Fatal diffuse alveolar haemorrhage mimicking acute exacerbation in idiopathic pulmonary fibrosis treated with nintedanib

A 75‐year‐old man was referred to our hospital with a 1‐year history of persistent dry cough and progressive dyspnoea on exertion. He was treated with aspirin due to thrombosis of internal carotid artery. He was diagnosed with idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP), and started on inhaled N‐acetylcysteine therapy and pirfenidone. Since his clinical condition progressively deteriorated after 6 months, he was switched from pirfenidone to nintedanib. As a result, his general condition worsened rapidly. He was diagnosed with acute exacerbation (AE) of IPF, and was treated with methylprednisolone pulse and recombinant human soluble thrombomodulin. Despite the administration of these treatments, he died of severe haemoptysis four days after the onset of AE. Autopsied lungs revealed significantly dark red‐brown appearance corresponding to diffuse alveolar haemorrhage (DAH) histopathogically with a background pattern of UIP with fibrotic change. Notably, there was no evidence of diffuse alveolar damage suggesting IPF‐AE.