Diffuse alveolar hemorrhage in allogeneic bone marrow transplantation. A postmortem study

Diffuse Alveolar Hemorrhage After Pediatric Hematopoietic Stem Cell Transplantation

Pulmonary complications are common following hematopoietic cell transplantation (HCT) and contribute significantly to its morbidity and mortality. Diffuse alveolar hemorrhage is a devastating non-infectious complication that occurs in up to 5% of patients post-HCT. Historically, it carries a high mortality burden of 60–100%. The etiology remains ill-defined but is thought to be due to lung injury from conditioning regimens, total body irradiation, occult infections, and other comorbidities such as graft vs. host disease, thrombotic microangiopathy, and subsequent cytokine release and inflammation. Clinically, patients present with hypoxemia, dyspnea, and diffuse opacities consistent with an alveolar disease process on chest radiography. Diagnosis is most commonly confirmed with bronchoscopy findings of progressively bloodier bronchoalveolar lavage or the presence of hemosiderin-laden macrophages on microscopy. Treatment with glucocorticoids is common though dosing and duration of therapy remains variable. Other agents, such as aminocaproic acid, tranexamic acid, and activated recombinant factor VIIa have also been tried with mixed results. We present a review of diffuse alveolar hemorrhage with a focus on its pathogenesis and treatment options.

[Diagnostic strategy for acute respiratory failure in patients with haematological malignancy]

INTRODUCTION

About 15% of patients with haematological malignancy develop acute respiratory failure (ARF), necessitating admission to intensive care where their mortality is of the order of 50%.

STATE OF THE ART

The prognosis of these patients is not determined by the pathological characteristics of the malignancy but by the cause of the acute respiratory failure. In effect, the need to resort to mechanical ventilation in the presence of dysfunction of other organs dominates the prognosis. Even if the use of non-invasive ventilation in these patients has reduced the need for intubation and reduced the mortality, its prolonged use in the most severely affected patients prevents the optimal diagnostic and therapeutic management.

PERSPECTIVES

Fibreoptic bronchoscopy with broncho-alveolar lavage (BAL) is considered the cornerstone of aetiological diagnosis but its diagnostic effectiveness is poor, at best 50%, and this has led to increasing interest in high resolution CT scanning and regularly reawakens a transitory enthusiasm for surgical lung biopsy. Furthermore, in hypoxaemic patients, fibreoptic bronchoscopy with BAL may be the origin of the resort to mechanical ventilation, and thus increased mortality. The place of recently developed non-invasive tools is under evaluation. In effect, though the individual performance of diagnostic molecular techniques on sputum, blood, urine or naso- pharyngeal secretions has been established, the combination of these tools as an alternative to BAL has not yet been reported.

CONCLUSION

This review deals with acute respiratory failure in patients with haematological malignancy. It includes a review of the recent literature and considers the current controversies, in particular the risk-benefit balance of fibreoptic bronchoscopy with BAL in severely hypoxaemic patients.