| From your Guide Dr.MANI |  | |
Pulmonary Stenosis | ||
| From your Guide Dr.MANI | | |
Pulmonary Stenosis | ||
| |
Pulmonary stenosis is one of the simpler abnormalities of the heart. But even this requires some
basic knowledge about the structure of the heart.
What is Pulmonary Stenosis ?
The word "pulmonary" denotes "to do with the lungs". The pulmonary valve is located between the
right ventricle and the pulmonary artery. It regulates blood flow into the lungs, and prevents blood
from leaking back into the right ventricle.
Sometimes, this pulmonary valve is extremely narrow, and blocks the smooth flow of blood into the
lungs. This condition is called Pulmonary Stenosis - or PS, in short. At other times, the pulmonary
valve itself is normal, but there is an obstruction to blood flow from the right ventricle at other
levels. For instance, there may be abnormal bundles of muscle below the pulmonary valve which
obstruct flow. This is called "sub-valvular" pulmonary stenosis. Or occassionally, there may be a
narrowing of the pulmonary artery or its branches above the pulmonary valve. This is called
"supra-valvular" pulmonary stenosis.
What happens in PS ?
I have emphasized in earlier discussions the importance of blood flow to the lungs. The lungs are
the only organs in the body where blood can be purified by the addition of oxygen, and removal of
waste materials, like carbon-dioxide. This oxygen containing blood is distributed to the rest of the
body. Without oxygen for energy, the other organs cannot carry out their normal work.
In PS, blood flow to the lungs is reduced. So the amount of blood getting oxygenated is less than
normal. In patients who have very slight narrowing, there is not much effect. But when the block
becomes severe, symptoms begin. Usually children with pulmonary stenosis have a limited
tolerance to exercise. They become tired easily at play, and have to rest. Rarely, giddiness and
fainting may occur. Some children complain of palpitations - which is an uncomfortable awareness
of their own heart-beat. In very severe PS, there may be mild cyanosis - a bluish discoloration of
the body. The cyanosis is caused by veno-arterial mixing across the wall between the right and left
atrium.
The diagnosis usually is obvious on medical examination. Confirmation may be obtained by tests
like echocardiography, or sometimes by cardiac catheterization.
What needs to be done for PS ?
In PS, the smooth flow of blood into the lungs is obstructed. This needs to be relieved. In the early
stages of the disease, not many effects are seen. But if left untreated for many years, it may cause
problems. The right ventricle, which pumps blood into the lungs, is now forced to work harder
against the blocked pulmonary valve. To do this, the right ventricle wall becomes thicker by
addition of more muscle - a condition called "hypertrophy". But even the stronger right ventricle
cannot keep up this hard work forever. Finally, it "fails" to pump blood effectively, producing
sudden worsening of symptoms. At this stage, urgent treatment becomes necessary, and carries a
higher risk.
So although PS is usually not an emergency, it is advisable to seek treatment early rather than
delaying the process till complications set in.
What are the options for treating PS ?
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