2022-06-06

Can The Fever Be Reduced To 38.5 ℃ With Medicines?

Normal range of body temperature

Fever means that the body temperature rises beyond the normal range under the action of a pyrogenic source or when the function of the thermoregulatory center is caused by various reasons. The normal range is generally 36 to 37 °C, and the fluctuation does not exceed 1 °C.

There is no mention of temperature differences between adults and children in Diagnostics (8th Edition). However, women's body temperature is slightly higher before menstruation and during pregnancy, and the body temperature is slightly lower in the elderly due to low metabolic rate. Measurements may vary slightly depending on the method.

Diagnostics (8th edition) states that the normal value of the axillary test is 36-37°C, the normal value of the oral test is 36.3-37.2°C, and the normal value of the anus test is 36.5-37.7°C.

How is fever graded?

Based on oral temperature, fever can be divided into 4 grades:

Low heat: 37.3-38°C, medium heat: 38.1-39°C, high heat: 39.1-41°C, ultra-high heat: above 41°C.

At the same time, the 2016 Italian "SIP Guidelines: Management of Fever in Children" pointed out that it is recommended that children under 4 weeks of age should use a digital thermometer to measure axillary temperature; if they are ≥ 4 weeks old, use a digital thermometer or infrared thermometer to measure axillary temperature.

Fever ≠ Hyperthermia

Fever is not a disease, it helps the body to inhibit the growth and reproduction of pathogens, promote the increase of neutrophils and the proliferation of T-lymphocytes to fight infection.

There is currently no evidence that fever (not hyperthermia) causes adverse outcomes such as brain damage. On the premise that the body is not dehydrated and has an open environment to dissipate heat, it will regulate its body temperature within a relatively safe range.

Hyperthermia, however, is a manifestation of a disturbance in the body's homeostasis, in which the body produces more heat than it dissipates, and is characterized by dry, hot skin, and central nervous system symptoms (delirium, convulsions, and coma).

Hyperthermia should be managed promptly, as the risk of adverse outcomes associated with fever increases when the body temperature is above 40°C.

Antipyretic timing - Seize the time to cool down

Antipyretic treatment belongs to symptomatic treatment, and it can cure the symptoms but not the root cause.

1. The timing of drug antipyretic

(1) Look at changes in body temperature

The author has not found the recommended temperature range for adults to use drugs to reduce fever. This part mainly discusses "children" and "critically ill patients".

The 2011 edition of the American AAP Guidelines for the Use of Fever and Antipyretic Drugs in Children pointed out that antipyretic drugs can be used when the temperature is higher than 38.3 °C to improve the overall comfort of children.

The 2016 edition of Evidence-Based Guidelines for Diagnosis and Treatment of Acute Fever of Unknown Etiology in Chinese Children Aged 0 to 5 For children with low fever, oral acetaminophen or ibuprofen is recommended to reduce fever.

Fever has been shown to be independently associated with death in ICU patients. Sustained hyperthermia (>40°C) may exacerbate cerebral edema and induce multiple organ failure. It is generally accepted that medical and/or physical cooling is required for body temperature >40°C. Commonly used antipyretics are non-steroidal anti-inflammatory drugs.

However, there is no consistent management opinion for critically ill patients with body temperature between 38.3 °C and 40 °C.

(2) Look at the mental state and behavior changes of the person with fever

Taking children with fever as an example, the primary goal of antipyretic treatment is to improve the overall comfort of the child. When there are changes in activity, sleep, and behavior, drugs can be used to reduce fever.

Pediatricians emphasized children's overall comfort and symptoms of critical illness, not once normothermia.

2. How many ways to reduce fever?

(1) Physical cooling

Clothing less and keeping your environment cool are good non-drug treatments for fever. At the same time need to add enough water. A warm water bath can lower body temperature.

(2) Antipyretic drugs

Antipyretics for adults: non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, aspirin, diclofenac sodium, etc.), glucocorticoids (dexamethasone, methylprednisolone, etc., for acute inflammatory response syndrome Or in severe cases, unconventional medication).

Antipyretics for children: Only acetaminophen and ibuprofen are recommended, and the combined or alternate use of acetaminophen and ibuprofen is not recommended for antipyretic in children.

A Cochrane systematic review showed that acetaminophen combined with ibuprofen or alternated with ibuprofen was more effective in lowering body temperature than either drug alone, but did not improve comfort.

Some studies have shown that although acetaminophen combined with warm water for a short period of time has better antipyretic effect on the basis of antipyretic, it will significantly increase the discomfort of children.

Therefore, it is not recommended to use warm water rubbing baths to reduce fever on the basis of combined drug antipyretics, let alone ice water or ethanol rubbing baths to reduce fever.

Antipyretic treatment - Learn how to cool down

In the face of fever patients, more emphasis is placed on finding the heat source and treating the cause.

Clinically, the causes of fever are divided into two categories: infectious and non-infectious, and infectious fever is more common. Fever diagnosis is a complicated process, so I will not go into details here, but only attach the fever diagnosis flowchart for reference.

Summary

Taking domestic guidelines as a reference: children with rectal temperature ≥ 39.0 °C (oral temperature 38.5 °C, axillary temperature 38.2 °C), or discomfort and depression due to fever, can use drugs to reduce fever; critically ill patients with body temperature > 40 °C need to use drugs (NSAIDs) cooling and/or physical cooling.

Antipyretics for children include acetaminophen and ibuprofen, and antipyretics for adults include non-steroidal anti-inflammatory drugs and glucocorticoids (non-conventional medication).

Combination or alternate use of antipyretics is not recommended, nor is it recommended to combine rubbing baths to cool down on the basis of drug antipyretics.

Antipyretic is symptomatic treatment, and clinical treatment should focus on finding the source of heat and treating the cause.