Diagnostic Utility of Flexible Bronchoscopy in Recipients of Solid Organ Transplants

Epidemiology and Prognosis of Invasive Fungal Disease in Chinese Lung Transplant Recipients

This study explored the epidemiology, risk factors, and prognosis of invasive fungal disease (IFD) in Chinese lung transplant recipients (LTRs). This retrospective cohort study included patients who received lung transplants at four hospitals in South China between January 2015 and June 2019. The participants were divided into IFD and non-IFD (NIFD) groups. The final analysis included 226 LTRs (83.2% males) aged 55.0 ± 14.2 years old. Eighty-two LTRs (36.3%) developed IFD (proven or probable diagnosis). The most common pathogens were Aspergillus (57.3%), Candida (19.5%), and Pneumocystis jiroveci (13.4%). Multivariate logistic regression revealed that anastomotic disease [odds ratio (OR): 11.86; 95% confidence interval (95%CI): 4.76–29.54; P < 0.001], cytomegalovirus (CMV) pneumonia (OR: 3.85; 95%CI: 1.88–7.91; P = 0.018), and pre-transplantation IFD (OR: 7.65; 95%CI: 2.55–22.96; P < 0.001) were associated with higher odds of IFD, while double-lung transplantation (OR: 0.40; 95%CI: 0.19–0.79; P = 0.009) was associated with lower odds of IFD. Logistic regression analysis showed that anastomotic disease was associated with higher odds of death (OR: 5.01; 95%CI: 1.24–20.20; P = 0.02) and that PJP prophylaxis was associated with lower odds of death (OR: 0.01; 95%CI: 0.001–0.11; P < 0.001). Invasive fungal disease is prevalent among LTRs in southern China, with Aspergillus the most common pathogen. Prophylaxis should be optimized based on likely pathogens.

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.

Pneumonia in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the AST Infectious Diseases Community of Practice review the diagnosis and management of pneumonia in the post-transplant period. Clinical presentations and differential diagnosis for pneumonia in the solid organ transplant recipient are reviewed. A two-tier approach is proposed based on the net state of immunosuppression and the severity of presentation. With a lower risk of opportunistic, hospital-acquired, or exposure-specific pathogens and a non-severe presentation, empirical therapy may be initiated under close clinical observation. In all other patients, or those not responding to the initial therapy, a more aggressive diagnostic approach including sampling of tissue for microbiological and pathological testing is warranted. Given the broad range of potential pathogens, a microbiological diagnosis is often key for optimal care. Given the limited literature comparatively evaluating diagnostic approaches to pneumonia in the solid organ transplant recipient, much of the proposed diagnostic algorithm reflects clinical experience rather than evidence-based data. It should serve as a template which may be modified according to local needs. The same holds true for the suggested empiric therapies, which need to be adapted to the local resistance patterns. Further study is needed to comparatively evaluate diagnostic and empiric treatment strategies in SOT recipients.

Role of bronchoalveolar lavage in the management of immunocompromised patients with pulmonary infiltrates

Pulmonary infiltrates are a significant cause of morbidity and mortality in immunocompromised patients and remain a diagnostic challenge due to the broad range of etiologies that include infection and malignancy. Empiric therapy may be sub-optimal and can adversely impact outcome. Therefore, a confirmed diagnosis is necessary and flexible bronchoscopy with bronchoalveolar lavage (BAL) may be a useful diagnostic tool. Samples are obtained for microbiological and cytological testing, but the procedure carries risk of complications including the adverse events related to moderate sedation. A review of published literature on BAL in immunocompromised patients from the year 2000 was undertaken focusing on diagnostic yield, complication rate, mortality as well as factors impacting these outcomes. Studies in which the majority of patients were supported on mechanical ventilation were excluded. A total of 23 studies (7 prospective and 16 retrospective) met inclusion criteria. This covered 3,395 procedures in 3,192 patients with a mean age of 47.4 years; 60.3% male gender. Diagnostic yield ranged from 26% to 69% with no clear association between diagnostic yield and etiology of immunosuppression or clinical/radiological presentation. Post BAL modification of treatment as an indicator for clinical utility ranged from 11% to 84%; and complication rate ranged from 1% to 52%. No specific factors were associated with increased adverse event rate. This review provides a summary of the data on the use of BAL for diagnosis of pulmonary infiltrates in immunocompromised patients, highlighting the heterogeneity of patients, significant variation in findings reported and the need for more data to optimize patient selection.

Utility of fiber-optic bronchoscopy in pulmonary infections among abdominal solid-organ transplant patients: A comprehensive review

Pulmonary infections are frequent complications in abdominal solid-organ transplantation (aSOT) which may threaten patient and allograft survival. Accurate diagnosis and treatment of pulmonary infections in this population can be challenging. Immunosuppressive therapy not only increases the risk of acquiring opportunistic and non-opportunistic infections, but it also impairs the inflammatory responses associated with microbial invasion which in an otherwise normal host produce clinical and radiologic responses that allow for early identification of the offending pathogen. Serologic testing is not a reliable diagnostic modality. Direct microbiological sampling is often necessary to make a definitive diagnosis early in the clinical course to optimize timely, targeted therapy while reducing the risk of developing antimicrobial resistance, and minimize adverse effects of therapy, if any. Fiber-optic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) or transbronchial lung biopsy (TBB) offers such diagnostic advantage and possesses a potential therapeutic value too. This comprehensive review discusses the potential benefits of FOB alongside its risks and complications, indications and contraindications, and techniques. Additionally, the essay highlights FOB's utility and yield specifically with regard to type and timing of infections in aSOT patients.

Severe infections in critically ill solid organ transplant recipients

BACKGROUND

Severe infections are among the most common causes of death in immunocompromised patients admitted to the intensive care unit. The epidemiology, diagnosis and treatment of these infections has evolved in the last decade.

AIMS

We aim to provide a comprehensive review of these severe infections in this population.

SOURCES

Review of the literature pertaining to severe infections in critically ill solid organ transplant recipients. PubMed and Embase databases were searched for documents published since database inception until November 2017.

CONTENT

The epidemiology of severe infections has changed in the immunocompromised patients. This population is presenting to the intensive care unit with specific transplantation procedure-related infections, device-associated infections, a multitude of opportunistic viral infections, an increasing number of nosocomial infections and bacterial diseases with a more limited therapeutic armamentarium. Both molecular diagnostics and imaging techniques have had substantial progress in the last decade, which will, we hope, translate into faster and more precise diagnoses, as well as more optimal empirical treatment de-escalation.

IMPLICATIONS

The key clinical elements to improve the outcome of critically ill solid organ transplant recipients depend on the knowledge of geographic epidemiology, specific surgical procedures, net state of immunosuppression, hospital microbial ecology, aggressive diagnostic strategy and search for source control, rapid initiation of antimicrobials and minimization of iatrogenic immunosuppression.

The diagnostic yield and complications of open lung biopsies in kidney transplant patients with pulmonary disease

BACKGROUND

The purpose of this study was to assess the efficacy of open lung biopsy (OLB) in determining the specific diagnosis and the related complications in patients with undiagnosed diffuse pulmonary infiltrates.

METHODS

This single center, retrospective study included adult kidney transplant patients who underwent OLB. The patients had diffuse pulmonary infiltrates without definitive diagnoses and failed to respond to empiric antibiotic treatment. We analyzed the number of specific diagnoses, changes in treatment and the occurrence of complications in these patients. A logistic regression was used to determine which variables were predictors of hospital mortality.

RESULTS

From April 2010 to April 2014, 87 patients consecutively underwent OLB. A specific diagnosis was reached in 74 (85.1%) patients. In 46 patients (53%), their therapeutic management was changed after the OLB results. Twenty-five (28.7%) patients had complications related to the OLB. The hospital mortality rate was 25.2%. Age, SAPS3 score and complications related to the procedure were independent predictors of all-cause mortality.

CONCLUSIONS

OLB is a high-risk procedure with a high diagnostic yield in kidney transplant patients with diffuse pulmonary infiltrates who did not have a definitive diagnosis and who failed to respond to empiric antibiotic treatment. Complications related to OLB were common and were independently associated with intra-hospital mortality.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration as a New Diagnostic Tool for Invasive Pulmonary Mycoses

Early diagnosis of invasive pulmonary mycoses in immunocompromised patients is a major determinant of effective treatment. However, making a reliable diagnosis is challenging and often requires transbronchial or even surgical lung biopsy. We provide evidence that endobronchial ultrasound-guided transbronchial needle aspiration may be an attractive, less invasive diagnostic method. Endobronchial ultrasound-guided transbronchial needle aspiration was not only a diagnostic clue in the presented kidney transplant recipient with invasive pulmonary mycosis but was useful in assessment of treatment efficacy.

Transbronchial cryobiopsy in immunocompromised patients with pulmonary infiltrates: a pilot study

BACKGROUND

In immunocompromised patients with pulmonary infiltrates, transbronchial lung biopsies (TBB) obtained by forceps has been shown to increase the diagnostic yield over simple bronchoalveolar lavage. Cryo-TBB is a novel modality for obtaining lung biopsies. We aimed to evaluate for the first time the efficacy and safety of cryo-TBB in immunocompromised patients.

METHODS

Fifteen immunocompromised patients with pulmonary infiltrates underwent cryo-TBB. During the procedure two to three biopsy samples were taken. Procedure characteristics, complications, and the diagnostic yield were retrospectively evaluated.

RESULTS

Most patients (n = 11) were immunocompromised due to hematological malignancies. The remaining four patients were receiving chronic immunosuppressive treatment due to previous solid-organ transplantation (n = 2) or collagen-vascular disease (n = 2). No major complications occurred in the cryo-TBB group. The mean surface area of the specimen taken by cryo-TBB was 9 mm(2). The increase in surface area and quality of biopsy samples translated to a high percentage of alveolated tissue (70 %) that enabled a clear histological detection of the following diagnoses: noncaseating granulomatous inflammation (n = 2), acute interstitial pneumonitis consistent with drug reaction (n = 5), nonspecific interstitial pneumonia fibrotic variant (n = 1), diffuse alveolar damage (n = 3), organizing pneumonia (n = 3), and pulmonary cryptococcal pneumonia (n = 1). Diagnostic information obtained by cryo-TBB led to change in the management of 12 patients (80 %).

CONCLUSION

Cryo-TBB in immunocompromised patients with pulmonary infiltrates provides clinically important diagnostic data with a low complication rate. These advantages should be further compared with traditional forceps TBB in a prospective randomized trial.

Diagnostic bronchoscopy in solid-organ and hematopoietic stem cell transplantation

Fiberoptic bronchoscopy is a valuable diagnostic tool in solid-organ and hematopoietic stem cell transplant recipients presenting with a range of pulmonary complications. This article provides a comprehensive overview of the utility and potential adverse effects of diagnostic bronchoscopy for transplant recipients. Recommendations are offered on the selection of patients, the timing of bronchoscopy, and the samples to be obtained across the spectrum of suspected pulmonary complications of transplantation. Based on review of the literature, the authors recommend early diagnostic bronchoscopy over empiric treatment in transplant recipients with evidence of certain acute, subacute, or chronic pulmonary processes. This approach may be most critical when an underlying infectious etiology is suspected. In the absence of prompt diagnostic information on which to base effective treatment, the risks associated with empiric antimicrobial therapy, including medication side effects and the development of antibiotic resistance, compound the potential harm of delaying targeted management.

Pulmonary infections in transplant recipients

PURPOSE OF REVIEW

Hematopoietic stem cell as well as solid-organ transplantation is being carried out with increasing frequency throughout the world. Lower respiratory tract infections (LRTIs) remain a common life-threatening complication faced by the transplant recipients. The purpose of this review is to provide up-to-date information on pulmonary infections among the transplant recipients, especially emphasizing the endemicity of microorganisms, epidemiology, work-up of infections, and principles of their management.

RECENT FINDINGS

A lower respiratory tract infection such as pneumonia is the most frequent of all the infections and is associated with high morbidity and mortality. Factors increasing the risk of pulmonary infections include surgical techniques, immune status, chemoradiotherapy, alloimmune mechanisms between the host and the graft, and the environment. A high degree of suspicion, computed tomography (CT) scan of the chest, and flexible bronchoscopy are required in most to establish the diagnosis.

SUMMARY

Proper management of LRTI in transplant recipients requires a high degree of suspicion, thorough knowledge of the epidemiology and endemicity of the suspected organisms, CT scan of the chest, and expertise at bronchoscopy. Utmost teamwork among transplant physicians, infectious disease specialist, and bronchoscopist is essential.