5. Vascular diseases

Question 1

Types of vascular disease

Answer 1

1. Benign nephrosclerosis

2. Accelerated nephrosclerosis

Question 2

Definition of benign nephrosclerosis

Answer 2

Renal pathology associated with the sclerosis of renal arterioles & small arteries; due to longstanding or poorly controlled hypertension

Question 3

Morphology of nephrosclerosis

Answer 3

1. Arteries: atherosclerosis
2. Arterioles: hyaline arteriolosclerosis
3. Patchy ischemic atrophy (interstitial fibrosis, glomerular changes, tubular atrophy)

Question 4

Pathological effects & complications of nephrosclerosis

Answer 4

1. Proteinuria (may be nephrotic range)

2. Mild reduction in GFR

Question 5

Definition of accelerated nephrosclerosis

Answer 5

Renal pathology due to malignant hypertension

Question 6

Pathogenesis of accelerated nephrosclerosis

Answer 6

1. Malignant hypertension typically develops in:
   - Pre-existing benign hypertension
   - Chronic renal diseases
2. Initiating stimuli results in increased renal vascular permeability & increased release of PDGF
   - Causes fibrinoid necrosis & hyperplastic arteriolosclerosis
3. Changes in arterioles narrow lumen of afferent arteriole
   - Decreases GFR & salt delivery to distal tubules
   - Triggers increased renin production
   - Increased renin production increases angiotensin II
   formation, which in turn constricts renal vessels, hence establishing a self-perpetuating cycle

Question 7

Morphology of accelerated nephrosclerosis

Answer 7

1. Hyperplastic arteriolosclerosis (onion-skin appearance)

2. Fibrinoid necrosis

Question 8

Pathological effects & complications of accelerated nephrosclerosis

Answer 8

1. Renal failure (after initial proteinuria & hematuria)
2. Associated lesions in malignant hypertension:
   - Papilledema
   - Retinal hemorrhages
   - Encephalopathy