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High Blood Pressure ("Hypertension")

Hypertension, or elevated blood pressure, is not an uncommon finding in children and young adults. There are many potential causes of hypertension, most of which vary by age. In particular, the causes of hypertension in adults are very different from that seen in pediatrics.


Adults develop calcium and cholesterol plaques within our arteries (the blood vessels that carry blood from the heart to the different parts of the body) that ultimately may block enough blood from reaching our body’s vital organs. These plaques also cause stiffening of the blood vessels walls and increase the resistance that the heart must pump against; therefore, the heart must generate a larger pressure to pump the same amount of blood to the rest of the body. This is a process that develops over time, and fortunately rarely happens in children.


In fact, hypertension in children is rarely due to the heart. The one heart-related cause of hypertension is "coarctation of the aorta". The aorta is the major blood vessel that leaves the heart and supplies oxygenated blood to the entire body. If this blood vessel has a narrowed segment (i.e., coarctation), the parts of the body downstream from the narrowing (i.e., abdomen, legs, etc) will not receive an adequate blood supply, whereas the parts of the body upstream from the narrowing (i.e., head, neck, arms, etc) will see an elevated blood pressure. The effects of coarctation depend on severity (i.e., degree of narrowing), location of the narrowing, and the age of the patient. Coarctation of the aorta is considered a congenital heart disease (i.e., present at birth) and can be diagnosed with an echocardiogram. Sometimes, however, the aorta cannot be adequately seen with ultrasound (i.e., young adults, adults) and needs to be evaluated with an MRI or CT scan.


Regardless of the cause, hypertension may result in thickening of the heart muscle ("hypertrophy") if it persists for a prolonged period of time. Imagine going to the gym to lift weights. The resistance we put on our muscles with the heavy weights triggers changes in our muscles to allow them to compensate and accommodate the heavier weights. In other words, our muscles become bigger and thicker. Our heart is also a muscle. So, in much the same way, when our heart is exposed to high blood pressure in our arteries, it must learn to adapt to the heavier load that is now being imposed on it. The heart muscle's initial response is also to grow bigger and thicker. This is called myocardial ("heart muscle") hypertrophy. This adaptation is a process that develops over time (i.e., weeks to months). An echocardiogram enables us to directly visualize the heart muscle and make precise measurements. A thickened heart, in the context of elevated blood pressure, is a sign of long-standing hypertension.


Another cause of hypertension in children is related to the kidneys. The kidneys act as filters for our body. So when the kidneys are unable to filter our blood properly, the pressure within our blood vessels begins to rise. Therefore, a renal ultrasound is often a very important part of the diagnostic evaluation for a patient with hypertension.  This is especially important in children or young adults who have a history of kidney or urinary tract infections during childhood, which may result in scarring within the kidney and resultant hypertension.


Other causes of high blood pressure include endocrinologic conditions where there is an imbalance in the production (or elimination) of certain hormones or chemicals the body produces. Examples include elevations in thyroid hormone, cortisol, renin/aldosterone, or catecholamine concentrations. These hormones/chemicals are important components of the body's ability to manage its "metabolism" (energy utilization and production) and it's ability to respond to physical/chemical stress imposed on the body. Some of these hormones/chemicals help regulate blood pressure in response to changes in the body's environment (i.e., exercise, changes in posture/position).


Explore Further the Physiologic Basis of Blood Pressure:
What do the Numbers Mean?  |  How Pressures Change in the Heart  |  How Does Blood Flow?  
Heart Problem Diagnosis



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Children's Heart Institute

P. O. Box 10066 McLean, VA 22102

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