Hypertension (in addition to a number of medical conditions) may be considered as primary or secondary. Explain these concepts giving three examples of secondary hypertension and their pathophysiology.
Most of the conditions that cause secondary hypertension involve the overproduction of one of the body's hormones. Some of the medical problems that can cause secondary hypertension include:
Kidney disease. Secondary hypertension is related to damaged kidneys or to an abnormal narrowing of one or both renal arteries. The renal arteries are the major blood vessels that bring blood to each kidney. When the kidney's blood supply is reduced by a narrowing (called renal artery stenosis), the kidney produces high levels of a hormone called renin. High levels of renin trigger the production of other substances in the body that raise blood pressure, particularly a molecule called angiotensin II.
Adrenal disease. The adrenal glands sit on top of the kidneys and produce several hormones that help regulate blood pressure. Sometimes, one or both adrenal glands make and secrete an excess of one of these hormones. Three different types of adrenal gland conditions cause high blood pressure:
Pheochromocytoma. A tumour of the adrenal gland that overproduces the hormones epinephrine (adrenalin) and norepinephrine (noradrenalin). Hyperaldosteronism (also called Conn's syndrome). Both adrenal glands can overproduce the salt-retaining hormone aldosterone or it can arise in a benign adrenal tumour. Hypercortisolism (also called Cushing's syndrome). Both adrenal glands can overproduce the hormone cortisol or it can arise in a benign or malignant tumour.
Hyperparathyroidism. A hormone called parathormone is made by four tiny glands in the neck called parathyroid glands. If the glands produce too much hormone, calcium levels in the blood increase. People with hyperparathyroidism are more likely to have high blood pressure. The exact reason for this association is not known.
Roger was a symptomatic and only came in for a check up. Why is it important for this 'silent disease' to be detected and appropriately treated?
As blood flows through arteries it pushes against the inside of the artery walls. The more pressure the blood exerts on the artery walls, the higher the blood pressure will be. The size of small arteries also affects the blood pressure. When the muscular walls of arteries are relaxed, or dilated, the pressure of the blood flowing through them is lower than when the artery walls narrow, or constrict. Blood pressure is highest when the heart beats to push blood out into the arteries. When the heart relaxes to fill with blood again, the pressure is at its lowest point. Blood pressure when the heart beats is called systolic pressure. Blood pressure when the heart is at rest is called diastolic pressure. When blood pressure is measured, the systolic pressure is stated first and the diastolic pressure second. Blood pressure is measured in millimeters of mercury (mm Hg). For example, if a person's systolic pressure is 120 and diastolic pressure is 80, it is written as 120/80 mm Hg. The American Heart Association has long considred blood pressure less than 140 over 90 normal for adults. However, the National Heart, Lung, and Blood Institute in Bethesda, Maryland released new clinical guidelines for blood pressure in 2003, lowering the standard normal readings. A normal reading was lowered to less than 120 over less than 80.
Hypertension is a major health problem, especially because it has no symptoms. Many people have hypertension without knowing it. In the United States, about 50 million people age six and older have high blood pressure. Hypertension is more common in men than women and in people over the age of 65 than in younger persons. More than half of all Americans over the age of 65 have hypertension. It also is more common in African-Americans than in white Americans....
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