Types of Pulmonary Hypertension
The World Health Organization divides pulmonary
hypertension (PH) into five groups. These groups are organized based on the
cause of the disease.
In all groups, the average pressure in the pulmonary
artery is higher than 25 mmHg at rest or 30 mmHg during physical activity. The
pressure in a normal pulmonary artery is about 15 mmHg at rest.
(Note that group 1 is called pulmonary arterial
hypertension (PAH) and groups 2 through 5 are called pulmonary hypertension.
However, together all groups are called pulmonary hypertension.)
Group 1 PAH includes:
- PAH that has no known cause.
- PAH that's inherited (passed from parents to
children through the genes).
- PAH that's caused by conditions such as:
- Congenital
heart disease. This is heart disease that's present at birth.
- HIV infection.
- The use of certain diet medicines and street
drugs (such as cocaine).
- Thyroid diseases.
Group 2 includes PH with left heart disease.
Conditions that affect the left side of the heart, such as
mitral
valve disease or long-standing
high
blood pressure, can cause left heart disease and PH.
Group 3 includes PH linked to lung conditions such
as COPD
(chronic obstructive pulmonary disease) and interstitial (IN-ter-STISH-al) lung
disease. Interstitial lung disease refers to a group of lung diseases that
cause scarring of the lung tissue. Group 3 also includes PH linked to sleep
disorders that cause breathing problems, such as
sleep
apnea.
Group 4 includes PH due to blood clots in the lungs
or blood clotting disorders. This group also includes PH due to
sickle
cell anemia.
Group 5 includes PH due to various other diseases or
conditions. Examples include
sarcoidosis,
Langerhans cell histiocytosis, and
lymphangioleiomyomatosis
(LAM). This type of PH also may be due to an object, such as a tumor, pressing
on the pulmonary blood vessels.
Sometimes other terms are used to describe the
different types of PH. Group 1 PAH that has no known cause may be called
primary or idiopathic (id-ee-o-PATH-ick) PAH. When PH occurs with or is caused
by another disease or condition, it may be called secondary PH. |