Reversible pulmonary artery hypertension in association with interferon-beta therapy for multiple sclerosis.

The patient was a 32-year-old woman referred to a neurologist in 2008 for walking difficulty and easy fatigue. Physical examination revealed spastic paraparesis. The patient had history of some neurological symptoms since 2003 which were neglected because of little functional impairment and self-limitation. Brain and cervical magnetic resonance imaging (MRI) fulfilled Barkhof criteria for multiple sclerosis (MS). A thorough paraclinical investigation was done and was negative for any other possible explanation for her clinical and MRI presentation. Treatment with subcutaneous interferon beta 1a (IFN-β1a, REBIF@) three times a week began with the diagnosis of relapsingremitting MS (RRMS). She developed weakness of lower extremities after two months that partially responded to intravenous (IV) corticosteroids. She was referred to our center due to increased disability score during eight months period despite regular subcutaneous IFN-β1a injections without any obvious relapse. She also suffered from tachycardia, palpitation and easy fatigue. The treatment regimen changed to mitoxantrone with the impression of secondary progressive course, also propranolol started for palpitation. Baseline echocardiography before mitoxantrone injection showed an ejection fraction of 62% for left ventricle, with moderate tricuspid regurgitation and moderate pulmonary artery hypertension (PAH) with pulmonary artery pressure (PA pressure) of 61 mmHg. At that time, she had normal cardiopulmonary physical examination. A workup for PAH started which revealed tachycardia in electrocardiogram (ECG), and normal chest X-ray, spirometry and ventilation-perfusion scan of lungs. Laboratory investigations for vasculitis were negative. She had low level of thyroid stimulating hormone (TSH), normal total T4 level and increased T3 resin uptake (T3RU) at this time. These findings interpreted as thyroiditis due to IFN-β1a treatment discontinued 7 days before. Her thyroid function returned to normal levels about 10 days later and her palpitation disappeared; propranolol gradually discontinued. She received 20 Iranian Journal of Neurology