Low-grade fever

Introduction Low fever means that the body temperature is between 37.3 ° C and 38 ° C. Long-term low-grade fever means continuous fever for more than two weeks, excluding intermittent fever.

Cause

Many diseases can cause low fever. Fever is a symptom. Rheumatism, tuberculosis, chronic inflammation, low immunity and other diseases can cause persistent low fever. Long-term psychological stress and emotional instability can also cause central nervous system disorders, resulting in unexplained persistent low fever. Problems with any system of the body can cause persistent low fever. What is the cause of low-grade fever? It is difficult to detect through routine examinations such as blood, urine, and stool. Some low-grade fever caused by bacterial infections can only be discovered through bacterial culture.

Unknown low fever can not abuse drugs. Fever is one of the reactions of the body against disease. Taking hypothermic patients with hypothermia is not conducive to the treatment of the disease. Indiscriminate use of antipyretics, as well as the risk of leukopenia and aplastic anemia. When the body temperature is above 38 °C, the use of antipyretics should be considered.

Continuous low fever should be treated as soon as possible, and a comprehensive examination should be carried out as soon as possible. Early malignant tumors or early symptoms of bacterial infection are also low-grade fever.

an examination

Related inspection

Body temperature measurement

Low-grade fever can be divided into functional low-grade and organic low-grade burning.

Functional low fever:

Its clinical feature is that the body temperature is increased by 0.3~0.5 °C compared with normal, and generally does not exceed 38 °C. Common are:

1 Physiological low fever: seen in women before or during pregnancy:

2 Seasonal low-grade fever: every summer, there is slight heat accompanied by fatigue, loss of appetite, natural relief in autumn, called summer heat:

3 Environmental low-grade fever: About 10% of workers in high-temperature environments have low-grade fever

4 neurological low fever:

Clinically, young people between the ages of 20 and 30 are more common. The patient's temperature is 0.3°C-0.5°C higher than that of normal people. Low-grade fever varies from a few months to several years, and the general condition is better and the weight is not reduced. These patients account for about 1/3 of the total number of patients with long-term low-grade fever, and the prognosis is good.

Organic low fever:

There are many diseases that cause organic low fever. Common causes are tuberculosis, biliary tract infection, chronic infection, urinary tract infection, rheumatism, hepatitis, and tumor. Others are hyperthyroidism, anemia, connective tissue disease, and status after streptococcal infection.

Differential diagnosis

The most common form of long-term low-grade fever is tuberculosis infection. Tuberculosis is still more common in children. In addition to low-grade fever, children still have personality changes. The original active child became lazy and did not love to move. The original quiet child was impatient, tempered, loss of appetite, weight loss, sweating or sweating at night, fatigue, paleness, neck and other superficial Lymph node enlargement, etc. For this purpose, it should be used as tuberculin test (OT) or triple skin swab (PPD-PHA). If it is a positive result, it can be used as a reference, because the child can also see a positive reaction after inoculation with BCG. In addition, in the past, tuberculosis has been passed, and a positive reaction can also occur. Further, it is necessary to check the erythrocyte sedimentation rate. Generally, during TB activity, the erythrocyte sedimentation rate can be increased. Finally, X-rays should be used to check the lungs for tuberculosis. If all the above tests are negative, you can rule out tuberculosis

Long-term low-grade fever is also seen in viral infections, mainly found in infants and young children, more common in throat infections, and no systemic manifestations. There are no obvious abnormalities in the general examination, and there are no respiratory symptoms. Most of them are high-grade fever after a certain virus infection, and the low-grade fever does not retreat for a long time. Older children with pharyngeal streptococcus or Staphylococcus aureus infection, can also be expressed as long-term low-grade fever, can be used for pharyngeal secretion culture, if you can find bacteria, you can confirm the diagnosis. For streptococcal infection, blood can also be taken to check anti-streptolysin (referred to as anti-"O"), such as high titer, indicating that there has been streptococcal infection. If the anti-"O" is obvious, you should also think about the possibility of rheumatic fever. You should pay attention to whether there is joint pain or swelling, whether there is ring erythema on the skin, and whether the heart changes. These are the basis for the diagnosis of rheumatic fever. Girls with low fever should pay attention to urinary tract infections, and urine can be checked to determine.

Long-term low-grade fever may also be unrelated to infection, but caused by other diseases or other causes. In the case of blood diseases, leukemia, aplastic anemia, hemolytic anemia, etc. can be seen for long-term low-grade fever.

If your child has anemia, hemorrhage, jaundice, etc., check your ear blood to find out if it is related to it.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.