The Clinical Significance of a 'Crazy-Paving' Pattern on Chest Radiology.

A crazy-paving pattern is a non-specific radiological sign which is characterized by the presence of diffuse ground-glass attenuation associated with interlobular septal thickening and intralobular lines. It was initially described as a pathognomonic sign of pulmonary alveolar proteinosis. However, it can be also found in many other diffuse acute and chronic lung diseases including diffuse alveolar haemorrhage (DAH), a rare and life-threatening clinical syndrome which can be caused by many conditions, the most frequent of these being capillaritis associated with systemic autoimmune diseases. In this case report, we describe an 82-year-old female patient with acute respiratory failure and bilateral pulmonary infiltrates with the characteristic crazy-paving pattern. The final diagnosis was isolated DAH induced by microscopic polyangiitis. The patient was treated with IV high dose prednisolone and cyclophosphamide and was mechanically ventilated. Nevertheless, her clinical status progressively deteriorated and she died after 3 days from acute respiratory distress syndrome. LEARNING POINTS: A crazy-paving pattern is a non-specific radiological sign which is characterized by the presence of diffuse ground-glass attenuation associated with interlobular septal thickening.The presence of a crazy-paving pattern together with a progressive fall in haemoglobin levels suggests diffuse alveolar haemorrhage (DAH).A panel for collagen vascular diseases and vasculitis should be immediately performed in patients suspected of having DAH.