Under the control of the thermoregulatory center, normal people often maintain a dynamic balance in the process of heat generation and heat dissipation. When the body is under the action of heat source or the body temperature center is dysfunctional, the heat generation process increases, but the heat dissipation cannot be increased or decreased accordingly. A body temperature of ≥37.3℃ is called fever.

Infectious fever

Include fever caused by invasion of various pathogens such as bacteria, viruses, mycoplasma pneumoniae, rickettsia, fungi, spirochetes and parasites.

Noninfectious fever

1. Aseptic necrotic tissue absorption: including physical and chemical factors or mechanical injuries, such as extensive burns, internal bleeding, trauma or tissue damage after major surgery; Tissue necrosis or cell destruction, such as malignant tumor, leukemia, acute hemolysis, etc.

2. Allergy: such as rheumatic fever, serum sickness, drug fever, connective tissue disease and some malignant tumors.

3. Endocrine and metabolic diseases: for example, when hyperthyroidism occurs, the heat production increases, and the heat dissipation of patients with severe dehydration decreases, which increases the body temperature.