Secondary High Blood Pressure
Secondary high blood pressure refers to high blood pressure that has a known cause. Doctors are able to identify an underlying illness or condition that’s triggering your blood pressure to increase. This form of high blood pressure occurs infrequently, affecting only about 5 percent of people with increased blood pressure.
As opposed to essential high blood pressure, which doctors can treat but not cure, secondary high blood pressure often can be cured. Once the underlying disease or condition is corrected, blood pressure typically decreases. In many people, their blood pressure returns to normal. The following are several illnesses and conditions that can lead to secondary high blood pressure:
1. Kidney Disease: Your kidneys are one of the main regulators of your blood pressure. If a condition or illness, such as an injury, inflammation or the development of fluid-filled sacs (cysts), causes your kidneys to quit functioning normally, your blood pressure can increase.
2. Adrenal Disease: Your adrenal glands make hormones, including the hormones epinephrine (adrenaline), norepinephrine (noradrenaline), aldosterone and cortisol, that help regulate your blood pressure and heart rate. Overgrowth of your adrenal cells or development of a tumor that affects release of these hormones into your bloodstream can lead to high blood pressure.
3. Thyroid disease: Hormones made by your thyroid gland regulate all aspects of your metabolism, from the rate at which your heart beats to the speed at which you burn calories. When your thyroid gland releases excessive amounts of hormones (hyperthyroidism), your heart rate speeds up and demands on your cardiovascular system are increased. This extra strain can lead to the development of high blood pressure. A decrease in thyroid hormones (hypothyroidism) can also cause high blood pressure. The condition is thought to increase blood pressure by increasing fluid retention.
4. Blood vessel abnormalities: In rare cases, secondary high blood pressure can result from a birth defect in which your aorta narrows after it branches off into the arteries that lead to your neck and arms. Blood pressures in the upper parts of your body are high, but those in your abdomen and legs are lower. This defect most often occurs in young people with high blood pressure.
Secondary high blood pressure also can result from narrowing of one or both of the arteries leading to your kidneys. The narrowing causes release of the hormone rennin, which increases blood pressure. The condition may result from accumulation of plaque or an abnormality that causes the middle layer of an artery wall to become too thick. This form of artery wall thickening, called fibromuscular dysplasia, occurs more often in women than men.