Abstract
Pulmonary alveolar proteinosis (PAP) is a rare entity characterised by dysfunction of alveolar macrophages, concomitant with accumulation of surfactant (phospholipoprotein material) in the alveolar space, without inflammatory infiltration or interstitial involvement. The clinical picture of PAP is poor, because it often starts insidiously with progressively worsening dyspnoea (cardinal symptom), leading over time to hypoxaemic respiratory failure. The prevalence of PAP is about 7 cases per million individuals, the peak incidence is between 30 years and 50 years of age, and the male:female ratio is 2:1, with smokers more commonly affected. From a pathogenetic point of view, this syndrome can be classified into primary (idiopathic) PAP, subclassified as autoimmune (90% of cases) and hereditary, congenital PAP and PAP of secondary cause. Most of the time, bronchoalveolar lavage confirms the diagnosis. In terms of treatment, the excess accumulated surfactant is effectively removed through whole-lung lavage.