Diagnostic yield and safety of bronchofiberscopy for pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a diffuse lung disease characterized by the abnormal accumulation of surfactant-like material within the alveolar spaces and distal bronchioles. If high-resolution computed tomography (HRCT) indicates the presence of PAP, a definitive diagnosis of PAP is established when consistent pathological findings are obtained. Herein, we retrospectively studied the yield and safety of bronchofiberscopy in the diagnosis of PAP.

One hundred and fifty consecutive patients with PAP were prospectively registered in the PAP cohort database of the National Hospital Organization Kinki-Chuo Chest Medical Center between January 1991 and December 2018. We examined 86 patients who underwent bronchofiberscopy with bronchoalveolar lavage (BAL) and transbronchial lung forceps biopsy (TBLB).

The patients included 56 men and 30 women, with a median age of 57 years. All patients had autoimmune PAP, and the median level of anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies was 42.8 μg/mL. The diagnostic yield was 90.7% (78/86) with BAL and 81.4% (70/86) with TBLB. The combination of BAL and TBLB increased the yield to 98.8%. Age, disease severity score, and frequency of traction bronchiectasis on HRCT were significantly different between the TBLB-positive and TBLB-negative groups. No patient developed serious complications due to bronchofiberscopy; TBLB-related complications included pneumothorax (3.5%) and minimal bleeding (7.0%).

Bronchofiberscopy, in combination with BAL and TBLB, is an effective and safe method for the diagnosis of PAP, with a yield of 98.8%.