Hypertension - Aetiology, Pathophysiology and Treatment Flashcards
What is the no. 1 cause of preventable mortality/morbidity in the world?
Hypertension.
2mmHg rise in BP:
7% increased risk mortality from IHD
10% increased risk mortality from stroke.
Most —-/—— treatment ever reviewed by nice.
Cost effective.
What are the end organ damage complications of hypertension?
Brain - haemorrhage, stroke, cognitive decline.
Retinopathy
Peripheral vascular disease
Kidney - renal failure, dialysis, transplantation, proteinuria.
Heart - LVH, coronary heart disease, congestive heart failure, MI.
When does BP vary?
Physical and mental stress cause it to rise.
Define hypertension.
That blood pressure above which the benefits of treatment outweigh the risks in terms of morbidity and mortality.
What is BP distribution like in the population?
Exhibits a normal distribution within the population (bell shaped curve).
What did the Framingham study find?
Increasing BP is associated with a progressive increase in the risk of stroke and CV disease.
Risk rises exponentially not linearly with pressure. Age plays significant role also.
At what blood pressure is a patient hypertensive?
Different guidelines.
BHS 140/90
JNC 140/90 opt <120/<80
WHO-ISH 140/90
What are the NICE definitions for the three stages of hypertension?
Stage 1 hypertension - clinical BP is 140/90mmHg +. ABPM daytime average 135/85mmHg +.
Stage 2 hypertension - clinical BP is 160/100mmHg +. ABPM daytime average 150/95mmHg +.
Severe hypertension - clinical systolic BP is 180mmHg or diastolic BP is 110mmHg +.
What is the aetiology in the majority of cases?
In 90% cases no cause can be found.
Primary hypertension.
What is the aetiology in the rest of the cases?
Secondary hypertension as a result of:
chronic renal disease, renal artery stenosis, endocrine disease, Cushings, Conn’s syndrome, Pheochromocytoma, GRA…
What factors increase risk of morbidity in hypertension?
Smoking (adds 10/20 mmHg) Diabetes mellitus (5-30x inc MI) Renal disease Male (x2) Hyperlipidaemia Previous MI/stroke LVH (x2).
Say the risk factors for CV disease in order of their risk.
Low fitness, hypertension, smoking, diabetes, obesity, high cholesterol.
Blood pressure is controlled by an integrated system, what are the prime contributors to blood pressure?
CO, HR, SV and peripheral vascular resistance.
All of which can be manipulated by drug therapy.
What is the effect of the sympathetic system on the CV system?
Vasoconstriction, reflex tachycardia, increased CO.
Action of sympathetic system are rapid and account for second to second BP control.
Which system is pivotal in long term BP control?
The Renin-Angiotensin-Aldosterone system.
What is the RAAS responsible for?
Maintenance of sodium balance
Control of BP and blood volume.
What is the RAAS stimulated by?
Fall in BP
Fall in circulating volume
Sodium depletion.
Where is renin released from?
Juxtaglomerular apparatus.
What does renin do?
Converts angiotensinogen to angiotensin I.
What converts angiotensin I into angiotensin II?
Angiotensin converting enzyme (ACE).
What is the role of angiotensin II?
It is a potent vasoconstrictor, anti-natriuretic peptide, stimulator of aldosterone release from adrenal glands.
Also a potent hypertrophic agent which stimulates myocyte and smooth muscle hypertrophy in the arterioles.
What is aldosterone?
A potent anti-natriuretic and antidiuretic peptide.
What are poor prognostic indicators in hypertensive patients?
Myocyte and smooth muscle hypertrophy.
Partially explains why hypertension and risks of hypertension persist in some patients despite treatment.