Fever of Unknown Origin

Fever of unknown origin (FUO) has been recognized as a disease state for over100 years.
The first commonly accepted definition of FUO was published in 1961 and included fever greater than 101F (38.3C) on multiple occasions at least 3 week duration of fever without identifiable cause despite at least a 1 week inpatient evaluation.

Overtime, this definition was considered both too rigid and too ill defined.
Given the impracticality of prolonged hospitalizations and advancing technology for diagnosis, the duration of work up was shortened to 3 days inpatient evaluation and/or 3 outpatient clinic visits.

• Original Document

这是FUO(不明原因发烧)的综合指南，第一个普遍接受的 FUO 定义是1961 年发布的，包括多次发烧超过三十八度三，发烧持续时间至少 3 周，并且就算住院至少 1 周但仍无明确原因。后面这个定义被认为过于僵化且过于模糊。又改成了三天住院评估和/或三次门。除了有关评估持续时间的所有时间要求，还应该将 FUO 定义为完成最低限度检查后缺乏已知病因的发烧。

常见原因就感染性，自身免疫和结缔组织疾病，其他炎症过程和恶性肿瘤。结缔组织疾病和自身免疫性疾病是青少年 FUO 比儿童更常见的原因。
总体上有超过两百种病因可导致 FUO