Hypertension Flashcards
What is hypertension?
This is the persistent elevation of BP in the systemic arterial circulation to a level higher than expected for the age, sex and race of the individual, such that treatment does more good than harm
What is blood pressure?
This is the outwards hydrostatic pressure exerted on the blood vessel walls, by the blood
What are the 2 different blood pressures?
Systolic - during ventricular contraction
Diastolic - during ventricular relaxation
What is meant by mean arterial pressure (MAP)?
This is the average pressure over one whole cardiac cycle
What is the calculation for MAP?
. (2 x Diastolic) + Systolic
. MAP = ———————————-
. 3
What is the normal value of MAP?
70-105mmHg
What is the normal range of systolic blood pressure?
90 - 120 mmHg
What is the normal range of diastolic blood pressure?
60 - 80 mmHg
What is pulse pressure?
This is the difference between systolic and diastolic blood pressure
What is the normal range of pulse pressure?
30 - 50 mmHg
What receptors detect changes in blood pressure?
Baroreceptors
Where are the baroreceptors located in the body?
Aortic baroreceptors
Carotid baroreceptors
What is the site of first synapse in the medulla to baroreceptor signals?
Nuceus tractus solitarius (NTS)
How does increased blood pressure affect the firing rate of baroreceptors?
It increases the firing rate of baroreceptors
Via which nerve do impulses from the aortic baroreceptors reach the medulla?
Vagus nerve
Via which nerve do impulses from the carotid baroreceptors reach the medulla?
Hering’s branch of Glossopharyngeal nerve
What is released by the heart in response to cardiac distension?
Natriuretic peptides
What are the 2 types of natriuretic peptide?
ANP - Atrial distension
BNP - Ventricular distension
What is the effect of natriuretic peptide release?
They cause the secretion of water and Na+ from the kidneys, as well as decreasing renin release and therefore causing vasodilation to decrease blood pressure
How are most cases of hypertension found?
Incidentally during regular health checks
What are some symptoms of acute malignant hypertension?
Headache
Blurred vision
Nausea
Vomiting
Chest pain
Altered mental status
What are some clinical signs of hypertension?
Pulses bruits
Hypertensive retinopathy
What are some ways in which hypertension can be classified?
Primary / secondary
Stage 1 / Stage 2 / Severe
Benign / Malignant / White coat
What is meant by primary hypertension?
This is hypertension with no singular identifiable cause
What are some risk factors for primary hypertension?
Age
Smoking
Family history
Obesity
High alcohol intake
High salt intake
How do effervescent tablets increase risk of mortality from hypertension?
They have a high sodium level and so increase risk of mortality 2 fold
What is meant by secondary hypertension?
This is hypertension caused by an identifiable singular cause, removal or reversal of which will lead to normalisation of blood pressure
What are some common causes of secondary hypertension?
Renal disease
Obstructive sleep apnoea
Aldosteronism
Reno-vascular disease
Drugs e.g. corticosteroids, NSAIDs, contraceptive pill
Pregnancy e.g. pre-eclampsia
What is aldosteronism?
This is the autonomous excretion of aldosterone, without the need of the RAAS pathway
What are some less common causes of secondary hypertension?
Cushing’s syndrome
Liddel’s syndrome
Phaeochromocytoma
Aortic coarction
Hyperparathyroidism
Inter-cranial tumour
Polycystic kidney disease
Fibromuscular dysplasia
What is meant by benign hypertension?
This is the stable elevation of blood pressure over many years
What are some possible consequences of benign hypertension?
Left ventricular hypertrophy
Congestive heart failure
Atheroma formation
Thickening of tunica media
Aneurysm rupture
Renal disease
What is the more common name for malignant hypertension?
Accelerated phase hypertension
What is malignant hypertension?
This is an acute, severe elevation of BP, with a diastolic pressure >130-140 mmHg
What are some complications of malignant hypertension that make it an emergency?
Cerebral oedema
Acute renal failure
Acute heart failure
Haemorrhage (Haemorrhagic stroke)
What is white coat hypertension?
This is an increased blood pressure during medical consultations, often due to increased stress or anxiety
How is white coat hypertension clinically classified?
A discrepancy of more than 20/10 mmHg between clinical and daytime average ABPM
What blood pressure is defined as stage 1 hypertension?
Clinic BP > 140/90 mmHg
AMBP > 135/85 mmHg
What blood pressure is defined as stage 2 hypertension?
Clinic BP > 160/100 mmHg
AMBP > 150/95 mmHg
What blood pressure is defined as severe hypertension?
Clinical BP > 180/110 mmHg
What is resistant hypertension?
Hypertension that does not respond to treatment using ACEis, ARBs or diuretics
What are some possible causes of resistant hypertension?
Non-concordance
White coat effect
Pseudo-hypertension
Lifestyle factors (e.g. cocaine use)
Drug interactions
2º hypertension
True resistance
What are the 2 methods of hypertension diagnosis?
Ambulatory blood pressure monitoring (AMBP)
Home blood pressure monitoring
What does diagnosis via ambulatory pressure monitoring require?
At least 2 measurements per hour during the patients usual waking hours (14 / day)
What does diagnosis via home blood pressure monitoring require?
2 consecutive seated measurements, 1 minute apart
BP is recorded twice a day for at least 4 days, but preferably 7
Measurements on the 1st day are discarded and the average of the remaining days is used
What are some tests that can be performed in hypertension?
Urine sampling - Proteinuria - albuminurea
Blood testing - Glucose, Electrolytes, raised Creatine, eGFR, cholesterol
12-lead ECG
Fundoscopy
What are the 4 grades of hypertensive retinopathy in fundoscopy?
I - Slight narrowing of retinal arterioles (≥1:2 arteriovenous ratio)
II - Severe narrowing of retinal arterioles (<1:2 arteriovenous ratio)
III - Bilateral soft exudates or flame haemorrhages
IV - Bilateral optic nerve oedema
What are some ECG findings that may suggest hypertension?
ST depression on leads V4-6 due to LV hypertrophy
What are some lifestyle management strategies in hypertension?
Exercise
Smoking cessation
Decrease salt, caffeine and alcohol intake
How will stage I hypertension often by managed?
Through lifestyle factors alone
How much does 1kg of weight loss decrease blood pressure by on average?
1mmHg
How does exercise affect mortality in hypertension?
15 minutes of daily physical activity decreases mortality by 14%, with every extra 15 minutes reducing mortality by 4%
What part of the kidneys controls the RAAS pathway?
Juxtaglomerular apparatus
What are the 3 components of the juxtaglomerular apparatus?
Macula cells
Granular cells
Mesangial cells
Describe the role of the juxtaglomerular apparatus in the RAAS pathway and blood pressure control
Macula dense cells are found in the renal tubule and detect low Na+ levels
Extra-glomerular granola cells detect renal artery hypotension
These stimulate the release of renin
Describe the RAAS pathway
Renin coverts angiotensinogen to angiotensin I
ACE converts angiotensin I to II
Angiotensin II stimulates aldosterone release
Aldosterone stimulates ADH release
Where is angiotensinogen synthesise?
The liver
Where is angiotensin converting enzyme (ACE) found?
In the lung endothelium
What is the action of angiotensin II?
This causes vasoconstriction and stimulates thirst
What is the function of aldosterone?
This causes Na+ and thus water retention
How do ACE inhibitors work?
They block the conversion of angiotensin I to angiotensin II, which prevents vasoconstriction and decreases Na+ and water retention, therefore decreasing blood pressure
What are some examples of ACE inhibitors?
Lisinopril
Ramipril
Enalopril
Perindopril
What are some side effects of ACE inhibitors?
Dry cough
Renal dysfunction
Angioneurotic oedema
What form of hypertension are ACE inhibitors contraindicated in?
Pregnancy induced hypertension
How do ARBs work?
They are angiotensin receptor blockers, so prevent the effects of angiotensin II on the body, preventing vasoconstriction and Na+ and water retention
What are some examples of ARBs?
Losartan
Irbesartan
Candesartan
Valsartan
What is a possible side effect of ARB use?
Renal dysfunction
What type of hypertension are ARBs contraindicated in?
Pregnancy induced hypertension
How do diuretics work?
They block the reabsorption of Na+ in the kidneys, thus increasing the levels of excreted water
What are the 2 types of diuretic?
Thiazide diuretics - Mild
Loop diuretics - Stronger
In what conditions are thiazide diuretics most indicated in?
Hypertension
In what conditions are loop diuretics most indicated in?
Congestive heart failure
Oedema
What are some examples of loop diuretics?
Furosemide
Bumetanide
What are some examples of thiazide diuretics?
Bendroflumethiazide
Indapamide
What are some side effects of diuretics?
Hypokalaemia -> Tiredness
Hyperglycaemia -> Diabetes
Hyperuricaemia -> Gout
Impotence
Arrhythmia
How do calcium channel blockers work?
They block calcium channels in the heart, therefore slowing action potential triggering by the SA node and decreasing muscle contraction, therefore decreasing SVR and workload of the heart
What are the 2 types of Ca2+ channel blockers?
Dihydropyridine
Rate-limiting
Where do dihydropyridine Ca2+ work?
On vascular smooth muscle, not in the heart
Where do rate-limiting calcium channel blockers usually work?
Mostly on the heart, decreasing heart rate
What are some examples of dihydropyridine Ca2+ channel blockers?
Amplodipine
Nicardipine
What are some examples of rate-limiting Ca2+ channel blockers?
Verapamil
Diltiazem
In what conditions are rate limiting Ca2+ channel blockers indicated?
Hypertension
Heart failure
Angina
Supraventricular tachycardias
What are some examples of potent vasodilator drugs?
Hydralazine
Minoxidil
What is a common side effect of minoxidil?
Hypertrichosis (Excessive hair growth)
What are some examples of alpha 2 agonists used as anti-hypertensives?
Methyldopa
Clonidine
What are some examples of alpha 1 antagonists used as anti-hypertensives?
Prazosin
Terazosin
Doxazosin
What type of drug is dobutamine?
A ß-adrenoceptor agonist
What type of drug is digoxin?
A cardiac glycoside
How do cardiac glycosides (Digoxin) work?
They are synthesised from foxgloves (Digitalis purpurea)
It blocks the sodium potassium pump
This prevents the building of a concentration gradient for the Na+/Ca2+ exchanger
This increases intracellular Ca2+ levels, leading to an increased force of contraction
They also increase vagal activity, slowing AV conduction and slowing heart rate
What is the progression of treatment in patients with hypertension, who are under 55 and caucasian, or have diabetes?
1 - ACEi or ARB (Or ß-Blocker in young female)
2 - Add calcium channel blocker
3 - Add thiazide-like diuretic
4 - Add spironolactone
What is the progression of treatment in patients over 55, or patients who are black afro-carribean?
1 - Calcium channel blocker
2 - Add ACEi or ARB (or ß-blocker in young female)
3 - Add thiazide-like diuretic
4 - Add spironolactone
What are the treatment aims for blood pressure in people under 80 years old?
< 140/90 mmHg
What are the treatment aims for blood pressure in people over 80 years old?
< 150/90 mmHg
What are the treatment aims for blood pressure in patients with diabetes?
< 130/80 mmHg
