A cluster of diffuse alveolar hemorrhage cases after the 2011 Tohoku Region Pacific Coast Earthquake

Abstract Background Diffuse alveolar hemorrhage (DAH) is a clinical syndrome that presents with progressively hemorrhagic bronchoalveolar lavage fluid (BALF) in serial samples and generally has a poor prognosis. The South Miyagi Medical Center, located on the inland side of southern Miyagi Prefecture, documented an increase in the number of patients with DAH after the 2011 Tohoku Region Pacific Coast Earthquake. Methods We describe the clinical features of post-earthquake DAH in comparison to pre-earthquake DAH. We analyzed the data of the DAH patients we have been able to follow for at least 6 months since we started performing bronchoscopy and bronchoalveolar lavage (BAL) for all patients with interstitial lung disease in August 2009 until September 2011, and separated these patients into pre- and post-earthquake groups according to the earthquake date of March 11, 2011. Results Post-earthquake DAH patients tended to test positive for infectious agents and showed higher serum IgE titers, with BALF that exhibited a tendency to higher silica concentrations. Post-earthquake DAH generally had a better prognosis than pre-earthquake DAH. Conclusions In describing the clinical features of post-earthquake cases of DAH, this report documents the possibility of an infection- and/or dust-induced, partially allergic, and relatively benign form of DAH.