Thrombophlebitis causing Pyrexia of unknown origin diagnosed by PET-CT

Pyrexia of Unknown Origin is defined as a temperature of more than 38.3°c on more than one occasion for at least three weeks, with an unclear diagnosis after one week in hospital. We describe a case of an 82-year-old male with Pyrexia of Unknown Origin in which no diagnosis could be established despite multiple investigations. Positron emission tomography computerized tomography (PET-CT) scan, performed to exclude malignancy, revealed the unexpected finding of an infected thrombus as the source of the pyrexia. Our case demonstrates the pivotal role of PET-CT in diagnosing the cause of Pyrexia of unknown origin. PET-CT is now easily accessible to clinicians and should be considered in the search for an elusive diagnosis of Pyrexia of Unknown Origin. *Correspondence to: Salma Kamaledeen, Specialist Registrar, Clinical Radiology, Queen Alexandra Hospital, Portsmouth, UK, E-mail: salma.kamaledeen@doctors.org.uk