Lecture 10.2: Hypertension Flashcards
What is Hypertension?
Persistent elevation of blood pressure in the systolic circulation
What are Risk Factors for Hypertension? (6)
- Family History
- Diet
- Hypercholesterolemia
- High Cholesterol
- Smoking
- Lack of Active Lifestyle
Mean Arterial Pressure Equation
Mean Arterial Pressure = Cardiac Output x Systemic Vascular Resistance
Cardiac Output Equation
Cardiac Output = Stroke Volume x Heart Rate
Angiotensin 1 vs 2
- Angiotensin I is in turn cleaved by angiotensin-
converting enzyme (ACE) to produce
angiotensin II - Angiotensin II in turn causes vasoconstriction
and increases BP
What is Primary Hypertension?
- No known cause
- 95% of Hypertension cases
What is Secondary Hypertension?
- Has a known cause
What are some causes of Secondary Hypertension? (17)
- Renal Artery Stenosis
- Chronic Kidney Disease
- Coarctation of the Aorta
- Gestational HTN
- Pre-eclampsia
- Autonomic Dysfunction
- Medications
- Non-adherence to Antihypertensives
- Alcohol
- Obstructive Sleep
- Apnoea
- Obesity
- Hyper-aldosteronism
- Hypercortisolaemia
- Phaechromocytoma
- Acromegaly
- Thyroid Dysfunction
Stages of High BP: High Normal (BP readings)
130/80 mmHg to 139/89 mmHg
Stages of High BP: Stage 1 (BP readings)
- In Clinic: 140/90 mmHg to 159/99 mmHg
- Out of Office: 135/85 mmHg to 149/94
mmHg
Stages of High BP: Stage 2 (BP readings)
- In Clinic: 160/100 mmHg or higher but less
than 180/120 - Out of Office: 150/95 mmHg or higher
Stages of High BP: Stage 3 (BP readings)
Systolic 180 mmHg or higher or diastolic of 120 mmHg or higher
End Organ Damage: Eyes (4)
- Arteriolar Narrowing
- Haemorrhages
- Macular Exudate
- Papilloedema
End Organ Damage: Heart
- Hypertrophy
End Organ Damage: Kidney
- Reduced GFR -> CKD
Hypertensive Emergencies
- Malignant Hypertension
- Hypertensive Encephalopathy
- Pre-eclampsia
- Acute Stroke
- Acute Pulmonary Oedema
- Acute Coronary Syndrome (ACS)
- Aortic Dissection
What Drugs have an effect on the ANS? (2)
- β-blockers
- α-blockers
What Drugs have an effect on systemic vascular resistance?
- Calcium Channel Blockers (CCBs)
- Because muscle contraction is largely
dependent upon influx of calcium, its inhibition
causes relaxation of vascular and arterial
smooth muscle cells - Thus arterial vasodilation
- Thus ↓ BP
What Drug has an effect on effective circulating volume? Mechanism?
- Thiazide Diuretics
- Reduce BP by increased urination and sodium
loss - Thus decreased blood volume, thus ↓ BP
What Drugs inhibit Angiotensin I to Angiotensin II conversion? Mechanism?
ACE-Inhibitors (Angiotensin Converting Enzyme Inhibitors)
What Drug inhibits Angiotensin II? Mechanism?
Angiotensin-II Receptor Blocker (ARBs)
Antagonise receptor binding of angiotensin II to AT1 receptors
What does the AT1 Receptor promote? (4)
- Various intracellular signalling pathways
resulting in hypertension - Endothelial dysfunction
- Vascular remodelling
- End organ damage
What Drug inhibits Aldosterone? Mechanism?
- Spironolactone (reduces BP as is aldosterone-
antagonist) - Act on the collecting duct of the nephron
- Competes with aldosterone for the
mineralocorticoid receptor - Prevents aldosterone-induced potassium
excretion and sodium resorption
Effect of Angiotensin II
- Increases in blood pressure
- Influences renal tubuli to retain sodium and
water - Stimulates aldosterone release from adrenal
gland
Effect of Aldosterone on CVS
- Causes sodium and water retention
- Which causes increased blood volume
- Subsequent increase in blood pressure
Examples of ACEIs
Ramipril
Lisinopril
Examples of ARBs
Candasartan
Losartan
Examples of CCBs
Amlodipine
Felodipine
Examples of Thiazide Diuretics
Indapamide
Bendroflumethiazide
Examples of β-blockers
Propanolol
Bisoprlol
Labetalol
Atenolol
Examples of α-blockers
Doxazosin
β-blockers MOA
α-blockers MOA
What is Paroxysmal Nocturnal Dyspnea?
It is a sensation of shortness of breath that awakens the patient, often after 1 or 2 hours of sleep, and is usually relieved in the upright position
