Thermoregulation of the body is carried out reflexively and is an indicator of general health. Normally, the temperature is 36–370 C, with daily fluctuations within 10 C on various surfaces of the body. Indicators above average occur against the background of systemic diseases, among which are:
- generalized and local infectious and inflammatory processes (tuberculosis, helminthic infestations, pyelonephritis, abscesses);
- infectious diseases (Flu, acute respiratory viral infections, acute respiratory infections, etc.)
- metabolic diseases;
- psychogenic fevers;
- malignant neoplasms;
- inflammation of connective tissue and bone marrow (vasculitis, osteomyelitis, endocarditis, Libman's disease);
- blood diseases.
In addition, disturbances in the body's thermoregulation occur due to hemorrhages and tumors of the hypothalamus, and injuries to the conduction tract.
Symptoms
The mechanism for increasing body temperature is due to the effect of exogenous and endogenous pyrogens (bacteria, metabolic products, endotoxins, immune cells) on the thermoregulation center in the anterior region of the hypothalamus. As a result, the content of a substance that changes sensitivity to heat and cold signals increases. An increase in body temperature is accompanied by chills, headache and heart pain, hyperhidrosis, suffocation, and may later develop a skin rash, nausea and vomiting.
Causes of low-grade fever
Detection of low-grade fever raises the question of what lies at the heart of the disorder before the patient and his doctor. If the symptom was preceded by a disease or long-term treatment, then the answer may be directly related to them, but there are cases when low-grade fever does not contain anything of the kind, but only incipient dysfunction. Drawing up a temperature curve, careful analysis of accompanying changes in well-being and laboratory diagnostics help identify the causes.
What diseases cause low-grade fever?
The main causes of low-grade fever usually include:
- sluggish inflammatory process - a complex, local and general pathological process resulting from damage to the cellular structures of the body or the action of a pathogenic irritant: chronic tonsillitis,
- pneumonia,
- acute and chronic hepatitis,
- pyelonephritis,
- ulcerative colitis,
- Crohn's disease;
- hyperthyroidism,
- helminthiasis,
It is noteworthy that low-grade fever of an infectious nature is characterized by:
- poor temperature tolerance,
- preservation of daily physiological temperature fluctuations,
- positive reaction to taking an antipyretic.
by :
- slight and sometimes imperceptible occurrence of elevated temperature,
- no daily fluctuations,
- lack of response to antipyretics.
When is low-grade fever safe?
Medical science knows cases of low-grade fever when it develops without any particular danger to health. There are several rare developing factors of low-grade fever as follows:
- neurosis - emotional stress, stress in personal life and at work can cause a stable increase in body temperature, for example, towards the end of the working day; if this is accompanied by general weakness and chronic fatigue, decreased performance, then the person is able to seriously think about the disease, which is completely unnecessary; at the same time, do not underestimate the existing problem; over time, it can indeed develop into psychosomatic illnesses;
- temperature tail - in a person who has suffered any infectious disease, the temperature may remain elevated even after recovery; if the illness was severe, then it can persist for up to 2 months or even six months; it is important not to ignore the presence of low-grade fever in this case, because it may be a sign of both relapse and chronicity of the process; without much panic, doctors simply recommend monitoring blood tests over time;
- pregnancy - low-grade fever sometimes becomes a companion to pregnancy, which is again explained by hormonal changes; a slight increase in body temperature in the absence of other worrying symptoms should not become a reason for panic for the expectant mother, however, one cannot turn a blind eye to this, because the temperature can indeed be of a physiological nature.
Low-grade fever during pregnancy
Low-grade fever is often reported to a woman about pregnancy, that is, in the first weeks it is quite normal. The mechanism of temperature formation in this case is subject to hormonal changes: progesterone is actively produced, affecting the temperature center in the brain, heat transfer decreases, which means the temperature rises, which is easy to notice from the basal temperature if a woman measures it during pregnancy planning.
Low-grade fever during pregnancy most often lasts during the first trimester, then gradually decreases, and sometimes even lingers. Low-grade fever in the initial stages of pregnancy is usually accompanied by mild malaise - drowsiness, nasal congestion, decreased performance, and fatigue. Such a symptom complex can easily be confused with a common cold, and therefore doctors recommend seeking advice from them in case of any ailment, so as not to miss a serious illness.
A strong increase in temperature should not be allowed, if only because the environment surrounding the baby should not overheat, this can lead to damage to its tissues or the development of defects in the central nervous system, as well as cause placental abruption or premature birth. For the woman herself, prolonged low-grade fever and especially degrees above 37.5 ° C are fraught with dilation of blood vessels, which means a decrease in blood pressure and insufficient blood supply to the placenta. If the mercury column of the thermometer has surpassed 38 degrees, then it’s time to take action.
The likelihood of developing seasonal viral diseases, the risk of ectopic pregnancy, as well as pyelonephritis, cytomegalovirus, herpes, tuberculosis, which can manifest during pregnancy, are analyzed.
Low-grade fever in a child
Low-grade fever in a child often becomes a cause for significant concern for parents. This is correct, since in young children an increase in body temperature becomes almost the only symptom of the disease; in older adults, low-grade fever accompanies characteristic and very popular diseases at their age - adenoiditis and other focal inflammations, helminthiasis, manifestations of allergies and even more dangerous diseases (oncological , blood diseases, tuberculosis, asthma).
If a child’s temperature remains in the range of 37-38 °C for 3 weeks or more, a set of diagnostic procedures is indicated:
- blood test - clinical and biochemical with determination of rheumatic tests;
- urine analysis - general, as well as cumulative samples, 24-hour urine testing, sterility analysis;
- stool analysis for worm eggs - over time;
- radiography of the paranasal sinuses;
- X-ray of the lungs;
- tuberculin tests;
- electrocardiography;
- Ultrasound of internal organs.
The test results become an indication for consultations with highly specialized physicians.
It should be noted that prolonged low-grade fever is often normal for:
- children under 1 year of age , which may be due to a reaction to the BCG vaccine,
- children from 8 to 14 years old , which may be due to the presence of intense “critical” phases of growth and development.
Diagnostics
Anamnestic data are important: duration of fever, temperature readings, concomitant symptoms, presence of chronic diseases. In case of unclear genesis and pathological condition, the following studies are prescribed for more than three weeks:
- urine and blood tests (general and biochemical);
- coagulogram;
- aspirin test;
- chest x-ray;
- electrocardiogram;
- tuberculin test;
- thermometry;
- Ultrasound of the abdominal cavity and kidneys.
Additionally, to identify the true causes of increased body temperature, a CT or MRI of the brain is performed, consultations with an ENT doctor, dentist, gynecologist, endocrinologist, immunologist, venereologist. In some cases, determination of the content of microorganisms in biological materials, laboratory diagnosis of HIV infection, and testing for malaria are indicated. To exclude tumor processes and metastases, skeletal scintigraphy, CT scan of the abdominal organs, and bone marrow puncture are performed.
Prolonged rise in temperature after COVID-19
Many patients who have recovered from COVID-19 often continue to have an increase in body temperature to 37.2 - 37.5. Why is this happening? Let's figure it out.
The thermoregulation center is located in a part of the brain called the hypothalamus.
The hypothalamus controls the processes of the endocrine system, which is closely interconnected with the most important organs for thermoregulation - the adrenal glands and the thyroid gland. Thus, when the ambient temperature drops, the release of thyroid hormones, which accelerate metabolism, increases and, as a result, heat formation increases. When the weather changes, the adrenal glands release hormones into the blood that constrict or dilate blood vessels, including those of the skin. Because of this, the level of heat transfer changes.
Physiological fluctuations in body temperature during the day can be 1-1.3 degrees. Moreover, it always increases in the evening and can be normal from 16 to 18 hours in the axillary region within the range of 37.0 - 37.2. This is due to biorhythms and physiological processes in the body (lactation, menstruation in women, reaction to stress, pain, food intake, physical activity, special climatic conditions).
Coronavirus is known to have a damaging effect on the nervous system. Those. fluctuations in body temperature are explained by direct damage to the nervous system. Recovery takes a long time, sometimes several months.
The symptom of low-grade fever is a manifestation of post-Covid syndrome, which has not yet been treated. This is a kind of asthenic syndrome that arose after an illness associated with a significant inflammatory process. Recovery may take several months.
But the nervous system can be helped to recover faster:
► Sleep 7-9 hours every night.
► If possible, arrange a “quiet hour” during the day.
► Minimize the time spent on screens of devices such as a smartphone, tablet, computer or TV.
► Get enough rest.
► Maintain the room temperature at 22 degrees, constantly ventilate for fresh air.
► Maintain water regime – circular shower, contrast shower.
► Eat a balanced and healthy diet: eat plenty of fresh fruits and vegetables, protein, no fast food, fried foods, alcohol or caffeine. It is possible to use enteral nutrition with a high content of protein and energy, for example Nutridrink Compact Protein 125 g (1 plastic bottle) per day for 3-4 weeks.
► Walk in the fresh air and have regular light physical activity (physical therapy, yoga, especially breathing practices, meditation).
► Taking vitamin D in a prophylactic dosage of 2000 IU per day, Magne B6 forte, 1 tablet 3 times per day for 1 month.
► The use of acupuncture is also recognized as evidence-based medicine as a way to recover from illnesses.
However, it is very important for people who have problems with the endocrine system to contact an endocrinologist and monitor their indicators. Additionally, you can determine the level of iron, ferritin, and vitamin D in the blood. If there are abnormalities in the tests, begin appropriate treatment. And in any case, if a low-grade fever appears and persists for a long time, you should consult a doctor to identify possible problems.
What else is important besides measuring body temperature?
People in the process of recovery, especially the elderly, should regularly monitor their pulse and blood pressure, be vigilant about cardiac complaints, and monitor oxygen levels using a pulse oximeter. Normal oxygen saturation is between 96 and 100% and should not fall below 88% during exercise. Therefore, it is important to measure saturation before, during and after exercise.
If after suffering a coronavirus infection you do not feel the same as before, then the All Medicine Clinic has special rehabilitation programs after COVID-19 that will help improve your well-being!
You can find out more by phone or by following the links:
Outpatient rehabilitation program at the All Medicine Clinic
