Subfebrile body temperature( subfebrile fever, subfebrile) - Causes, symptoms and treatment. MF.

Subfebrile body temperature( subfebrile fever, subfebrile condition) - a constant increase in body temperature ranging from 37.1 ° C to 38.0 ° C, marked for a long time, from two weeks to several months or years.

Causes of subthermal temperature

Possible causes of subfebrile temperature not associated with

1. An increase in body temperature can be caused by a decrease in heat transfer, for example, when atropine is introduced, or by increased heat production during overheating.
2. Increase in the formation of energy and heat production in the body with subsequent subfebrile condition occurs with 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 overexertion can lead to a violation of thermoregulation due to activation of the hypothalamus.
5. Premenstrual syndrome - an increase in body temperature due to an increase in the blood levels of steroid hormones and their metabolites( etiocholanolone, pregnane), and is not a targeted biological response, but 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 some women may remain elevated throughout pregnancy, which is associated with an increase in progesterone production.
7. A short-term increase in body temperature can be during intense physical activity in a hot room.

Possible causes of subfebrile temperature associated with

disease All diseases leading to subfebrile body temperature increase can be divided into two large groups:

I. A rise in body temperature associated with the action of pyrogens - substances that get into the body from outside or formed inside it, cause a fever.

1. Of the infectious diseases , the most frequent cause of subfebrile is a chronic nonspecific focal infection( chronic rhinitis, sinusitis, gall bladder empyema, pancreatitis, adnexitis, chronic cholecystitis, lung abscess, pleural empyema, prostatitis, etc.).However, a chronic infectious process is not always accompanied by an increase in body temperature to subfebrile digits. Therefore, only the disappearance of subfebrile temperature after the sanation of the focus of infection allows us to establish a relationship between them. Under certain conditions( a weak immune response of the organism due to various causes, insufficient activity of pathogenic microflora or significant suppression of antibacterial drugs, etc.), instead of febrile fever, subfebrile body temperature will take place even in patients with severe purulent and septic processes. In modern conditions, often there are hidden forms of sepsis( blood infection).Infectious endocarditis( inflammation of the inner shell of the heart - endocardium) sometimes develops sluggishly and can last for a long time only by malaise and fever in the range of low-grade figures without severe symptoms of intoxication, while maintaining the ability to work. The subfebrile condition may be one of the first manifestations of small forms of tuberculosis: bronchoadenitis, the primary complex, early tuberculosis intoxication, focal, infiltrative tuberculosis, etc. These forms of tuberculosis are most often erased and under the mask of various diseases. Usually there is an increase in body temperature in the evening to 37.2 ° C - 37.3 ° C for several hours, with a subsequent decrease to normal figures and lower. Subfebrile may also occur when parasites and worms are infected.

Do not forget about sexually transmitted infections. The widespread uncontrolled use of antibiotics in modern reality can lead to a long asymptomatic course of a number of diseases( eg, chlamydia, syphilis, etc.), when a subfebrile increase in temperature will be the only sign of the disease. HIV infection can also be accompanied by a subfebrile increase in temperature, which is possible even before positive laboratory tests are established.

The reason for the increase in body temperature to subfebrile digits in infectious processes is the production of pathogenic flora of specific endotoxins with weak pyrogenicity( the ability to raise human body temperature) and a weak ability to elicit an adequate immune response.

2. Rheumatism, rheumatoid arthritis, collagenoses, sarcoidosis, chronic enteritis, ulcerative colitis, postinfarction syndrome, drug allergies are associated with changes in the immune response of the organism, subfebrile fever. The mechanism of occurrence of a subfebrile condition in this case the following: amplification of endogenous( internal) pyrogen synthesis by specific cells( monocytic-macrophage cells) and their activity increases owing to increase of sensitivity of an organism. Also, processes of aseptic melting of tissues that cause a so-called resorptive fever, for example, with recurrent myocardial infarction, lung infarction, hemorrhages in the body cavity and tissue, etc., also have significance.

It is also possible to raise the temperature for allergic reactions( for example,on medicinal preparations, at a vaccination).

3. In malignant tumors of , subfebrile temperature may be one of the earliest manifestations of the disease, sometimes 6-8 months ahead of its other symptoms. At the same time in the development of subfebrile plays the role of the formation of immune complexes that trigger an immune response, but the earliest increase in body temperature is associated with the production of a tumor tissue protein that has pyrogenic properties. In most tumors, this protein can be found in the blood, urine, tumor tissue. In the absence of local manifestations of a malignant tumor, the combination of a subfebrile increase in body temperature with specific changes in blood is diagnostic. Subfebrile condition is typical for exacerbation of chronic myelogenous leukemia and lymphocytic leukemia, lymphomas and lymphosarcomas.

II.Subfebrile fever, which occurs without the participation of pyrogens , is observed in diseases and conditions that violate the function of thermoregulation.

In case of violations of the endocrine system( pheochromacitoma, thyrotoxicosis, pathological menopause, etc.), subfebrile fever can be a consequence of increased energy and heat formation in the body.

The existence of the so-called thermoneurosis , characterized by the presence of a subfebrile condition, is possible as a manifestation of persistent heat transfer disorder as a result of a functional damage to the temperature center occurring in autonomic dysfunction in children, adolescents and young women. Such subfebrile fever often depends on the intensity of physical and mental activity, often characterized by a large range of diurnal temperature fluctuations( about 1 °) and its normalization during night sleep.

Thermoregulation disorders can be a manifestation of the organic pathology of the nervous system at the level of the brainstem. Similarly, in the emergence of subfebrile fever, a definite value may have a mechanical irritation of the hypothalamus. Head trauma, endocrine dislocations are the factors provoking the violation of thermoregulation. There are cases of subfebrile fever in iron deficiency anemia.

The difficulty in diagnosing the functional causes of subfebrile fever is that approximately half of the patients have foci of chronic infection.

Inspection at subfebrile temperature

When examining patients about subfebrile temperature, it is necessary to exclude a false subfebrile condition. One should 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 various methods. In the latter case, attention is drawn to the discrepancy between temperature and pulse.

If a false subfebrile condition is excluded, then an epidemic and clinical examination of the patient is necessary. In view of the extensive list of causes of subfebrile fever, an individual approach to the examination of each patient is needed. The patient finds out not only information about previously transferred diseases and surgical interventions, but also conditions of life and professional data. Be sure to find out hobbies, recent travel, the use of any drugs or alcohol, possible contact with animals. Be sure to conduct a detailed physical examination. A standard laboratory examination is then carried out.

1. The general analysis of blood: it is possible to increase the number of leukocytes in infectious diseases, hemolytic anemia in malignant neoplasms.
2. General analysis of urine: with chronic infections of the urinary tract in the urine appear white blood cells, protein.
3. Radiography of chest organs - specific signs of gangrene of the lung, an abscess of the lung, tuberculosis( in the presence of this pathology) will be seen.
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 on RW( syphilis).
8. Blood culture with sensitivity to antibiotics is carried out with suspicion of sepsis.
9. Urine culture with susceptibility to antibiotics should be performed with urinary tract infections.
10. Sowing sputum on mycobacterium tuberculosis.

If this examination did not help to establish the diagnosis, ultrasound of the abdominal and pelvic organs should be performed, blood donated to oncomarkers, blood to rheumatoid factor, thyroid hormones( TTG, T3, T4), and more invasive diagnostic procedures( biopsy).In a number of cases, computed tomography and magnetic resonance imaging can be informative.

Treatment at subfibril temperature

A rise in temperature within the low-grade digestion practically does not worsen the general condition of the patient and, therefore, does not require symptomatic treatment. The temperature decreases when the disease is eliminated or the cause that led to this condition. For example, with adnexitis, prostatitis and other foci of chronic infection, antibacterial therapy is necessary. With neuropsychiatric disorders, sedatives and antidepressants are used. However, it must be remembered that self-medication( especially antibacterial drugs, hormonal drugs, salicylates, etc.) without elucidating the cause of subfebrile temperature is unacceptable, since these drugs can influence the course of the disease, "lubricate" the severity of specific symptoms, can harm the patient,further complicate the course of the disease, and also make it difficult to correctly diagnose.

Than subfebrile temperature is dangerous

Subfebrile condition is dangerous because it can be overlooked for a long time and can be detected by chance. But due to the fact that the symptom does not bring physical suffering to the patient, examination, and, consequently, full treatment is postponed for an indefinite period. However, prolonged subfebrile fever can serve as a symptom of life-threatening diseases such as HIV infection, malignant tumors, bacterial endocarditis, etc.

Which doctors should be treated at subfebrile temperature

Therapist. Depending on the attendant symptoms and the identified cause of fever, you may need the help of doctors: an infectious disease specialist, an endocrinologist, a cardiologist, an otolaryngologist.

Physician therapist Kletkina Yu. V.