Essential hypertension Flashcards
(46 cards)
What is hypertension?
sustained elevation of systolic and diastolic blood pressure (> 140/90 mmHg)
What are the causes of hypertension?
Causes:
• primary (idiopathic/essential)
o No identifiable cause
• secondary: o renal disease (salt/H2O imbalance) o adrenal tumours (aldosterone) o aortic coarctation (narrowing of aorta) o Steroids, Rx
What are some hypertension related diseases?
Cerebrovascular
• Infarction: thrombotic – will cause ischaemic damage within the cerebral vessels
Cardiac
• Angina/MI
• CHF (congestive heart failure)
• Sudden death
Renal
• Chronic renal failure
• End stage renal disease
Retinopathy
• Sclerosis/Arterial
• Haemorrhage/Exudate
Large artery disease
• Carotid artery stenosis
How does hypertension cause organ damage in the blood vessels?
Blood vessels themselves undergo atheroma and aneurysm formation in large vessels, elastic reduplication in small vessels due to increased blood pressure
How does hypertension cause organ damage in the heart?
left ventricular hypertrophy, left heart failure (LHF).
How does hypertension cause organ damage in the lungs?
pulmonary oedema due to LHF
How does hypertension cause organ damage in the kidney?
nephrosclerosis, renal failure
How does hypertension cause organ damage in the eye?
retinal capillary damage, haemorrhages, exudates.
How does hypertension cause organ damage in the brain?
microaneurysms and stroke, ischaemic cortical atrophy/ dementia
What is hypertensive heart disease?
Increased load causes concentric left ventricular hypertrophy (increase in cell and muscle size in the heart) – causes weakening of the heart and reduced contractility, can lead to heart failure
How can a hypertensive patient experience massive intracerebral haemorrhage?
Massive intracerebral haemorrhage due to ruptured microaneurysm in the hypertensive patient
What affects blood pressure?
Cardiac output and the peripheral resistance
- CO x TPR = BP
What can high blood pressure arise from?
- Increased ECFV (extracellular fluid volume) – venous return to the heart can affect it
- Increased production of vasoconstrictor agents
- Reduction in production of vasodilator agents
What are some of the factors to be considered when diagnosing hypertension?
- BP cut off value (Usual value >140 and/or > 90 mmHg)
- Age (increases with age)
- Ethnic group (e.g. more common in African Americans
What are the causes of hypertension?
Causes of essential hypertension is still not known but genetic and environmental factors are believed to be important
What are important genetic/environmental factors for essential (primary) hypertension?
• Increased activity of hormonal system such as :
o Sympathetic nervous system (SNS)
o Renin-angiotensin-aldosterone system (RAA)
- Obesity/ Insulin resistance – can lead to inflammatory changes
- Endothelial dysfunction – big impact on atherosclerosis development
- Capillary rarefaction – decrease in density of vessels, can have impact on vascular resistance
- Defect in vascular smooth muscle contraction/relaxation
- Defects in renal sodium handling
Why is treatment of hypertension important?
Reduction in blood pressure level reduces relative risk of consequences
A 5-mmHg reduction in diastolic BP for 5 years will:
• Reduce strokes by 42%
• Reduce MI by 16%
• Reduce vascular mortality by 21%
What are the goals of antihypertensive therapy?
- Adequate Blood Pressure Control (< 140/90 mmHg)
- Prevention of Target Organ Damage
- Controlling other cardiovascular risk factors
- No detrimental metabolic side-effects
Why is the classification of hypertension important?
It can impact on the care pathway
What are the treatments and management for hypertension?
- Nonpharmacological (Life-style modification)
- Pharmacological treatment
- Surgical e.g. for Conn’s syndrome (adrenal gland increases in aldosterone)
What are the targets for life-style management for hypertension?
- Maintain normal weight (BMI 20-25%): can reduce by 1-2 mmHg/Kg
- ↓ Salt intake (≤ 100 mmol/day = 6 g NaCl): can reduce by 2-8 mmHg
- ↓ Alcohol intake (≤ 3 u/day men, ≤ 2 u/day women): can reduce by 2-4 mmHg
- Increase Fruits & vegetables intake (≥ 5 portions/day): can reduce by 8-14 mmHg
- Increase Regular exercise (≥ 30 min/day x 3 days/wk): can reduce by 4-9 mmHg
What are the pharmacological treatments/major classes of antihypertensive drugs?
- Renin inhibitors
- ACE inhibitors
- Angiotensin II receptor blockers
- Calcium channel antagonists
- Diuretics (loop diuretics, thiazides, potassium sparing)
- Adrenergic (a1 /b1) receptor antagonists
- Centrally acting a2 receptor agonists (rarely used for essential e.g. pregnancy)
- Other vasodilators
Some key issues to consider in selecting drug therapy?
- Essential vs secondary hypertension
- Evidence of efficacy
- Side effects of drug
- Drug interactions
- Individual demographics
- Coexisting diseases
- Quality of life
- Economic considerations
What drugs are prescribed to under 55s?
- Under 55 – ace inhibtors/angiotensin receptor blocker
- Ca channel blocker added if ACE inhibitor wasn’t effective
- Drugs are usually added to the already existing prescription until one works
