Given that the prefix sub from the Latin language means "about, under", and febris is translated as "fever", it is easy to guess what it is - subfebrile body temperature. We are talking about an overestimated indicator of the thermal state of the body. Further - in more detail about why the subfebrile temperature is kept, whether it is necessary to knock it down and what tests will be taken to find out the cause of the condition, close to febrile.
In the body of every he althy person, there are “automatic settings” for thermoregulation. An indicator that is within 36.6 ° C is considered normal. Minor physiological changes by 0.5 °C are allowed, both up and down. If the thermometer rises to 38-39 ° C, they speak of a febrile temperature, but if it is above 39 ° C, it is a pyretic one.
In the understanding of most people, low-grade body temperature is 37-37.5 ° C, withIn this case, doctors point to a higher rate - at 37.5-38 ° C. Domestic doctors do not consider such a thermal regime of the body to be feverish. Therefore, at subfebrile temperature, interventions to reduce it are not allowed.
Main reasons
Any increase in body temperature is a consequence of disturbances in the flowing limbic-hypothalamic-reticular process. In simple terms, the thermal regime is set by the hypothalamus, which works like a thermostat. Exposure to external or internal pyrogens provokes the release of inflammatory mediators that affect neurons responsible for thermoregulation. Pyrogens are located in the hypothalamus, which, in turn, responds systemically, setting the body to a new level of heat output.
The causes of subfebrile temperature are various pathologies, infectious diseases. The list of ailments accompanied by this symptom is very extensive, as it includes several groups:
- Infectious diseases - influenza, Epstein-Barr virus, SARS, tuberculosis, mononucleosis, cytomegalovirus, gastroenterocolitis, Lyme disease, AIDS, syphilis, etc.
- Parasitic pathologies - giardiasis, helminthiasis, leishmaniasis, toxoplasmosis.
- Inflammatory foci in the body - chronic diseases of the upper respiratory tract and nasopharynx, soft tissue damage (furunculosis, abscess), focal pneumonia, pancreatitis, cystitis, pyelonephritis, etc.
- Disturbances in the thyroid gland - hyper- and hypothyroidism, thyrotoxicosis.
- Autoimmune diseases - rheumatoid arthritis, systemic lupus erythematosus, Bechterew's disease, Crohn's disease, congenital pathologies.
In addition, low-grade fever may occur due to the destruction of red blood cells in stroke, acute heart attack, compression syndrome. Doctors call this phenomenon hemolysis - it causes tissue necrosis, to which the body reacts with an increase in heat transfer. The bar on the thermometer can rise with a severe allergic reaction, regardless of its etiology.
Subfebrile condition as a sign of a cold
Mild fever accompanies a variety of diseases that appear without symptoms. Subfebrile temperature is, in fact, their only sign that occurs at the initial stage of development. In addition to the "near-febrile" condition, the disease may not declare itself in any other way, which is the main reason for the delayed diagnosis.
Regardless of the causes of subfebrile temperature, it is characterized by periodic or constant presence. Sometimes the thermometer readings can rise for a short time, but more often, patients have permanent low-grade fever in the range of 37-38 ° C.
If we consider a slight fever in a person as a sign of a particular pathology, then if it is present with a cough, nasal congestion, headache, you can suspect a cold, SARS or flu. Protracted low-grade fever sometimes indicates focal pneumonia, pulmonary tuberculosis. Mostly throughout the daybody temperature in patients may be within the normal range, but in the second half of the day, in the evening it rises to pre-febrile values. Persistent low-grade fever, which manifests itself every 1-2 days, is a typical manifestation of malarial plasmodium.
By the way, fever is often considered a residual phenomenon of the transferred ARVI, a post-infection syndrome. The thermal regime stabilizes, as a rule, after the final recovery, strengthening of immunity and drug withdrawal.
Increased temperature with inflammation
With bronchitis, subfebrile temperature is kept within 37.7 °C. Approximately to the same mark, the thermometer rises with pneumonia. The characteristic subfebrile temperature in tonsillitis is 37-37.5 °C. Sufficiently long slight heat may remain after a sore throat. But even with such diseases of the respiratory tract, subfebrile condition lasting more than 10 days should alert. If an infectious-inflammatory pathology acquires a chronic decompensated course with frequent exacerbations, the tissues of the heart and kidneys begin to undergo intoxication, as a result of which infective endocarditis, glomerulonephritis, and inflammation of the bile ducts may develop.
Against the background of the progression of diseases of the genitourinary system, a slight increase in body temperature is a very common symptom. Subfebrile temperature with cystitis, like its other signs, disappears after antibacterial drug treatment. But if the pre-febrile state does not disappear after a course of therapy, you canmake an assumption that the inflammatory process managed to affect the kidneys. It should be borne in mind that a stable subfebrile temperature, the values of which do not change throughout the day, refers to the symptoms of infective endocarditis.
Subfebrile condition can occur after the removal of a molar tooth or any surgical intervention. Among the reasons for the increase in temperature, the leading position belongs to the reaction of the body to a damaging factor or a bacterial infection.
Another possible cause of an altered heat index is a herpes virus infection or hepatitis C. During the day, body temperature can remain within the normal range, and at night it can rise to 37.2-37.5 °C.
Incurable diseases
Subfebrile temperature is one of the symptoms of blood diseases. Most often, this symptom is observed in lymphocytic leukemia, various forms of lymphoma, lymphosarcoma, myeloid leukemia, and kidney tumors. Constant weakness and elevated body temperature for several months may indicate an early stage of the malignant process. It is worth noting that patients who have undergone a course of radio- and chemotherapy also experience mild fever over a long period. The reason for this is a weakened immune system.
As you know, the human immunodeficiency virus acts slowly, so an increase in body temperature in a diagnosed HIV infection to 37.7-38 ° C can be perceived as an indicator of a general weakening of the body's defenses. For these patients, anyinfection can bring serious complications or be fatal.
Vegetovascular dystonia
Based on the physiology of our body, it is important to understand that normal thermoregulation requires the full functioning of all internal organs, glands and blood vessels, which are coordinated by the autonomic nervous system. It is she who ensures the constancy of the internal environment and the adaptability of the body to the effects of external factors. Even minor disturbances in the functioning of the autonomic system can lead to a subfebrile increase in body temperature.
With vegetovascular dystonia, in addition to unreasonable temperature jumps, other neurocirculatory disorders (for example, changes in blood pressure, increased or slow heartbeat), the development of muscle hypotension and excessive sweating are also possible.
Until recently, subfebrile temperature in medicine remained a symptom of an unexplained etiology. To date, it is already known for sure that mild fever can occur due to a malfunction in thermoregulation against the background of congenital or acquired diencephalic syndrome. Depending on the reasons for the development of vegetative-vascular dystonia, several types of it are distinguished in medicine:
- genetic;
- infectious-allergic;
- traumatic;
- psychogenic.
Anemia
Low hemoglobin and subfebrile thermometer values are in close biochemical relationship with each other. Iron deficiency anemia can lead toto a violation of the production of hemoglobin and a decrease in its concentration in red blood cells that transport oxygen to the cells. Lack of oxygen, in turn, causes disturbances in metabolic processes. That is why, in addition to other signs of iron deficiency, subfebrile condition is quite often noted. Persons under the age of 18 are most prone to developing anemia. In parallel with the increase in body temperature, their appetite decreases, there is a slight weight loss.
However, not only iron deficiency can lead to a decrease in hemoglobin levels in the blood. The cause of oxygen starvation of cells is often anemia caused by a lack of folic acid, cyanocobalamin and other B vitamins. These trace elements are responsible for the synthesis of hemoglobin in the bone marrow. This type of anemia is called precision anemia, and it is also accompanied by low-grade fever. If anemia is not treated, atrophic lesions of the mucous membranes of the gastrointestinal tract may develop.
Female subfebrile condition
If none of the above factors is the cause of the patient's fever, you should pay attention to her menstrual cycle. The temperature in women often rises to subfebrile values before the approaching "critical days" and is one of the variants of the norm for the course of premenstrual syndrome. It should be noted that periodic and minor changes in thermoregulation should not cause concern. An increase in performance of no more than 0.5 degrees is usually associated with the active production of female hormones and products.their metabolism.
In addition, mild heat and hot flashes follow women during menopause. These changes in well-being are also associated with hormonal changes.
In pregnant women, the cause of subfebrile temperature no more than 37.5 ° C is an increase in the concentration of progesterone in the blood, produced by the corpus luteum of the ovaries, and its effect on the hypothalamus. This symptom can occur in the first trimester. At a later date, these indicators will stabilize.
If a pregnant woman constantly has subfebrile temperature, it is necessary to exclude the manifestation of TORCH infections, which include toxoplasmosis, hepatitis B, rubella, cytomegalovirus and herpes. TORCH infections pose a threat to the fetus - it is these diseases, if the mother becomes infected with them during pregnancy, that can lead to the development of congenital pathologies. If the infection was present in the woman's body at the time of conception, it cannot be ruled out that it was activated against the background of weakened immunity. Therefore, pregnant women need to be vigilant, monitoring their body temperature daily, and in case of persistent low-grade fever, undergo an appropriate examination.
Why occurs in childhood
Subfebrile temperature in a child is most often a symptom of an infection of the upper respiratory tract, nasopharynx and ears. In babies under two years of age, teething and routine vaccinations may be the cause of this condition. According to many pediatricians, unstable thermoregulation in children under five years of age is notshould cause special worries if it is not accompanied by any additional symptoms, since at an early age an increase in indicators is easily provoked by physical activity, overheating, hypothermia. Much less often, subfebrile temperature in a child is caused by diencephalic syndrome, a congenital malfunction of the hypothalamus.
The reason for the change in thermoregulation in adolescence is considered a hormonal imbalance that arose against the background of puberty. At the same time, the possibility of pathological problems cannot be ignored. In adolescents, subfebrile temperature can serve as a symptom of blood cancer, thyroid diseases, autoimmune diseases. Children under 16 are at risk for juvenile rheumatoid arthritis and systemic lupus erythematosus, both difficult to treat and accompanied by fever.
Can low-grade fever be a side effect of long-term medication? This question is often asked to children's specialists, but it is unlikely that it will be possible to answer it unambiguously. The substances of individual medications are indeed capable of influencing thermoregulation, among them atropine, antibiotics, diuretics, anticonvulsants, antipsychotic drugs. For example, with prolonged antibiotic therapy, the immune system is seriously affected, which is indicated by an increase in body temperature. But each organism reacts to drugs differently, therefore, to generalize and declare with one hundred percent certainty about the effect of drugson temperature readings would be wrong.
How to measure the temperature of a child
Children's temperature should not be taken:
- immediately after waking up;
- after eating;
- after intense physical activity;
- when crying, tantrums, agitated.
Indicators may be overestimated for natural physiological reasons. During rest, the temperature may drop. A slight decrease in the column on the thermometer is also possible if the child has not eaten for a long time. To measure the temperature, it is necessary to wipe the armpit dry. The thermometer should be firmly clamped and held for at least 10 minutes.
Diagnosis
With a problem such as subfebrile condition, you can contact one of these doctors:
- TB doctor;
- family doctor;
- general practitioner;
- infectionist.
But you need to understand that none of the experts will be able to say that finding out the cause of subfebrile temperature is the simplest task. Making a correct diagnosis with this symptom will require a comprehensive examination, a series of laboratory tests.
When subfebrile temperature in the first place will require an assessment of the so-called temperature curve. To compile it, the patient must use the temperature measurements that he takes every day once every 12 hours. For example, at 9.00 in the morning and at 21.00 in the evening. Measurements are carried out for a month, the results will be analyzed by the attending physician. If aspecialist to make sure that subfebrile condition persists, the patient will have to consult narrow-profile doctors:
- otolaryngologist;
- cardiologist;
- TB doctor;
- endocrinologist;
- dentist;
- oncologist.
When subfebrile temperature, the patient must be given a referral for a blood test. If all indicators are normal, the examination is continued. In addition to the general analysis, the patient will have to undergo a number of other blood tests:
- for sexually transmitted diseases (syphilis, HIV), viral hepatitis B and C;
- on TORCH infection;
- for rheumatoid factor;
- on thyroid hormones;
- for tumor markers.
If these results do not give an answer to your question, you will also have to pass a urine test, a fecal test for worm eggs and a bacteriological culture of sputum for tuberculosis.
Treatment
It is worth noting right away that it is not necessary to bring down the subfebrile temperature. If in this situation the doctor prescribes the intake of antipyretic drugs, it remains only to conclude that he is incompetent. At a low temperature, there is no need to take Aspirin, Paracetamol or Ibuprofen tablets, despite the fact that low-grade fever has been observed for a long time.
It is not necessary to bring down subfebrile temperature with drugs. All you need to do in this case is to seek medical help from qualified doctors. With absenceadditional symptoms and complaints of deterioration in well-being, there is no need to treat subfebrile temperature. Prescribing the correct therapy is almost impossible if the etiology of this condition remains unclear.
For prevention
Literally a hundred years ago, low-grade fever was called a "general malaise" and it was advised to treat it with a balanced diet, proper rest, avoidance of stress and walks in the fresh air. And as strange as it may sound, for many, these recommendations were not useless.
Today, the treatment of subfebrile temperature depends solely on the pathogenesis of the disease. If the change in thermoregulation occurs frequently or is permanent, a doctor should be consulted without delay. Especially if there are no other symptoms by which the disease could be recognized.
In some cases, even after undergoing a comprehensive examination, it is still not possible to determine the cause of subfebrile fever. Such patients need to pay close attention to their own he alth and the state of the immune system. To bring thermoregulatory processes back to normal, you need:
- Do not delay the treatment of foci of infection in the body and the diseases they provoke.
- Avoid stressful situations and worries.
- Minimize the consumption of unhe althy foods.
- Quit alcohol and smoking.
- To fully relax and observe the daily routine.
- Get moderateexercise and walk in the fresh air.
