Pulmonary arterial hypertension is a part of the broader condition called pulmonary hypertension. There is the presence of abnormally high blood pressure or hypertension in the pulmonary artery (artery of the lungs), which means that the pressure is more than 25mm Hg at rest or greater than 30 mm Hg while exercising. This progressive disorder occurs when the arteries carrying blood become constricted or narrower. This increases the resistance to the flowing blood or makes it harder for blood to flow. To counter this resistance, the heart increases the pressure in the pulmonary artery to pump the blood from the chambers. This increased blood pressure can damage the heart chambers causing the muscles to weaken. It can be fatal if left untreated.

The symptoms of pulmonary arterial hypertension begin to surface when the increased blood pressure is not able to withstand increased resistance. This results in insufficient blood flow from the lungs to the rest of the body. This causes shortness of breath, which is the most commonly visible symptom.

1. Symptoms of pulmonary arterial hypertension
Pulmonary arterial hypertension in its early stages is hardly noticeable. The signs and symptoms will not present themselves for months or even years. They are likely to be experienced when the disease has progressed and the symptoms have worsened.

• Shortness of breath after exertion
• Racing pulse or heart palpitations
• Excessive fatigue
• General tiredness or weakness
• Fainting spells or dizziness
• Chest pain or pressure
• Swelling or puffiness in the ankles, legs, and abdomen due to accumulation of fluid
• Bluish colour in the lips and skin
• Blood with cough in some cases
• Hoarseness due to compression of nerves in the chest as the artery has enlarged.

2. Causes of pulmonary arterial hypertension
The exact cause of pulmonary arterial hypertension is not known. Researchers believe that an injury can cause contraction of smooth muscle cells resulting in narrowing of the arteries. However, the cause of injury is unknown. It is also believed that the vessels are sensitive to certain factors on whose exposure they tend to constrict or narrow.

• Heredity

Genetics are a common cause behind the development of pulmonary arterial hypertension. The genes regulate the number of cells in certain tissues. With mutation in the genes, either the cell grows uncontrollably or goes on dividing. This results in overgrowth of lungs in the arteries, leading to narrowing of the arteries.

• Medications

Certain prescription drugs, illegal or unapproved drugs such as methamphetamines, or toxic products when consumed knowingly or unknowingly can cause pulmonary arterial hypertension.

• Congenital heart disease

These are the abnormalities present at birth. The newborn’s circulatory system is not able to adapt to breathing outside the womb.

• Connective tissue disorders such as scleroderma

It is an autoimmune disease characterised by fibrosis, vascular alterations, and autoantibodies. Pulmonary arterial hypertension is a complication of this rare disease.

• HIV infection

A virus that lowers immunity and makes the body more susceptible to diseases.

• Chronic liver cirrhosis

Can also cause pulmonary arterial hypertension.