Ch 18 - Disorders of blood flow and blood pressure Flashcards
What are disorders of the Arterial Circulation? Hyperlipidemia?
There are 3 types of arteries: large elastic arteries, (aorta and distal branches), medium sized arteries (coronary and renal arteries), small arteries and arterioles that pass through tissue. Each of these can be effected by disease.
Hyperlipidemia - is a medical condition characterized by an elevation of any or all lipid profiles and or lipoproteins in the blood. Primary - probably genetic based. Secondary - may result from diseases such as diabetes, thyroid disease, renal disorders, liver disorders, and cushing syndrome, obesity, alcohol consumption, estrogen administration and other drugs. It is strong associated with atherosclerosis and morbidity and mortality.
Lipoprotein metabolism and transport. - because lipids, (cholesterol and triglycerides) are insoluble in plasma, they are encapsulated by special fat carrying proteins called lipoproteins. Exogenous pathway - involves the chylomicron transport of dietary triglycerides and cholesterol from the intestines to the liver. The chylomicrons are synthesized in the wall of the small intestine. They transfer triglycerides to peripheral tissues, especially adipose tissue and skeletal muscle, for energy and storage.
Endogenous pathway - The liver is the central site for handling of lipids: it is able to store glycerols and fast in its cells; synthesize triglycertides; and use esterified cholesterol and triglycerides to form VLDL. VLDL carry their triglycerides to fat and muscle cells, where the triglycerides are removed.
What are low density lipoproteins LDL? What are high density lipoproteins HDL? Hypercholesterolemia?
LDL are sometimes called bad cholesterol, is the main carrier of cholesterol. 60% goes to the liver and the rest to extrahepatic tissues like adrenal cortex.
Depending on the pt they can come in different sizes which explains how some have severe atherosclerosis.
HDL or good cholesterol is synthesized by several pathways, including direct secretion by the intestine and liver. It shows an inverse relation between HDL and the development of atherosclerosis. It is low in cholesterol and rich in surface phospholipids facilitates the clearance of cholesterol from atheromatous plaques and transports it to the liver where it may be excreted rather than reused in the formation of VLDL
Hypercholesterolemia refers to inc levels of cholesterol in the blood. Primary is genetic based - may be a defective synthesis of the apolipoproteins, a lack of lipoprotein receptors, defective receptors or defects in the handling of cholesterol in the cell. Secondary causes obesity, sedentary lifestyle and diabetes mellitus, medications.
Diagnosis - pt s complete lipid profile after an overnight fast.
Management - a reduction in LDL continues to be the primary target for cholesterol lowering therapy, particularly in pt at risk for CAD. Focuses on dietary and therapeutic lifestyle changes, exercise smoking cessation and weight reduction. Can use lipid lowering drugs, they work in dec cholesterol production, dec cholesterol absorption form the intestine, removing cholesterol from the bloodstream
What is Atherosclerosis?
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials. It denotes the formation of fibrous plaque in the intimal lining of the large and medium sized arteries such as the aorta and its branches, the coronary arteries and the cerebral arteries.
Risk factors - genetic, smoking and behaviors for eating and exercise or lack of. and diabetes. There may be a connection to infectious agents.
Pathogenesis and mechanisms - 3 different stages fatty streaks, fibrous atheromatous plaques and complicated lesions. The lesions begin to encroach on the lumen of the artery can cause hemorrhage or ulceration as well as thrombosis. Can affect any artery it usually is the ones supplying the heart, brain, kidneys, lower extremities and small intestine.
What is vasculitis?
Vasculitides are a group of vascular disorders that cause inflammatory injury and necrosis of the blood vessel wall. Can be in any organ or vessel, so have many signs and symptoms. Usually have mani - fever, myalgia, arthralgia and malaise. Two of the most common vasculitis are direct invasion of the vascular wall by an infectious agent and immune mediated inflammation. 3 types of disease small, medium and large vessel diseases see table 18-3.
Treatment is corticosteroid and immunosuppressant agents.
What are the arterial disease of the Extremities? Peripheral Arterial Disease?
Disorders of the circulation in the extremities often are referred to peripheral vascular disorders. It produces ischemia, pain, impaired function, and in some cases infarction and tissue necrosis.
Peripheral Arterial Disease PAD - refers to the obstruction of large arteries that supply the body’s peripheral structures rather than its central structures. Usually found in the lower extremities can result from atherosclerosis, inflammatory processes leading to stenosis, embolism, or thrombus formations. Either acute or chronic, most commonly in men in their 60-70s. Smoking and diabetes are the strongest risk factors.
Signs - are usually gradual, so like pain with walking. Some might get numbness or aching feeling. The foot is often cool, and the popliteal and pedal pulses are weak or absent. Limb color blanches on elevation and becomes deep red when down. Blood flow is reduced to the extent that it no longer meets minimal needs of the resting muscle and nerves, ischemic pain at rest, ulceration and gangrene develop. Diagnostic methods include inspection of the limbs subcutaneous atrophy, brittle toenails, hair loss, pallor, coolness.
Can use doppler US for detecting pulses and blood pressure of the foot. US, MRI and CT arteriography and contrast.
Treatment - measures directed at protection of the affected tissues and preservation of functional capacity. Avoidance of injury and to address other risk factors smoking, hypertension, hyperlipidemia and diabetes. Drugs therapy includes antiplatelet therapy and other useful for statins. Percutaneous or surgical intervention is reserved for pt. with disabling claudication or limb threatening ischemia. Stent placement might work.
What is thromboangiitis obliterans?
Thromboangiitis obliterans or Buerger disease, is a recurring progressive nonatherosclerotic inflammation and thrombosis of small and medium sized arteries and veins, usually the plantar and digital vessels in the foot and lower leg. Can be the arm and hand. It usually is a disease of young heavy smokers. Has been suggested that tobacco may trigger an immune response in susceptible persons or it may unmask a clotting defect.
Symptoms - pain is the predominant. It is usually related to distal arterial ischemia. Is sensitive to the cold, peripheral pulses are weak or absent. Changes in color of extremities, can cause thick malformed nails.
Diagnosis is the same as atherosclerotic disease.
Treatment is the cessation of smoking or using any nicotine. If doesn’t stop then amputation of both lower and upper extremities is the eventual outcome.
What is Raynaud Phenomenon?
Reynaud is a functional disorder caused by intense vasospasm of the arteries and arterioles in the fingers and less often the toes. Two types primary is seen in otherwise healthy young women and is often precipitated by exposure to cold or by strong emotions and usually is the fingers. Secondary is associated with previous vessel injury such as frostbite, occupational trauma with heavy vibrating tools, collagen diseases, neurologic disorders, chronic arterial occlusive disorders or drugs.
The ischemic phase is manifested by changes in skin color that progress from pallor to cyanosis, a sensation of cold, and changes in the sensory perception such as numbness and tingling. In severe nails may become brittle, and the skin over the tips of the affected fingers may thicken. Ulceration and superficial gangrene of the fingers, although infrequent, may occur.
Treatment - stopping smoking and protection from the cold. The entire body not just the hands. Avoidance of emotional stress. Vasoconstrictor medications such as in cold or allergy drugs should be avoided. Use of phophodiesterase inhibitors that produce arterial vasodilation. Surgical interruption of sympathetic nerve pathways may be used with severe
What are aneurysms and dissection?
Aneurysm is a pathological outpouching or sac like dilation in the wall of the blood vessel usually caused by weakening of the vessel wall. They can occur in arteries and veins, but are most common in the arteries. Two types true aneurysm is bounded by a complete vessel wall and the blood remains within the vascular compartment. A false aneurysm represents a localized dissection or tear in the inner wall of the artery with formation of an extravascular hematoma that causes vessel enlargement. Many different kinds.
Aortic aneurysms may involve any part of the aorta. Multiple aneurysms may be present. Signs and symptoms depend on the size and location. With thoracic and abdominal the worst is rupture. The likehood of rupture inc with size. They can be substernal, back or neck pain. Can also be dyspnea, stridor, or a brassy cough caused by pressure on the trachea. Usually develop after the age of 50 and are atherosclerosis related.
Diagnostic - US, echocardiography, CT, MRI. Usually are asymptomatic and are often identified incidentally.
Treatment - Risk factor modification - hypercholesterolemia and high blood pressure should be controlled and smoking discontinued. Surgical repair if frequently the treatment of choice
Aortic Dissection - is an acute, life threatening condition. It involves hemorrhage into the vessel wall with longitudinal tearing or the vessel wall to form a blood filled channel. Often occurs without evidence of previous vessel dilation.
Symptoms - excruciating pain.
Diagnosis - aortic dissection is based on history and physical examination. Aortic angiography, transesophageal echocardiography, CT and MRI.
Treatment - may be medical or surgical. Medical focuses on control of hypertension and the use of drugs that lessen the force of systolic blood ejection from the heart. Surgical is resection or replacement with a prosthetic graft.
What are disorders of Arterial Blood Pressure?
In hypertension and disease conditions that affect blood pressure, changes in blood pressure usually are described in terms of systolic and diastolic pressures, pulse pressure and mean arterial pressure.
Mechanisms of blood pressure regulation
Short term regulation, those acting over seconds or minutes are intended to correct temporary imbalances in blood pressure, such as occur during physical exercise and changes in body position. Neural mechanisms is vested in centers that are located in the reticular formation of the medulla and lower third of the pons, where integration and modulation of ANS responses occur. The cardiovascular center - parasympathetic stimulation of the heart produces a slowing of the heart rate and sympathetic produces an inc in heart rate and cardiac contractility. see p 421
Humoral - of blood pressure relies on a number of mechanisms, renin-angiotensin-aldosterone system and vasopressin. Epinephrine can inc heart rate, cardiac contractility and vascular tone. p423
Longterm regulation - are largely vested in the kidneys and their role in regulation of extracellular fluid volume. If too much extracellular fluid, the arterial pressure rises and the rate at which water and sodium are excreted by the kidney is inc.
What is hypertension?
Or high blood pressure is the most common issue. Systolic above 140 and diastolic above 90. Two types
Primary (essential) - which no cause can be identified.
Risk factors - genetics, race and age related inc in blood pressure.
Lifestyle risk factors - high salt intake, excessive calorie intake and obesity, and excessive alcohol consumption. Stress can raise blood pressure acutely. Smoking and a diet high in saturated fats and cholesterol. Abdominal fat is more insulin resistant
Secondary - due to another disease condition. it usually can be corrected or cured by surgery or specific medical treatment. usually yonger than 30 and older then 50. Most common are kidney disease, adrenal cortical disorders, pheochromocytoma, and coarctation of the aorta. Oral contraceptives and illicit drugs or apnea.
Renal hypertension - is caused by reduced renal blood flow and activation of the renin angiotensin aldosterone mechanism. Two types 1. atherosclerosis of the proximal renal artery 2. Fibromuscular dysplasia, a noninflammatory vascular disease that affects the renal arteries and branch vessels.
Diagnostic tests - overall renal function, imaging studies US, CT, MRI.
Treatment - is to control the blood pressure and stabilize renal function. Angioplasty has been shown to be an effective longterm treatment=. ACE angiotensin converting enzyme inhibitors may be used. but can cause hypotension and renal dysfunction.
What are disorders of adrenocortical hormones? Pheochromocytoma? Coarctation of the Aorta? Oral Contraceptive Drugs?
Inc levels of adrenocortical hormones also can give rise to hypertension. Primary hyperaldosteronism (from adenoma) and excess levels of glucocorticoid (cushing). these hormones facilitate Na and water retention by the kidney. Usually a Na restricted diet often produces a dec in hypertension. Blood test, CT, MRI can be used to localize lesion. They are usually treated with surgery. Or diuretics spironolactone.
Pheochromocytoma - are rare catecholamine secreting tumors of adrenal chromaffin cells. Cause the secretion of norepinephrine and epinephrine causing hypertension. Causing headache, excessive sweating, and palpitations.
Diagnostic blood and urinary CT and MRI.
Treatment is surgical removal of tumor
Coarctation of the Aorta - is a congenital condition in which a narrowing or constriction of the lumen of the aorta exists. Causing inc blood pressure.
Treatment is surgical repair or balloon angioplasty.
Oral contraceptive drugs - is the most common in young women - cause is largely unknown. It usually disappears after the drug is discontinued. It might not return to normal is usually in women over 35 and smokers
What is target organ damage?
Hypertension is usually asymptomatic. If they do occur it is usually related to the damage caused to organs from longterm hypertension. It inc the work of the left ventricle it can cause hypertrophy to compensate for inc pressure.
Diagnosis - by repeated blood pressure measurement, other tests are done to see presence or extent of organ damage.
Main objectives is to achieve and maintain BP below 140/90 with the goal of preventing morbidity and mortality. Include lifestyle modification.
Drugs - diuretics - de vascular volume, B-adrenergic receptor inhibitors - dec heart rate, cardiac output, and renin release by the kidney, calcium channel blockers - dec peripheral vascular resistance by inhibiting the movement of calcium into arterial smooth muscle cells, central a-adrenergic agonists - act in a negative feedback manner to dec sympathetic outflow from CNS, a adrenergic receptor blockers - receptors on vascular smooth muscle causing vasodilatation and reduction in peripheral vascular resistance and vasodilators. Usually a step wise approach
What is a hypertensive crisis?
Small number of pt. develop an accelerated or severe form of hypertension. Systolic greater then 180 or diastolic greater 120.
Signs - labs of end organ damage, mental status changes, intracranial hemorrhage, retinopathy, aortic dissection, cardiac ischemia or congestive heart failure or acute renal failure. CNS is susceptible to High BP
Treatment - immediate and rigorous medical and intensive care unit with continuous monitoring of arterial BP
Hypertension in special populations?
Pregnancy - preeclampsia - eclampsia BP above 140/90 and proteinuria developing after 20 weeks of gestation. Caused by first pregnancies and subsequent pregnancies in women with multiple fetuses, diabetes mellitus, collagen vascular disease or underlying kidney disease or hydatidiform mole. Eclampsia is seizures.
Gestational hypertension - is development of new hypertension without proteinuria after 20 weeks gestation. If it leads to preeclampsia 15-40% require early delivery.
Preeclampsia superimposed on chronic hypertension - is they already have hypertension and then get pregnant are predisposed to preeclampsia.
Treatment - Na diet usually is not recommended. in preeclampsia delivery of the fetus is curative. Bed rest is traditional therapy
In children - is a growing problem. Secondary is the most common caused by kidney abnormalities. Endocrine causes adrenal cortical disorders.
Diagnosis and treatment - appropriate cuff and repeated measurement over time. Treatment includes non pharmacologic and if necessary drugs.
In the Elderly - prevalence inc with age. Inc wall stiffness, less able to store energy needed.
treatment is the same as the rest of pt.
What is orthostatic hypotension?
Refers to an abnormal drop in BP that occurs when a person stands after having been in the seated or supine position. Its defined as a dec in systolic BP of at least 20 mm Hg or diastolic BP of at least 10 mmHg within 3 minutes of standing. Dizziness and syncope may occur.
Causes - reduced blood volume, drug induced hypotension, altered vascular responses, bed rest and ANS dysfunction.
Treatment - directed toward alleviating the cause. or helping the pt toward how to cope with the disorder and prevent falls and injuries. Support hose, avoiding alcohol and exercising vigorously in a warm environment Number of drugs can be used.
