Risk factors For Hypertension
Increasing age, race (esp. African-Americans), obesity, high-sodium diet, genetics, smoking, sedentary life style
Classification of Hypertension:
Primary (essential or idiopathic) hypertension—95% of cases. Secondary hypertension—can be explained by a specific disease
Primary hypertension physiology
renin-angiotensin-aldosterone system, endothelin-1 in particular is vascoconstrictive. Hyperinsulinemia & insulin resistance
is a hormone-producing endocrine gland in its own right—endothelin-1 in particular is vascoconstrictive.
Hyperinsulinemia & insulin resistance
account for about ½ of all cases of essential hypertension
Factors for Secondary hypertension(caused by a specific disease)
most common cause; for instance, renal artery stenosis causes reduced renal perfusion & activation of the renin-angiotensin-aldosterone system.
Endocrine disorder examples
-Adrenocortical hormone excess (both mineralocorticoids & glucocorticoids),
-Hypo- or hyper-thyroidism
increases systemic vascular resistance, therefore blood pressure; also narrows renal arteries as in #1 above
-Elevated intracranial pressure
-spinal cord injuries can cause autonomic hyperreflexia
Drugs That cause secondary Hypertension
amphetamines, steroids, oral contraceptives, caffeine, nicotine, cocaine
Isolated systolic hypertension in the elderly
affects about ½ of people > age 65; Defined as systolic BP > 140 with diastolic < 90, More common in women Associated with decreased arterial distensibility
Hypertension during pregnancy
BP normally decreases in 1st & 2nd trimesters, returns to normal in 3rd. Defined as BP > 140/90 after 20 weeks of pregnancy
Predisposing factors to Hypertension during Pregnancy
Young (teenage) & older (late 30's & 40's) mothers, Multiple fetuses, Preexisting diabetes, HTN, renal, or cardiovascular disease
Accelerated (malignant) hypertension
rapidly progressive, potentially fatal; diastolic BP > 120; present < 1% of hypertensives; 1-year mortality if untreated = 90%! Most likely in males, African-Americans, middle-aged, bilateral renal artery stenosis, targets kidneys.
Cardiac Effects of hypertension
left ventricle (LV) must work harder to overcome resistance to ejection of blood (afterload) This causes LV hypertrophy, increases myocardial O2 consumption, raises risk of ischemia, heart failure.
Vascular effects of hypertension
Atherosclerosis & arteriosclerosis—lesions in brain, retinas, kidneys. HTN is one of the leading preventable causes of renal failure
Signs & symptoms of hypertension
very few!! "silent killer", Signs/symptoms usually only appear when target organ damage occurs. Strokes, cerebrovascular disease, Coronary artery disease in all its forms, Development & rupture of aortic aneurysms, Renal problems
white coat phenomenon
term used to denote individuals who have blood pressures that are higher than normal in the medical environment,but whose blood pressures are normal when they are going about their daily activities.
Ambulatory blood pressure monitoring
measures blood pressure at regular intervals throughout the day and night. It is believed to be able to reduce the white coat hypertension effect.
Lifestyle modifications of hypertension
weight reduction, decrease alcohol consumption, sodium restriction, high K+ & Ca2+ intake, exercise, cholesterol reduction
Typically begin with diuretics or β-blockers, ACE (angiotensin converting enzyme) inhibitors & angiotensin receptor blockers useful in hypertension, congestive heart failure & diabetes.
Low blood pressure Causes What two problems
Shock—inadequate blood pressure to perfuse vital organs. Orthostatic hypotension—excessive drop in blood pressure when upright posture assumed.