Pulmonary alveolar proteinosis in children: An unusual presentation with significant clinical impact.

Pulmonary alveolar proteinosis (PAP) - an unusual diffuse lung disease characterized by alveolar accumulation of phospholipoprotein material, with a peak incidence in third to fourth decade and male predominance is also described in children. Recorded prevalence is 0.1/100,000 individuals. Major clinicopathogenetic subtypes include autoimmune (idiopathic) associated with granulocyte-macrophage colony-stimulating factor autoantibodies, secondary form, and the congenital form (associated with surfactant gene mutations). Common presenting features include dyspnea, cough, low-grade fever, inspiratory crackles, and digital clubbing. Pulmonary function shows a restrictive ventilatory defect. X-rays show bilateral patchy to extensive consolidations, and bronchial lavage yields a milky fluid. Characteristic microscopic findings on lung biopsy include filling of terminal bronchioles and alveolar spaces by deep pink granular PAS-positive material. Whole lung lavage is the safest and most effective form of treatment. We present brief profiles of two young children identified as having PAP, along with follow-up data on one of them.