Hypertension

Question 1

Epidemiology

Affects?

Answer 1

1 billion
Leading global cause of death
Distinction between hypertensive+ normatensive= arbitary
Updated guidelines= emphasis is on home BP monitoring vs office (5-10mmHg lower)

Question 2

BP and age
BP and mortality risk
BP and attributable burden

Answer 2

Increase age= increase BP
Increase age= increase pulse pressure
(Increase age= increase SBP but increase age= no change in DBP which actually flattens out and decreases therefore increase difference between SBP and DBP)

No reliable threshold for mortality risk as BP increases

50% of attributable burden have a normal SBP

Question 3

Hypertension classification

Answer 3

Primary= unidentifiable cause (85% cases)
Secondary= Identifiable cause  (15% cases)

Question 4

General causes of primary hypertension?

Answer 4

1) Genetics: Monogenic (rare)/ Complex polygenic (common)

2) Environment: Dietary Na, Obesity, Alcohol etc

Question 5

BP and dietary Na

Answer 5

Major factor in rise of BP with age

people with no Na in diet don’t have rise in BP with age

Question 6

Established hypertension is associated with these changes in values:

Answer 6

Increased TPR
Decreased arterial compliance
Normal cardiac output
Normal blood volume/ ECV
Central shift in volume (Secondary to reduced venous compliance)

Question 7

What causes the elevated TPR in hypertension?

Answer 7

Active narrowing of arteries ( Short term vasoconstriction)
Structural narrowing of arteries (lumen gets smaller and wall gets thicker)
Capillary loss (Blood going through reduced area of vessels)

Question 8

Isolated systolic hypertension
Ranges?
Age of people with it?
Cause?

Answer 8

Systolic BP ≥ 140 mmHg, diastolic BP ≤ 90 mmHg
Condition of people over age 60
Due to increasing stiffness of medium/large arteries= pulse wave reflected and is greater by the time it reaches brachial artery
Does NOT mean that TPR increases

Question 9

Specific causes of primary hypertension

Answer 9

Kidney
Regulates Na/H2O/ECF volume
Almost all monogenic causes of hypertension affect renal Na excretion (you can transplant hypertension)

Endocrine/ paracrine factors

Increased sympathetic nervous system activity

Question 10

Hypertension associated with changes to…

Answer 10

Heart
Large arteries
Eye
Microcirculation
Kidney

MELKH

Question 11

Hypertension and the heart

Answer 11

Increase in left ventricular wall mass (LVMI)= changes in chamber size= more likely to lead to arrhythmias= heart failure+ sudden death

Question 12

Hypertension and large arteries

Causes?

Answer 12

Arterial rupture/ dilations (aneurysms)= thrombosis/ haemorrhage (e.g. strokes)

Increased thickness of large arteries= acceleration of atherosclerosis: result of it, not a cause

Question 13

Hypertension and eye

Answer 13

Microvascular damage:
Thickening of the wall of small arteries
Arteriolar narrowing
Vasospasm (arterial spasm= vasoconstriction= tissue death)
Impaired perfusion
Increased leakage into the surrounding tissue

Question 14

Hypertension and microcirculation

Answer 14

Reduction in capillary density= decreased perfusion in organs
Elevated capillary pressure= damage and leakage

Question 15

Primary hypertension and kidney

Answer 15

Granular capsular surface
Cortical thinning, renal atrophy
Renal dysfunction- reduced glomerular filtration rate+ increase albumin loss into urine
NB: GFR declines with age even without high BP, which speeds up deterioration

Question 16

Accelerated hypertension and kidney

Answer 16

Subcapsular haemorrhages

Rare but leads to rapidly progressive renal failure

Question 17

Lifestyle modification to treat hypertension

Answer 17

Weight loss
Eat healthy
Exercise
Less alcohol

Question 18

Hypertension drugs

Answer 18

ACE inhibitors
reduce amount of Ang II produced (which increases BP)
(AngII still produced because there are other mechanisms for it’s production)

Angiotensin receptor blockers- alleviate bad effects of Ang II in kidney

Diuretics

1) Loop diuretics: Used in patients experiencing hypertensive crisis (lots of fluid in body)
2) Thiazide diuretics- more common, don’t work through diuresis but because they slowly reduce PVR (uncertain mechanism)

Beta blockers- not that great in stroke reduction through

1) Blockage of β1 receptors in heart= Reduced rate and force of contraction= Reduced cardiac output
2) Blockage of β1 receptors in kidney= Reduced secretion of renin= Reduced activity of RAAS

Calcium channel blockers
1) Major mechanism
In vascular smooth muscle
Reducing Ca2+ influx reduces actin myosin cross bridge cycling
2) Minor mechanism
In the heart
Inhibition of Ca2+ influx reduces contractility (negative inotropy) and rate of conduction (negative dromotropy)

Question 19

Hypertension= increased risk of?

Answer 19

Coronary heart disease
stroke
peripheral vascular disease/atheromatous disease
heart failure
atrial fibrillation
dementia /cognitive impairment 
retinopathy