Hypertension, or high blood pressure, is usually a lifelong disease that causes very few symptoms until it is very advanced. Diagnosis and assessment consists of measuring recumbent, sitting, and standing blood pressures. Repeated, reproducible measurements of elevated blood pressures are indicative of hypertension.
Levels that are considered hypertensive are related to age. Borderline hypertension is adults is said to be present if blood pressure is consistently measured at 140/90 to 160/95. Diastolic pressure in the range of 95-104 is considered mild hypertension while that of 105-114 are moderate and severe hypertension occurs at pressures of 115 and above. Most frequently hypertension exists as mixed systolic and diastolic hypertension.
The prognosis for untreated hypertension is not good. End organ damage due to damaged blood vessels in the kidney, heart, and brain lead to renal failure, coronary artery disease and stroke. Black people are at a greater risk than whites, men more so than women, and postmenopausal women are more at risk than those still under the protective effects of female hormones. Family history, smoking, stress, obesity, age, diabetes, and hyperlipidemia are all positive risk factors for hypertension.
Hypertension is usually multifactorial in its causation. A specific cause of hypertension is often elusive. Indeed, no definite cause can be identified in 90% of patients. Patients in whom no specific cause can be identified are said to have essential or idiopathic hypertension. Other causes, such as renovascular, Cushing’s disease, primary aldosteronism, or constriction of the aorta are behind secondary hypertension.
Treatment often begins with nonpharmacologic means such as dietary sodium restriction or weight loss. Sodium restriction is effective in about 50% of patients with mild hypertension. Patients should avoid processed foods and adding table salt during cooking or at meals. Weight reduction is effective in reducing blood pressure in up to 75% of overweight patients with mild to moderate hypertension.
Pharmacologic interventions are usually implemented in steps. Diuretics are the first drug group used with sodium restriction and thiazide diuretics are very effective in patients with mild to moderate hypertension. Loop diuretics are used when the kidneys are not functioning properly and spironolactone may be used in cases of hyperaldosteronism. Drugs that alter sympathetic nervous system affects on blood pressure are often a second stage treatments. Vasodilators, converting enzyme inhibitors and/or calcium channel blockers are newer and very effective treatments.
Hardening of the arteries, or atherosclerosis, is the cause of more than half of all mortality in developed countries and the leading cause of death in the US. When it affects the coronary arteries, it is the underlying cause of most heart attacks and a common cause of congestive heart failure and arrhythmias.
The pathological process begins very early with a fatty streak composed of lipid deposited in the intima of arteries. Modified macrophages known as foam cells accumulate in the plaque region. These foam cells accumulate lipids, especially oxidized low-density lipoproteins.
When the lesion becomes infiltrated with fibrous material it protrudes into the lumen of the artery. The lesion itself rarely occludes the artery but rather it is blood clots that form on top of the plaque that close off the channel.
Chronic lesions become calcified and the elasticity of the vessel is decreased. This hardening of the arteries causes an increase in resistance to blood flow and therefore an increase in blood pressure. Any vessel in the body may theoretically be affected by atherosclerosis, but the aorta, coronary, carotid and iliac arteries are most frequently affected. Ischemia or infarction of specific regions causes specific symptoms and clinical outcomes.
High blood pressure, elevated cholesterol, smoking, diabetes, age, sex (males have a higher incidence until the age of 75 when the risk evens out), physical inactivity, and family history of heart disease are risk factors for the development of atherosclerosis. Pharmacologic interventions can be very beneficial in hyperlipidemic patients.
A local abnormal dilation of an artery due to a congenital defect or weakness of the vessel wall is known as an aneurysm. Atherosclerosis is a common cause of aortic aneurysms while those in the periphery are usually caused by damage due to trauma or bacterial or fungal infection. The dialation begins as a weakness in the medial layer of the artery. The danger of aneurysms are rupture, emboli to a peripheral artery, pressure on surrounding tissues, and the obstruction of blood flow to organs fed by arterial branches. The rupture of an aneurysm is often fatal dependent on the vessel involved.
Venous thrombosis and thrombophlebitis
Venous obstruction may be permanent or temporary. Obstruction of a portion of the trunk or main branches causes vessels distal to the obstruction to dilate and can result in permanent damage to valves and vessel walls due to pressure, hypoxemia, stretch, and malnutrition. Edema may result from damage to peripheral vessels.
Injury to veins can cause clots to form in response to inflammation or trauma to the endothelium. Stasis of the venous blood contributes to the formation of a blood clot or thrombus. As the thrombus grows along the axis of blood flow, part of it may break off and become an embolus that can lodge in downstream capillary beds and prevent blood flow to the served area. Most often emboli lodge in the pulmonary capillaries. When thrombosis occludes a vessel, collateral vessels may compensate. If collateral circulation is inadequate then edema can result.
Treatment includes anticoagulant therapy or surgical removal if the thrombus is large.
Inflammation of a vein, usually in the leg, due to the presence of a thrombus is called thrombophlebitis. Such inflammation can occur due to chemical damage, bacterial infection or from an unknown origin. Thrombophlebitis in deep veins of the legs causes calf pain and tenderness