Positive naproxen test in psychogenic fever

Abstract

Pyrexia of unknown origin (PUO) broadly includes any febrile illness lasting ≥ 3 weeks with a temperature > 38.3°C (100.9°F) on at least 2 occasions in the absence of a known immunocompromised state and an uncertain diagnosis after a thorough assessment including history taking, physical examination, and appropriate investigations.1 PUO can be due to infectious, inflammatory, neoplastic, or other miscellaneous causes. Treatment with naproxen has been shown to result in lysis of fever within 24 hours in patients with PUO due to noninfectious causes, while patients with infectious conditions show little response.2,3 Hence, the naproxen test has been proposed as a useful diagnostic tool to differentiate PUO of infectious from noninfectious, especially neoplastic, etiology. However, the low sensitivity and specificity of the naproxen test has limited its wider acceptability.4 Psychogenic fever, also known as functional hyperthermia, is an underrecognized potential etiology of PUO.5 Here, we report a case of PUO, in the context of acute stress and depression, with a positive naproxen test.