Clinical data and CT findings of pulmonary infection caused by different pathogens after kidney transplantation

Radiological presentation of active pulmonary tuberculosis in kidney transplant recipients: a retrospective study of four cases and a review of the literature

Although kidney transplantation is the best therapeutic option for patients with chronic kidney disease, the immunosuppression required greatly increases susceptibility to infections that are responsible for high post-transplant mortality. Pulmonary tuberculosis (TB) represents a major cause of such infections, and its early diagnosis is therefore quite important. In view of that, we researched the manifestations of active pulmonary TB in kidney transplant recipients, through chest X-ray and computed tomography (CT), as well as determining the number of cases of active pulmonary TB occurring over a 3.5-year period at our institution. We identified four cases of active pulmonary TB in kidney transplant recipients. The CT scans provided information complementary to the chest X-ray findings in all four of those cases. We compared our CT findings with those reported in the literature. We analyzed our experience in conjunction with an extensive review of the literature that was nevertheless limited because few studies have been carried out in lowand middle-income countries, where the incidence of TB is higher.

Padrões tomográficos de agentes etiológicos da pneumonia durante o primeiro ano após transplante renal

Objetivo

Avaliar os padrões tomográficos relacionados aos agentes etiológicos da pneumonia em pacientes durante o primeiro ano após transplante renal.

Materiais e Métodos

Foram analisados dados de prontuários de 956 pacientes submetidos a transplante renal, no período de 2013 a 2018, em um centro transplantador renal do nordeste do Brasil. Nos pacientes que desenvolveram pneumonia, os agentes etiológicos foram classificados em bactérias piogênicas, micobactérias, fungos, vírus e pneumonia polimicrobiana, enquanto os padrões tomográficos foram classificados em consolidação, broncopneumonia, pneumonia intersticial e nódulos e massas. Para verificar associação estatística entre micro-organismos e padrões tomográficos, foi utilizado o teste exato de Fisher, com p < 0,001.

Resultados

Foram encontrados 101 casos de pneumonia, dos quais 60 (59,4%) tiveram agente etiológico identificado, sendo as bactérias piogênicas as mais frequentes, detectadas em 22 (36,7%) dos casos. Entre os pacientes com agente causal identificado, o padrão tomográfico predominante foi o de nódulos e massas, identificado em 25 (41,7%) casos. Foi observada associação entre bactérias piogênicas e o padrão de consolidação, fungos com nódulos e massas, bem como entre agentes virais e padrão intersticial.

Conclusão

Foi demonstrada associação estatística entre micro-organismos causadores de pneumonia e padrões tomográficos, informação que pode contribuir para o planejamento da terapia de pacientes transplantados renais.

Pulmonary infections after renal transplantation: a prospective study from a tropical country

Pulmonary infection is a leading cause of morbidity and mortality in renal transplant recipients. In a prospective study, we characterized their epidemiology in a tropical country with high infectious disease burden. Adult renal transplant recipients presenting with pulmonary infections from 2015 to 2017 were evaluated using a specific diagnostic algorithm. 102 pulmonary infections occurred in 88 patients. 32.3% infections presented in the first year, 31.4% between 1 and 5, and 36.3% beyond 5 years after transplantation. Microbiological diagnosis was established in 69.6%, and 102 microorganisms were identified. Bacterial infection (29.4%) was most common followed by tuberculosis (23.5%), fungal (20.6%), Pneumocystis jiroveci (10.8%), viral (8.8%), and nocardial (6.9%) infections. Tuberculosis(TB) and bacterial infections presented throughout the post-transplant period, while Pneumocystis (72.7%), cytomegalovirus (87.5%) and nocardia (85.7%) predominantly presented after >12 months. Fungal infections had a bimodal presentation, between 2 and 6 months (33.3%) and after 12 months (66.7%). Four patients had multi-drug resistant(MDR) TB. In 16.7% cases, plain radiograph was normal and infection was diagnosed by a computed tomography imaging. Mortality due to pulmonary infections was 22.7%. On multivariate Cox regression analysis, use of ATG (HR-2.39, 95% CI: 1.20-4.78, P = 0.013), fungal infection (HR-2.14, 95% CI: 1.19-3.84, P = 0.011) and need for mechanical ventilation (9.68, 95% CI: 1.34-69.82, P = 0.024) were significant predictors of mortality in our patients. To conclude, community-acquired and endemic pulmonary infections predominate with no specific timeline and opportunistic infections usually present late. Nocardiosis and MDR-TB are emerging challenges.

Chest X-ray and chest CT findings in patients diagnosed with pulmonary tuberculosis following solid organ transplantation: a systematic review

The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

High-resolution CT findings of pulmonary Mycobacterium tuberculosis infection in renal transplant recipients

OBJECTIVE

Renal transplantation recipients are at increased risk of Mycobacterium tuberculosis infection because of immunosuppression. The aim of this study was to assess high-resolution CT (HRCT) findings in renal transplantation recipients diagnosed with pulmonary tuberculosis (TB).

METHODS

We reviewed HRCT findings from patients diagnosed with pulmonary TB, established by M. tuberculosis detection in bronchoalveolar lavage, sputum or biopsy sample. Two observers independently reviewed HRCT images and reached consensus decisions on the presence and distribution of: (i) miliary nodules, (ii) cavitation and centrilobular tree-in-bud nodules, (iii) ground-glass attenuation and consolidation, (iv) mediastinal lymph node enlargement and (v) pleural effusion.

RESULTS

The sample comprised 40 patients [26 males, 14 females; median age, 45 years (range, 12-69 years)]. The main HRCT pattern was miliary nodules (40%), followed by cavitation and centrilobular tree-in-bud nodules (22.5%), ground-glass attenuation and consolidation (15%), mediastinal lymph node enlargement (12.5%) and pleural effusion (10%). The distribution of findings in patients with miliary nodules was random. In patients with cavitation and centrilobular tree-in-bud nodules, 66.6% of abnormalities were found in the upper lobes. Pleural effusion was unilateral in 75% of cases. The overall mortality rate was 27.5%. This rate was 50% in patients with miliary nodules, and 72.6% of all deaths occurred in this group. Thus, mortality was increased significantly in patients with miliary nodules (p < 0.05).

CONCLUSION

The main HRCT finding in renal transplantation recipients with pulmonary TB was miliary nodules, followed by cavitation and centrilobular tree-in-bud nodules. Miliary nodules were associated with a worse prognosis in these patients.

ADVANCES IN KNOWLEDGE

We report the first series on HRCT findings of microbiologically confirmed pulmonary TB exclusively in renal transplantation recipients. The main HRCT finding was miliary nodules, and mortality was increased significantly in these patients.

Radiological spectrum of pulmonary infections in patients post solid organ transplantation

Pneumonia remains an important source of morbidity and mortality in transplant recipients. Since clinical findings are nonspecific and cultures may be time-consuming, imaging plays an important role in establishing the probable etiology of pneumonia. Plain films are used as an initial study. However, they have a limited capacity in differentiating the causative factors. HRCT is used as a problem-solving tool in patients with unclear plain film findings and/or no response to treatment. The main advantage of HRCT is a very detailed depiction of the lung parenchyma. Even though HRCT findings are not always specific, there are several sings that are more common in certain types of pneumonia. The aim of the article is to present radiological findings suggestive of a particular causative microorganism and show how they can narrow the differential diagnosis when coupled with clinical data.