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.

Risk factors

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:

  • anxiety 

  • arteriosclerosis 

  • coarctation of the aorta  

  • diabetes

  • drugs such as alcohol toxicity or cocaine

  • excess sodium (salt) in the diet

  • habitual alcohol use

  • obesity

  • pain

  • renal artery stenosis  

  • renal disease

  • stress

  • use of certain medications (such as appetite suppressants, cold preparations, and migraine medications)

Symptoms

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

  • confusion

  • ear noise or buzzing

  • headache

  • heart failure

  • irregular heartbeat

  • nosebleed

  • tiredness

  • vision changes

Diagnostic Tools

Many tests are used to diagnose hypertension. Usually, more than one test will be done before a definitive diagnosis can be made. These tests may include:

  • physical examination and patient history

  • blood pressure test  (office or ambulatory)

  • blood tests (kidney function, electrolytes)

  • blood count

  • urinalysis

  • metabolic tests (thyroid, cathecholamines)

  • renal ultrasound 

  • doppler ultrasound

  • sleep study

Treatment Options

Changes in lifestyle such as weight loss, increased exercise, moderate alcohol consumption, 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  

  • beta–blockers 

  • calcium channel blockers

  • diuretics

Prevention 
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

  • increasing exercising (as recommended)

  • maintaining a healthy weight 

  • maintaining a proper diet

  • modifying salt intake

  • reducing alcohol consumption

  • quitting smoking

Renovascular Hypertension occurs when the arteries that carry blood to the kidneys become narrow.

Risk factors
The cause of renovascular hypertension, a form of secondary hypertension, is usually caused by a blockage in the artery supplying blood to the kidneys. The risk factors are the same as a heart attack.

Diagnostic Tools
Many tests are used to diagnose renovascular hypertension. Usually, more than one test is done before a definitive diagnosis can be made. These tests may include: 

  • physical examination and patient history

  • renal scan  

  • doppler ultrasound

  • arteriogram 

  • conventional or magnetic resonance renal angiography

  • MRA 

Treatment Options

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  

  • beta–blockers 

  • calcium channel blockers

  • diuretics

When medications and lifestyle changes do not work, surgical reconstruction or bypass of a narrowed artery may be performed. Procedures such as balloon angioplasty or stenting of the narrowed artery may be used instead of surgery.

If medical treatment options do not work, then physicians may consider the following: 

  • surgical bypass of the renal arteries (revascularization)

  • percutaneous transluminal renal angioplasty or stent placement

Prevention

Steps to prevent or to reduce the risk of renovascular hypertension include:

  • adjusting dietary to control hypertension, such as modifying sodium intake

  • eating a low fat diet rich in fruits and vegetables and low in animal fat

  • increasing exercising (as recommended)

  • maintaining a healthy weight 

  • modifying salt intake

  • reducing alcohol consumption

  • quitting smoking