Fluorodeoxyglucose Positron Emission Tomography Imaging in Pneumocystis jiroveci Pneumonia

Abstract

Fever or pyrexia of unknown origin (PUO) is commonly defined as body temperature higher than 38.3°C on several occasions for a period of at least 3 weeks with uncertain diagnosis after initial routine obligatory investigations. In most cases of PUO, there is an uncommon presentation of a common disease which includes infection, noninfectious inflammatory diseases, malignancy, and miscellaneous causes. We present an interesting case of a 48-year-old man with PUO, who is a known case of multiple myeloma on immunosuppressive therapy, where 18F-fluorodeoxyglucose positron emission tomography-computed tomography was able to detect occult cause of infective etiology.

Keywords: 18F-fluorodeoxyglucose; Pneumocystis carinii; Pneumocystis jiroveci pneumonia; positron emission tomography-computed tomography; pyrexia of unknown origin.

Figure 1

Whole-body fluorodeoxyglucose positron emission tomography scan maximum intensity projection image reveals diffuse increased metabolic activity in bilateral lungs with physiological fluorodeoxyglucose uptake in rest of the visualized body

Figure 2

High-resolution computed tomography (left), and fused fluorodeoxyglucose positron emission tomography and high-resolution computed tomography (right) images reveals hypermetabolic ill-defined confluent ground-glass opacities with interstitial thickening near completely involving bilateral lungs