Secondary hypertension accounts for the other 5–10% of cases, meaning that the high blood pressure is caused by another condition, usually renal disease or an adrenal gland tumor.
Hypertension has many serious effects on the body. It causes changes in the blood vessel walls, making them prone to further injury.
Increased damage makes the blood vessels more likely to develop atherosclerosis (see Clinical View: In Depth on page 708). In addition, hypertension causes undue stress on arterioles, resulting in thickening of the arteriole walls and reduction in luminal diameter, a condition called arteriolosclerosis. Furthermore, hypertension causes thickening of the renal arteries, leading to renal failure, and it can greatly damage the cerebral arteries, making them prone to rupture, which results in a fatal brain hemorrhage or stroke. Finally, hypertension is a major cause of heart failure owing to the extra workload placed on the heart.
Since hypertension is initially asymptomatic (meaning no noticeable symptoms are present), it has been dubbed the “silent killer.”
Everyone is encouraged to have their blood pressure checked early in life, and regularly, to make sure they are not suffering from hypertension. Mild hypertension may be controlled by losing weight, eating a healthy diet, exercising regularly, and not smoking. Stress is also associated with hypertension; thus, reducing stress, or learning to manage it, is important in treatment. In many instances, however, medication may be needed to control hypertension. Diuretics increase urine output, thereby reducing salt and water retention and consequently lowering blood volume. Beta-blockers slow the heart rate and lower heart output, while ACE (angiotensin-converting enzyme) inhibitors block angiotensin II (a protein that constricts arterioles), thereby increasing vasodilation.
source : human anatomy
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