Hypertension Flashcards
Primary/Essential Hypertension
A blood pressure which is associated with significant cardiovascular risk
Causes of Primary/Essential Hypertension
Not really known - multifactorial
Obesity? - Angiotensinogen produced by adipocytes
Insulin Resistance? Excessive Alcohol Consumption Genetics? - Activity of RAAS Environment? Foetal Programming? Low birth weight? Salt sensitivity? Age? - Stiffening of aorta Ethnicity?
Causes of Secondary Hypertension
Renal Disease Renovascular Disease Conn's Syndrome - Increased aldosterone levels where patient retains Na+ and thus fluid Cushing's Syndrome Hyperthyroidism Phaeochromocytoma Pregnancy Drugs (NSAIDs, Corticosteroids, Sympathomimetics)
***Don’t memorise these
NICE Hypertension Treatment Targets
SBP < 140mmHg (<140mmHg in diabetes/<130 with complications)
DBP < 90mmHg (<80mmHg in diabetes)
Goals of hypertension treatment
Reduction in cardiovascular damage Preservation of renal function Limitation or reversal of LV hypertrophy Prevention of Ischaemic Heart Disease Reduction in mortality due to stroke & MI
Formula for BP
Cardiac Output x Total Peripheral Resistance
Role of ACEIs in hypertension treatment
Renin is produced when kidneys detect low BP, Na+ or sympathetic stimulation
This makes Angiontensin I which is converted to AII via ACE.
ACEIs inhibit ACE and controls BP by:
- Reducing arterial and venous vasoconstriction
- Reduced salt & water retention
What does RAAS have a very significant effect on
Blood Pressure
Effect of Bilateral Renal Artery Stenosis on RAAS
Increases renin production significantly, increasing BP
AT1 Receptor Antagonists
Block action of Angiotensin II at AT 1 Receptor
Similar effect to ACEis without cough as a side effect
Vasodilators/Ca2+ channel inhibitors for Hypertension treatment
Inhibit voltage operated Ca2+ channels on vascular SM
- Leads to vasodilation and reduction in TPR thus BP
Dihydropyridines (e.g. amlodipine) best for hypertension as they don’t depress cardiac tissue
Rate-limiting (e.g. verapamil) has greater effects on cardiac tissue
Diurtetics for Hypertension Treatment
Thazide-like (e.g. Indapamide)
- Second line antihypertensives
Inhibit Na+/Cl- in distal convoluted tubule
Reduction in circulating volume
Important Side Effects
- Hyperkalaemia
- Postural Hypotension
- Impaired glucose tension
Alpha blockers
Last-line antihypertensives
- Widespread side effect
Competitive receptor antagonists of a1-adrenoceptors
e.g. Doxazosin, prazosin
Beta-blockers for hypertension treatment
Reduction in sympathetic drive to heart, reducing cardiac output and cuase a reduction in sympathetically evoked renin release
Some Beta-blockers are B1 selective (Atenolol) while others are B non-selective (Propranolol)
Blocks renin from juxtaglomerular cells
May block bronchial B2 receptors - contraindicated in Asthma and caution in COPD
Adverse Effects of ACEIs
Cough
Severe first dose hypertension
Renal Damage
Adverse Effects of Calcium Channel Blockers
Peripheral Oedema (e.g. swollen ankles) as they cause vasodilation of small arterioles Postural Hypotension Some constipation
Adverse Effects of Thiazides (Diuretic)
Diabetogenic
Alter Lipid Profile
Hypokalaemia
Postural Hypotension
Adverse Effects of Beta Blockers
Bronchospasm
Adverse Effects of Alpha-blockers
Widespread
Postural hypotension
(affects sympathetic control of BP)
Lifestyle changes to treat hypertension
Alcohol consumption should be reduced Weight Reduction Avoiding excess caffeine Reducing fat and salt intake Increasing fruit & oily fish in diet Increasing exercise
Importance of smoking cessation in hypertension treatment
Smoking does not increase BP, but it does increase risk of cardiovascular incidents
Choice of antihypertensive in diabetics
ACE Inhibitors
Choice of antihypertensive in ischaemic heart disease
Beta Blockers
Choice of antihypertensive in patients with CHF
ACE Inhibitors
Treatment of Hypertension with:
Type 2 Diabetics
<55 years & non-black
Step 1
ACEi/AT1 RA
Step 2
ACEi/AT1 RA + CCI or Diuretic
Step 3
ACEi/AT1 RA + CCI + Diuretic
Step 4
Referral, Add spironolactone, a-blocker or Beta blockers
**ACD Guidance
Treatment of Hypertension for patients >55 years or black
Step 1
CCI
Step 2
CCI + ACEi/AT1 RA or Diuretic
Step 3
CCI + ACEi/AT1 RA + Diuretic
Step 4
Referral, Add spironolactone, a-blocker or Beta blockers
**ACD GUIDANCE
Centrally Acting Antihypertensives
Act on brain to reduce BP
Types
Alpha-methyl dopa: False substrate result in an analogue of NA acting at central a2-adrenoceptors
- Used to treat hypertension in pregnancy as it is safe to use
Moxonidine: An imidazoline which activates central imidazoline receptors
Clonidine: a2-adrenoceptor agonist which acts centrally to decrease sympathetic output
***They’re really not that important don’t stress about them
What anti-hypertensives are very contraindicated in pregnancy
ACE Inhibitors
