1. Hypertension

Question 1

Definition of hypertension

Answer 1

Sustained blood pressure of 140/90mmHg or above

Question 2

Causes of hypertension

Answer 2

1. Primary (essential) hypertension (90-95%)
   - Idiopathic, complex, multifactorial disorder
   - Environmental influences (stress, smoking, obesity, physical inactivity, high salt intake)
   - Vasoconstrictive influences
   - Impairment of sodium excretion (e.g. Liddle syndrome: Na+ channel mutation resulting in increased Na+ reabsorption)
2. Secondary hypertension (5-10%) (RENAL)
   - Renal (acute glomerulonephritis, chronic renal disease, polycystic disease, renal artery stenosis, renal vasculitis, renin-producing tumours)
   - Endocrine (Cushing’s syndrome, acromegaly, hyperaldosteronism, pheochromocytoma)
   - Neurologic (increased intracranial pressure)
   - Aortic (coarcation, atherosclerotic rigidity of aorta)
   - Labile (psychogenic, stress-related)

Question 3

Occurrence of malignant hypertension

Answer 3

Occurs in small minority of hypertensive patients (5%),
may occur in a previously normotensive patient but more
often superimposed on a pre-existing benign hypertension

Question 4

What does malignant hypertension demonstrate?

Answer 4

Demonstrates rapidly rising blood pressure:

• Systolic pressure > 200mmHg
• Diastolic pressure > 120mmHg

Question 5

Clinical manifestations of malignant hypertension

Answer 5

1. Renal failure
2. Retinal hemorrhage
3. Papilledema (edema of the head of optic nerve)

Question 6

Pathological effects of hypertension

Answer 6

1. Blood vessels
   - Arteriolosclerosis
   - Accelerated atherosclerosis
   - Aortic aneurysms
2. Heart
3. Kidneys
   - Hypertensive nephrosclerosis (glomerular scarring due to hypertensive damage to arteries & arterioles within the kidney)
4. Central Nervous System
   - Cerebral hemorrhage
   - Cerebral thrombosis
   - Hypertensive encephalopathy

Question 7

Definition of arteriolosclerosis

Answer 7

Degenerative changes in the walls of small arteries & arterioles

Question 8

Types of arteriolosclerosis

Answer 8

1. Hyaline arteriolosclerosis

2. Hyperplastic arteriolosclerosis

Question 9

Hyaline arteriolosclerosis

Answer 9

1. Present in benign hypertension as well as other conditions (hypertensive nephrosclerosis, diabetic microangiopathy)
2. Homogenous pink hyaline thickening with associated luminal narrowing
3. Due to plasma protein leakage across injured endothelial cells & increased smooth muscle cell matrix synthesis in response to chronic haemodynamic stress

Question 10

Hyperplastic arteriolosclerosis

Answer 10

1. Present in malignant hypertension
2. Vessels exhibit ‘onion-skin’ lesions (concentric laminated thickening of the walls with luminal narrowing)
   - Laminations consist of smooth muscle cells with thickened, reduplicated basement membranes
3. Often accompanied by fibrinoid necrosis/necrotizing arteriolitis (fibrinoid deposits with vessel wall necrosis)
   - Seen most commonly in malignant nephrosclerosis

Question 11

Definition of hypertensive heart disease

Answer 11

Stems from pressure overload & resultant ventricular hypertrophy

Question 12

Minimal criteria for left-sided (systemic) hypertensive heart disease

Answer 12

Hypertension + left ventricular (concentric) hypertrophy in the absence of other cardiovascular pathology

Question 13

Pathogenesis of left-sided (systemic) hypertensive heart disease

Answer 13

1. Systemic hypertension → LV pressure overload → LV hypertrophy (and eventual dilation)
2. Increased LV wall thickness imparts a stiffness that impairs diastolic filling
3. Leads to secondary left atrial dilation
4. Eventually leads to LV failure

Question 14

Pathological Effects & Complications of left-sided (systemic) hypertensive heart disease

Answer 14

1. Pulmonary venous hypertension
2. Chronic heart failure
3. Sudden death

Question 15

Disorders predisposing to right-sided hypertensive heart disease (cor pulmonale)

Answer 15

1. Diseases of pulmonary parenchyma (COPD, diffuse pulmonary interstitial fibrosis, pneumoconioses, cystic fibrosis, bronchiectasis)
2. Diseases of pulmonary vessels (saddle embolus, recurrent pulmonary thromboembolism, extensive pulmonary arteritis, primary pulmonary hypertension)
3. Disorders inducing pulmonary arterial constriction (metabolic acidosis, hypoxaemia, chronic altitude sickness, sleep apnea, obstruction of major airways)
4. Disorders affecting chest movements (kyphoscoliosis, marked obesity)

Question 16

Pathogenesis of right-sided hypertensive heart disease (cor pulmonale)

Answer 16

1. [Acute cor pulmonale] Massive pulmonary embolism → RV dilation without hypertrophy
2. [Chronic cor pulmonale] Pulmonary hypertension → RV pressure overload → RV hypertrophy (and eventual dilation)