Hypertension means elevated pressure. The term is usually used to mean elevated blood pressure. Several factors which determine blood pressure. One is the amount of blood pumped by the heart. The other is resistance to blood flow in the body. Therefore, anything that increases the amount of blood pumped by the heart can cause the blood pressure to increase. This included exercise, taking certain types of medication or drugs, and retaining fluid. In a similar fashion, anything that increases resistance to blood flow can increase the blood pressure. This includes taking certain types of medication, anxiety, or certain types of kidney problems. There are normal blood pressures that vary by size, age and race. Only when the blood pressure is above the normal values established for an individual is it called hypertension. Once the value is noted to be elevated, the cause is figured out.
The most common cause of hypertension is probably normal types of activity such as exercise or anxiety. However, it is quickly noted that these are expected causes of high blood pressure and the blood pressure returns to normal when the activity or anxiety stops. It is only when the blood pressure stays elevated without any “normal” causes that the hypertension is called abnormal. In addition, it is important to obtain the blood pressure reading accurately using the correct blood pressure cuff size and the correct technique.
The most common cause of abnormal hypertension is called essention hypertension. We do not know exactly what the mechanism is. In children, one of the common causes is kidney abnormalities. In addition, there is an abnormality of the aorta called coarctation which may cause high blood pressure in the upper half of the body.
Hypertension is first evaluated by a history and physical examination paying attention to the possible causes such as an abnormal aorta or kidney problems. Special tests may be obtained to further evaluate the aorta and kidneys such as an ultrasound of the heart called an echocardiogram and an ultrasound of the kidneys. Urine and blood samples may be obtained to help look at how the kidneys are working. A pediatric nephrologist (kidney specialist) may be asked to look at a child and help decide the cause and the treatment. If an abnormality of the aorta such as coarctation is suspected, a pediatric cardiologist may be asked to evaluate the patient.
If there is a structural abnormality such as coarctation of the aorta or kidney problem, this is addressed first. If there are no correctable underlying abnormalities, medicines are used to treat the high blood pressure. These include diuretics, ACE inhibitors, beta-blockers as well as calcium channel blockers, which work in a fairly similar fashion as beta-blockers.
The reason for treating hypertension is to prevent complications such as heart failure, coronary artery disease and strokes. Hypertension is one of the causes of plaque buildup in the walls of the coronary arteries and arteries that go to the brain. Clots and obstruction can form in these areas causing injury to the heart or injury to the brain.
In addition, the heart has to pump harder against higher than normal pressures if hypertension is present. Just like muscles get bigger with lifting weights, the heart becomes thicker when pumping against higher pressures. With time, a thick heart does not work as well because of changes in the muscle walls. The end result is a damaged heart and heart failure.
With treatment and good blood pressure control, the long-term outlook for hypertension is excellent. Without treatment, there is the risk of heart failure, stroke and heart attacks. Any of these can lead to a decreased quality of life and a shortened lifespan.