Fever of Unknown Origin (FUO) in Elderly Patients

Objective: Fever of unknown (FUO) origin remains challenging in geriatric patients. Geriatric patients have a blunted immune response responsible for altered fever mechanisms and immune cells responses. Consequently, FUO could be inappropriately named and could be changed in Inflammation of unknown origin (IUO) in this specific population. Furthermore, the studies of FUO in this group are (out)dated and the diagnostic methods have evolved achieving a better sensitivity and specificity. The aim of our study is to assess the spectrum of diseases responsible of FUO or IUO in elderly patients compared to younger patients and to define the diagnostic approach using new diagnostic investigations. The second aim of our study is to assess the usefulness of inflammatory markers, demographic data and comorbidity to differentiate the cause of FUO/IUO. Design: Patients with FUO or IUO will prospectively be recruited at the geriatric unit and the internal medicine unit of the UZ hospital during four years. The demographic, social and medical data will be screened. All diagnostic methods will be described.