Hypertension Flashcards
What conditions is hypertension a risk for?
- Stroke
- Ischaemic heart disease
- Heart failure
- Chronic kidney disease
- Cognitive decline
- Premature death
How do we manage BP that differs between arms?
- If the difference in readings between arms is more than 15 mmHg, repeat the readings
- If the readings between arms stay different by 15 mmHg, measure subsequent BP in the arm with the higher reading
How do we diagnose hypertension?
- If the BP measured in clinic is 140/90 or more
- Take a second measurement during the consultation
- If the second measurement is substantially different from the first, take a third measurement
Record the lower of the last 2 measurements as the clinic BP
- If clinic BP is between 140/90 and 180/20, offer ambulatory BP monitoring to confirm the diagnosis of hypertension
- If ABPM is unsuitable, offer home BP monitoring
What should we do whilst waiting for confirmation of a diagnosis of hypertension?
- Investigations for target organ damage
- Formal assessment of cardiovascular risk using a CV risk assessment tool (QRISK3)
How should we measure blood pressure?
- 2 consecutive measurements are taken, at least 60s apart and with the patient seated
If HBPM:
- Blood pressure is recorded 2x a day, in the morning and evening
- BP recording continues for at least 4 days, ideally 1 week
What BP is diagnostic of hypertension?
- Clinic BP of 140/90 or higher
and - ABPM daytime average or HBPM average of 135/85 or higher
What should we do if someone’s blood pressure is subclinical?
If hypertension is not diagnosed:
- Measure patient’s BP in clinic at least every 5 years, and measure it more frequently if the blood pressure is close to 140/90
How does ABPM work?
- Ensure that at least 2 measurements per hour are taken during usual waking hours
- Use the average value of at least 14 measurements taken to confirm a diagnosis of hypertension
What are the stages of hypertension?
Stages:
1: 140-159/90-99 (mild)
2: 160-179/100-109 (moderate)
3: >180/>110 (severe)
Isolated systolic hypertension: >140/<90
Why is staging of hypertension important?
Risk stratification of the patient
- Guides towards our next management steps
What is a hypertensive crisis?
Also known as malignant hypertension
Hypertensive urgency:
- BP elavated
- No target organ damage (heart, kidneys, brain)
- 180/110
- Symptoms: headache, shortness of breath, epistaxis, anxiety
Management: oral medication, outpatient setting
Hypertensive emergency (malignant hypertension):
- BP so high, target organs damaged
- 180/120
- Can happen at lower pressures
- Symptoms: cheat pan, shortness of breath, back pain, numbness, weakness, vision changes, difficulty speaking
- Can result in encephalopathy
- As BP rises causes cerebral oedema, builds pressure in skull and leads to dysfunction
Management: IV medication, vasodilator, calcium channel blocker or beta blocker
(relax arteries)
Which bloods should be done to assess cardiovascular risk when investigating suspected hypertension?
- Bloods (RBC, U&Es, random blood gluocse, cholesterol)
- Urine
- ECG
- CXR
What assessment tool is used to understand cardiovascular risk in suspected hypertension?
QRISK3
How do we calculate BP?
BP = cardiac output x peripheral resistance
CO = HR x SV
How does the RAAS work?
- BP drops
- Less blood flow to kidneys
- Kidneys release renin
- Angiotensinogen becomes Angiotensin I when renin is released
- Angiotensin I becomes angiotensin II due to ACE (angiotensin converting enzyme)
- Angiotensin II is the most potent vasconstrictor in the body
- This causes vasoconstriction
- Peripheral resistance increases
- BP increases
Renin also causes the release of aldosterone
- Aldosterone causes increase in Na+ reabsorption and H2O reabsorption
- This increases blood volume
- This increases BP
If BP increases too much, this damaged blood vessels and activated the sympathetic system, reducing blood flow to the kidneys
How is blood pressure controlled short-term?
- Central nervous system response
- Baroreceptors
- Chemoreceptors
How is arterial pressure raised?
- Sympathetic nervous system releases noradrenaline from nerve terminals
- NA acts on the alpha adrenergic receptors of the VSMC
- All arterioles constrict
- Heart is directly stimulated
Not innervated: capillaries, precapillary sphincters and metarterioles
Which receptors does adrenaline affect, and what are its clinical uses?
Adrenaline
Receptors: β1 = β2 > α1* = α2*
Clinical uses: anaphylactic shock, cardiogenic shock, cardiac arrest
Which receptors does noradrenaline affect, and what are its clinical uses?
Noradrenaline
Receptors: β1 = α1 >
β2 = α2
Clinical uses: severe hypotension and septic shock
Which receptors does dopamine affect, and what are its clinical uses?
Dopamine
Receptors: β1 = β2 > α1*
Clinical use: acute heart failure, cardiogenic shock
Which receptors dobutamine affect, and what its clinical uses?
Dobutamine
Receptors: β1 > β2 > α1
Clinical use: acute heart failure, cardiogenic shock, refractors heart failure
How do baroreceptors work?
- Nerve endings in all large thoracic and neck arteries
- Major populations: carotid sinus, arch of the aorta
- Activated on stretch
If baroreceptors sense increased BP
- Secondary signals from tractus solitarius
- Inhibition of vasoconstrictor centre and excitation of vagal parasympathetic centre
What are chemoreceptors?
Chemoreceptors
- Sensitive to low O2, high CO2 and acidosis
Chemoreceptor organs: - 2 carotid bodies (one each bifurcation)
- 1-2 aortic bodies (adjacent to aorta)
- Separate blood supply
- Reduction in blood flow (reducation in pressure <80 mmHg) causes metabolic stimulation
- Excitatory effect on vasomotor centre
How is blood pressure controlled long term?
- Renin angiotensine aldosterone system
- Vascular remodelling and contractility
Where does aldosterone act and what does it do?
Aldosterone
- Principal cells of the collecting tubules
- Distal tubules
- Collecting ducts
Increases absorption of Na+ and secretion of K+ and H+
What is primary hyperaldosteronism?
The body produces too much aldosterone
Leads to long-standing hypertension and hypokalaemia
Causes:
- Unilateral aldosterone producing adenoma or Conn’s syndrome (50-60%)
- Bilateral adrenal hyperplasia (40-50%)
Consequences: high aldosterone leads to low K+ and low H+
= hypokalaemic alkalosis
This is due to more Na/Cl reabsorption in the kidneys, which results in more K+ extretion
Presentation:
- Hypokalaemia
- Muscle weakness
- Cramping
- Palpitations
Hypokalaemia induced nephrogenic diabetes insipidus: polyruria + polydipsia
Complications of long standing hypertension
What is Addison’s Disease?
Adrenal insufficency: the adrenal glands produce too little cortisol and aldosterone
Presentation:
- Lethargy
- Weight loss
- Fainting
- Hyperpigmenting skin creases
- Postural hypotension
- Dehydrated
- Hyponatraemia
- Hyperkalaemia
- Acidotic
Investigations:
- Short SynACTHen test
- Tetracosactide (synacthen) 250µg IV/IM
- Check blood cortisol at 0 mins and 30 mins
- Cortisol at 30 mins should be >600nmol/L
Treatment:
- Glucocorticoid, mineralocorticoid and sex steroid production are reduced!
- Bracelet
- Acutely ill -> hydrocortisone IV
What changes are seen in the blood arterioles in essential hypertension?
Essential hypertension
- Increase in wall thickness
- Reduction in lumen diameter
- Increase in wall to lumen ratio
- Preservation or mild impairment of endothelial function
What changes are seen in the blood arterioles in Type II diabetes and hypertension?
T2DM + Diabetes
- Increase in wall thickness
- No change/increase in lumen diameter
- Impairment of endothelial function
What is metabolic syndrome?
Metabolic syndrome:
- Elevating blood pressure
- Dyslipiaemia
- Exacerbation of insulin resistance
All caused by adipose tissue causing increased vascular tone
What is the first line treatment for hypertension?
Younger than 55 = ACEi/ARB
Older than 55 or black = CCB
Any age + T2DM = ACEi-ARB
What is the second line treatment for hypertension?
Either:
ACEi/ARB + CCB
OR
ACEi/ARB + Diuretic
What is the third line treatment for hypertension?
Always:
ACEi/ARB + CCB + Diuretic
What is the fourth line treatment for hypertension?
- Further diuretic therapy
- Alpha blocker
- Beta-blocker
Consider seeking specialist advice
What is seen in hypertensive retinopathy?
Hypertensive retinopathy
- Flame haemorrhages
- Hard exudates
- Cotton wool spot
- Papilloedema
What end-organ damage is seen consequential to hypertension?
End-organ damage
- Eyes: hypertensive retinopathy
- Brain: hypertensive cerebrovascular disease
- Heart: left ventricular hypertrophy, ischaemic heart disease, with or without heart failure
- Kidneys: hypertensive nephropathy
What are the causes of secondary hypertension?
10% of hypertension cases
Causes:
- Renal diseases
Kidneys don’t function well - struggle to regulate water and Na+, increases in fluid in body, and then BP
Ex: polycystic kidney disease - fluid filled cysts
- Glomerular disease
Poorer filtration of water and Na+
- Renovascular hypertension
Narrowing of arteries that supply kidneys with blood
Kidneys assume dehydration and hold onto more fluid
- Cushing’s syndrome
High levels of circulating glucocorticoids, facilitiate water and Na+ retention, increasing BP - Primary aldosteronism
Too much aldosterone increases NA+ and water retention - Phaeochromocytoma
Tumour growing on the adrenal glands, increase BP b release of epinephrine and norepinephrine - Sleep apnea
Start stop breathing, reduced O2 intake, so blood pumps harder
Blood flow increases at night, and so increases BP at night - Obesity
Higher body weight increases blood volume, which increases flow and therefore BP - Brain tumours and encephalitis
Reduced blood flow to parts of the brain, as the above increase the pressure in the skull the body increases BP in force more blood into the brain
What clinical features are suggestive of secondary hypertension?
- Severe or resistant hypertension
- An acute rise in BP over a previously stable value
- Proven age of onset before puberty
- Age less than 30 years with no family history of hypertension and no obesity
What clinical features are seen in renovascular disease?
- Acute elevation in serum creatinine of at least 30% after administering ACEi or ARB
- Moderate to severe hypertension in patient with
- Diffuse atherosclerosis
- Unilateral small kidney
- Asymmetry in renal size of more than 1.5cm that cannot be explain by other reasons
- Moderate to severe hypertension in patients with recurrent episodes of flash pulmonary oedema
- Onset of stage II hypertension after 55 years
- Systolic or diastolic abdominal bruit
What clinical features are seen in primary renal disease?
- Elavated serum creatinine concentration
- Abnormal urinanalysis
Which drugs may cause elevations in BP?
- Oral contraceptives
- NSAIDS
- Stimulants (eg cocaine, methyphenidate)
- Calcineurin inhibitors
- Antidepressants
What clinical features are suggestive of phaeochromocytoma?
- Paroxysmal elevations in BP (night time)
- Triad of headache (pounding), palpitations, and sweating
What clinical features are suggestive of primary aldosteronism?
- Unexplained hypokalaemia with urinary potassium wasting
- More than 50% patients are normokalaemic
What clinical features are suggestive of Cushing’s syndrome?
- Cushingoid faces
- Central obseity
- Proximal muscle weakness
- Eccymoses
- History of glucocorticoid use
What clinical features are suggestive of sleep apnea syndrome?
- Primarily obese men who snore loudly in sleep
- Daytime somnolence
- Fatigue
- Morning confusion
What clinical features are suggestive of coarctation of the aorta?
- Hypertension in the arms with diminished or delayed femoral pulses
- Low or unobtainable BP in the legs
What clinical features are suggestive of hypothyroidism?
- Symptoms of hypothyroidism
(menorrhagia, weight gain, fatigue, lethargy, thinning hair, hoarse voice, dry skin, cold intolerance) - Elevated serum thyroid stimulating hormone
What clinical features are suggestive of primary hyperparathyroidism?
Elevated serum calcium
What lifestyle changes can help with hypertension?
- Healthy diet
- Reduced salt
- Reduced coffee
- Quitting smoking
- Reduced alcohol intake
- Regular exercise
- Relaxation therapies and methods
What are the risk factors for essential hypertension?
- Being overweight
- Being stressed
- Eating too much salt
- Excessive alcohol
- Too much caffeine
- Smoking cigarettes
- Not enough fruit and veg
- Not enough exercise
- Family history
- Caribbean or African descent
