Fever can be understood as a systemic alarm triggered by the invasion of a foreign pathogen into the body; the pathogen itself and the resulting inflammatory exudates and other macromolecules are the first step in triggering the alarm, that is, the exogenous pyrogen. Since these macromolecules cannot enter the blood-brain barrier and affect the temperature center, they can only act on neutrophils and mononuclear phagocytes to produce a series of cytokines: interleukin family, interferon, tumor necrosis factor, etc., which is the second step of the alarm – endogenous pyrogens. It is these endogenous pyrogens that act on the hypothalamic thermoregulatory center and cause fever.
Non-pyrogenic fevers do not have this series of changes and are mostly caused by heat production > heat dissipation; i.e., increased heat production: hyperthyroidism, persistent epilepsy; or decreased heat dissipation: atropine poisoning, massive water loss, blood loss, etc., as well as fever due to direct damage to the temperature center.
Do glucocorticoids have an antipyretic effect? According to pharmacology textbooks, glucocorticoids have antipyretic effects by the following mechanisms.
(1) Glucocorticoids inhibit the release of cytokines and inflammatory transmitters (TNFα, IL-6, etc.), resulting in a reduction of endogenous pyrogenic sources and inhibition of hypothalamic pyrogenic responses. It has obvious cooling and anti-inflammatory effects.
(2) In addition, its powerful anti-inflammatory effect also leads to a significant decrease in leukocyte infiltration and phagocytosis and increases the stability of lysosomes, which to some extent also has an effect on the reduction of body temperature.
(3) Directly acting on the hypothalamic thermoregulatory center, reducing its sensitivity to thermogenic agents and causing a rapid decrease in body temperature to normal.
(4) Reduces the sensitivity of peripheral thermogenic effectors, resulting in a decrease in heat production and facilitating antipyretic.
How are glucocorticoids used to reduce fever in clinical practice?
Therefore, theoretically speaking, glucocorticoids do have an antipyretic effect on pyogenic fever, while for the application of non-pyrogenic fever, there is a lack of certain theoretical basis.
1, severe infection: the application of glucocorticoids in the clinic also follows the above theory: that is, for patients with severe infections: such as severe meningitis, sepsis, septic shock, etc.; the application of glucocorticoids to reduce fever is more frequent.
2.Autoimmune diseases: In addition, for fever caused by some autoimmune diseases, such as rheumatic fever, systemic lupus erythematosus, rheumatoid arthritis, etc., they can also be applied as appropriate.
3.Continued hyperthermia: For patients with persistent hyperthermia in hematological system diseases and advanced cancer, when other antipyretic drugs are ineffective, glucocorticoids, as a “killer drug”, often have good effects as well, bringing the body temperature down to normal quickly.
4. Central fever: For patients with central hyperthermia, when the application of physical cooling is ineffective, glucocorticoids can also be considered to lower the temperature, but at this time, the main focus is on regulating the body function.
Why do the guidelines say no?
However, the Guidelines for the Clinical Application of Glucocorticoids issued by the Chinese Medical Association in 2011 specifically states that glucocorticoids should not be used solely for the purpose of reducing fever, especially when fever is caused by infectious diseases. The guidelines of the Chinese Medical Association’s Pediatrics Branch also state: In view of the lack of evidence and literature on the use of glucocorticoids as antipyretic agents, the use of glucocorticoids as antipyretic agents for fever reduction in children is opposed. The 2nd edition of the HCH textbook of pharmacology also states that they should not be misused until the cause of the fever is clearly diagnosed, as this may mask the symptoms and make the diagnosis difficult.
The major guidelines indicate this, and for good reason.
And because the significant antipyretic effect of glucocorticoids is actually a double-edged sword: for some diseases where the diagnosis is not yet clear, rapid cooling may mask the primary cause and delay treatment. For children with glucocorticoids, the rapid decrease in body temperature may lead to shortness of breath, fainting and other symptoms of deficiency. Due to the immunosuppressive function of glucocorticoids, using them to lower body temperature may reduce the immune defense response, aggravate the infection and give an opportunity for bacteria, viruses and other pathogens to take advantage of the situation.
Therefore, although glucocorticosteroids are effective in reducing fever, they should not be abused.
Individual physicians are eager to reduce fever quickly for a while and apply them to patients with non-pyrogenic fever or upper respiratory tract infections. Behind the joy of bringing down the body temperature in a short period of time, there are huge hidden dangers for future treatment!
How can they be used to reduce fever safely?
Glucocorticosteroids are rapid in relieving fever and last for a long time, and their correct application can temporarily reduce fever and other symptoms. Although they have more side effects, they are used clinically to reduce fever in small doses and for short periods of time, and have no significant effect on the human body. For patients with acute infectious hyperthermia who do not respond well to antipyretic and anti-inflammatory drugs, glucocorticoids can be used, if necessary, on the basis of adequate and effective antibacterial drug treatment after laboratory tests and various test specimens are taken.