There are few things that frighten a person as much as the unknown. A child's slightly elevated body temperature (from 37°C to 38°C) for a long time is one of those phenomena that instills panic in parents. How dangerous is low-grade fever? What is he talking about? How to treat it and is it necessary to do it? Lots of questions! Let's try to figure them out.
Since childhood, we all know that normal body temperature is 36.6 °C. However, it turns out that this is just a myth. Indeed, in fact, this indicator for the same person can change repeatedly over different periods. The thermometer can give different numbers within one month even with full health.
Temperature: where did you start galloping to?
Temperature changes are typical mainly for girls - their temperature usually rises slightly during ovulation and normalizes with the onset of menstruation. Regardless of a person's gender, temperature fluctuations can occur throughout the day. In the morning, immediately after waking up, the temperature is minimal, and in the evening it usually rises by half a degree. Stress, eating, physical activity, taking a bath or drinking hot (and intoxicating) drinks, being on the beach, wearing too warm clothes, emotional outburst and much more can cause a slight temperature jump. And there are also people for whom the normal mark on the thermometer is not 36.6 °C, but 37 °C or even a little higher. But if a child’s usual body temperature has always been normal, and suddenly measurements taken with the same thermometer over a long period of time and at different times of the day begin to show higher numbers, parents usually begin to get nervous.
What is the normal human body temperature?
A normal temperature for a person is considered to be between 35.5 and 37.4 degrees inclusive, that is, 37 is not a fever, and 36 is not a loss of strength. This is natural: during sleep, metabolic processes slow down and body temperature decreases, and while awake, especially during physical and emotional stress, body temperature rises. Therefore, morning temperatures are usually lower than afternoon or evening temperatures. Also, body temperature depends on the method and place of its measurement, the gender of the person measuring it, his age and condition. And for women - depending on the phase of the cycle or pregnancy. A child’s body temperature is more labile and depends to a greater extent on the ambient temperature and the state of the body. In addition, each person has his own individual norms, such as, for example, there are adapted norms for heart rate and blood pressure.
All these features should be taken into account when drawing up a temperature curve - a graph with which you can determine whether a person really has a low-grade fever. It should also be remembered that different parts of the human body have different temperatures. And if the temperature in the armpit is 36.6 °C, then in the mouth it will be about 37 °C, and in the rectum even higher - 37.5 °C.
To correctly draw up a schedule, it is necessary to keep a diary for several days and measure the temperature at different points - under the arm, in the mouth, rectally, at the same time and under the same conditions (immediately after sleep, before meals, after meals , before and after taking a bath, etc.). Then, based on the diary, a graph is drawn up that clearly demonstrates at what time of day the temperature rises. We can talk about true low-grade fever when the temperature rises at all measurement points.
Diseases that can cause low-grade fever
Low-grade fever differs from infectious fever in that it lasts for a long time and is most often asymptomatic. In acute infectious diseases, the temperature rises sharply, is accompanied by symptoms of intoxication (bone aches, headache) and is accompanied by active complaints (catarrhal phenomena - runny nose, sore throat, cough, etc.) and decreases to normal after recovery. Low-grade fever is often impossible to bring down even with antipyretic drugs.
The so-called temperature center located in the hypothalamus, a region of the brain, is responsible for thermoregulation in the body. It receives information from receptors, and depending on it, either triggers cooling or warming mechanisms. Hormones also take part in these processes, the failure of which can also be the cause of low-grade fever. But it is important to understand that if body temperature rises, it means:
- foreign proteins have appeared in the blood and the body reacts to their appearance (this is what happens with infections - bacterial and viral) and inflammation - this temperature is called fever;
- some other malfunction occurred in the body that affected the functioning of the temperature center (for example, hormonal levels changed);
- there was some direct impact on the temperature center (traumatic brain injury, brain tumor).
Acute viral infections cannot cause long-term low-grade fever, and the persistence of an elevated body temperature signals the addition of a secondary infection, often bacterial, i.e. about the complication. But sluggish inflammatory, bacterial or viral processes can increase body temperature to average values. Often, such “chronic” temperature can be caused by diseases of the urinary system (chronic pyelonephritis, indolent cystitis), diseases of the gastrointestinal tract (pancreatitis, cholecystitis, colitis), and inflammatory processes of the genitourinary system. Most likely, other unexpressed symptoms will be observed, depending on where the inflammation is localized - pain, weakness, loss of appetite, bowel dysfunction, nausea, cloudy urine, changes in stool, etc. However, this is often due to If the inflammation is sluggish, a person may not notice a deterioration in health for a long time or may not pay attention to it, and temperature in this case will be the only symptom.
In acute viral diseases (measles, rubella, chickenpox, influenza), the exception is the so-called “temperature tails” - conditions when a low temperature continues to persist for a long time after recovery. This temperature returns to normal within a few weeks (sometimes it lasts up to six months), but other possible post-infectious complications must be excluded.
Separately, it is necessary to say about viral diseases of herpetic origin, which cause long-term low-grade fever. First of all, these are the Epstein-Barr virus, which can cause “chronic fatigue syndrome,” cytomegalovirus, which causes infectious mononucleosis, herpes viruses types 1 and 2, and herpes virus type 6. All of them come to us “under the guise” of acute viral diseases, but they remain in the body for a long time, and it is not always easy to recognize them.
In addition, infectious diseases such as toxoplasmosis, tuberculosis, viral hepatitis, and HIV can cause prolonged low temperature. At the same time, the clinical symptoms of these dangerous diseases can be erased, that is, in addition to fever, weakness, loss of appetite, increased fatigue and sweating, the patient may no longer notice anything. Infection with helminthic infestations can also increase the temperature for a long time to subfebrile levels. And although this is not the most common cause of fever, it cannot be ruled out, especially if the patient experiences intestinal discomfort and loses weight.
With cancer, foreign proteins also appear in the human body, which he tries to get rid of. That is why prolonged low-grade fever can be a sign of cancer, sometimes the first and for a long time the only one.
Autoimmune disorders, as a result of which the body begins to perceive its own healthy cells as foreign proteins and destroy them, can also be accompanied by prolonged low-grade fever. The most common of them are rheumatoid arthritis, systemic lupus erythematosus, and Crohn's disease. Symptoms of autoimmune diseases can vary depending on which tissues are destroyed. With arthritis, the patient may experience pain in the joints, with Crohn's disease - abdominal pain, problems with stool, even the appearance of blood in the stool, with systemic lupus erythematosus - joint and muscle pain, in addition, this disease is characterized by the appearance of a specific rash.
Another group of pathologies that can cause fever is associated with hormonal changes. Most often this occurs with diseases of the thyroid gland, especially hyperthyroidism, with excessive production of hormones by the gland. In this case, the metabolism accelerates, the temperature rises to low values (most often - up to 37.5). The patient may also experience weight loss, shortness of breath, sweating, irritability, tremor, and tachycardia. In addition, hormonal changes can increase body temperature in adolescents, women in menopause, as well as in pregnant and breastfeeding women, especially at the very beginning of lactation (during lactation, body temperature in the armpit area is higher than normal, so it is measured more often in the elbow crease) . As for pregnancy, sometimes a rise in temperature is the first sign that a woman is expecting a baby. It can appear even before the delay of menstruation and before other symptoms - nausea, dizziness, swelling of the mammary glands. This is a normal variant that does not require treatment from doctors.
Brain tumors, including benign ones, as well as traumatic brain injuries affect the functioning of the temperature center located in the brain, so in these conditions a person may also experience prolonged low-grade fever. However, often rises in temperature can be caused by psychogenic causes - stress, neuroses, depression. In medicine, there are also such concepts as “thermoneurosis” and “low-grade fever of unknown etiology.” These diagnoses are often caused by disturbances in the patient’s emotional state, but more often this is a diagnosis of exclusion and can only be discussed after a full examination and exclusion of other pathologies.
Where do the legs of the “tail” come from?
Everyone knows that elevated body temperature indicates the presence of an inflammatory process in the body or the presence of infection. But sometimes the thermometer readings remain above normal even after recovery. Moreover, this can continue for several months (from 2 to 6). This is often how post-viral asthenia syndrome is expressed. Doctors in this case use the term “temperature tail”. A slightly elevated (subfebrile) temperature caused by the consequences of an infection is not accompanied by changes in tests and goes away on its own. However, here lies the danger of confusing asthenia with incomplete recovery, when an increase in temperature indicates that the disease, which had subsided for a while, began to develop anew. In addition, prolonged low-grade fever may indicate that the child has dangerous diseases. Therefore, it is imperative to understand where the legs of the “temperature tail” grow from.
Temperature 37.1 °C in a child
At a temperature of 37.1 °C in a child, if there are no other symptoms of health problems, in most cases natural causes can be assumed: excessively warm clothes, a hot room, active games, etc.1
But even if such a temperature is accompanied by a runny nose, loss of appetite and other signs of the onset of upper respiratory tract diseases, drastic measures should not be taken. With ARVI and influenza, an increase in body temperature can be considered a positive sign - this means that the immune system has been activated and has begun to fight pathogens1,4.
Therefore, all you need to do is consult a doctor and regularly measure your child’s temperature. And only when it rises to 38 °C should antipyretic drugs intended for children of a certain age group be taken1,4.
Causes of fever: method of elimination
Urine and blood tests, lung X-rays, and ultrasound will help you understand why your temperature is rising.
First of all, you need to exclude all suspicions of inflammatory, infectious and other serious diseases (tuberculosis, thyrotoxicosis, iron deficiency anemia, chronic infectious or autoimmune diseases, tumors). First, you need to contact a therapist who will draw up an individual examination plan. As a rule, in the presence of an organic cause of low-grade fever, an increase in temperature is combined with other characteristic symptoms: pain in different parts of the body, weight loss, lethargy, increased fatigue, sweating. When palpated, an enlarged spleen or lymph nodes may be detected. Usually, finding out the reasons for the appearance of low-grade fever begins with a general and biochemical analysis of urine and blood, X-ray of the lungs, and ultrasound of the internal organs. Then, if necessary, more detailed studies are added - for example, blood tests for rheumatoid factor or thyroid hormones.
“Hot” guys and girls Most parents whose children constantly have a fever, worrying about them, create hothouse conditions for them: they are exempted from physical education and visiting sports clubs, they are unnecessarily bundled up on the street, they are not allowed to run and jump, they are protected from their peers, and sometimes even transferred to home schooling. True, such measures do not help, but rather prevent these already anxious and suspicious children from getting rid of thermoneurosis. Therefore, it is better if the parents of such children and adolescents stop strangling them with excessive care, and begin to harden and strengthen them. Children with impaired thermoregulation need:
- correct daily routine;
- regular nutritious meals with an abundance of fresh vegetables and fruits;
- taking vitamins;
- sufficient exposure to fresh air;
- physical education classes (except for team games);
- hardening (the method is effective with regular rather than one-time use).
Sometimes a temperature above normal can accompany the presence of a source of chronic infection in the body (for example, tonsillitis, sinusitis, inflammation of the appendages and even caries). But in practice, this cause of low-grade fever is quite rare. However, if a child suffers from one of the listed diseases, he must be treated, even if the disease is not accompanied by fever.
Yes, this is neurosis!
Every fourth schoolchild from 10 to 15 years old has an elevated temperature regularly
If examinations have shown that there is order on all fronts, it seems that you can calm down, deciding that this is the individual nature of the child. But this is true, but not true.
Low-grade fever is not uncommon; according to statistics, almost every fourth modern child aged 10 to 15 years suffers from this. Typically, such children are somewhat withdrawn and slow, apathetic or, conversely, anxious and irritable. Where does their elevated temperature come from? It turns out that it appears not at all because their body accumulates too much heat, but because it does not transfer it well to the environment. Disorder of the thermoregulation system at the physical level can be explained by spasm of superficial vessels located in the skin of the upper and lower extremities. Also, in the body of children with long-term fever, disruptions in the endocrine system can occur (their adrenal cortex and metabolism are often disrupted). Doctors consider this condition as a manifestation of vegetative-vascular dystonia syndrome, and even gave it a name - thermoneurosis. And although this is not a disease in its pure form, because no organic changes occur, it is still not the norm, since a prolonged elevated temperature is stress for the body. Therefore, this condition must be treated. But, of course, not antibiotics or antipyretics - they are not only not harmless, but in this case they are also not effective. Medicines for low-grade fever are generally rarely prescribed. More often, neurologists recommend massage and acupuncture (to normalize the tone of peripheral vessels), as well as herbal medicine and homeopathy. Psychotherapeutic treatment often has a positive effect.
