What is the morphology of hypertension?

 Morphology of Hypertension

Hypertension (high blood pressure) causes both macroscopic (gross) and microscopic (histological) changes in various organs, especially the blood vessels, heart, kidneys, brain, and retina. The changes vary depending on whether the hypertension is benign (chronic) or malignant (accelerated).

Microscopic Morphology

What is the morphology of hypertension?


🔹 Blood Vessels

1. Benign Hypertension (Chronic)

  • Hyaline arteriolosclerosis:

    • Homogeneous, eosinophilic hyaline thickening of arteriolar walls

    • Due to leakage of plasma proteins and increased ECM by smooth muscle

    • Common in kidneys → benign nephrosclerosis

  • Fibroelastic hyperplasia (in larger arteries):

    • Thickening of the intima and duplication of internal elastic lamina

2. Malignant Hypertension

  • Hyperplastic arteriolosclerosis:

    • "Onion-skin" appearance: concentric, laminated thickening of arteriolar walls

    • Due to proliferation of smooth muscle cells and basement membrane

  • Fibrinoid necrosis:

    • Necrosis of vessel walls with deposition of fibrin-like material

    • Often affects arterioles in the kidney and brain

🔹 Heart

  • Left ventricular hypertrophy (LVH):

    • Enlarged cardiac myocytes with large, boxcar nuclei

    • Interstitial fibrosis may be present

  • Can lead to myocardial ischemia and heart failure

🔹 Kidneys

In Benign Hypertension:

  • Benign nephrosclerosis:

    • Hyaline arteriolosclerosis

    • Granular surface of kidneys

    • Patchy tubular atrophy and interstitial fibrosis

In Malignant Hypertension:

  • Malignant nephrosclerosis:

    • Hyperplastic arteriolosclerosis

    • Fibrinoid necrosis of arterioles

    • Flea-bitten appearance due to petechial hemorrhages

🔹 Brain

  • Small vessel disease → lacunar infarcts

  • Intracerebral hemorrhages (especially in basal ganglia)

  • Microaneurysms (Charcot-Bouchard aneurysms)

🔹 Retina

  • Arteriolar narrowing, arteriovenous nicking

  • Cotton-wool spots (microinfarcts), flame-shaped hemorrhages

  • Papilledema in malignant hypertension

Macroscopic (Gross) Morphology

Organ Gross Changes
Heart Left ventricular hypertrophy (thickened wall) , may lead to dilation and failure
Kidneys (benign) Granular surface due to scarring (benign nephrosclerosis)
Kidneys (malignant) Small, petechial hemorrhages → “flea-bitten” appearance
Brain Hemorrhagic strokes, small infarcts
Retina Not visible grossly, diagnosed via ophthalmoscopy

Summary Table

Type Microscopic Feature Affected Organs
Benign Hypertension Hyaline arteriolosclerosis Kidneys, retina, heart
Malignant Hypertension Hyperplastic arteriolosclerosis, fibrinoid necrosis Kidneys, brain, retina
Heart Myocyte hypertrophy, interstitial fibrosis Heart
Kidney Tubular atrophy, glomerular sclerosis Kidney
Retina Hemorrhages, exudates, papilledema (malignant) Retina


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