Pediatric fever is a common and frequent symptom, and there are many causes of fever. Common causes can be divided into infectious fever: caused by various pathogens such as bacteria, viruses, mycoplasma, pinworms, etc.; non-infectious fever: such as massive blood loss, dehydration, endocrine abnormalities, immune response, tissue destruction, necrotic tissue absorption and heat dissipation dysfunction, etc. can cause fever. The younger the child is, the worse the thermoregulatory function is, so the body temperature can easily fluctuate and cause fever. It can be said that fever is the clinical manifestation of many diseases with the same symptoms in children. However, fever is the first symptom of many diseases, so do not rush to reduce the fever for your child before a clear diagnosis is made. If necessary, go to the hospital for treatment. Measurement of body temperature 1, exercise, prolonged sun exposure, wearing too much clothing and other factors will raise the body temperature, if these phenomena, it is appropriate to remove these factors and rest 15 to 30 minutes before measuring the body temperature. 2, electronic thermometer is suitable for general family use, if the use of mercury thermometer, special attention must be paid to avoid the risk of mercury thermometer breakage accident. 3, mercury thermometer measurement time: oral temperature: 2 to 5 minutes axillary temperature: 3 to 10 minutes anal temperature: 1 to 3 minutes 4, anal temperature: anal temperature measurement value is closer to the body’s true central body temperature. Measurement method: soapy water or alcohol to clean the thermometer, rinse with cold water (do not use hot water), rub a little Vaseline and other lubricants on the end. The child should be placed in a prone position with the abdomen facing downwards, on the adult’s lap or on the bed, with one hand holding the child’s lower back above the buttocks, and the other hand sticking the thermometer into the anal opening at a depth of about 0.5 to 1 inch (about 1.5 to 2.5 centimeters), without going too deep. The electronic thermometer should be left to beep for about 1 minute to be read, while other thermometers should be left to be read after 1 to 3 minutes. 5, oral temperature: the average measurement value is lower than the central body temperature of about 0.5OC. Children over 5 years old can be measured in this way, but the mercury oral thermometer is prohibited to avoid the accident of oral thermometer rupture. Hot or cold water should not be consumed within 15 to 30 minutes before the measurement to avoid measurement errors. Measurement method: Clean the thermometer with soapy water or alcohol and rinse it with cold water (do not use hot water). Turn on the electronic thermometer switch, place the inductive end under the child’s tongue and leave it for about 1 minute, the thermometer can be read after the beeping sound. 6, ear temperature: infants under three months ear temperature and the correlation between the central body temperature is not good, it is not recommended to use. 7.Axillary temperature: The average measurement value is about 0.8OC lower than the central body temperature. Newborns who are not suitable for measuring body temperature by anal temperature and ear temperature can consider using this method to measure body temperature, or measuring the back temperature with an axillary thermometer. 8, skin surface temperature: in the forehead to measure the skin surface temperature (including forehead temperature gun) or infrared measurement of skin surface temperature, are underestimated the phenomenon of central body temperature, is not recommended. The method of touching the skin to determine whether there is a fever, the accuracy is extremely poor. Definition of fever 1. The definition of fever is a central body temperature ≥ 38℃. 2. When the central body temperature is between 37.5℃ and 38℃, it can be normal or low grade fever depending on the change of individual’s basal body temperature and environmental temperature, and it is necessary to refer to the body temperature measured before and after and other clinical phenomena to determine whether there is fever. The mechanism of fever 1, the locus of body temperature: the thermoregulatory center is located in the anterior part of the inferior optic thalamus, where there is a theoretical locus of body temperature, and various physiological reactions of the body will maintain a constant body temperature with the high or low locus of body temperature. 2.Fever: The inflammatory response is caused by the secretion of various cytokines by immune system cells such as macrophages, which act on the inferior optic thalamus to cause a rise in the body temperature locus. 3.Hypothermia: The body temperature locus does not rise, but the central body temperature exceeds 38℃, for example, wearing too many clothes in a hot environment, wrapping the baby too tightly, poor heat dissipation, exercising, taking a sauna, heat stroke, etc. Physiological reactions to fever 1. When the body temperature locus rises, the body feels cold, and when the locus rises strongly, there will be chills to increase heat, and the peripheral blood vessels contract to reduce heat loss, so there will be cold extremities. 2. The body temperature locus of hypothermia does not change, and the body reacts by feeling too hot, and vasodilation occurs in the peripheral blood vessels to dissipate heat. The effect of fever on the human body 1, some immunological studies show that a moderate fever can enhance the effectiveness of the immune system, there are also studies that show that antipyretic drugs may suppress the immune response, but slow down the speed of the removal of respiratory viruses and increase the mortality rate of sepsis in animals, so a moderate fever is biologically beneficial. 2. Fever needs to generate excess heat, so it increases oxygen consumption, carbon dioxide production and cardiac output, which can increase the heart burden of patients with heart disease and chronic anemia, increase the lung burden of patients with chronic lung disease, and worsen the metabolic abnormalities of patients with diabetes and inborn metabolic abnormalities. 3. Some children between 3 months and 6 years of age may have fever that leads to febrile cramps. 4.Unless the disease directly affects the brain such as encephalitis or meningitis, fever below 41℃ will not cause direct damage to the patient’s brain. When do you need to reduce fever? 1. Any high body temperature caused by non-inflammatory reactions can be reduced. 2. Except for the special cases listed in the next article, fever does not necessarily require the use of antipyretics, especially when the body temperature does not exceed 39°C or more. 3. For patients with fever in the following cases, it is recommended to reduce the fever when the body temperature exceeds 38°C: ① chronic lung disease, adult respiratory distress syndrome; ② heart disease with heart failure or cyanotic heart disease; ③ chronic anemia; ④ diabetes mellitus and other metabolic abnormalities; ⑤ febrile spasms neurological diseases with a history or seizures; ⑥ other people with discomfort due to fever.