A Rare Presentation of Tuberculosis in Transplanted Kidney on Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography Scan.

Tuberculosis (TB) is currently the world's leading cause of infectious mortality. Infective complications are common after renal transplantation. TB is one of the leading infections following renal transplantation; however, TB affecting the transplanted kidney is a rare presentation. Reactivation of the Mycobacterium tuberculosis is the most common mode of infection. The use of immunosuppressive agents such as cyclosporin, azathioprine, and steroids advance the onset of TB to an earlier date which most often presents as a fever or pyrexia of unknown origin (PUO). The use of 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG-PET/CT) scan images of the whole body and provides the metabolic map of the infection as well as also helps in its radiological localization and characterization and selecting the most appropriate site of the biopsy. Currently, the combined FDG-PET/CT scan modality is the investigation of the choice of physicians for the diagnosis of PUO. Not only the diagnosis but 18F-FDG-PET/CT is also very valuable in assessing early disease response to therapy, and plays an important role in cases where conventional microbiological methods are unavailable for monitoring response to the therapy in cases of pulmonary, extrapulmonary, or multidrug resistant TB.