There are thousands of causes of fever, but very limited antimicrobial drugs

Patient: "Pharmacist, my child has a fever of 40 degrees. The doctor told him to drink water and take antipyretics. Can he not take some cefuroxime? How can he bear this fever?"

Pharmacist: "The child has roseola infantum, which is a viral infection. Cephalexin is not effective. As long as the fever is reduced and more care is given, the fever will subside and the rash will disappear. Generally, the child will recover in one week. Don't be too nervous! Cephalexin is an antibiotic. If overused, it may not only cause adverse reactions in children, but also increase bacterial resistance. When the child actually suffers from a bacterial infection, commonly used antibiotics may not be effective."

In the hospital, we often encounter patients with fever and discomfort, and anxious and worried family members, who always think that the disease can be quickly driven away by using antibiotics. However, body temperature is often not controlled in one or two days. Antibiotics are not the "ultimate magic weapon" to relieve fever.

So, what is fever? What are the causes of fever? Why can't antibiotics be used in all cases?

What body temperature is considered a fever?

Fever refers to a pathological increase in body temperature due to various reasons. It is a systemic response of the human body to pathogenic factors. Generally speaking, when the oral temperature exceeds 37.3℃ (the axillary temperature is 0.2~0.4℃ lower than the oral temperature), or the rectal temperature exceeds 37.6℃, it is called fever. In addition, fever may also occur during special periods or specific circumstances such as ovulation, pregnancy, strenuous exercise, emotional excitement, high temperature environment, and after surgery.

There are many causes of fever, among which disease is the most common. It can be divided into two categories: infectious and non-infectious diseases, with infectious diseases being the main cause.

Use of antibiotics for infectious fever according to the situation

Infectious fever includes fever caused by various acute and chronic infectious diseases and acute and chronic systemic and focal infections. Fever may be caused by various pathogens such as viruses, bacteria, fungi, parasites, etc. that enter the body and cause infection.

Infectious fever caused by bacteria, fungi, and some parasites is the "main battlefield" of antibiotics. The rational use of antibiotics can play an important role in controlling infection. However, for simple viral infections, antibiotics are powerless because they cannot kill viruses and cannot control fever. For example, common colds, influenza, chickenpox, roseola infantum, infantile bronchiolitis, herpetic pharyngitis, etc. are mostly infections caused by respiratory viruses, enteroviruses, herpes viruses, etc., and antibiotics are useless. Only for some special patients with fever, antibiotics can be used to prevent secondary bacterial infections and treat mixed infections such as viruses and bacteria.

Antibiotics are not necessary for non-infectious fever

The causes of non-infectious fever include: blood diseases, such as leukemia, malignant reticulocyte disease, etc.; malignant tumors, such as lymphoma, lung cancer, etc.; allergic reactions, such as rheumatic fever, drug fever, serum sickness, etc.; connective tissue diseases, such as systemic lupus erythematosus, dermatomyositis, polyarteritis nodosa, rheumatoid arthritis, etc.; endocrine diseases, such as hyperthyroidism, thyroiditis, adrenal dysfunction, etc.; intracranial diseases, such as cerebral hemorrhage, severe brain trauma, epilepsy, etc.; others, such as heat stroke, major surgery, fractures, extensive burns, barbiturate poisoning, severe dehydration, bleeding, sterile abscesses, tissue necrosis, vascular infarction, autonomic dysfunction, etc.

For non-infectious fever, antibiotics can only sigh in despair and be of no help. If used improperly, they may even add fuel to the fire. For example, antibiotics occasionally cause fever (drug fever), and the key to treatment is to discover and stop using suspected antibiotics.

The causes of fever are complex, which often makes diagnosis difficult. The first step in treatment is to unravel the cause of the fever and then treat both the symptoms and the root cause.

Antimicrobial drugs are only used to treat fever caused by bacterial, fungal and other infections, and their application range is limited. Indiscriminate use of antimicrobial drugs is not only ineffective, but may also be counterproductive.

Fever is common, don’t underestimate it.

Seek medical attention promptly for a clear diagnosis.

Antimicrobial drugs are limited.

Carefully identify whether it is applicable.

There are thousands of reasons for fever.

Finding the cause is the key.

Author: Shao Yun, Pharmacist and Deputy Director of the Department of Pharmacy, the Third Affiliated Hospital of Zhengzhou University

Review expert: Ren Yanli, chief pharmacist of the Gynecology and Pediatrics Group of the Henan Pharmaceutical Association Hospital