Benign and malignant nephrosclerosis

Know the definitions and complications of benign and malignant hypertension

• Benign HTN: Uncomplicated HTN of long duration and mild  moderate severity

• Malignant HTN: DBP >140 mmHg

• Associated w/ papilledema

• Complications
• Stroke
• Congestive heart failure
• Renal failure
• Myocardial infarction
• Arterial aneurysm

Know the gross appearance, vascular change, and glomerular change in benign nephrosclerosis. Are these vascular changes diagnostic of benign nephrosclerosis?

• Gross Appearance

• Size is normal to moderately reduced
• Outer cortical surfaces show even granularity resembling leather (figure 21-48)
• Cortical area is narrowed
• Both sides have equal size/appearance
• No deformation of calyces

• Vascular changes

• Hyalinization and thickening of arterioles due to endothelial injury and leakage of plasma proteins and lipids from circulation

• Interlobular and arcuate arteries show fibroelastic hyperplasia: duplication of elastic lamina and increase in fibrous tissue in media → narrowing of lumina

• These vascular changes result in tubular loss and atrophy, interstitial fibrosis, and glomerular changes due to ischemia

• Lesions are NOT diagnostic or specific

  • May occur in normotensive, elderly individuals

• Glomerular changes

• Wrinkling of GBM

• Sclerosis of tufts

• Collagen inside and outside Bowman’s capsules

Know that malignant HTN occurs in only 5% of all patients and is predominant in young individuals, males, and blacks.

Know gross appearance, vascular changes and glomerular change in malignant HTN

• Gross appearance

  • Size depends on duration of disease

  • Petechial hemorrhages due to rupture of arterioles/glomerular capillaries are seen on cortical surface, giving it a flea-bitten appearance

• Vascular changes

  • Fibrinoid necrosis of arterioles and necrotizing arteriolitis due to inflammatory infiltrate w/in the wall

  • Hyperplastic arteriolitis: Concentric thickening of intima by cell proliferation and deposition of collagen in arterioles and interlobular arteries, giving an onion skin appearance

• Glomerular changes

  • Necrosis of glomeruli and infiltration w/ PMNs

  • Thrombosis in capillary loops

  • Ischemic atrophy/infarct of renal parenchyma secondary to thrombosis and narrowing of arterioles

Know the clinical manifestations and causes of death in patients with malignant HTN and benign HTN

• Benign HTN

  • Only 1-5% die of renal failure

  • Majority die of heart failure, MI, and CVA

  • More prone to develop RF in volume depletion, surgical stress, and GI bleeding

  • Clinical manifestations

    • May be asymptomatic

    • Morning headache

    • Blurring of vision

    • Mild proteinuria

    • Moderate loss of concentrating power

• Malignant HTN

  • 90% die of renal failure

  • 50% survive 5 years

  • Clinical manifestations

    • Symptoms of left ventricular failure

    • Symptoms of intracranial HTN - headache, nausea, vomiting, visual impairment

    • Hypertensive encephalopathy – loss of consciousness, convulsions

    • Proteinuria and/or hematuria w/ normal renal function or ARF

Category: Pathology Notes