Atherosclerosis : The Aetiology of Hypertension Flashcards
<p>What are the most common causes of death due toraised blood pressure?</p>
<p>Ischemic heart disease and stroke</p>
What end organ damage is associated with hypertension?
<p>Describe blood pressure throughout the day</p>
<p>Fluctuates widely -</p>
<p></p>
<p>Physcial stress and mental stress</p>
<p>What is the definintion of hypertension?</p>
<p>That blood pressure above which the benefits of treatment outweigh the risks in term of morbidity and mortality</p>
<p>What is the blood pressure distribution in a population?</p>
<p>Exhibits a normal bell shaped curve</p>
<p>Each population has its own bell shaped curvre</p>
<p>What is the relationship between increased blood pressure and stroke/cardiovascular disease?</p>
<p>•Risk however rises exponentially and not linearly with pressure</p>
<p>Age also plays a significant role</p>
<p>What is 'optimal' blood pressure in terms of american opinion?</p>
<p>Opt <120/<80</p>
<p>What blood pressure is hypertension diagnosed at?</p>
<p>Varies - roughly 140/90</p>
<p>What does ABPM stand for?</p>
<p>Ambulatory blood pressure monitor – measures blood pressure every half hour – inflates the cuff every half hour at night time?</p>
<p>What is defined as stage 1 hypertension?</p>
<p>Clinic blood pressure is about 140/90 mmHg or higher</p>
<p>ABPM daytime average 135/85 mmHg or higher</p>
<p>What is defined as stage 2 hypertension?</p>
<p>•Clinic blood pressure is 160/100 mmHg or higher</p>
<p>ABPM daytime average 150/95 mmHg or higher</p>
<p>What is defined as severe hypertension?</p>
<p>Clinic systolic blood pressure is 180 mmHg or higher or diastolic blood pressure is 110 mmHg or higher</p>
<p>What is more common, primary and secondary hypertension?</p>
<p>Primary - where no cause is found</p>
<p>90% of cases</p>
<p>What are some of the causes of secondary hypertension?</p>
<p></p>
<p>Chronic renal disease</p>
<p>Renal artery stenosis</p>
<p>Endocrine disease - cushing's, conn's syndrome and paechromocytoma, GRA</p>
<p>How many deaths worldwide is high blood pressure responsible for?</p>
<p>The number 1 medical cause of death world-wide</p>
<p> Directly and indirectly responsible for >20% of all deaths</p>
<p>Which factors increase risks associated with hypertension?</p>
<p>Cigarette smoking</p>
<p><strong>Diabetes mellitus -</strong>–5-30 X increase MI</p>
<p>Renal disease</p>
<p><strong>Male - 2 x risk</strong></p>
<p>Hyperlipidaemia</p>
<p>Previous MI or stroke</p>
<p><strong>Left ventricular hypertrophy - 2 x risk</strong></p>
<p>What parts of the human body are responsible for blood pressure?</p>
<p>–Cardiac output</p>
<p>•Stroke volume</p>
<p>•Heart rate</p>
<p>–Peripheral vascular resistance</p>
<p>What is the effect of the sympathetic nervous system on:</p>
<p>Stroke volume</p>
<p>Heart rate</p>
<p>Total peripheral resistance?</p>
<p>–increased cardiac output - contractility increases</p>
<p>–reflex tachycardia</p>
<p>–vasoconstriction</p>
<p>These increase blood pressure.</p>
<div>•The actions of the sympathetic system are rapid and account for second to second blood pressure control</div>
<p>What type of bloo pressure control is RAAS responsible for?</p>
<p>Long term</p>
<p>What is RAAS responsible for?</p>
<p>Maintainance of sodium balance</p>
<p>Control of blood volume</p>
<p>Control of blood pressure</p>
<p>What is RAAS stimulated by?</p>
<p>–fall in BP</p>
<p>–fall in circulating volume</p>
<p>–sodium depletion</p>
<p></p>
<p>•Any of the above stimulate renin release from the juxtaglomerular apparatus</p>
<p>•Renin converts angiotensinogen to angiotensin I</p>
<p>•Angiotensin I is converted to angiotensin II by angiotensin converting enzyme (ACE)</p>
<p>Angiotensin is a potent?</p>
<p>Vasoconstrictor</p>
<p>Anti-natiuretic peptide</p>
<p>Stimulator of aldosterone release from the adrenal glands (aldosterone increases the reabsorption of sodium from the loop of henle - reduces diuresis)</p>
<p>What is the effect of angiotensin 2 on myocyte and smooth muscle?</p>
<p>Causes myocyte and smooth muscle hypertrophy in the arterioles - arteries eventually get small and narrow and the can't dilate -•can’t respond appropriately to relaxation - highly susceptible to damage.</p>
<p>In general what are the aetiologies of hypertension?</p>
<p>–Polygenic</p>
<p>•Major genes</p>
<p>•Poly genes</p>
<p>–Polyfactorial</p>
<p>•Environment</p>
<p>•Individual and Shared</p>
<p>What are the likely causes?</p>
<p>•Increased reactivity of resistance vessels and resultant increase in peripheral resistance</p>
<p>–as a result of an hereditary defect of the smooth muscle lining arterioles</p>
<p>•A sodium homeostatic effect</p>
<p>In essential hypertension the kidneys are unable to excrete appropriate amounts of sodium for any given BP. As a result sodium and fluid are retained and the BP increases</p>
<p>Failure in sodium pumping mechanism in the kidney.</p>
<p>Abnormality in the kidney specifically the portion that secretes sodium and water – reset point is raised – kidney starts to respond to high blood volume at a later point.</p>
<p>Other factors</p>
<p>•Age</p>
<p>•Genetics and family history</p>
<p>•Environment – stressfulness brings about a high blood pressure</p>
<p>•Weight</p>
<p>•Alcohol intake – most common for young scotsmen</p>
<p>•Race – afrocarribean – hypertensive in western area – high salt diets</p>
<p>How does blood pressure vary with age?</p>
<p>BP tends to rise with age, possibly as a result of decreased arterial compliance</p>
<p>What are the dangers of treating the elederly for high blood pressure?</p>
<p>Lowering blood pressure too much can cause syncope - loss of confidence.</p>
<p>What are the benefits of hypertehypertension treatment in the elderly?</p>
<div>–treating both diastolic and systolic hypertension in the elderly significantly reduces stoke and MI.</div>
<p>Describe the trends in hypertension in the family</p>
<p>–A history of hypertension tends to run in families</p>
<p>–The closest correlation exists between sibs rather than parent and child - the childrenshare same genes and <strong>environment</strong></p>
<p></p>
<p><strong>Environment plays a large influence in the development of hypertension</strong></p>
<p>How much influence do individual genes have in the incidence of high blood pressure?</p>
<div>–To date >30 genes recognised as important but individually they account for at most 0.5mmHg each</div>
<p>What is the influence of stress?</p>
<p>–Mental and physical stress both increase blood pressure</p>
<p>–However removing stress does nor necessarily return blood pressure to normal values</p>
<p>–True stress responders who have very high BP when they attend their doctor but low normal pressures otherwise tend to be highly resistant to treatment</p>
<p>What is the effect of reducing salt intake?</p>
<p>–Reducing salt intake in hypertensive individuals does lower blood pressure</p>
<p>–However reducing salt intake in normotensives appears to have little effect</p>
<p>–However there are real difficulties in achieving this level of salt restriction (fast food)</p>
<p>What is the relationship between alcohol and blood pressure?</p>
<p>–Small amounts of alcohol tend to decrease BP</p>
<p>–Large amounts of alcohol tend to increase BP</p>
<p></p>
<p>–If alcohol consumption is reduced BP will fall over several days to weeks.</p>
<p>–Average fall is small 5/3 mmHg</p>
<p>What is the relationship between obesity and blood pressure?</p>
<p>Obese patients have a higher blood pressure</p>
<p>How much of hypertension is partly or completely attritable to obesity?</p>
<p>up to 30%</p>
<p>What happens when an obese person loses weight?</p>
<p>Blood pressure falls</p>
<p>–In untreated patients a weight loss of 9Kg has been reported to produce a fall in BP of 19/18 mmHg</p>
<p>–In treated patients a fall in BP of 30/21 mmHg has been reported</p>
<p>–Weight reduction is the most important non-pharmacological measure available</p>
<p>How does birth weight affect chances of developing hypertension?</p>
<p>The lower the birth weight the higher the likelihood of developing hypertension and heart disease</p>
<p>How does the blood pressure of caucasians and black populations compare when living in the same environment?</p>
<p>–Caucasians have a lower BP than black populations living in the same environment</p>
<p>–Black populations living in rural Africa have a lower BP than those living in towns</p>
<p>Why do caucasians generally have a lower blood pressure than black populations?</p>
<p>–Possibly black populations are more susceptible to stress when living in towns</p>
<p>–Respond in different ways to changes in diet</p>
<p>–Black populations are genetically selected to be salt retainers and so are more sensitive to an increase in dietary salt intake</p>
<p>What are the causes of secondary hypertension?</p>
<p></p>
<p><strong>•Renal disease: 20% of resistant hypertension</strong></p>
<p>–chronic pyelonephritis</p>
<p>–fibromuscular dysplasia</p>
<p>–renal artery stenosis – narrowing of arteries</p>
<p>polycystic kidneys – atheromas plaque</p>
<p><strong>•Drug Induced</strong></p>
<p>–NSAIDs</p>
<p>–Oral contraceptive</p>
<p>–Corticosteroids</p>
<p><strong>•Pregnancy</strong></p>
<p>–pre-eclampsia</p>
<p><strong>•Endocrine</strong></p>
<p>–Conn’s Syndrome</p>
<p>–Cushings disease</p>
<p>–Phaeochromocytoma – tumour on adrenal – increase in adrenaline release</p>
<p>–Hypo and hyperthyroidism</p>
<p>–Acromegaly</p>
<p><strong>•Vascular</strong></p>
<p>–Coarctation of the aorta</p>
<p><strong>•Sleep Apnoea</strong></p>
<p></p>
<p>What is the result of a stenosed kidney?</p>
<p>Produces a lot of renin - increases the bloods pressure</p>
<p>How can you look for coartication in the clinical environment?</p>
<p>Produces a differences between radial pulses – narrowing slows pulse rate down</p>
