Pulmonary alveolar proteinosis (PAP) is a disease characterized by accumulation of surfactant in alveoli due to defects in surfactant clearance. The accumulation impairs gas exchange and can cause respiratory failure. Whole lung lavage is the primary treatment and improves symptoms in most patients by removing surfactant from the lungs. Exogenous GM-CSF may also be used but does not provide a cure. The document provides details on the pathophysiology, clinical presentation, diagnosis, and management of PAP.