Hypertension Flashcards
(40 cards)
What is the definition of hypertension?
That blood pressure above which the benefits of treatment outweigh the risks in term of morbidity and mortality
What is the difference between primary and secondary hypertension?
Primary - no cause for the hypertension can be found and is about 90% of all patients
Secondary - a cause for the hypertension can be found and is about 10% of all patients. Such as chronic renal failure, renal artery stenosis and endocrine diseases.
Blood pressure changes throughout the day, what causes this?
emotion
stress
exercise
What else can influence what your BP is?
diet obesity age medication on illicit drugs stresses
What are some of the main complications of high blood pressure?
End organ damage:
- brain: stroke, haemorrhage, cognitive decline
- kidney: renal failure, proteinuria
- eye: retinopathy
- heart: LVH, MI
- blood vessels: peripheral vascular disease
Oedema
Is the clinic BP larger or smaller than the ABPM (Ambulatory Blood Pressure Monitoring)?
Clinical BP tends to be larger as the patient is sometimes more stressed in hospital and since its only one reading it isn’t a good representation of what the patients BP is like daily.
Whereas the ABPM is taken over 24 hours when the patients fluctuates their emotions and an average is taken.
How many stages of Hypertension is there?
3
stage 1
stage 2
severe hypertension
What are the blood pressure for the three stages of hypertension?
- Clinic BP >140/90 mmHg
ABPM daytime average >135/85 mmHg - Clinic BP >160/100 mmHg
ABPM daytime average >150/95 mmHg
Severe >180/110 mmHg
What are some risk factors for high blood pressure?
Cigarette smoking Diabetes mellitus Renal disease Male Hyperlipidaemia Previous MI or stroke Left ventricular hypertrophy Age Weight Alcohol intake Race Genetics
all of these are taken into account when calculating the risk of hypertension to a particular patient.
Assign Risk Calculator is used which takes into account their postcode.
Compare short and long term control of blood pressure.
Short term = arterial/carotid baroreceptors
• Vagus nerve and glossopharyngeal nerve respectively carry sensory fibers to medullary cardiovascular centres.
• This will trigger the vagus nerve or sympathetic nerves to decrease or increase the contractility of the heart and therefore affecting the heart rate and BP.
Long term = kidney permeability and plasma volume
• RAAS increases permeability of the conducting duct of the nephron by the release of renin from the juxtaglomerular.
• Therefore, more water is reabsorbed.
• Plasma volume increases
• Renin is released from the juxtaglomerular apparatus which converts angiotensinogen to angiotensin I which is then converted to angiotensin II by an ACE enzyme.
• Angiotensin II
- vasoconstrictor
- increases permeability of water in the conducting duct
- stimulates release of aldosterone which increases the reabsorption of Na+ back into the blood.
- Stimulates myocyte and smooth muscle hypertrophy – this is a poor prognosis indicator
Name some causes of secondary hypertension.
renal failure
drug induced - NSAIDS, oral contraception
pregnancy - preeclampsia
endocrine - cushings, Conns syndrome, acromegaly
coarctation of aorta
sleep apnoea
A true diagnosis of hypertension has to proven to ensure the patient will receive the correct treatment.
How is this done?
ABPM is used to measure their blood pressure over a long period of time.
While sleeping their should be a dip in BP as the parasympathetic system has been activated which reduces heart rate and hence BP. If this is not present and the BP remains high throughout the night then this shows a poor prognosis.
How can end organ damage be measured?
LVH - echocardiography, ECG
Proteinuria - albumin creatine ratio (ACR)
Kidney function - renal ultrasound, eGFR (glomerulus filtration rate)
After prescribing medication to a patient for hypertension, a target BP has to be set.
Why is this done and what is the target BP normally?
This is done to ensure the BP is controlled well.
Target BP normally =
What are the two ways hypertension is treated?
- stepped approach
- low dosage of several drugs - to reduce side effects
What drug are young people with high renin prescribed for hypertension?
ACE inhibitors
- to reduce the conversion of angiotensin I to angiotensin II
- reduces the permeability of conducting duct
- therefore less water is reabsorbed which decreases plasma volume and hence BP.
What drug are elderly people prescribed with low renin for hypertension?
Calcium channel blockers (CCB) - block Ca L type channels so it takes longer for the pace maker potential to be reached.
Thiazide- Type Diuretic - blocks reabsorption of Na so there is a higher conc of Na inside the conducting duct which pulls water into the conducting duct. This increases diuresis.
State the stepped approach for treating hypertension and what drugs should be used at each stage.
- CCB (over 55, black/afrocarribean)
Thiazide type diuretic (high risk heart disease/oedema/intolerance of CCB)
ACEI/ARB (under 55/not afrocarribean/women of bearing age) - Add thiazide type diuretic such as clortalidone or indapamide (so now have two drugs prescribed)
- Add CCB, ACEI, Diuretic together
- Consider treatment for resistant hypertension:
Consider higher-dose thiazide-like diuretic treatment if the blood potassium level is higher than 4.5 mmol/l.
If over 55 years
- a calcium channel blocker
If young
- An ACEI or ARB
- if a single agent doesn’t control BP then use the two together
The following questions will be a description of the different antihypertensives.
…
Angiotensin Converting Enzyme Inhibitors (ACEI)
- mechanism
- contradictions
- adverse drug reactions
- drug drug interactions
- prevent the conversion of angiotensin I to angiotensin II so reduces the permeability of the conducting duct so less water can be reabsorbed.
- renal failure, renal artery stenosis, hyperkaleamia
- cough, renal impairment, first dose can cause hypotension
- NSAIDs, potassium supplements, potassium sparing diuretics
Give some examples of ACEIs
RAMIPRIL, Perindopril
Angiotensin II Antagonists (ARB)
-mechanism
- Competitively block the actions of angiotensin II at the angiotensin AT1 receptor
Give some examples of ARBs
LOSARTAN, VALSARTAN, CANDESARTAN, IRBESARTAN
What is the benefit of ARBs compared to ACEIs
ARBs don’t give a cough
