In clinical practice, many patients have prolonged hypothermia with no detectable cause. A prolonged temperature between 37.4 and 38.4°C for more than a month is called prolonged hypothermia. Second, other infectious diseases, such as cholecystitis or viral hepatitis in the internal organs, and chronic inflammation of the urinary system, may lead to the occurrence of prolonged hypothermia, which may not be detected without careful examination. Third, some rheumatic system diseases may also lead to the occurrence of prolonged hypothermia, such as connective tissue disease or rheumatoid arthritis, which may lead to the possibility of hypothermia in patients.