05/03/2025
Pulmonary alveolar proteinosis (PAP) is a rare lung disease characterized by the abnormal accumulation of surfactant-derived lipoprotein material within alveoli, impairing gas exchange.
It is classified into three types: autoimmune (most common, caused by GM-CSF autoantibodies), secondary (associated with infections, malignancies, or inhalational exposures), and congenital (due to genetic mutations affecting surfactant metabolism). Symptoms include progressive dyspnea, cough, and hypoxemia. Diagnosis is confirmed via high-resolution CT (crazy paving pattern), bronchoalveolar lavage (milky fluid with PAS-positive material), or lung biopsy.
Treatment includes whole lung lavage for severe cases, while GM-CSF therapy and emerging biologics offer targeted approaches.