PT  - JOURNAL ARTICLE
AU  - Cristina Fernandez
AU  - Nick J Beeching
TI  - Pyrexia of unknown origin
AID  - 10.7861/clinmedicine.18-2-170
DP  - 2018 Apr 01
TA  - Clinical Medicine
PG  - 170--174
VI  - 18
IP  - 2
4099  - http://www.rcpjournals.org/content/18/2/170.short
4100  - http://www.rcpjournals.org/content/18/2/170.full
SO  - Clin Med2018 Apr 01; 18
AB  - The syndrome of pyrexia of unknown origin (PUO) was first defined in 1961 but remains a clinical challenge for many physicians. Different subgroups with PUO have been suggested, each requiring different investigative strategies: classical, nosocomial, neutropenic and HIV-related. This could be expanded to include the elderly as a fifth group. The causes are broadly divided into four groups: infective, inflammatory, neoplastic and miscellaneous. Increasing early use of positron emission tomography–computed tomography (PET-CT) and the development of new molecular and serological tests for infection have improved diagnostic capability, but up to 50% of patients still have no cause found despite adequate investigations. Reassuringly, the cohort of undiagnosed patients has a good prognosis. In this article we review the possible aetiologies of PUO and present a systematic clinical approach to investigation and management of patients, recommending potential second-line investigations when the aetiology is unclear.