A Case of Interstitial Pneumonia whose Symptoms were Exacerbated by Treatment of Pulmonary Arterial Hypertension

Abstract

A 55-year-old woman has been receiving prednisolone, the immunosuppressive medication for non-specific interstitial pneumonia since January 2001. Her respiratory symptoms had been stable until October 2009, when she started to experience the exacerbation of dyspnea on exertion due to pulmonary arterial hypertension (PAH). After treatment with bosentan and sildenafil was initiated, the pulmonary vascular resistance was significantly improved. On the contrary, dyspnea was rather aggravated. Every episode of severe dyspnea and hypoxemia occurred after she took bosentan and sildenafil. We reasoned that either bosentan or sildenafil, or both of these medications caused exacerbation of the mismatching of ventilation and perfusion of the regions of the lung by dilating constricted vessels, which had been contributing to the balanced ventilation and perfusion. Our case led us consider that treatment of PAH may aggravates dyspnea and hypoxemia by increasing a mismatching of ventilation and perfusion of the lung in the patients with abnormal ventilation and perfusion balance at baseline.