Hypertension - Causes, Symptoms And Treatment
Alternative names :- High blood pressure
Hypertension, an elevation in diastolic or systolic blood pressure, occurs as two major types: essential (primary) hypertension, occurring in 95% of cases with no identifiable cause, and secondary hypertension, occurring in 5 % of cases as a result from renal disease or another identifiable cause. Malignant hypertension is a severe, fulminant form of hypertension common to both types. Hypertension is a major cause of stroke, heart disease, and renal failure.
Hypertension affects 15% to 20% of adults in the United States and the risk increases with age. Incidence is higher in those with less education and lower income.
Men have a higher incidence of hypertension from youth to middle adulthood; thereafter, women - in particular, postmenopausal women have a higher incidence. According to Harvard Medical School, high blood pressure kills over 100,000 women annually and causes heart failure in 60% of affected women. Furthermore, high blood pressure poses a serious problem in pregnancy.
Essential hypertension usually begins insidiously as a benign disease that slowly progresses to a malignant state. If untreated; even mild cases can cause major complications and death. Carefully managed treatment, which may include lifestyle modifications and drug therapy, improves the prognosis. Untreated, it carries a high mortality rate. Severely elevated blood pressure (hypertensive crisis) may be fatal.
What causes Hypertension ?
Risk factors for primary hypertension include:
- family history
- advancing age
- sleep apnea
- race (most common in blacks)
- tobacco use
- high sodium intake
- high saturated fat intake
- excessive alcohol consumption
- sedentary lifestyle
- excess renin
- mineral deficiencies (calcium, potassium, and magnesium)
- diabetes mellitus.
Causes of secondary hypertension include:
- chronic renal disease (most common)
- coarctation of the aorta
- renal artery stenosis and parenchymal disease
- brain tumor, quadriplegia, and head injury
- pheochromocytoma, Cushing's syndrome, hyperaldosteronism, and thyroid, pituitary, or parathyroid dysfunction
- hormonal contraceptives, cocaine, epoetin alfa, sympathetic stimulants, monoamine oxidase inhibitors taken with tyramine, estrogen replacement therapy, and nonsteroidal anti inflammatory drugs
- excessive alcohol consumption
- pregnancy-induced hypertension, also called gestational hypertension or preeclampsia.
Several theories help explain the development of hypertension, including:
- changes in the arteriolar bcd, causing increased peripheral vascular resistance
- abnormally increased tone in the sympathetic nervous system that originates in the vasomotor system centers, causing increased peripheral vascular resistance
- increased blood volume resulting from renal or hormonal dysfunction
- an increase in arteriolar thickening caused by genetic factors, leading to increased peripheral vascular resistance
- abnormal renin release, resulting in the formation of angiotensin II, which constricts the arteriole and increases blood volume.
Signs and symptoms of Hypertension
Although hypertension is commonly asymptomatic, these signs and symptoms may occur:
- elevated blood pressure readings on at least two consecutive occasions after initial screening
- occipital headache (possibly worsening on rising in the morning as a result of increased intracranial pressure) with possible nausea and vomiting, epistaxis possibly due to vascular involvement
- bruits (which may be heard over the abdominal aorta or carotid, renal and femoral arteries) caused by stenosis or aneurysm
- dizziness, confusion and fatigue caused by decreased tissue perfusion due to vasoconstriction of blood vessels
- blurry vision as a result of retinal damage
- nocturia caused by an increase in blood flow to the kidneys and an increase in glomerular filtration
- edema caused by increased capillary pressure.
If secondary hypertension exists. other signs and symptoms may be related to the cause. For example. Cushing's syndrome may cause truncal obesity and purple striae. whereas patients with pheochromocytoma may develop headache. nausea. vomiting. palpitations. pallor. and profuse perspiration.
Complications of hypertension include:
- hypertensive crisis. peripheral arterial disease. dissecting aortic aneurysm. coronary artery disease. angina. myocardial infarction (MI), heart failure, arrhythmias and sudden death
- transient ischemic attacks, stroke, retinopathy and hypertensive encephalopathy
- renal failure.
These tests help diagnose hypertensions:
- Serial blood pressure measurements of more than 140/90 mm Hg confirm hypertension.
- Urinalysis may show protein, casts, red blood cells, or white blood cells, suggesting renal disease; presence of catecholamines associated with pheochromocytoma; or glucose. suggesting diabetes.
- Laboratory tests may reveal elevated blood urea nitrogen and serum creatinine levels. suggesting renal disease
or hypokalemia indicating adrenal dysfunction (primary hyperaldosteronism).
- Complete blood count may reveal other causes of hypertension. such as polycythemia or anemia.
- Excretory urography may reveal renal atrophy. indicating chronic renal disease. One kidney smaller than the other suggests unilateral renal disease.
- Electrocardiography may show left ventricular hypertrophy or ischemia.
- Chest X-rays may show cardiomegaly.
- Echocardiography may reveal left ventricular hypertrophy.
Treatment of Hypertension
In July of 2003. the U.S. Preventative Services Task Force strongly recommended blood pressure screening as the first step of treatment in all adults over age 18 because of evidence that early detection and treatment of high blood pressure can significantly reduce the risk of cardiovascular disease.
For treatment of high blood pressure, the National Heart, Lung and Blood Institute, which is part of the National Institutes of Health, published new High Blood Pressure Guidelines in May of 2003. It recommends the following stepped-care approach:
- Step 1 - Help the patient initiate necessary lifestyle modifications. including weight reduction, moderation of alcohol intake. regular physical exercise, reduction of sodium intake, and smoking cessation.
- Step 2 - If the patient fails to achieve the desired blood pressure or make significant progress. continue lifestyle modifications and begin drug therapy. Drug therapy is individualized and guided by associated diseases. Preferred drugs include thiazide diuretics, angiotensin-converting enzyme (ACE) inhibitors, or betaadrenergic blockers. These drugs have been proven effective in reducing cardiovascular morbidity and mortality. If diuretics, ACE inhibitors, or betaadrenergic blockers are ineffective or contraindicated, the physician may prescribe calcium antagonists, alphalreceptor blockers, or alpha-beta blockers. These drugs, although effective in reducing blood pressure, have yet to be proven effective in reducing morbidity and mortality.
- Step 3 - If the patient fails to achieve the desired blood pressure or make significant progress, increase the drug dosage, substitute a drug in the same class, or add a drug from a different class.
- Step 4 - If the patient fails to achieve the desired blood pressure or make significant progress, add a second or third agent or a diuretic (if one isn't already prescribed). Second or third agents may include vasodilators, alphal-antagonists, peripherally acting adrenergic neuron antagonists, ACE inhibitors, and calcium channel blockers.
Treatment of secondary hypertension focuses on correcting the underlying cause and controlling hypertensive effects.
Typically, hypertensive emergencies require parenteral administration of a vasodilator or an adrenergic inhibitor or oral administration of a selected drug, such as nifedipine, cap topril, clonidine, or labetalol, to rapidly reduce blood pressure. The initial goal is to reduce mean arterial blood pressure by no more than 25% (within minutes to hours) and then reduce it to 160/110 mm Hg within 2 hours while avoiding excessive decreases that can precipitate renal, cerebral, or myocardial ischemia. Examples of hypertensive emergencies include hypertensive encephalopathy, intracranial hemorrhage, acute left-sided heart failure with pulmonary edema, and dissecting aortic aneurysm. Hypertensive emergencies are also associated with eclampsia or severe pregnancy induced hypertension, unstable angina, and acute MI.
Medications may include diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), or alpha blockers. Medications such as hydralazine, minoxidil, diazoxide, or nitroprusside may be required if the blood pressure is very high.
Special considerations or prevention
To encourage adherence to antihypertensive therapy, suggest that the patient establish a daily routine for taking medication. Warn that uncontrolled hypertension may cause stroke and heart attack.
- Advise her to avoid high-sodium antacids and over-the-counter cold and sinus medications, which contain harmful vasoconstrictors.
- Encourage a change in dietary habits. Help the obese patient plan a weight-reduction diet; tell her to avoid high-sodium foods (pickles, potato chips, canned soups, and cold cuts) and table salt.
- Lose weight if you are overweight.
- Help the patient examine and modify her lifestyle (for example, by reducing stress and exercising regularly).
- If a patient is hospitalized with hypertension, find out if she was taking her prescribed medication. If she waSn't, ask why. If the patient can't afford the medication, refer her to an appropriate social service agency.
- When routine blood pressure screening reveals elevated pressure, make sure the cuff size is appropriate for the patient's upper arm circumference. Take the pressure in both arms in lying, sitting, and standing positions. Ask the patient if she smoked, drank a beverage containing caffeine, or was emotionally upset before the test. Advise the patient to return for blood pressure testing at frequent, regular intervals.
- Exercise to help your heart.
- To help identify hypertension and prevent untreated hypertension, participate in public education programs dealing with hypertension and ways to reduce risk factors. Encourage public participation in blood pressure screening programs. Routinely screen all patients, especially those at risk (including blacks and people with family histories of hypertension, stroke, or heart attack).
- Adjust your diet as needed. Decrease fat and sodium -- salt, MSG, and baking soda all contain sodium. Increase fruits, vegetables, and fiber.