pulmonary alveolar proteinosis

Pulmonary Alveolar Proteinosis (PAP) is a rare lung disease characterized by excessive accumulation of surfactant lipids and proteins in alveoli and terminal airways. It is caused by impaired GM-CSF signaling [1]. Surfactant is synthesized and secreted by alveolar type II epithelial cells, and removed by uptake and catabolism by these cells, and the alveolar macrophages. Patients with PAP usually describe gradual onset of progressive exertional dyspnea and non-productive cough. However, an asymptomatic presentation is observed in up to 25% of cases, even in the presence of diffuse radiographic changes. Three recognized subtypes exist. Autoimmune PAP is associated with neutralizing GM-CSF autoantibodies and accounts about 90% of cases. Secondary PAP may occur in the context of any disease that reduces the abundance or functionality of alveolar macrophages, resulting in impaired surfactant clearance. Congenital PAP is the result of genetic mutations that disrupt GM-CSF signaling, including mutations in the α- or β-chains of the GM-CSF receptor [1-3].

Introduction: Total bronchoalveolar lavage (BAL) continues to be the treatment of choice for alveolar proteinosis (AP), facilitating the removal of lipoprotein material. The purpose of this article is to evaluate the impact of haemodynamic, biochemical, and respiratory parameters, as well as the complications and evolution of patients undergoing this procedure. Methods: Retrospective, observational, and descriptive study of BAL. The technique was performed in the Intensive Care Unit. Blood gases, blood pressure, central venous pressure, body temperature, and fluid balance were analyzed. Results: Including eight patients, thirty-eight BAL were performed from 2008 to 2021. The mean instillation of saline at each session was 13.464 ± 4.002 ml per lung. No significant changes were observed before and after BAL in heart rate and blood pressure. Mean central venous pressure increased by 2.59 cm H20. The pO2 initial was 126 mmHg with a final mean of 69.7 mmHg, with statistical significance. The pCO2, HCO3 and pH parameters remained stable. Complications were observed during fifteen of the thirty-eight BAL (nine with arterial hypotension, three with glottic oedema, one acute pulmonary oedema, one pneumothorax, and one cardiorespiratory arrest). In terms of evolution, one case had a clinical-radiological resolution, one case of exits, one required lung transplantation, and the remaining five remained stable. Conclusion: This study demonstrates that the procedure, is well tolerated haemodynamically and that the biochemical alterations to which the patient is subjected are not compromised. With few complications and good results in delaying the progression of AP.