cardiovascular pathology

Question 1

define hypertension

Answer 1

level of blood pressure above which investigation and treatment do more good than harm

Question 2

epidemiology of hypertension

Answer 2

leading global cause of death affecting approx. 1 billion people; distribution is unimodal and any distincion between normal and abnormal is arbitrary

Question 3

ambulatory blood pressure

Answer 3

threshold 5-10mmHg lower than “office” blood pressure; recorded automatically at regular intervals over 24hrs

Question 4

effect of age on mean blood pressure and pulse pressure

Answer 4

rises with age; diastolic doesn’t so greater gap (pulse); majority of >60 expected to be hypertensive, almost everyone by >80

Question 5

aetiology of primary hypertension: genetics

Answer 5

monogenic (rare - almost all affect renal Na+ excretion e.g. Liddle’s syndrome), complex polygenic (common)

Question 6

aetiology of primary hypertension: environment

Answer 6

dietary salt (Na+), obesity, lack of exercise, alcohol, birthweight, pregnancy

Question 7

primary hypertension % cases

Answer 7

idiopathic; 85-95% cases

Question 8

causes of primary hypertension

Answer 8

kidneys (e.g. affect Na+ excretion), endocrine, high sympathetic nervous system activity

Question 9

secondary hypertension % cases

Answer 9

known cause; 5-15% cases

Question 10

causes of secondary hypertension

Answer 10

renal disease, Conn’s syndrome (secrete aldosterone), tumours secreting catecholamines, oral contraceptive pill, pregnancy-associated hypertension, rare genetic causes

Question 11

calculate mean arterial pressure

Answer 11

cardiac output x total peripheral resistance

Question 12

what is established hypertension associated with

Answer 12

increased TPR, decreased arterial compliance, normal cardiac output, normal blood volume, central shift volume

Question 13

name 3 causes of elevated total peripheral resistance

Answer 13

active narrowing of arteries, structural narrowing of arteries, capillary loss

Question 14

what happens in isolated systolic hypertension

Answer 14

larger arteries become stiff for idiopathic reasons, not increasing TPR; leads to SBP > 140, DBP <90; incidence increases with age

Question 15

7 consequences of hypertension

Answer 15

congestive heart failure, stroke, heart failure, aneurysms, dementia, retinopathy, vascular disease, renal dysfunction

Question 16

how does hypertension affect the heart

Answer 16

left ventricular hypertrophy, leading to cardiomegaly; leads to heart failure

Question 17

how does hypertension affect large arteries

Answer 17

wall thickness increases to withstand increased wall stress

Question 18

how does hypertension cause aneurysms

Answer 18

dilations of medium-large arteries leading to thrombosis and/or haemorrhage upon rupture

Question 19

how does hypertension cause strokes

Answer 19

due to clotting and thrombosis, not rupture

Question 20

how does hypertension affect eyes

Answer 20

damaged retinal capillaries (retinopathy) and reduced blood flow as narrowed arteries; increased leakage into surrounding tissue

Question 21

how does hypertension affect microcirculation

Answer 21

reduces capillary density and elevates capillary pressure, causing damage and leaking

Question 22

how does hypertension cause microalbuminuria

Answer 22

increases albumin loss in urine, due to reduced glomerular filtration rate

Question 23

lifestyle treatment for hypertension

Answer 23

weight loss, exercise, healthy eating, less alcohol

Question 24

drugs used to treat hypertension

Answer 24

ACE inhibitors, angiotensin receptor blockers, diuretics, B-blockers, Ca2+ channel blockers

Question 25

aims of hypertension drug treatments

Answer 25

stop arteriolar vasoconstriction, ADH and aldosterone secretion, and tubular Na+ reabsorption; decrease total peripheral resistance and water retention

Question 26

when are loop diuretics used

Answer 26

crisis to block water reabsorption

Question 27

thiazide diuretic features

Answer 27

don’t work through diuresis, but slowly reduce total peripheral resistance

Question 28

how do B-blockers work

Answer 28

beta 1 receptors in heart blocked so reduction in rate and force of contraction, reducing cardiac output; in kidneys stop renin secretion

Question 29

how do Ca2+ channel inhibitors work

Answer 29

major effect in vascular smooth muscle to reduce Ca2+ influx, reducing cross bridge cycling; minor effect in reducing contractility and rate of conduction in heart