The Causes of Pulmonary Hypertension

There are many causes of pulmonary hypertension. If you have pulmonary hypertension, an important first step in deciding on the best therapy is to determine the underlying cause of your condition. Simply, this is because aggressively treating the underlying cause is, in most cases, the best way to prevent or slow the progression of the pulmonary hypertension.

Recently, the World Health Organization (WHO) has classified the causes of pulmonary hypertension into five groups (Groups I through V). While this new classification system certainly has value, it is more straightforward for patients who are dealing with this condition to think of it as having only two major categories: primary and secondary pulmonary hypertension.

• Here's the WHO classification for pulmonary hypertension, if you're interested in reading about it in more detail.

Primary Pulmonary Hypertension

Primary pulmonary hypertension - also called idiopathic pulmonary hypertension - simply means that no underlying cause can be identified for the condition. Primary pulmonary hypertension is rare (occurring in 1 or 2 people out of a million), and is more likely to occur in women than in men. It is now thought that many cases of primary pulmonary hypertension are associated with a genetic defect.

The treatment of pulmonary hypertension strongly relies on treating the underlying cause, so doctors should not settle on a diagnosis of primary pulmonary hypertension until all forms of secondary pulmonary hypertension have been carefully ruled out.

Secondary pulmonary hypertension

The term "secondary" pulmonary hypertension simply means that the pulmonary hypertension has been caused by some underlying medical condition. If you have pulmonary hypertension, it is critical to leave no stone unturned in attempting to identify an underlying cause.

The medical conditions which can produce pulmonary hypertension include heart disorders, lung disorders, connective tissue diseases, drugs, and a smattering of other medical conditions.

Cardiac disorders that can cause pulmonary hypertension include:

• cardiomyopathy
• diastolic dysfunction
• mitral stenosis or mitral regurgitation
• aortic stenosis or aortic regurgitation
• constrictive pericarditis
• congenital heart disease

Two forms of congenital heart disease, in particular, may escape notice until you reach adulthood and begin showing signs of pulmonary hypertension. These are atrial septal defect and ventricular septal defect.

Lung disorders that can cause pulmonary hypertension include:

• chronic obstructive pulmonary disease (COPD)
• interstitial lung disease
• sleep apnea
• chronic pulmonary embolus

Connective tissue diseases that can cause pulmonary hypertension include:

• systemic sclerosis, or scleroderma
• lupus
• rheumatoid arthritis

Drugs that can cause pulmonary hypertension include:

• the appetite suppressant drugs fenfluramine, dexfenfluramine, and diethylpropion
• amphetamines, methamphetamines and cocaine
• chemotherapeutic drugs

Other medical conditions that can cause pulmonary hypertension include:

• HIV/AIDS
• schistosomiasis
• various forms of liver disease
• chronic hemolytic anemia

Summary

There are many causes of pulmonary hypertension, which can make identifying the underlying cause difficult. Nonetheless, because treatment is primarily aimed at the underlying cause, if you have pulmonary hypertension it is critically important to take whatever steps may be necessary to find an underlying cause for your condition.

_Sources:

_{Galie, N, Hoeper, MM, Humbert, M, et al. Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Respir J 2009; 34:1219.}