发热超过38℃,持续3周以上,经比较全面的检查和化验仍查不出原因者,称为未明热。按照这个标准,大多数病毒感染、手术后热和罕见的习惯性体温过高等均可不必考虑。长期原因未明发热的诊断是内科难题之一,约5～8％的病例可自行消退。长期反复发作达一年以上者称慢性发热。 Jacoby等未明热原因归纳为:(1)三大类主要原因,(2)少见疾病。未明热的三大类主要原因 Fever over 38 ℃, for more than 3 weeks, after a more comprehensive inspection and testing still can not find out the reason, known as not yet hot. According to this standard, most virus infections, postoperative fever and rare habitual hyperthermia may not have to consider. Long-term causes of unknown fever diagnosis is one of the medical problems, about 5 to 8% of the cases subsided on their own. Long-term recurrent attack for more than one year that chronic fever. Jacoby and other unexplained fever can be summarized as: (1) three main types of causes, and (2) rare diseases. Unclear three main categories of the main reasons