Causes Of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) can arise from a variety of underlying conditions and factors, which are typically categorized into several distinct groups to aid in diagnosis and treatment planning.

Idiopathic And Hereditary Causes

One of the primary classifications includes idiopathic pulmonary arterial hypertension, where the cause remains unknown despite thorough investigation. In addition, hereditary PAH may be linked to specific genetic mutations, often identified in families with a history of the condition. Certain drugs and toxins have also been shown to trigger PAH, further contributing to this category.

Associated Conditions

Connective Tissue Disorders And Other Related Diseases

PAH can also be associated with a range of other diseases, including connective tissue disorders, portal hypertension of genetic origin, and congenital heart defects. Additionally, schistosomiasis, a parasitic disease common in certain regions, has been linked to the development of pulmonary hypertension.

Left-Sided Heart Disease

Another major category involves left heart-related pulmonary hypertension. This may result from dysfunction in left ventricular systolic or diastolic function, valvular heart disease, or acquired and congenital obstructions in the left ventricular inflow or outflow tracts. These structural issues can lead to increased pressure in the pulmonary vasculature over time.

Lung Disease And Hypoxia

Chronic lung diseases and conditions that lead to low oxygen levels are also significant contributors to pulmonary hypertension. These include interstitial lung disease, mixed obstructive and restrictive lung disorders, sleep-disordered breathing, alveolar hypoventilation syndromes, and chronic exposure to high altitudes. Pulmonary developmental abnormalities can also fall into this classification.

Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) occurs when blood clots in the lungs do not dissolve naturally and instead lead to long-term blockages in the pulmonary arteries. This condition is distinct from other forms of PAH and often requires specialized treatment approaches.

Other Rare And Complex Causes

Systemic And Metabolic Conditions

Some cases of PAH are linked to systemic or metabolic disorders that are less commonly recognized. These include hematologic conditions such as chronic hemolytic anemia and myeloproliferative disorders, as well as post-splenectomy states. Other systemic diseases like sarcoidosis, lymphangioleiomyomatosis, and pulmonary Langerhans cell histiocytosis may also contribute to PAH. Additionally, rare metabolic diseases such as glycogen storage disorders and thyroid dysfunction have been associated with the condition.