Congenital Pulmonary Alveolar Proteinosis: An Exceptional Cause of Diffuse Interstitial Lung Disease

Abstract

Introduction: Pulmonary alveolar proteinosis is a rare respiratory disease characterized by the accumulation of surfactant-derived material in the lungs. It is commonly revealed by progressively increasing exertional dyspnoea contrasting with a poor clinical examination in the context of a diffuse infiltrating pneumonia. Bronchoalveolar lavage is the key to diagnosis. Genetic PAPs are usually diagnosed at birth or in childhood. PAPs of genetic origin mainly include surfactant production disorders, lysinuric protein intolerances and mutations of the GM-CSF receptor. CSF treatment is ineffective. On the other hand, large therapeutic lung lavage seems to be effective. The course of PAP is variable, ranging from spontaneous resolution to death from respiratory failure or lung infection. Case Report: A 3- month-old girl with family history of first-degree consanguineous parents, who was having a background of a Progressive worsening of respiratory symptoms and who was referred to our department for the treatment of diffuse pneumonia. The respiratory functional explorations objectified a restrictive syndrome. Chest X-ray revealed Bilateral alveolar-interstitial syndrome with left basal condensation and a Chest CT scan showed diffuse infiltrating pneumopathy, reasons why a bronchoalveolar lavage was performed showing a milky appearance. It contains a large amount of proteinaceous eosinophilic acellular granular material, which is PAS - positive. There are also foamy macrophages with PAS-positive intracellular inclusions. Those data are consistent with the diagnosis of PAP. The genetic study had shown an alpha chain mutation of the GM-CSF receptor confirming the diagnosis of primary alveolar proteinosis of genetic origin. The Evolution After two therapeutic bronchoalveolar lavages of both lungs was favorable with a clear decrease in pulmonary signs of effort. Conclusion: Alveolar proteinosis is a rare etiology of chronic interstitial lung disease in children. The diagnosis of certainty is do ne thanks to BAL and the treatment is based on therapeutic BAL sessions. The primitive forms are frequent and their prognosis seems be inversely correlated with age at onset.