Nephrosclerosis

Slide 1 · Nephrosclerosis

Vascular remodeling, cortical scarring, and severe hypertensive injury

Renal pathology

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Define nephrosclerosis by the compartments involved.

Connect vascular wall injury to ischemic nephron loss.

Recognize characteristic gross and microscopic alterations.

Distinguish ordinary nephrosclerosis from severe hypertensive injury.

Slide 3 · The kidney in systemic vascular disease

Mechanism

Renal vessels are involved secondarily in many kidney diseases.

Systemic vascular disorders can also produce primary renal injury.

Hypertension and renal disease have a bidirectional clinical relationship.

Schematic

Renal vascular injury

Vessel remodeling

Perfusion falls

Parenchymal injury

Renal scarring

Slide 4 · Nephrosclerosis is a pattern, not one lesion

Core teaching points

It is a constellation of non-specific structural abnormalities.

Glomerular, tubular, interstitial, arterial, and arteriolar damage coexist.

No individual component alone defines the whole pattern.

Schematic

Vessels

Wall narrowing

Glomeruli

Sclerosis

Tubules

Atrophy

Interstitium

Fibrosis

One combined renal phenotype

Slide 5 · Four tissue components define the pattern

Core teaching points

Glomerulosclerosis: Scarring of glomerular tufts.

Tubulointerstitial damage: Tubular atrophy and interstitial fibrosis.

Arteriosclerosis: Disease of small arterial walls.

Arteriolosclerosis: Disease of the arteriolar walls.

Schematic

Vessels

Wall narrowing

Glomeruli

Sclerosis

Tubules

Atrophy

Interstitium

Fibrosis

One combined renal phenotype

Slide 6 · Hypertension is an association, not a prerequisite

Core teaching points

Nephrosclerosis is strongly associated with elevated blood pressure.

A nephrosclerotic pattern can also occur without hypertension.

Interpret the histology within the patient’s vascular context.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 7 · Age contributes to nephrosclerotic change

Mechanism

The frequency of nephrosclerosis rises with advanced age.

Aging contributes to remodeling of small renal arteries.

Age-associated vascular change may coexist with hypertension.

Schematic

Medial + intimal remodeling

Hyaline wall deposition

Narrowed vascular lumen

Focal renal ischemia

Slide 8 · Population observations require careful interpretation

Greater frequency in people of African descent than in people of Northern European descent.

This is a population-level observation, not a lesion-specific marker.

The biopsy pattern alone cannot identify ancestry or causation.

Slide 9 · Two processes produce the arterial lesions

Mechanism

Medial and intimal thickening alter vessel geometry.

Arteriolar hyalinization increases wall thickness.

Both routes converge on luminal narrowing and ischemia.

Schematic

Medial + intimal remodeling

Hyaline wall deposition

Narrowed vascular lumen

Focal renal ischemia

Slide 10 · Drivers of medial and intimal thickening

Mechanism

Hemodynamic changes, including hypertension, remodel the wall.

Aging also participates in wall thickening.

Genetic defects can contribute in some individuals.

Schematic

Medial + intimal remodeling

Hyaline wall deposition

Narrowed vascular lumen

Focal renal ischemia

Triggers: Hemodynamics · age · genetic contributions

Slide 11 · Vascular remodeling reduces the lumen

Morphologic interpretation

Medial and intimal layers occupy more of the vessel cross-section.

A narrower lumen restricts downstream tissue perfusion.

The pathologic impact is focal rather than uniformly distributed.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 12 · Hyalinization begins with endothelial injury

Mechanism

Injured endothelium permits plasma proteins to enter the vessel wall.

Wall proteins accumulate as eosinophilic hyaline material.

Hypertension may contribute to the endothelial damage.

Schematic

Plasma proteins enter injured wall

Slide 13 · Hyaline arteriolosclerosis: Structural consequence

Morphologic interpretation

Homogeneous hyaline thickens the arteriolar wall.

The residual lumen becomes narrow.

The lesion is a vascular substrate for ischemic renal injury.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 14 · Wall thickness and lumen diameter are linked

Morphologic interpretation

The disease process is not simply increased vessel caliber.

Intramural material and wall remodeling encroach on the lumen.

Downstream parenchyma experiences reduced blood supply.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 15 · Arteriosclerosis and arteriolosclerosis are distinct terms

Morphologic interpretation

Small arteries exhibit intimal and medial structural remodeling.

Arterioles commonly show hyaline wall thickening.

Both vessel classes contribute to nephrosclerosis.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 16 · The vascular-to-parenchymal cascade

Mechanism

Wall thickening → luminal loss → reduced renal perfusion.

Persistent focal ischemia injures glomeruli and tubules.

Scarring ultimately decreases functional renal mass.

Schematic

Wall remodeling

Lumen narrows

Focal ischemia

Nephron scar

Functional loss

Slide 17 · Why ischemic injury is patchy

Morphologic interpretation

The degree of narrowing varies between small vascular territories.

Some nephron regions scar while adjacent regions remain preserved.

This heterogeneity explains the uneven cortical microscopic pattern.

Schematic

Cortical capsule

Gray/pink = scarred regions · blue = preserved nephrons

Slide 18 · The ultimate outcome is nephron loss

Mechanism

Glomerular and tubulointerstitial damage accumulate together.

Atrophic tubules no longer maintain normal functional mass.

Scar replaces previously functioning cortex.

Schematic

Wall remodeling

Lumen narrows

Focal ischemia

Nephron scar

Functional loss

Slide 19 · Gross kidney size is variable

Morphologic interpretation

Kidneys may remain near normal size.

Others are moderately reduced in size.

Average kidney weights of approximately 110–130 g.

Schematic

Fine, repeated cortical surface irregularities

Slide 20 · Fine cortical granularity is characteristic

Morphologic interpretation

The cortical surface has a fine, even granular texture.

The texture to grain leather.

The finding reflects numerous small underlying scars.

Schematic

Fine, repeated cortical surface irregularities

Slide 21 · Why the renal cortex shrinks

Morphologic interpretation

Cortical scar formation removes functioning parenchyma.

Loss of cortical volume accounts for most of the decreased mass.

Gross shrinkage therefore has a microscopic structural basis.

Schematic

Fine, repeated cortical surface irregularities

Slide 22 · A granular surface reflects multiple small scars

Morphologic interpretation

Many subcapsular scars subtly alter the renal contour.

Small regions of better-preserved cortex remain between them.

The aggregate produces diffuse fine granularity.

Schematic

Fine, repeated cortical surface irregularities

Slide 23 · Arterioles show narrowed lumina

Morphologic interpretation

Microscopy demonstrates thickened arteriolar walls.

Hyalinization contributes to luminal encroachment.

The lesion is termed hyaline arteriolosclerosis.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 24 · How to read a hyaline arteriole schematic

Morphologic interpretation

Locate the luminal space first.

Identify broad homogeneous material in the surrounding wall.

Ask whether the lumen is narrowed relative to the wall.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 25 · Subcapsular scarring explains the surface change

Morphologic interpretation

Microscopic scars occur immediately beneath the capsule.

Sclerotic glomeruli and tubular dropout characterize these sites.

Their arrangement produces the fine cortical irregularity.

Schematic

Cortical capsule

Gray/pink = scarred regions · blue = preserved nephrons

Slide 26 · Scarring alternates with preserved tissue

Morphologic interpretation

Damaged cortical fields are not always confluent.

Sclerotic glomeruli and lost tubules occur beside viable nephrons.

This variability is expected with segmental vascular ischemia.

Schematic

Cortical capsule

Gray/pink = scarred regions · blue = preserved nephrons

Slide 27 · Tubular dropout identifies lost renal parenchyma

Morphologic interpretation

Scarring sites contain fewer recognizable tubules.

Tubular loss is coupled with adjacent interstitial fibrosis.

The pattern is a component of chronic tubulointerstitial injury.

Schematic

Cortical capsule

Gray/pink = scarred regions · blue = preserved nephrons

Slide 28 · Interlobular and arcuate arteries are involved

Morphologic interpretation

Disease extends beyond the smallest arterioles.

Both interlobular and arcuate arteries develop wall remodeling.

Their lesions add to downstream luminal narrowing.

Schematic

Baseline artery

Intimal and medial growth

Slide 29 · Fibroelastic hyperplasia: A layered arterial lesion

Morphologic interpretation

Medial hypertrophy increases wall mass.

The internal elastic lamina is replicated.

Myofibroblastic intimal tissue expands the wall inward.

Schematic

Baseline artery

Intimal and medial growth

Slide 30 · Internal elastic lamina replication

Morphologic interpretation

Multiple elastic layers appear within the remodeled arterial wall.

This accompanies medial hypertrophy and intimal thickening.

The combined lesion is designated fibroelastic hyperplasia.

Schematic

Baseline artery

Intimal and medial growth

Elastic-layer replication contributes to fibroelastic hyperplasia

Slide 31 · Intimal myofibroblastic accumulation

Morphologic interpretation

Myofibroblastic tissue contributes to intimal thickening.

Expansion of the intima further restricts the lumen.

This process accompanies arteriolar hyalinization.

Schematic

Baseline artery

Intimal and medial growth

Slide 32 · Age and blood pressure intensify arterial remodeling

Mechanism

Fibroelastic hyperplasia increases in severity with age.

Hypertension is associated with greater severity.

It often coexists with hyaline arteriolosclerosis.

Schematic

Medial + intimal remodeling

Hyaline wall deposition

Narrowed vascular lumen

Focal renal ischemia

Slide 33 · Patchy ischemic atrophy has two tissue targets

Mechanism

Tubules and interstitium develop atrophy and fibrosis.

Glomeruli develop several ischemic structural alterations.

Both components reflect restricted local perfusion.

Schematic

Luminal narrowing

Tubular atrophy + fibrosis

Glomerular alterations

Slide 34 · Tubular atrophy and interstitial fibrosis

Morphologic interpretation

Atrophic tubules occur within ischemic cortical territories.

Interstitial fibrosis occupies part of the damaged tissue.

Together these lesions signify established chronic scarring.

Schematic

Cortical capsule

Gray/pink = scarred regions · blue = preserved nephrons

Slide 35 · Glomerular basement membrane collapse

Morphologic interpretation

Ischemic glomeruli may have collapsed capillary loops.

The glomerular basement membrane becomes folded or collapsed.

This is one of several routes toward a sclerotic glomerulus.

Schematic

Collapsed tuft

Slide 36 · Collagen deposition in Bowman space

Morphologic interpretation

Ischemic glomeruli can accumulate collagen in Bowman space.

This adds extracellular scar material around the tuft.

The change accompanies other chronic glomerular alterations.

Schematic

Collagen in Bowman space

Slide 37 · Periglomerular fibrosis

Morphologic interpretation

Fibrous tissue may expand around the glomerular capsule.

Scarring is therefore not restricted to the glomerular tuft.

Periglomerular fibrosis links the glomerulus with interstitial injury.

Schematic

Periglomerular scar

Slide 38 · Global glomerulosclerosis is an endpoint

Morphologic interpretation

The entire glomerular tuft may become sclerosed.

The former filtration unit is replaced by scar.

Numerous affected glomeruli contribute to lost functional mass.

Schematic

Sclerosed tuft

Slide 39 · Global and segmental sclerosis can coexist

Morphologic interpretation

Both global and segmental glomerulosclerosis.

Vascular narrowing can be part of the sequence leading to either.

Neither pattern is exclusive to nephrosclerosis.

Schematic

Sclerosed tuft

Slide 40 · Larger ischemic territories produce regional scars

Morphologic interpretation

Pronounced ischemia may involve a large parenchymal region.

Wedge-shaped infarcts or regional scars can result.

The macroscopic pattern differs from fine diffuse granularity.

Schematic

Regional scar

Slide 41 · Severe ischemic scarring can resemble renal ablation injury

Core teaching points

Marked regional nephron loss may induce similar histologic changes.

Morphologic resemblance does not establish the same cause.

Source context and distribution are essential to interpretation.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 42 · Integrating the vascular and tissue findings

Core teaching points

Identify arterial or arteriolar luminal narrowing.

Look for neighboring glomerular and tubulointerstitial scarring.

Correlate the microscopic pattern with a granular cortical surface.

Schematic

Wall injury

Hyalinization

Ischemia

Reduced perfusion

Nephrons

Scarring

Kidney

Cortical loss

One combined renal phenotype

Slide 43 · Typical clinical course is not rapidly uremic

Clinical interpretation

Uncomplicated nephrosclerosis usually does not cause uremia.

Structural injury may nevertheless reduce functional renal mass.

Clinical severity therefore differs from morphologic presence.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 44 · Two groups at increased risk of renal failure

Clinical interpretation

Hypertensive people of African descent.

Patients with severe blood pressure elevation are also at risk.

These groups are described epidemiologically, not as a biopsy rule.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 45 · Accelerated hypertension changes the clinical trajectory

Mechanism

Severe blood pressure escalation may coincide with rapid renal decline.

The accelerated or malignant phase is linked to rapid renal failure.

This differs from the usual slow, patchy nephrosclerotic pattern.

Schematic

Wall remodeling

Lumen narrows

Focal ischemia

Nephron scar

Functional loss

Slide 46 · Severe (malignant) hypertension is a systemic syndrome

Clinical interpretation

Very high blood pressure accompanied by organ injury.

Renal failure and retinal vascular changes are central features.

It is more than the presence of hyaline arteriolosclerosis.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 47 · The blood-pressure description

Clinical interpretation

The text describes systolic pressure above 180 mm Hg.

It also describes diastolic pressure above 120 mm Hg.

Interpret these numbers as this textbook description, not a stand-alone current diagnostic algorithm.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 48 · Retinal findings point to severe vascular injury

Clinical interpretation

Retinal hemorrhages and exudates may be present.

Papilledema may occur, but is not required in the description.

Papilledema represents optic-disc swelling linked to elevated intracranial pressure.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 49 · Severe hypertension primarily injures microvessels

Mechanism

Endothelial injury and microvascular damage become prominent.

Intimal cellular proliferation can rapidly narrow small vessels.

Fibrinoid necrosis may accompany proliferative arteriolar lesions.

Schematic

Luminal narrowing

Tubular atrophy + fibrosis

Glomerular alterations

Slide 50 · Hyperplastic arteriolosclerosis forms onion-skin layers

Morphologic interpretation

Concentric intimal proliferation surrounds the vascular lumen.

The arrangement has an onion-skin appearance.

Interlobular arteries and larger arterioles are typical sites.

Schematic

Concentric intimal cell proliferation

Slide 51 · Onion-skin proliferation may obliterate a vessel

Morphologic interpretation

Multiple cellular layers markedly expand the intima.

The residual lumen may become critically narrow or obliterated.

This is the proliferative arteriolar lesion of severe hypertension.

Schematic

Concentric intimal cell proliferation

Slide 52 · Fibrinoid necrosis is a separate severe lesion

Morphologic interpretation

Arterioles may show destructive fibrinoid change.

This is different from bland hyaline arteriolosclerosis.

Severe hypertension can involve both proliferative and necrotizing injury.

Schematic

Destructive wall change (conceptual)

Slide 53 · Glomerular injury may include microthrombi

Morphologic interpretation

Fibrinoid injury can affect glomerular structures.

Microthrombi may be present inside glomeruli.

This helps explain overlap with thrombotic microangiopathic patterns.

Schematic

Collapsed tuft

Small luminal thrombi (conceptual)

Slide 54 · Microangiopathic hemolysis may accompany vascular injury

Clinical interpretation

Severe microvascular endothelial injury may damage red cells.

A microangiopathic hemolytic anemia can result.

This laboratory phenotype is not unique to a single underlying disease.

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 55 · Severe hypertension and TMA overlap morphologically

Core teaching points

Both may show endothelial injury and microvascular disease.

Both can produce glomerular microthrombi and hemolysis.

Overlapping tissue injury does not establish identical pathogenesis.

Schematic

Severe hypertension

TMA

Endothelial injury

Overlap ≠ identical cause

Slide 56 · TMA and hypertension remain pathogenetically distinct

Core teaching points

Robbins explicitly separates their pathogenetic origins.

Characteristic TMA molecular defects are not present in hypertension.

Differential diagnosis requires clinical and etiologic integration.

Schematic

Severe hypertension

TMA

Endothelial injury

Overlap ≠ identical cause

Slide 57 · Ordinary nephrosclerosis versus severe hypertension

Feature

Ordinary nephrosclerosis

Severe hypertensive injury

Vascular wall

Hyaline arteriolosclerosis; Fibroelastic change

Hyperplastic arteriolosclerosis; Fibrinoid necrosis

Parenchyma

Patchy atrophy, sclerosis, fibrosis

May include necrosis and microthrombi

Clinical pattern

Uremia unusual if uncomplicated

Rapid renal failure may occur

Editable comparison derived descriptions

Slide 58 · Three arteriolar patterns to discriminate

Lesion

Hallmark

Implication

Hyaline

Homogeneous wall material

Narrowed arteriole

Hyperplastic

Concentric cellular “onion skin”

Marked lumen reduction

Fibrinoid necrosis

Destructive fibrinoid wall change

Severe vascular injury

Editable comparison derived descriptions

Slide 59 · Morphology exercise: A small narrowed arteriole

Problem to solve

A thickened, homogeneous, eosinophilic wall encroaches on the lumen.

There is no stated concentric cellular onion-skin proliferation.

Which named arteriolar process best fits this description?

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 60 · Morphology exercise: Reasoning

Morphologic interpretation

Homogeneous proteinaceous wall thickening favors hyaline arteriolosclerosis.

The narrowing predicts focal downstream ischemia.

Search the surrounding cortex for glomerular and tubular scars.

Schematic

Relatively open lumen

Thickened hyaline wall

Slide 61 · Case exercise: A finely granular kidney

Problem to solve

The kidney is mildly reduced in size and finely granular.

Subcapsular scars contain sclerotic glomeruli and tubular dropout.

What vascular lesion would integrate these findings?

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 62 · Case reasoning: Connect cortex to vessels

Core teaching points

Small-vessel hyalinization and luminal narrowing are expected.

Focal ischemia links vascular changes to subcapsular scars.

The ensemble is compatible with nephrosclerosis.

Schematic

Wall injury

Hyalinization

Ischemia

Reduced perfusion

Nephrons

Scarring

Kidney

Cortical loss

One combined renal phenotype

Slide 63 · Case exercise: Rapidly progressive vascular injury

Problem to solve

Severe hypertension coincides with renal failure and retinal hemorrhages.

Biopsy shows concentric intimal cellular proliferation.

What further vascular lesion may accompany this pattern?

Schematic

Vascular change

Renal consequence

Clinical interpretation

Slide 64 · Case reasoning: Severe hypertensive injury

Morphologic interpretation

Onion-skin intimal proliferation is hyperplastic arteriolosclerosis.

Arteriolar or glomerular fibrinoid necrosis may coexist.

Glomerular microthrombi and hemolysis can complicate the picture.

Schematic

Concentric intimal cell proliferation

Slide 65 · Diagnostic interpretation should be multilevel

Core teaching points

Vessel changes identify the ischemic substrate.

Glomerular and tubulointerstitial scars measure tissue consequences.

Clinical history distinguishes chronic from rapidly progressive injury.

Schematic

Wall injury

Hyalinization

Ischemia

Reduced perfusion

Nephrons

Scarring

Kidney

Cortical loss

One combined renal phenotype

Slide 66 · Mechanism and morphology: Final synthesis

Mechanism

Wall remodeling and hyalinization reduce vascular lumina.

Ischemia produces patchy nephron scars and cortical shrinkage.

Severe hypertensive injury adds cellular proliferation and necrosis.

Schematic

Wall remodeling

Lumen narrows

Focal ischemia

Nephron scar

Functional loss

Slide 67 · Key distinctions for pathology review

Level

Principal clue

Tissue consequence

Vessels

Hyalinization and intimal thickening

Reduced perfusion

Parenchyma

Glomerular sclerosis and tubular atrophy

Cortical scars

Severe injury

Onion skin and fibrinoid necrosis

Rapid failure may occur

Editable comparison derived descriptions

Slide 68 · Source and scope

Robbins, Cotran & Kumar: Pathologic Basis of Disease, 11th ed. (2026).

Chapter 20, The Kidney: “Vascular Diseases” and “Nephrosclerosis,” pp. 850–852.

Illustrations: original editable conceptual schematics; not histologic specimens.