacteria and viruses is present in the body, and the immune forces react to their presence by increasing the temperature. However, the concentration of pathogenic microorganisms is so low that they are unable to cause typical symptoms colds - cough, runny nose, sneezing, sore throat. In this case elevated temperature may go away after these infectious agents are killed and the body recovers.

Especially often, a similar situation can be observed in the cold season, during epidemics of colds, when infectious agents can attack the body over and over again, but run into the barrier of an alert immune system and do not cause any visible symptoms, except for an increase in temperature from 37 to 37 ,5. So if you have 4 days of 37.2 or 5 days of 37.1, and you still feel tolerable, this is not a reason to worry.

However, as we know, colds rarely last more than one week. And, if the elevated temperature lasts longer than this period and does not subside, and no symptoms are observed, then this situation is a reason to seriously think about it. After all, a constant low-grade fever without symptoms can be a harbinger or sign of many serious diseases, much more serious than a common cold. These can be diseases of both infectious and non-infectious nature.

Measurement technique

However, before worrying in vain and running to doctors, you should exclude such a banal cause of low-grade fever as measurement error. After all, it may well happen that the cause of the phenomenon lies in a faulty thermometer. As a rule, electronic thermometers, especially cheap ones, are guilty of this. They are more convenient than traditional mercury ones, however, they can often show incorrect data. However, mercury thermometers are not immune to errors. Therefore, it is better to check the temperature on another thermometer.

Body temperature is usually measured in the armpit. Rectal measurement is also possible and oral measurement. In the last two cases, the temperature may be slightly higher.

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The measurement should be taken while sitting, in calm state, in a room with normal temperature. If the measurement is carried out immediately after intensive physical activity or in an overheated room, then the body temperature in this case may be higher than normal. This circumstance should also be taken into account.

One should also take into account such a circumstance as temperature changes during the day. If in the morning the temperature is below 37, and in the evening the temperature is 37 and slightly higher, then this phenomenon may be a variant of the norm. For many people, the temperature may vary slightly during the day, increasing in the evening hours and reaching values ​​of 37, 37.1. However, as a rule, evening temperature should not be low-grade fever. In a number of diseases, a similar syndrome, when the temperature is higher than normal every evening, is also observed, so in this case it is recommended to undergo an examination.

Possible causes of prolonged low-grade fever

If you have a fever without symptoms for a long time, and you do not understand what this means, you should consult a doctor. Only a specialist, after a thorough examination, can say whether this is normal or not, and if it is abnormal, then what caused it. But, of course, it’s good to know for yourself what can cause such a symptom.

What body conditions can cause prolonged low-grade fever without symptoms:

• variant of the norm
• hormonal changes during pregnancy
• thermoneurosis
• temperature tail of infectious diseases
• oncological diseases
• autoimmune diseases - lupus erythematosus, rheumatoid arthritis, Crohn's disease
• toxoplasmosis
• brucellosis
• tuberculosis
• helminthic infestations
• latent sepsis and inflammatory processes
• foci of infection
• thyroid diseases
• anemia
• drug therapy
• intestinal diseases
• viral hepatitis
• Addison's disease

Variant of the norm

Statistics say that 2% of the Earth's population has a normal temperature of just above 37. But if you do not have a similar temperature with childhood, and low-grade fever appeared only recently - then this is a completely different case, and you are not included in this category of people.

Pregnancy and lactation

Body temperature is regulated by hormones produced in the body. At the beginning of such a period of a woman’s life as pregnancy, a restructuring of the body occurs, which, in particular, is expressed in an increase in production female hormones. This process can cause the body to overheat. As a general rule, a temperature of around 37.3ºC for pregnancy should not cause serious concern. In addition, the hormonal levels subsequently stabilize, and the low-grade fever goes away.

Typically, starting from the second trimester, a woman's body temperature stabilizes. Sometimes low-grade fever can accompany the entire pregnancy. As a rule, if an elevated temperature is observed during pregnancy, then this situation does not require treatment. Sometimes a low-grade fever with a temperature of about 37.4 may also be observed in women who are breastfeeding, especially in the first days after the appearance of milk. Here the reason for the phenomenon is similar - fluctuations in hormone levels.

Thermoneurosis

Body temperature is regulated in the hypothalamus, one of the parts of the brain. However, the brain is interconnected system and processes in one part of it can influence another. Therefore, such a phenomenon is very often observed when, when neurotic states– anxiety, hysteria – body temperature rises above 37.

This is also facilitated by the production of increased amounts of hormones during neuroses. Long-term low-grade fever can accompany stress, neurasthenic conditions, and many psychoses. With thermoneurosis, the temperature usually normalizes during sleep.

To exclude such a cause, it is necessary to consult a neurologist or psychotherapist. If you really have a neurosis or anxiety associated with stress, it is necessary to undergo a course of treatment, since shattered nerves can cause much big problems than low-grade fever.

Temperature "tails"

One should not discount such a banal reason as a trace from a previously suffered infectious disease. It is no secret that many flus and acute respiratory infections, especially severe ones, lead to immune system into a state of increased mobilization. And if infectious agents are not completely suppressed, the body can maintain an elevated temperature for several weeks after the peak of the disease. This phenomenon is called a temperature tail. It can be observed in both adults and children.

Therefore, if the temperature of + 37 ºС and above lasts for a week, then the causes of the phenomenon may lie precisely in a previously suffered and cured (as it seemed) illness. Of course, if you were ill shortly before the discovery of a constant low-grade fever with some kind of infectious disease, then there is nothing to worry about - low-grade fever is precisely its echo. On the other hand, such a situation cannot be called normal, since it indicates the weakness of the immune system and the need to take measures to strengthen it.

Oncological diseases

This reason also cannot be discounted. Often, low-grade fever is the earliest sign of a tumor. This is explained by the fact that the tumor releases pyrogens into the blood - substances that cause an increase in temperature. Low-grade fever especially often accompanies blood cancer - leukemia. In this case, the effect is caused by a change in blood composition.

To exclude such diseases, it is necessary to undergo a thorough examination and take a blood test. The fact that a persistent increase in temperature can be caused by such serious illness, as an oncological one, makes us take this syndrome seriously.

Autoimmune diseases

Autoimmune diseases are caused by an abnormal response of the human immune system. As a rule, immune cells - phagocytes and lymphocytes attack foreign bodies and microorganisms. However, in some cases, they begin to perceive the cells of their body as foreign, which leads to the appearance of the disease. In most cases, connective tissue is affected.

Almost all autoimmune diseases - rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease - are accompanied by an increase in temperature to 37 and above without symptoms. Although these diseases usually have a number of manifestations, however, early stage they may not be noticeable. To rule out such diseases, you need to be examined by a doctor.

Toxoplasmosis

Toxoplasmosis is very common infectious disease, which often occurs without noticeable symptoms, with the exception of elevated temperature. It often affects owners of pets, especially cats, which are carriers of the bacilli. Therefore, if you have furry pets at home and the temperature is low-grade, then this is reason to suspect this disease.

The disease can also be contracted through undercooked meat. To diagnose toxoplasmosis, you should take a blood test to check for infection. You should also pay attention to symptoms such as weakness, headaches, and loss of appetite. The temperature with toxoplasmosis cannot be reduced with the help of antipyretics.

Brucellosis

Brucellosis is another disease caused by an infection transmitted through animals. But this disease most often affects farmers who deal with livestock. Disease in initial stage expressed in relatively low temperature. However, as the disease progresses, it may take severe forms, while striking nervous system. However, if you do not work on a farm, then brucellosis can be ruled out as a cause of hyperthermia.

Tuberculosis

Alas, consumption, notorious in works of classical literature, has not yet become part of history. Millions of people currently suffer from tuberculosis. And this disease is now characteristic not only of places that are not as remote as many believe. Tuberculosis is a severe and persistent infectious disease that is difficult to treat even with modern medicine.

However, the effectiveness of treatment largely depends on how quickly the first signs of the disease were detected. To the most early signs illness includes low-grade fever without others clearly severe symptoms. Sometimes temperatures above 37 ºC may not be observed all day, but only in the evening hours.

Other symptoms of tuberculosis include increased sweating, fast fatiguability, insomnia, weight loss. To accurately determine whether you have tuberculosis, you need to perform a tuberculin test (Mantoux test) and also do fluorography. It should be borne in mind that fluorography can only reveal the pulmonary form of tuberculosis, while tuberculosis can also affect genitourinary system, bones, skin and eyes. Therefore, you should not rely only on this diagnostic method.

AIDS

Until about 20 years ago, a diagnosis of AIDS meant a death sentence. Now the situation is not so sad - modern drugs can support the life of an HIV-infected person for many years, even decades. It is much easier to become infected with this disease than is commonly believed. This disease does not only affect representatives of sexual minorities and drug addicts. You can catch the immunodeficiency virus, for example, in a hospital through a blood transfusion or through casual sexual contact.

Constant low-grade fever is one of the first signs of the disease. Let's note. that in most cases, weakened immunity in AIDS is accompanied by other symptoms - increased susceptibility to infectious diseases, skin rashes, and bowel dysfunction. If you have reason to suspect AIDS, you should consult a doctor immediately.

Worm infestations

Often, an infection in the body can be hidden and not show any signs other than fever. Foci of a sluggish infectious process can be located in almost any organ in cardiovascular system, gastrointestinal tract, bone and muscular systems. The urinary organs are most often affected by inflammation (pyelonephritis, cystitis, urethritis).

Often, low-grade fever can be associated with infective endocarditis - chronic inflammatory disease affecting the tissues surrounding the heart. This disease can be latent for a long time and not manifest itself in any other way.

Also Special attention worth paying attention to oral cavity. This area of ​​the body is particularly vulnerable to the effects of pathogenic bacteria because they can enter it regularly. Even simple untreated caries can become a source of infection, which will enter the bloodstream and cause a constant protective response of the immune system in the form of an increase in temperature. The risk group also includes patients with diabetes mellitus, who may experience non-healing ulcers that make themselves felt through increased temperature.

Thyroid diseases

Thyroid hormones, such as thyroid-stimulating hormone, play important role in regulating metabolism. Some thyroid diseases can increase the release of hormones. The increase in hormones may be accompanied by symptoms such as increased heart rate, weight loss, hypertension, inability to tolerate heat, deterioration of hair, and increased body temperature. There are also nervous disorders – increased anxiety, anxiety, absent-mindedness, neurasthenia.

An increase in temperature can also be observed with a lack of thyroid hormones. To exclude an imbalance of thyroid hormones, it is recommended to take a blood test to determine the level of thyroid hormones.

Addison's disease

This disease is quite rare and is expressed in a decrease in the production of hormones by the adrenal glands. It develops for a long time without special symptoms and is also often accompanied by a moderate increase in temperature.

Anemia

A slight increase in temperature can also cause a syndrome such as anemia. Anemia is a lack of hemoglobin, or red blood cells, in the body. This symptom may appear when various diseases, it is especially typical for heavy bleeding. Also, an increase in temperature can be observed with some vitamin deficiencies, lack of iron and hemoglobin in the blood.

Drug treatment

With low-grade fever, the cause of the phenomenon may be due to medication. Many medications can cause fever. These include antibiotics, especially penicillin drugs, some psychotropic substances, in particular antipsychotics and antidepressants, antihistamines, atropine, muscle relaxants, narcotic analgesics.

Very often, an increase in temperature is one of the forms allergic reaction for the drug. This version is perhaps the easiest to check - just stop taking the drug that causes suspicion. Of course, this must be done with the permission of the attending physician, since discontinuation of the drug can lead to much more serious consequences than low-grade fever.

Age up to one year

In infants, the causes of low-grade fever may lie in the natural processes of development of the body. As a rule, a person's temperature in the first months of life is slightly higher than that of adults. In addition, infants may experience disturbances in thermoregulation, which is expressed in a slight low-grade fever. This phenomenon is not a symptom of pathology and should go away on its own. Although, when the temperature rises in infants, it is still better to show them to the doctor to rule out infections.

Intestinal diseases

Many infectious intestinal diseases may be asymptomatic, except for a rise in temperature above normal values. Also, a similar syndrome is characteristic of some inflammatory processes in gastrointestinal diseases, for example, in nonspecific ulcerative colitis.

Hepatitis

Hepatitis types B and C – severe viral diseases affecting the liver. As a rule, prolonged low-grade fever accompanies sluggish forms diseases. However, in most cases it is not the only symptom. Typically, hepatitis is also accompanied by heaviness in the liver area, especially after eating, yellowing of the skin, pain in the joints and muscles, and general weakness. If you suspect hepatitis, you should consult a doctor as soon as possible, since prompt treatment reduces the likelihood of severe, life-threatening complications.

Diagnosis of the causes of prolonged low-grade fever

As seen, potential causes, which can cause disruption of the body's thermoregulation, there are great amount. And finding out why it happens is not easy. This may take a lot of time and require significant efforts. However, there is always something from which such a phenomenon is observed. And an elevated temperature always indicates something, usually that something is wrong with the body.

As a rule, it is impossible to determine the cause of low-grade fever at home. However, some conclusions about its nature can be drawn. All the reasons that cause elevated temperature can be divided into two groups - associated with some kind of inflammatory or infectious process and not related to it.

• In the first case, taking antipyretic and anti-inflammatory drugs, such as aspirin, ibuprofen or paracetamol, can restore normal temperature, albeit for a short time.
• In the second case, taking such drugs does not give any effect. However, one should not think that the absence of inflammation makes the cause of low-grade fever less serious. On the contrary, non-inflammatory causes of low-grade fever may include such serious things as cancer.

As a rule, diseases are rare, the only symptom of which is low-grade fever. In most cases, other symptoms are present, such as pain, weakness, sweating, insomnia, dizziness, hypertension or hypotension, pulse irregularities, and abnormal gastrointestinal or respiratory symptoms. However, these symptoms are often erased, and the average person is usually unable to determine a diagnosis from them. But for experienced doctor the picture may be clear.

In addition to your symptoms, you should tell your doctor about what actions you have recently performed. For example, did you communicate with animals, what foods did you eat, did you travel to exotic countries, etc. When determining the cause, information about the patient’s previous diseases is also used, because it is quite possible that low-grade fever is a consequence of a relapse of some long-treated disease.

To establish or clarify the causes of low-grade fever, it is usually it is necessary to undergo several physiological tests. First of all, this is a blood test. In the analysis, you should first of all pay attention to such a parameter as the erythrocyte sedimentation rate. An increase in this parameter indicates an inflammatory process or infection. Parameters such as the number of leukocytes and hemoglobin levels are also important.

To detect HIV and hepatitis, special blood tests are required. A urine test is also necessary, which will help determine whether there are inflammatory processes in the urinary tract. At the same time, attention is also paid to the number of leukocytes in the urine, as well as the presence of protein in it. To cut off the probability helminthic infestations A stool analysis is performed.

If the tests do not clearly determine the cause of the anomaly, then examinations of the internal organs are carried out. For this purpose they can be used various methods– Ultrasound, radiography, computed tomography and magnetic tomography.

A chest x-ray can help detect pulmonary tuberculosis, and an ECG can help detect infective endocarditis. In some cases, a biopsy may be indicated.

Establishing a diagnosis in the case of low-grade fever can often be complicated by the fact that the patient may have several potential causes of the syndrome, but it is not always easy to separate true causes from false ones.

What to do if you discover that you or your child have a persistent fever?

Which doctor should I contact with this symptom? The easiest way is to go to a general practitioner, and he, in turn, can give a referral to specialists - an endocrinologist, an infectious disease specialist, a surgeon, a neurologist, an otolaryngologist, a cardiologist, etc.

Of course, low-grade fever, unlike febrile fever, does not pose a danger to the body and therefore does not require symptomatic treatment. Treatment in such a case is always aimed at eliminating hidden reasons diseases. Self-medication, for example, with antibiotics or antipyretics, without a clear understanding of actions and goals is unacceptable, since not only can it be ineffective and blur clinical picture, but will also lead to the development of the real disease.

But the insignificance of a symptom does not mean that you should not pay attention to it. Vice versa, low-grade fever is a reason to undergo a thorough examination. This step cannot be postponed until later, reassuring yourself that this syndrome is not dangerous to health. It should be understood that behind such a seemingly insignificant malfunction of the body there can be serious problems. published .

P.S. And remember, just by changing your consumption, we are changing the world together! © econet

In pediatric practice, there are often cases when the main complaint of parents is the child’s fever.

will talk about the causes of low-grade fever in children.

Long-term low-grade fever is an increase in temperature within 37-38 degrees for 3 weeks.

Long-term low-grade fever is observed most common in children under 1 year of age (which is probably due to a reaction to the BCG vaccine), then there is a significant decline from 2 to 7 years of age And increase from 8 to 14 years , which is associated with the presence of intense “critical” phases of growth and development.

It is interesting that among adults, in 70-80% of cases, prolonged low-grade fever occurs in young women with symptoms of asthenia. This is explained physiological characteristics female body, ease of infection of the urogenital system, as well as a high frequency of psycho-vegetative disorders.

Most often, low-grade fever is observed in children under the age of 1 year, then there is a significant decrease between the ages of 2 and 7 years and an increase between 8 and 14 years.

It must be taken into account that prolonged low-grade fever is much less likely to be a manifestation of any organic disease, in contrast to prolonged fever with a temperature above 38 0 C. In most cases, prolonged low-grade fever reflects banal autonomic dysfunction.

Conventionally, the causes of prolonged low-grade fever can be divided into two large groups: infectious and non-infectious.

Infectious low-grade fever occurs in such diseases :

1. Tuberculosis, especially if the increase in temperature is combined with general weakness, emaciation, sweating, loss of appetite, prolonged cough, unfavorable fluorography and tuberculin tests, as well as the presence of contact with the patient open form tuberculosis.
2. Focal infection (sinusitis, tonsillitis, cholecystitis, dental problems and etc.).
3. Toxoplasmosis, giardiasis.

Low-grade fever may appear after an infectious disease (“fever tail”), as a reflection of post-viral asthenia syndrome. In this case, low-grade fever is benign in nature, is not accompanied by changes in tests and usually goes away on its own within 2 months (sometimes the “temperature tail” can last up to 6 months).

Prolonged low-grade fever non-infectious nature may be due to somatic pathology, but much more often it can be explained physiological reasons or the presence of psycho-vegetative disorders.

Physiological reasons. For many people, low-grade fever is constitutional in nature and is a variant of the individual norm. Low-grade fever can develop against the background of emotional and physical (sports) stress, appear after eating, when in a hot room, after exposure to insolation. Women may have low-grade fever in the second half menstrual cycle, which normalizes with the onset of menstruation; Rarely, low-grade fever is observed during the first 3-4 months of pregnancy.

Causes of non-infectious low-grade fever :

1. Endocrine disorders (thyrotoxicosis, pheochromocytoma, etc.).
2. Iron-deficiency anemia.
3. Rheumatic diseases.
4. Tumors.

According to some signs it is possible distinguish infectious low-grade fever from non-infectious .

For infectious low-grade fever is characterized by poor temperature tolerance, daily physiological temperature fluctuations are preserved (normal morning temperature is 1 degree lower than evening temperature), positive reaction to take an antipyretic. And when non-infectious- the temperature is well tolerated, daily fluctuations are absent or distorted (morning temperature is higher than evening temperature), there is no reaction to antipyretics.

To find out the reason low-grade fever, a variety of laboratory and instrumental studies are carried out.

Consultations with an ENT doctor, dentist, cardiologist, phthisiatrician, infectious disease specialist, endocrinologist, hematologist, and oncologist are scheduled.

Nothing hurts, but the thermometer is again showing 37.2, then 37.7?

There is no runny nose, cough, or any other cold symptoms.

And this has not been going on for the first week.

In the language of doctors this temperature (from 37 to 38 degrees) is called low-grade fever.

There are many reasons that cause low-grade fever.

It is believed that normal temperature human body equal to 36.6 degrees, and anything higher or lower is considered a deviation from the norm. But that's not true.

Numerous studies and cases from doctors' practice have proven that the most common average body temperature is 37 degrees.

A decrease or increase in temperature can be influenced by many factors that are in no way related to disease. If you notice a slight fluctuation in temperature up or down, don't panic. This condition can be caused by natural causes.

Natural temperature fluctuations

• representatives of the stronger sex are on average a little “cooler” than women, by about half a degree;
• with age, the temperature gradually decreases;
• a child's temperature may rise from crying for a long time or after active play;
• dishes with the addition of hot spices can slightly increase the temperature and speed up the heartbeat;
• after eating and after exercise, the temperature rises, this is quite natural;
• in women, elevated temperature can be observed during premenstrual syndrome;
• during the first trimester of pregnancy, the temperature can rise to 37.5 degrees;
• the difference between evening and morning temperature readings can be about a degree - in the morning it usually decreases, and between 18 and 22 hours it increases.

Neuroses and temperature “tail”

Everyone is familiar with the saying “all illnesses come from nerves.” In the case of low-grade fever, this is often true. A third of people suffering from temperature fluctuations owe their unpleasant symptoms to neurosis.

Such stress is most often caused by problems at work or in the family, mental or physical stress. Low-grade fever in such cases can be observed for several years.

Exists special term, defining this state - « thermoneurosis" Most often, teenagers, young women and students are susceptible to thermoneurosis.

Another common cause of low-grade fever is temperature tail. When a person suffers from an infectious disease, the temperature may remain elevated for several months after recovery. Sometimes the temperature tail can stretch for six months.

Remember that the temperature must be measured correctly. Armpit must be completely dry. The thermometer should be brought down to the “35” mark and held for at least ten minutes.

Causes of low-grade fever associated with diseases

There are two main groups of diseases that cause low-grade fever:

1. Non-inflammatory diseases.

Low-grade fever can be caused by diseases that are not inflammatory in nature. These include blood diseases, immune and endocrine diseases.

Thyrotoxicosis. For thyrotoxicosis thyroid releases too much into the blood thyroid-stimulating hormone. In addition to elevated temperature, the patient is worried about nervousness, insomnia, rapid heartbeat, hand tremors, and sweating.

Iron-deficiency anemia. Reduced quantity hemoglobin in the blood weakens the immune system, which often leads to unpleasant symptom like low-grade fever.

Systemic lupus . It's chronic autoimmune disease. In the first few weeks after the onset of the disease, fever is the only symptom. After this, symptoms of damage to the skin, joints and internal organs appear.

2. Inflammatory diseases.

Tuberculosis. In the presence of prolonged low-grade fever, the first step is to exclude a disease such as tuberculosis. In addition to low-grade fever, the patient is worried about weakness, lethargy, pain in chest, cough that does not stop for more than three weeks.

Infective endocarditis . Inflammation of the inner lining of the heart in the initial stage can be manifested by only one symptom - elevated body temperature.

Chronic focal infection. These include chronic inflammatory processes that are localized in a specific organ: tonsillitis, prostatitis, chronic andexitis, etc. Most people survive such illnesses without fever, but when the immune system is weakened, a low-grade fever occurs.

Chronic infectious diseases. Diseases such as Lyme disease, toxoplasmosis, and brucellosis are accompanied by low-grade fever. Very often, elevated body temperature remains the only symptom of the disease for a long time.

How to determine the cause of low-grade fever

Low-grade fever may appear due to many diseases, and there is no exact and single diagnostic method. To find out the cause, you need to seek help from a general practitioner.