Fever of Unknown Origin (FUO) refers to a medical condition characterized by the presence of a persistent and unexplained fever, typically lasting for three weeks or longer, with no apparent cause. This term is used when the underlying cause of the fever remains unidentified after a thorough evaluation, including an extensive medical history, physical examination, and appropriate laboratory investigations.
FUO is often considered a diagnostic challenge for physicians as it requires a comprehensive approach to identify the hidden source of the fever. Potential causes may include infections (such as tuberculosis or endocarditis), autoimmune disorders (such as rheumatoid arthritis or lupus), malignancies (such as lymphoma or leukemia), or less common conditions like drug-induced fever.
The diagnostic process for FUO involves a systematic evaluation, including imaging studies like X-rays, ultrasounds, and CT scans, as well as blood tests to analyze various parameters like complete blood count, blood cultures, liver and kidney function tests, autoimmune markers, and viral serologies. In some cases, more specialized tests, such as biopsies or nuclear medicine scans, might be required.
The treatment of FUO largely depends on identifying and addressing the underlying cause. Unfortunately, in some cases, the cause may never be determined, leading to the label "idiopathic FUO." Symptomatic treatment with antipyretic medications is usually employed to manage the fever and its associated symptoms until further diagnostic or therapeutic options are available.
In conclusion, Fever of Unknown Origin is a fever that persists for an extended period without an identified cause, often requiring extensive diagnostic investigations to determine the underlying condition.
