n. high *blood pressure, i.e. elevation of the arterial blood pressure above the normal range expected in a particular age group. Hypertension may be of unknown cause (essential hypertension or hyperpiesia). It may also result from kidney disease, including narrowing (stenosis) of the renal artery (*renovascular hypertension), endocrine diseases (such as Cushing’s disease or phaeochromocytoma) or disease of the arteries (such as coarctation of the aorta), when it is known as secondary or symptomatic hypertension.
Complications that may arise from hypertension include atherosclerosis, heart failure, cerebral haemorrhage, and kidney failure, but treatment may prevent their development. Hypertension is symptomless until the symptoms of its complications develop. Some cases of hypertension may be cured by eradicating the cause. Most cases, however, depend upon long-term drug therapy to lower the blood pressure and maintain it within the normal range. The drugs used include thiazide *diuretics, *ACE inhibitors, *calcium-channel blockers, *beta blockers, and *alpha blockers. Combinations of drugs may be needed to obtain optimum control. See also portal hypertension; pulmonary hypertension.... hypertension
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