Pulmonary Alveolar Proteinosis: a tricky case

<bold>Introduction:</bold> Pulmonary alveolar proteinosis is a rare lung disease caused by impairment in the alveolar surfactant production. Case presentation: a 49-year-old man, cocaine inhaler and active smoker, presented with progressive dyspnoea for two years. He presented with finger clubbing, fine crackles and respiratory failure. The HRCT showed crazy paving pattern. Firstly, he was diagnosed drug-induced lung disease after Bronchoalveolar Lavage (BAL) showing no abnormalities on cytology and microbiology and negative autoimmunity serological testing. He was discharged with systemic oral prednisone 1 mg/kg. At one month follow-up, despite cocaine cessation and steroid therapy, symptoms and radiological pattern worsened, requiring a new hospital admission and the increase of oxygen support. After multidisciplinary discussion our diagnostic approach was oriented towards rare interstitial lung disease, leading to a new BAL with positive Periodic acid- Schiff (PAS) stain. The clinical worsening despite cocaine cessation and steroid therapy, radiological findings, multidisciplinary discussion and BAL positivity led us to diagnosis of pulmonary alveolar proteinosis. The patient was then transferred to the reference local Centre for whole lung lavage (WLL). <bold>Conclusions:</bold> steroid-therapy failure oriented us towards a rare ILD, systemic steroids are also associated with worsening of PAP; Multidisciplinary approach should be considered in every suspected case of ILD.