Elevated pressure in the main artery to the lungs is termed pulmonary arterial hypertension or PAH. This rare disorder carries a poor prognosis and there is no cure. Many cases have no identifiable cause. However, there is an inherited form, and at least two genes have been identified that relate to the disease. Several drugs and toxins have been associated with cases of pulmonary arterial hypertension, as have other medical problems.
Idiopathic
The term idiopathic means without known cause. Many people with PAH have no identified trigger for their disease, and the idiopathic form is more common in younger patients, aged 20 to 30 years. It also has an increased incidence in black females.
Genetic
Some cases of pulmonary artery hypertension have been linked to gene mutations that are inherited from affected parents. There may be more genes that are involved, but two have been identified: BMPR2 and ALK1. These may be identified through blood and DNA testing.
Drugs or Toxins
Certain drugs have been linked to PAH. The well-known diet drugs dexfenfluramine and fenfluramine, which have been removed from the market, have been associated with the disease. In addition, some stimulant drugs such as amphetamines, methamphetamines and cocaine are potential offenders in causing pulmonary arterial hypertension.
Medical Conditions
Elevated blood pressure in the pulmonary arteries has been seen in association with a number of disease states. Lung disorders such as pulmonary emboli, or blood clots in the lungs, chronic obstructive pulmonary disease and pulmonary fibrosis or lung scarring, have been implicated. Primary heart disorders, including mitral valve disease and congestive heart failure, have also been linked to PAH.
Congenital heart disease refers to heart defects that are present at birth. This group of abnormalities, especially if blood flow is affected such as through a hole in the heart, carries an increased risk of PAH. Sleep apnea, as well as living at or visiting high altitudes are known risk factors.
AIDS may lead to pulmonary artery hypertension, as can scarring or cirrhosis of the liver. Scleroderma, systemic sclerosis and lupus are autoimmune disorders that may be causal. Sarcoidosis may affect many organs, including the lungs in the form of PAH. Thyroid disease is another PAH risk factor that can affect multiple body parts and sickle cell anemia has also been linked with elevated pulmonary artery pressures.
