Utility of Bronchoscopy with Bronchoalveolar Lavage among Hematologic Transplant Recipients in the Era of Noninvasive Testing

A Single-Center Study of the Utility of Bronchoalveolar Lavage in Critically Ill Patients With Haematological Malignancy or Stem Cell Transplants

INTRODUCTION

The aim of this study was to evaluate the yield of bronchoscopy-guided bronchoalveolar lavage (BAL) and decisions on management of antimicrobials in critically ill patients with hematological malignancy and/or hematological stem cell transplant (HSCT). The safety and tolerance of bronchoscopy were also reported.

METHODS

A retrospective cohort study was conducted by reviewing health charts of all adult patients with a hematological malignancy and/or an HSCT who were admitted to the intensive care unit and underwent bronchoscopy and BAL over four years from April 2016 to April 2020 at King Abdulaziz Medical City, Riyadh.  Results: The cohort included 75 critically ill patients. Of these 75 patients, 53 (70.7%) had HSCT (allogenic 66%, autologous 32.1%, haplogenic 3.8%). Computed tomography of the chest was abnormal in all patients. Predominant findings included airspace abnormalities, ground glass opacities, and others. The positive yield was found to be 20% for bacterial, 22% for viral, 21% for fungal, and other organisms were identified in 2%. Although cytology was not performed in 18 patients, malignant cells were identified on BAL in two patients. While the overall mortality of the cohort was high (46.7%), the vast majority (94.7%) tolerated bronchoscopy and BAL without any complications. However, three patients (4%) developed a pneumothorax and one patient bled and developed the acute respiratory distress syndrome post bronchoscopy.

CONCLUSIONS

BAL can identify and detect microorganisms directly influencing the clinical care of patients who have received non-invasive diagnostic tests that yielded negative culture results. Bronchoscopy and BAL are generally safe and well tolerated by critically ill patients with hematological malignancy or HSCT.

Evaluation of pulmonary abnormalities in recipients of hematopoietic cell transplants and cellular therapies

Hematopoietic cell transplant (HCT) and chimeric antigen receptor T-cell (CAR-T) therapy recipients are susceptible to multiple pulmonary complications that are caused by infectious and noninfectious processes. Numerous variables can be associated with specific pulmonary diseases including time from transplantation, presence of graft versus host disease (GVHD), underlying disease, and prolonged neutropenia and lymphocytopenia. Most pulmonary complications are infectious in origin, with bacterial pneumonia remaining the most common pulmonary infection, particularly before neutrophil engraftment. Invasive fungal infections continue to affect this patient population even when antifungal prophylaxis is used. Noninfectious pulmonary complications include a wide differential of pathologies in this population, and as clinical presentations of these various pulmonary disorders often overlap, clinicians frequently will use a multidisciplinary approach in diagnosing these abnormalities. Radiography, particularly with chest computed tomography (CT) imaging, is an essential tool in identifying pulmonary pathology and potential sources. While standard microbiological cultures of respiratory specimens are still utilized, their role is limited by low sensitivity and diagnostic yield. The likelihood of obtaining a diagnosis can be improved by using other microbiological assays, including fungal antigen tests and molecular diagnostic methods, particularly if specimens are collected via bronchoscopy. This review will highlight the more common causes of pulmonary diseases encountered after HCT and CAR-T and will examine the different methods in their diagnosis.

Novel approaches to the prediction and diagnosis of pulmonary complications in the paediatric haematopoietic stem cell transplant patient

PURPOSE OF REVIEW

Haematopoietic stem cell transplant (HSCT) remains the only curative treatment option for many children with relapsed leukaemia, primary immunodeficiencies and haemoglobinopathies. Unfortunately, infectious and noninfectious pulmonary complications following HSCT continue to cause significant morbidity and mortality. This review will focus on recent advances in the field that enhance clinically available diagnostic tools and the role of novel diagnostic techniques.

RECENT FINDINGS

Research continues to highlight the role of standard diagnostic modalities, including imaging using computed topography chest and Fluorodeoxyglucose-positron emission tomography (FDG-PET) in the diagnosis of posttransplant pulmonary infections. Similarly, bronchoalveolar lavage using bronchoscopy to obtain samples for microbiological analysis remains an important tool in the clinical and diagnostic algorithm for these children. The application of more novel diagnostic techniques such as metagenomic next-generation sequencing and the use of specific biomarkers remain potential future tools in children in whom the aetiology of posttransplant lung disease is unknown. The impact of the pulmonary microbiome on infectious and noninfectious pulmonary disease post HSCT is a future research direction.

SUMMARY

Pulmonary infectious complications post HSCT remain a devastating complication for children and their families. Despite improvements in standard and novel diagnostic modalities, the aetiology of pulmonary disease remains unknown for many patients. There is an urgent need for ongoing collaborative research to bridge this critical knowledge gap and lead to better patient outcomes.

Pulmonary Complications in Hematopoietic Stem Cell Transplant Recipients-A Clinician Primer

Hematopoietic stem cell transplants (HSCT) are becoming more widespread as a result of optimization of conditioning regimens and prevention of short-term complications with prophylactic antibiotics and antifungals. However, pulmonary complications post-HSCT remain a leading cause of morbidity and mortality and are a challenge to clinicians in both diagnosis and treatment. This comprehensive review provides a primer for non-pulmonary healthcare providers, synthesizing the current evidence behind common infectious and non-infectious post-transplant pulmonary complications based on time (peri-engraftment, early post-transplantation, and late post-transplantation). Utilizing the combination of timing of presentation, clinical symptoms, histopathology, and radiographic findings should increase rates of early diagnosis, treatment, and prognostication of these severe illness states.