Alveolar proteinosis due to toxic inhalation at workplace

Abstract

We report a clinical case of a 39-year old male, without any known previous medical condition but with occupational exposure to paints and dust cement, who presented an autoimmune pulmonary alveolar proteinosis (PAP) triggered by exposure to toxic inhalation at his workplace. PAP is a rare lung disease characterized by intra-alveolar abnormal accumulation of surfactant. The presence of a crazy-paving pattern in high-resolution computed tomography scan brings the suspicion of PAP although histopathology results of bronchoalveolar lavage are always required for its final diagnosis. The autoimmune form of PAP due to toxic inhalation, such as the one here described, is rare and it is usually difficult to establish a causal relationship.

Keywords: Alveolar proteinosis; Autoimmunity; Hypoxemia; Rare lung disease; Toxic inhalation.

Fig. 1

HRCT scan demonstrating combination of ground-glass opacities with thickened polygonal septal lines and intralobular reticulations compatible with a cobblestone appearance – “crazy paving” pattern.

Fig. 2

Milky appearance of the bronchoalveolar lavage fluid acquired during first WLL – tubes ordered from the beginning of procedure (no. 1) to the end (no. 8), demonstrating that the milky fluid is becoming lighter as the lipoproteinaceos material is being washed out from the lungs during the procedure.

Fig. 3

a Bronchoalveolar lavage filled with globular, homogeneous, eosinophilic proteinaceous material (arrow) (Thin prep, May-Grünwald-Giemsa stain). b The proteinaceous material, from bronchoalveolar lavage, stained positive with PAS, consistent with Pulmonary Alveolar Proteinosis (PAS histochemical stain).