|Year : 2022 | Volume
| Issue : 2 | Page : 194-195
Fluorodeoxyglucose Positron Emission Tomography Imaging in Pneumocystis jiroveci Pneumonia
Hemant Rathore1, Nirav Thaker2, Inder Talwar2
1 Department of Nuclear Medicine and PET CT, Bombay Hospital and Medical Research Centre, Mumbai, Maharashtra, India
2 Department of Radiodiagnosis, Bombay Hospital and Medical Research Centre, Mumbai, Maharashtra, India
|Date of Submission||15-Sep-2021|
|Date of Acceptance||04-Oct-2021|
|Date of Web Publication||08-Jul-2022|
Dr. Hemant Rathore
Department of Nuclear Medicine and PET CT, Bombay Hospital and Medical Research Centre, 12 Marine Lines, Mumbai - 400 020, Maharashtra
Source of Support: None, Conflict of Interest: None
| 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
|How to cite this article:|
Rathore H, Thaker N, Talwar I. Fluorodeoxyglucose Positron Emission Tomography Imaging in Pneumocystis jiroveci Pneumonia. Indian J Nucl Med 2022;37:194-5
|How to cite this URL:|
Rathore H, Thaker N, Talwar I. Fluorodeoxyglucose Positron Emission Tomography Imaging in Pneumocystis jiroveci Pneumonia. Indian J Nucl Med [serial online] 2022 [cited 2022 Aug 10];37:194-5. Available from: https://www.ijnm.in/text.asp?2022/37/2/194/350252
| Background and Procedure|| |
We describe a case of a 48-year-old man with pyrexia of unknown origin (PUO), who is a known case of multiple myeloma on immunosuppressive therapy, with remission of disease on recent bone marrow examination. This case presented with dry cough and fever over 4 weeks (100°F–102°F) and had an oxygen saturation of 97% on ambient air. The blood tests apart from mild leukopenia were fairly unremarkable. The chest radiography revealed subtle bilateral lung ground-glass opacities and referred for fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomographic (CT) scan to rule out the cause. The FDG-PET scan [Figure 1] revealed diffuse increased metabolic activity in bilateral lungs; the corresponding fused high-resolution CT (HRCT) images showed the acute lung changes in the form of hypermetabolic ill-defined confluent ground-glass opacities with interstitial thickening and crazy paving appearance near completely involving bilateral lungs along with mild bronchial and bronchiolar dilatation [Figure 2]. The imaging was suggestive of acute atypical pneumonia which was further investigated by bronchoalveolar lavage cytological examination and culture which demonstrated Pneumocystis jiroveci.
|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|
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|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|
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Pneumocystic jiroveci pneumonia (PJP), is also known as pneumocystic pneumonia or formerly pneumocystic carinii pneumonia, is caused by the ubiquitous unicellular eukaryote, P jiroveci, which is a rare cause of infection in the general population, but it is a more frequent cause of morbidity and mortality in immunocompromised persons who are especially with HIV AIDS, postorgan-transplant recipients, and those receiving long-term cytotoxic or steroid therapy, hematological malignancies, as well as other malignancies. PJP is classified as a fungal pneumonia but does not respond to antifungal therapy. These patients have a long clinical course over months to years, with stable symptoms and radiographic abnormalities corresponding to pathologic findings of traction bronchiectasis, honeycombing, and interstitial fibrosis.
In a study of 105 pneumocystic pneumonia immunocompromised patients, chest radiographic findings were divided into three stages: early stage; normal or nearly normal chest radiograph, mid-stage; bilateral pulmonary infiltrates, and late stage; bilateral pulmonary consolidation. Chest HRCT findings were also divided into three stages: early stage; bilateral diffuse ground-glass opacity, mid-stage; bilateral diffuse ground-glass opacity with patchy consolidations, and late stage; bilateral diffuse consolidation).
| Conclusion|| |
FDG-PET/CT imaging is a very sensitive diagnostic modality for the evaluation of fever of unknown origin by facilitating anatomical localization of focally increased FDG uptake and thereby guiding further diagnostic tests to achieve a final diagnosis. Few studies suggest that FDG-PET scan have an important role to play in the diagnosis and monitoring treatment response of pneumocystic pneumonia in the immunocompromised patients.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]