High blood pressure, also called hypertension, occurs when the systolic pressure is consistently over 140 mm Hg, or the diastolic blood pressure is consistently over 90 mm Hg.
There are two categories of hypertension: essential and secondary. The majority of cases of high blood pressure are essential hypertension, a type of hypertension without specific reason, but caused because the body cannot regulate the blood pressure within normal range. Secondary hypertension is commonly caused by stenosis, or narrowing, of the renal (kidney) arteries.
Most of the time, there is no identifiable cause for essential high blood pressure. Risk factors for high blood pressure (secondary hypertension) that results from a specific condition, habit, or medication may include:
- Coarctation of the aorta
- Drugs such as alcohol toxicity or cocaine
- Excess sodium (salt) in the diet
- Habitual alcohol use
- Renal artery stenosis
- Renal disease
Patients with high blood pressure generally have no symptoms. If patients experience a mild headache along with any of the following systems, it may be a sign of dangerously high blood pressure (malignant hypertension) or a complication from high blood pressure:
- Blood in urine
- Chest pain
- Ear noise or buzzing
- Heart failure
- Irregular heartbeat
- Vision changes
Changes in lifestyle such as weight loss, increased exercise, and a low fat diet with limited sodium intake may reduce hypertension. If these lifestyle changes do not work, medications for hypertension may include:
- ACE inhibitors or angiotensin receptor blockers
- Calcium channel blockers
- Alpha receptor blockers
Steps to prevent or to reduce the risk of high blood pressure include:
- Eating a low fat diet rich in fruits and vegetables and low in animal fat
- Exercising at least 30-60 minutes on most days of the week
- Maintaining a healthy weight
- Maintaining a proper diet
- Modifying salt intake
- Reducing alcohol consumption
- Quitting smoking
Renovascular hypertension, a form of secondary hypertension, occurs when the arteries that carry blood to the kidneys become narrow, usually because of a blockage.
For symptoms, treatment, and prevention see Hypertension above.
When medications and lifestyle changes do not work, surgical reconstruction of a damaged artery may be performed. Procedures, such as balloon angioplasty or stenting of the damaged artery may be used instead of surgery.