L43: Pathology Of Hypertension

Question 1

WHO guidelines / JNC-6 classification of hypertension

Answer 1

Repeated resting levels of systolic > 140 mmHg OR diastolic > 90 mmHg
—> repeated levels are needed due to
—> exercise, stress, isolated clinic hypertension

Optimal: 120/80
Normal: 130/85
Prehypertension: 130/85
Stage 1: 140/90
Stage 2: 160/100
Stage 3: 180/110

Question 2

Cardiac output affected by 2 factors

Answer 2

Cardiac factor: (HR)

• Heart rate
• Contractility

Non-cardiac factor: (SV)

• Blood volume
• Sodium intake
• Mineralocorticoid level

Question 3

Hypertension is caused by abnormal relationship between

Answer 3

BP = salt (CO) x renin (TPR)

• salt and renin: inverse relationship
• salt ↑ —> renin ↓ (since ↑ Na delivery to macula dense cells —> signal juxtaglomerular cell to ↓ renin release)

Extremes of spectrum of hypertensive patient:

Too much renin: malignant hypertension
- kidney tumour —> high renin release —> high aldosterone but kidney is not responding —> no negative feedback —> continue to release renin —> vasoconstriction

Too much salt: primary aldosteronism
- problem with adrenal cortex —> high aldosterone —> Na retention —> low renin + ↑ water retention

Question 4

2 types of hypertension

Answer 4

1. Essential hypertension (95%)
   - stage 1 (75%)
   - older patients
   - high salt - low renin
   - salt/fluid overload: treat with diuretics, beta blockers
   - renin level: low/normal/high

• some patients have increased NE level —> ↑ sympathetic drive to heart and vessel —> ↑ contraction, vasoconstriction, ↑ renin release —> hyperkinetic circulation
• moderate, severe, accelerated hypertension (25%)
• younger patients
• low salt - high renin
• high renin: treat with ACE inhibitor, alpha/beta-blockers
  —> ↑ peripheral resistance
  —> 1. Neural (alpha and beta adrenergic)
  —> 2. Local (autoregulation, pH, hypoxia)
  —> 3. Humoral (angiotensin, thromboxane, leukotriene, endothelin)

2. Secondary hypertension (5%): treat primary cause
   - tumours of adrenal medulla (phaeochromocytoma) —> NE/E release
   - tumours of adrenal cortex (adrenal adenoma)
   - structural renal problem —> renal artery stenosis

Question 5

Folkow vs Guyton theory

Answer 5

Folkow: hypertension —> neurogenic
Guyton: hypertension —> Na and renal function

Question 6

Pathological changes in hypertension

Answer 6

1. Left ventricular hypertrophy
2. Large vessel: atherosclerosis
3. Small vessel: hypertrophy, fibrinoid necrosis, aneurysm formation, atherosclerosis
4. Brain: haemorrhage, infarction
5. Kidneys: nephrosclerosis

Question 7

Non-pharmacological interventions to hypertension

Answer 7

1. Weight loss
2. Reduce Na intake
3. Reduce alcohol
4. Exercise