Mixed Connective Tissue Disease Complicated with Pulmonary Hypertension in Which Respiratory Failure Was Exacerbated by Pregnancy and Delivery: A Case Report

The prognosis for mixed connective tissue disease (MCTD) cases complicated with pulmonary hypertension (PH) remains poor. We report a case of MCTD complicated with PH in which respiratory failure was exacerbated by pregnancy and delivery. She experienced Raynaud phenomenon and exacerbating dyspnea on exertion, coughing, and oxygen desaturation in her pregnancy and the postpartum period and was admitted on the fifth day after delivery. Serological tests revealed a high titer of anti-U1 ribonucleoprotein (RNP) antibody. Chest computed tomography scan showed the nonspecific interstitial pneumonia (NSIP) pattern, and the right heart catheterization showed high mean pulmonary artery pressure. She was diagnosed with MCTD complicated with PH. Transbronchial lung cryobiopsy revealed a pathological finding suggestive of early plexiform lesions, indicating the cause of PH to be pulmonary arterial hypertension rather than the interstitial change in the lung. She was successfully treated with the combination therapy of immunosuppressants and a pulmonary vasodilator. When transbronchial cryobiopsy is performed in cases of interstitial pneumonia complicated with PH, pathological evaluation of pulmonary arterioles can be a good option because pulmonary vasodilators should be administered with great caution to other than pulmonary arterial hypertension.