When Dust Meets the Lungs: A Case of Pulmonary Alveolar Proteinosis in a Young Patient With Exposure to Silica

Document Type

Conference Proceeding

Publication Date

5-2025

Publication Title

American Journal of Respiratory and Critical Care Medicine

Abstract

Introduction: Silicosis is an interstitial lung disease caused by free crystaline silica inhalation, typically resulting in chronic pulmonary damage over decades of exposure. Alveolar silicoproteinosis is an acute complication that can arise after short-term exposure to high levels of silica dust leading to significant respiratory impairment. Case description A 28-year-old male with significant silica exposure while sandblasting for six years presented to another hospital with dyspnea and cough. Chest X-ray demonstrated bilateral interstitial infiltrates and a CT thorax revealed diffuse, extensive bilateral interstitial and parenchymal infiltrates. Patient was treated with antibiotics and discharged with plans for outpatient follow-up. After few months, the patient presented with dyspnea and hypoxia. A repeat CT thorax showed ground-glass opacifications, mediastinal lymphadenopathy, septal thickening, and traction bronchiectasis. Extensive infectious and autoimmune workup revealed positive histoplasmosis antibodies and patient was started on isavuconazonium sulfate as well as Bactrim for Pneumocystis Jirovecii pneumonia prophylaxis. A bronchoalveolar lavage (BAL) was positive for periodic acid-Schiff (PAS) staining, raising the possibility of pulmonary alveolar proteinosis (PAP), and showed numerous macrophages with lipoproteinaceous material accumulation. The patient subsequently underwent whole lung lavage with veno-venous extracorporeal membrane oxygenation support. Despite these interventions, persistent respiratory failure necessitated bilateral orthotopic lung transplantation, which was performed successfully.

Discussion: Accelerated silicosis is a form of silicosis with exposure lasting between 3 and 10 years, intermediate between acute and chronic forms. It results from excessive exposure to crystalline silica particles, most commonly affecting individuals in high-risk occupations such as sandblasting. Silicoproteinosis is a rare complication which leads to rapid deterioration of pulmonary function due to abnormal accumulation of proteineous material in the alveoli, similar to PAP. The initial manifestations typically include dry cough, chest pain and dyspnea. BAL reveals PAS-positive lipoproteineous material filling the airspaces, with minimal collagen disposition and fibrosis unlike in classic silicosis. High-resolution CT finidngs have been described in several studies as bilateral airspace consolidation, mainly involving the posterior aspect of the lungs, septal thickening and ground glass opacities. The combination of septal thickening surrounded by ground glass opacities forms the nonspecific but characteristic "crazy-paving'' pattern. These radiologic and histologic characteristics are essential for diagnosing and managing this severe condition. Treatment of silicoproteinosis is primarily supportive; while corticosteroid provides short-term clinical improvement, they have not shown long-term benefits and may increase the risk of infections. In our case, corticosteroid and whole lung lavage provided minimal clinical improvement, and ultimately the patient underwent lung transplant.

Volume

211

First Page

A6309

Last Page

A6309

Comments

American Thoracic Society International Conference, May 16-25, 2025, San Francisco, CA

DOI

10.1164/ajrccm.2025.211.Abstracts.A6309

ISSN

1535-4970

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