Proteinaceous Lung With COVID-19: The Mimicker

Pulmonary alveolar proteinosis (PAP) is a syndrome, in which surfactants get deposited slowly in alveoli, blocking the airway exchange. PAP severity also varies from mild to severe, presenting with dyspnea, cough, hemoptysis with or without fever. The radiological findings are ground-glass opacities along with septal thickening (Crazy Paving), consolidations, and less commonly air bronchograms. COVID-19 is a viral infection caused by SARS COV2 primarily affecting the lungs and causing atypical viral pneumonia. The clinical picture of the disease varies from a milder form of fever, dry cough with or without expectoration, to severe disease-causing respiratory distress, pneumonia, acute respiratory distress syndrome (ARDS), and even death. Radiologically, the findings of COVID-19 are similar to PAP. So, PAP mimics the COVID-19, posing a differential challenge, though our patient was a known case of PAP. Therefore, for proper management of the disease, it is important to differentiate it from other pathologies. In this case report, we describe a patient who was a known case of autoimmune pulmonary alveolar proteinosis. She presented with acute exacerbation in the emergency department and tested positive for COVID-19. We followed a systematic approach consisting of clinical, laboratory, radiologic parameters to differentiate the cause of this exacerbation.