Pulmonary hypertension (PH) is often confused with pulmonary arterial hypertension (PAH). Both diseases are characterized by high blood pressure in the lungs’ arteries. However, the difference lies in their cause. While PH is triggered by accompanying health conditions, high blood pressure in PAH is caused because the lungs’ arteries narrow down. This article explains the critical differences between PH and PAH in terms of their causes, diagnosis, prevalence, risk factors, etc.

1. Cause
As mentioned, pulmonary hypertension (PH) is caused when the blood pressure in the lungs increases due to accompanying health conditions. These conditions include sleep apnea, COPD, heart failure, etc. Hence, these ailments will need to be treated to manage PH.

In pulmonary arterial hypertension (PAH), the blood vessels themselves are responsible for increased blood pressure levels and not any other disease. The vessels in the lungs change and become narrow. PAH is considered one of the subgroups of PH.

2. Types
Pulmonary hypertension (PH) can be classified into four groups depending on the cause. According to the WHO, these groups are:

• Pulmonary arterial hypertension (PAH)
• PH due to left heart disease
• PH due to lung disease
• PH due to chronic blood clots in the lungs

Pulmonary arterial hypertension (PAH) can be classified into three types depending on what causes the blood vessels to narrow down:

• Idiopathic: no known cause
• Heritable: passed on from one generation to the next
• Drug and toxin-induced: triggered by overuse of drugs and toxins

3. Prevalence
Pulmonary arterial hypertension (PAH) is a lot rarer than pulmonary hypertension (PH). It can also be fatal in most cases. An estimated 50 to100 people per million have PAH, and currently, there is no cure for it.

4. Risk factors
Pulmonary hypertension (PH) is often diagnosed in people between the ages of 30 and 60. The risk can increase further if one has a family history of the condition, is overweight, has asbestos exposure, or lives at a high altitude. Pulmonary arterial hypertension (PAH), being a subtype of PH, has similar risk factors.

5. Diagnosis
Pulmonary hypertension (PH) is hard to diagnose during a routine physical exam. Even in its advanced stages, the symptoms can be confused with those of lung or heart diseases. To diagnose PH, a doctor would need to do a physical exam first and then inquire about the patient’s medical and family history. Pulmonary arterial hypertension (PAH), which is rarer than PH, is also hard to diagnose. The doctor would need to rule out other forms of PH before confirming the disease.

6. Men vs. women
Pulmonary arterial hypertension (PAH) is twice as common in women than men. Though it is not known why women are more susceptible to PAH, the role of hormones, such as estrogen, and autoimmune issues are being studied.