Pulmonary hypertension is a rare disease in which the arteries carrying blood to the lungs from heart become narrowed. It can be caused by many factors that lead to the narrowing of the arteries.

First cause is heredity. A child can inherit it from his parents. Street drugs like cocaine and some medicines used for dieting can also cause PH.Diseases like congenital heart disease, HIV and sickle cell disease can also cause PH. Mitral valve disease, sleep apnoea and Sarcoidosis can also cause type 2 PH commonly called secondary pulmonary hypertension.