L10 - Blood Pressure Control Flashcards
What is hypertension?
A sustained increase in blood pressure
What is the ideal range of blood pressure?
90/60mmHg - 120/80mmHg
Numerically Devine
a) stage 1 hypertension
b) stage 2
c) severe hypertension
a) greater than or equal to 140/90mmHg OR greater than or equal to 135/85mmHg ABPM average
b) greater than or equal to 160/100mmHg OR greater than or equal to 150/95mmHg ABPM average
c) greater than or equal to either 180 systolic or 110 diastolic
Primary hypertension is when the cause of the hypertension is unknown/can’t be narrowed down to a single factor, what percentage of hypertension cases does primary hypertension account for?
95%
Give some examples of secondary hypertension causes
Cushing syndrome/hyperaldosteronism/chronic renal disease/renovascular disease
What can high blood pressure lead to?
MI/heart failure/stroke/renal failure/retinopathy
High blood pressure is the 3rd biggest risk factors for premature death in England after what?
Smoking and poor diet
Hypertension exerts problems via two main ways one being an increased afterload on the heart as a result of increased peripheral resistance, what’s the other?
Vascular (arterial) damage
If hypertension is diagnosed what 5 areas of the body should be clinically checked regularly by your GP
Eyes Brain Heart Arteries Kidneys ((e.g. protein in urine)
MABP =?
CO X TPR
CO = SV X ?
HR
What is the short term regulation of BP?
The baroceptor reflex
Long term regulation of BP is under the control of neurohumoral responses such as…..
The renin/angiotensin system
Sympathetic NS
ADH
Atrial natriuretic peptide (ANP)
Low blood pressure stimulates the release of renin mainly at the level of the kidneys, what cells release renin?
Juxtaglomerular cells
Describe the three factors affecting renin release from juxtoglomerular cells
Low plasma sodium
Sympathetic stimulation of juxtoglomerular cells
Decreased renal perfusion
Explain how the sympathetic nervous system has an impact on long term BP regulation
High levels of sympathetic stimulation
Causes vasoconstriction of arterioles (chronic short term regulation via this) causes a reduction in GFR and thus Na retention, vasoconstriction also stimulates renin-angiotensin system
How is ADH involved in long term blood pressure regulation
Increases water retention via upregulation of AQP2 and also increases Na retention
Activated by plasma osmolarity and severe hypovolaemia
Describe the actions of ANP and how it’s release is stimulated
Causes vasodilation of afferent arteriolar of kidney:
Increases blood flow -> increases GFR -> inhibits sodium reabsorption so sodium is lost in urine
Stimulated by atrial stretch. Acts to decrease BP, if circulating volume is low ANP release is inhibited
Prostaglandins are local vasodilators, they work by enhancing GFR and reducing Na reabsorption, they are useful when levels of what are high?
Angiotensin II
Dopamine is made in the kidney from circulating levels of L-DOPA, what action does it have here?
Vasodilation and increasing GFR
Explain how renovascular disease causes a long term increase in blood pressure
Occlusion of the renal artery causes a fall in kidney perfusion pressure -> decreased perfusion to kidney -> activation of renin-angiotensin system -> vasoconstriction
How does
a) renal parenchyma disease
b) Cushing syndrome cause long term hypertension?
a) inadequate glomerular filtration -> activation of renin-angiotensin system
b) excess cortisol production -> acts on aldosterone receptors
Give some non-pharmacological approaches to treating hypertension
Exercise
Diet
Reduced Na+ intake
Reduced alcohol intake
Give an example of of an ACE inhibitor and an angiotensin receptor blocker
ACE inhibitor - ramipril
ARB - losartan
Give some examples of medication that treat hypertension
ACEI
ARB’s
Dihidyropyridine or ‘L type ca channel blockers’ (nifedipine)
Alpha 1 receptor blockers at SNS level (doxazosin)
Thiazides diuretics
Beta blockers explanation - target B1 receptors in heart, reduce hr only used in situations with MI as well
What are the five major effects of activation of the renin-angiotensin-aldosterone system?
Angiotensin I and II - stimulate sodium reabsorption/vasocontstriction/release of ADH/release of NA
Aldosterone - increase in sodium reabsorption and thus fluid retention
