What is pulmonary hypertension?
To understand pulmonary hypertension, it’s good to first know how the respiratory and circulatory systems work together. Keep in mind that the left and right sides of the heart have essentially different jobs.
- When you inhale, you breathe oxygen into your lungs. That oxygen is transferred to blood cells, and that blood (now “oxygenated”) is collected in the left side of the heart.
- The heart pumps out the oxygenated blood (through the arteries) to supply the rest of the body with oxygen.
- The blood – now devoid of oxygen – travels back (through the veins) to the right side of the heart.
- The right side of the heart collects the de-oxygenated blood, and pumps it (through the pulmonary artery) into the lungs.
- Then the cycle begins again: In the lungs, the blood cells drop off carbon dioxide (for us to exhale), picks up the oxygen that we inhale, and re-collects in the left side of the heart.
With pulmonary hypertension, the small arteries in the lung become narrowed or blocked. The heart therefore has to work harder to push the blood through the narrower passageways in the lungs, creating a higher pressure within the pulmonary artery. This higher pressure is pulmonary hypertension.
What are the types of pulmonary hypertension?
Pulmonary hypertension can be grouped into one of two categories, depending on what we know about what is causing it:
Idiopathic pulmonary hypertension (IPH)
- This diagnosis means that there is no clear cause of your child’s pulmonary hypertension.
- IPH occasionally runs in families, and sometimes the BMPR2 gene (or another gene) is involved.
Secondary pulmonary hypertension
This diagnosis means that the pulmonary hypertension is thought to be caused by or associated with something else. Possibilities include:
- some congenital (present at birth) abnormalities of the heart
- some lung diseases, often related to prematurity
- diseases that primarily affect other organs, such as scleroderma, some liver diseases, hereditary hemorrhagic telangiectasia, AIDS/HIV and sickle cell disease
- abnormal function of the left ventricle
- chronic thromboembolic disease, in which many small blood clots formed elsewhere travel into the lungs and are lodged there
- environmental factors, such as exposure to the drugs fenfluramine and dexfenfluramine (Fen-phen) or living at very high altitudes
It’s extremely important to learn whether your child’s PH is idiopathic or secondary, and if secondary, what is causing it – this is how your child’s doctor will determine the treatment plan.
What causes pulmonary hypertension?
Unfortunately, it’s a complicated question. We know that PH occurs when the heart has to work extra hard to move blood through the very small vessels of the pulmonary artery to the lungs, eventually causing the heart muscle to weaken. At the most physical level, this might occur for one or both of two reasons:
There are fewer of these small vessels. This may be because:
- fewer of them develop as the lung grows
- they become blocked off by small blood clots
- they become blocked off by the thickening of the intima (the lining of the artery)
The vessels are smaller than normal in diameter. This may be due to:
- an increased number and/or size of cells (smooth muscle and other types of cells)
- connective tissue disorders
- blood clots that form in the lungs
- congenital heart defects
- chronic liver disease
- sleep apnea
Researchers aren’t sure why these things happen, but many people group together types of PH based on presumed cause – keep reading for more information.
What are the symptoms of pulmonary hypertension?
Initial symptoms of PH are often minor, but slowly get worse over time. These symptoms can also occur as parts of other diseases, which can make it challenging for doctors to detect PH early. Be sure to consult your doctor if you experience any of the following symptoms.
The most common signs and symptoms of pulmonary hypertension are:
- shortness of breath while performing everyday activities (walking or climbing stairs)
- excessive fatigue
- fainting spells
- rapid heart beat
- low blood pressure
- swelling of legs and hands