Microscopic polyangiitis in a case of silica exposure: a rare presentation.

A 28-year-old male was admitted for breathlessness, haemoptysis, fever and fatigue. The patient had occupational exposure to silica dust. Arterial blood gas test ABG revealed hypoxemic respiratory failure. Chest CT demonstrated ground glass opacities with interlobular septal thickening and small centrilobular nodules with patchy areas of consolidation in bilateral lungs. He was mechanically ventilated for refractory hypoxemia. The treatment with cyclophosphamide and methylprednisolone lead to recovery and extubation. The final diagnosis was diffuse alveolar haemorrhage due to perinuclear antineutrophil cytoplasmic antibody (ANCA)-associated microscopic polyangiitis (p-ANCA-associated MPA). In a tuberculosis endemic country, for patients presenting with diffuse alveolar haemorrhage (DAH), with history of silica exposure, differential diagnosis of ANCA associated vasculitis must be considered.