Subfebrile temperature is an increase in temperature in the range of 37-38 degrees Celsius. The symptom is accompanied by chills, muscle and headaches, weakness. Subfebrile condition occurs in viral and chronic bacterial infections, endocrine pathology, malignant neoplasms, and other diseases. To find out why the temperature has risen, bacteriological and serological studies, ultrasound, and highly informative imaging methods are used. Temperature indicators are normalized with the right treatment of the underlying disease.
The rise in temperature to subfebrile during the day is observed during intensive sports training, hard physical work. In such cases, the key causes of temperature fluctuations are increased contractions of muscle fibers and increased heat production. Usually, the indicators return to normal after 1-2 hours. If this does not happen, and the general condition worsens, you should consult a doctor. Subfebrile condition is possible after prolonged exposure to the sun, especially in young children, whose thermoregulatory mechanisms are imperfect.
Any changes in the cerebral cortex due to psycho-emotional reactions lead to short-term disruptions in the work of the hypothalamic center of thermoregulation. Such an emotional state is accompanied by subfebrile body temperature, which is more typical for women prone to hysterical reactions. Subfebrile condition can persist for a long time with chronic stress, neurosis and neurosis-like conditions. A person does not tolerate a rise in temperature, he is worried about constant weakness and weakness, apathy, and appetite decreases.
In acute allergic reactions, subfebrile condition develops abruptly, in the first hours after contact with a trigger substance. Subfebrile temperature is accompanied by pathognomonic allergic symptoms: redness of the eyes and watery eyes, sneezing, clear discharge from the nose. Disorders persist for the entire period of action of the cause of the allergy. The temperature rarely exceeds 37.5°C. Against the background of a temperature reaction, a widespread rash in the form of blisters often occurs, combined with unbearable itching, swelling and redness of the skin.
With all respiratory diseases, except for influenza, the temperature rises to subfebrile. Pathogens are mainly localized in the epithelium of the respiratory tract, penetrate into the systemic circulation in small quantities and are not able to have a strong pyrogenic effect. An increase in the thermometer with ARVI is accompanied by an ache all over the body, headache, severe chills. The rise in temperature often occurs gradually, the fever lasts for 3-5 days. Typical causes of subfebrile condition are adenovirus and rhinovirus infection, colds.
Infection of the upper respiratory tract and ear caused by viruses, or limited bacterial inflammation, causes an increase in temperature to subfebrile numbers. Fever begins after a short (1-2 days) prodromal period, when there is heaviness in the head, muscle and joint pain, and drowsiness. Temperature indicators do not exceed 38 ° C, the skin is often pale, a glint in the eyes is characteristic. If untreated, elevated subfebrile temperature can persist for 2-3 weeks, which is typical for subacute inflammation. Common causes of low fever:
With simple bronchitis, the body temperature does not rise above 38 degrees, the fever lasts an average of 7-14 days. The general condition remains satisfactory, slight malaise, weakness are disturbing. Specific symptoms include cough, mild sore throat and chest pain. The presence of subfebrile temperature is characteristic of interstitial pneumonia. With this pathology, the temperature reaction comes to the fore and general signs - weakness, shortness of breath, and specific manifestations of pneumonia are slightly expressed.
Most infectious diseases caused by viruses are accompanied by subfebrile temperature, which rises to febrile only in case of severe course with massive viremia. The symptom occurs with a viral infection of any localization: with the involvement of the respiratory, digestive, urinary and other systems. The duration of low-grade fever ranges from several days with intestinal infections to several months in patients with chronic processes. Common viral causes in which subfebrile temperature is observed:
1-2 months after infection with the immunodeficiency virus, a constant subfebrile temperature occurs with flu-like symptoms - headaches and muscle pain, weakness. More often, temperature indicators for HIV are in the range of 37.2-37.5 ° C, not changing during the day. Fever is accompanied by fatigue, weakness, loss of appetite, decreased ability to work. Subfebrile body temperature is usually accompanied by skin lesions, characterized by polymorphic rashes.
Prolonged subfebrile temperature is characteristic of sluggish infectious processes. Most often, such a reaction is noted in tuberculosis: the thermometer values do not exceed 37.5 degrees, while the person constantly feels weakness and decreased performance. Sweating at night is characteristic. Periodic low-grade fever throughout the year and even several years is observed with brucellosis, a relapsing variant of Lyme disease. The symptom is combined with pain in the joints, various skin lesions.
Giardiasis, opisthorchiasis, amoebiasis are the causes that stimulate the production of endogenous biologically active substances and pyrogens. With such parasitic invasions, the temperature rises to subfebrile, which is accompanied by dyspeptic disorders. With ascariasis, subfebrile condition occurs during the period of migration of larvae, which is manifested by cough and shortness of breath, polymorphic rashes throughout the body. With helminthiases, subfebrile temperature is often determined against the background of pain and swelling of the joints, urticarial rash.
Typical causes of subfebrile temperature in women are a decrease in estrogen levels and hormonal changes during menopause. Subfebrile condition is detected during hot flashes, when it seems that the face and neck are “burning”, bright red spots form on the skin. Patients feel severe headaches, flies flickering before their eyes. Fever sometimes occurs during the first trimester of pregnancy due to increased synthesis of sex hormones. This condition requires a doctor's consultation in order to exclude the pathological causes of the development of subfebrile temperature.
In inflammatory bowel diseases (ulcerative colitis, Crohn's disease), the synthesis of active mediators and cytokines is increased, affecting the thermoregulatory center in the hypothalamus. Subfebrile temperature persists for a long time: typically alternating periods of remission with normalization of temperature indicators and periods of exacerbation. The main complaints are abdominal pain, stool disorders, loss of appetite. An alarming sign is the release of blood from the anus during an exacerbation, which indicates a deep destruction of the intestinal mucosa.
Subfebrile temperature often develops with increased synthesis of thyroid hormones, which enhance basal metabolism and thermogenesis. The symptom is determined constantly for several months, while the skin becomes hot and moist. Unlike other conditions that occur with a rise in temperature, thyrotoxicosis as a cause of subfebrile condition is characterized by an increase in appetite, resentment, irritability, aggressiveness. Occasionally, a temperature reaction manifests adrenal insufficiency (Addison's disease).
In systemic diseases of the connective tissue, subfebrile temperature is more often detected during an exacerbation caused by medication or external influences, less often a symptom is recorded constantly. The main causes of subfebrile condition are lupus erythematosus, rheumatism, vasculitis. Subfebrile temperature in adolescents is often associated with juvenile rheumatoid arthritis. With this collagenosis, the patient is concerned about pain in the joints, morning stiffness of movements, swelling and hyperemia of the skin.
Chronic subfebrile temperature, accompanied by weakness, loss of appetite, weight loss, is a typical sign of the oncological process. The fever starts for no apparent reason and lasts for several months. The appearance changes - the skin becomes pale, dark circles appear under the eyes, patients lose weight by 7-1 kg. The combination of subfebrile temperature, which often occurs in the evenings, with profuse night sweats, swollen lymph nodes is characteristic of leukemia and Hodgkin's lymphoma.
Sometimes subfebrile temperature becomes the result of medical interventions. In the early postoperative period, fever is a variant of the norm and lasts 2-3 days, after which the indicators should return to normal. An increase in temperature values after a blood transfusion or transplantation of internal organs is an unfavorable sign that indicates the incompatibility of the donor and recipient cells, when the immune system begins to reject the foreign tissue. In this situation, emergency medical attention is required.
Common causes of subfebrile temperature are the use of antibacterial drugs that destroy beneficial microflora, against which opportunistic microorganisms begin to dominate. Symptoms are determined 5-7 days after the start of treatment. The use of psychotropic drugs - psychostimulants, antidepressants, which affect all brain structures, causes persistent subfebrile condition up to 37.4-37.6 ° C. The temperature sometimes rises after taking atropine, corticosteroids, antihistamines.
Subfebrile temperature is recorded in many diseases, so the primary diagnosis is often carried out by a general practitioner. Its task is to assess all body systems, identify violations that could lead to a temperature rise. The examination includes advanced laboratory tests of blood and other biological materials, modern instrumental methods. The following have the greatest diagnostic value:
Subfebrile body temperature that persists for several days is a condition that requires immediate contact with a specialist to verify the cause. It is forbidden to take antipyretics, as they interfere with the body's fight against infection and lubricate the clinical picture. With symptoms of intoxication, you need to drink plenty of warm water (water, juices, herbal teas), food should be easily digestible and fortified. It is necessary to limit physical activity, with general malaise, it is advisable to observe bed rest.
There is a generally accepted opinion among doctors that at subfebrile temperature it is necessary to influence the causes of the condition, and the use of antipyretic drugs is considered inappropriate. Antipyretics are prescribed in exceptional cases for young children who are difficult to tolerate fever and are at risk of developing convulsive syndrome. After finding out the cause of prolonged subfebrile condition, the following groups of drugs are prescribed:
Subfebrile temperature in combination with bloody stools during exacerbation of inflammatory bowel diseases requires excision of ulcers or resection of the intestine with the formation of an anastomosis. Tumors from the lymphoid tissue are an indication for surgical intervention - radical lymphadenectomy after massive chemotherapy. With leukemia, bone marrow transplantation is successfully practiced, which allows you to restore the normal cellular composition of the blood and prevent severe infectious complications.