Therapeutic Research

Abstract

Patient：A 27–year–old female. Chief complaint：Breathing difficulty after delivery. History of present illness：The patient was referred to our hospital with increased thyroid–stimulating hormone（TSH; 5.221μU/mL）in the 5th week of pregnancy. She had breathing difficulty on effort in the 3rd trimester pregnancy, although, she could deliver the baby without any problems in the 38th week of pregnancy. Four days later, she suffered from critical breathing difficulty, which triggered hypoxemia. The increased right heart load on the electrocardiograms and the estimated right ventricular systolic pressure of 50 mmHg on the echocardiograms suggested that the patient should have pulmonary hypertension. The result of hematology in the 2nd trimester pregnancy was within the normal ranges（TSH 0.84μU/mL, triiodothyronine [T3] 2.6 pg/mL, thyroxin [T4] 1.1 ng/dL）, however, these values were exacerbated after delivery（TSH 0.007μU/mL, T3 9.0 pg/mL, T4 2.4 ng/dL）, suggesting that she also have hyperthyroidism. Thyroid scintigraphy identified silent thyroiditis. These findings supported that silent thyroiditis induced by pregnancy caused pulmonary arterial hypertension. The patient was immediately treated with bosentan according to the treatment algorism in pulmonar y hyper tension, but no significant effect was observed. Then, tadalafil was additionally administered, resulting in obvious improvement in pulmonar y arterial pressure on the echocardiograms and normalized electrocardiograms. Since medical treatment sufficiently improved breathing difficulty, home oxygen therapy was not required thereafter. Discussion：Tadalafil inhibits cGMP specific phosphodiesterase type 5（PDE–5）, which reduces cGMP concentrations in the pulmonar y vascular smooth muscle; thus lowering pulmonary arterial pressure. Only a handful of case reports have reported the effective use of tadalafil in Japan. This case report presents a new insight into the treatment of pulmonary hypertension.