Large Vessel Vasculitis

Slide 1 · Large Vessel Vasculitis

Arterial territories · Immune injury · Morphology · Clinical consequences

Giant cell arteritis and Takayasu arteritis

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

ORIENTATION

Identify the arterial territories preferentially affected by large-vessel vasculitis.

Link immune-mediated arterial wall injury to stenosis, ischemia, and remodeling.

Recognize the pathology and clinical consequences of giant cell and Takayasu arteritis.

Interpret overlapping histology and the limits of biopsy sampling.

Slide 3 · Large-vessel vasculitis: Operational definition

Noninfectious vessel-wall inflammation preferentially involving the aorta and its major branches.

Frequently extends to great arch vessels and large arteries supplying extremities.

“Large-vessel” describes a predominant pattern—not exclusive restriction to one caliber.

The distribution is preferential, not absolute.

Slide 4 · Distribution: The major arterial territories

Aorta / great vessels

Aorta

Central large-artery disease

Great arch branches

Head, neck and upper-limb circulation

Large extremity arteries

Reduced distal perfusion

The aorta and its first-order branches are the defining territories.

Slide 5 · Classification is based on predominant vessel caliber

Large-vessel pattern

Other patterns

Aorta and major branches

Giant cell arteritis

Takayasu arteritis

Medium: Main visceral arteries and branches

Small: Arterioles, capillaries and venules

Overlap occurs across categories

The predominant caliber guides classification; It does not define a strict boundary.

Slide 6 · Vascular caliber does not impose rigid boundaries

Giant cell arteritis may affect medium and even smaller arteries in addition to the aorta.

Takayasu arteritis involves medium and larger arteries, often centered on the aortic arch.

Distributions overlap; Classification is interpreted with morphology and clinical context.

Clinical-anatomic pattern is more informative than isolated vessel size.

Slide 7 · Two major large-vessel vasculitides

Large-vessel vasculitis

Giant cell arteritis

Takayasu arteritis

Both may be granulomatous and can involve the aorta.

Slide 8 · Why vascular location determines manifestations

Inflammation in a particular vascular bed

Wall injury and remodeling

Altered perfusion of dependent tissue

Systemic inflammation produces constitutional symptoms.

Local arterial lesions explain organ-specific ischemia.

An identical wall lesion can produce different symptoms in different territories.

Slide 9 · Normal arterial wall: Three functional layers

Intima

Layer adjoining the lumen

Media

Smooth-muscle and elastic wall

Adventitia

Outer connective-tissue layer

Arterial cross-section: Original native schematic, not a micrograph.

Slide 10 · Immune and infectious mechanisms must be separated

Immune-mediated arteritis

Infectious arteritis

Vessel-wall inflammation from an immune response

T-cell and other immune mechanisms contribute

Immunosuppression is relevant

Direct microbial invasion of vessel wall

Potential thrombosis, infarction or aneurysm

Immunosuppression can be harmful

A vascular inflammatory phenotype alone does not establish etiology.

Slide 11 · Inflammation causes luminal stenosis

Inflamed arterial wall

Intimal thickening / hyperplasia

Narrowed lumen

Distal perfusion deficit

Vascular pulses weaken when major proximal branches become severely narrowed.

Intimal remodeling converts mural inflammation into flow-limiting disease.

Slide 12 · Concentric wall change reduces effective lumen

Normal wall

Open central lumen

Thickening

Reduced luminal radius

Advanced lesion

Marked narrowing

Schematic geometry; Not a measured stenosis or microscopy image.

Slide 13 · Medial and elastic injury alter wall integrity

Granulomatous medial inflammation

Elastic lamina fragmentation / medial injury

Medial attenuation and fibrous remodeling

Giant cell arteritis damages the internal elastic lamina.

Takayasu arteritis may cause root dilation with valvular insufficiency.

Wall injury may coexist with stenosis; Morphology is not confined to the intima.

Slide 14 · Granulomatous inflammation is a frequent pattern

Giant cell arteritis classically has granulomatous inflammation, often centered on the internal elastic membrane.

Takayasu arteritis may exhibit giant cells and patchy medial necrosis.

Histologic features substantially overlap between these two diseases.

Slide 15 · Shared arterial injury: Lesion to phenotype

Arterial-wall inflammation

Stenosis or wall remodeling

Reduced downstream perfusion

Local ischemic manifestations

Neurologic, visual, limb, renal, and cardiac manifestations reflect the affected bed.

The organ harmed depends on the arterial territory involved.

Slide 16 · Large-vessel arteritis: Comparative framework

Feature

Giant cell arteritis

Takayasu arteritis

Typical age pattern

Usually >50 years

Usually <50 years

Principal territories

Head vessels; Also aorta

Aortic arch and major branches

Wall pathology

Often granulomatous

Often granulomatous

Distinctive clue

Temporal symptoms; Ocular risk

Upper-limb weak pulses

Age and site are helpful patterns; The lesions can overlap.

Slide 17 · Giant cell arteritis: Defining features

GIANT CELL ARTERITIS

Chronic arteritis classically showing a granulomatous inflammatory reaction.

Affects large and medium arteries, particularly those supplying the head.

Most prominent in older adults; Uncommon before age 50 years.

Slide 18 · Giant cell arteritis: More than temporal arteries

Aorta / great vessels

Aorta

Large-vessel aortitis

Carotid / vertebral

Head and neck arterial involvement

Temporal / ophthalmic

Headache and visual threat

“Temporal” is a convenient biopsy designation, not a complete disease map.

Slide 19 · Why the disease retains the name temporal arteritis

Temporal arteries are accessible for diagnostic biopsy.

The disease is not uniquely restricted to superficial temporal vessels.

A finding in temporal artery may signal involvement of vertebral and ophthalmic arteries.

Slide 20 · Ophthalmic involvement is the critical danger

Arteritis affecting the ophthalmic circulation can precipitate abrupt visual disturbances.

Clinical effects range from diplopia to complete loss of vision.

Potential irreversible blindness makes prompt recognition essential.

New visual symptoms in a compatible presentation require urgent evaluation.

Slide 21 · Giant cell arteritis: Proposed T-cell pathogenesis

Unknown vessel-wall antigen (hypothesized)

T-cell–mediated immune response

Inflammatory cytokines and wall injury

Granulomatous arteritis

The exact vessel-wall antigen remains uncharacterized in the supplied text.

The initiating antigen is uncertain; An immune-mediated mechanism is strongly supported.

Slide 22 · The initiating antigen is not established

A T-cell response to an as-yet uncharacterized vessel-wall antigen.

The predilection for head vessels is not satisfactorily explained.

Different embryologic vascular origins are presented as a hypothesis—not proven causation.

Slide 23 · Inflammatory mediators in giant cell arteritis

Activated T-cell response

IFN-γ and IL-17-associated inflammation

Macrophage-rich arterial injury

Antiendothelial-cell antibodies also may contribute.

The text lists mediators but does not establish a complete linear pathway.

Flow is a teaching simplification of supported relationships—not a validated molecular cascade.

Slide 24 · Evidence supporting immune causation

Histologic and genetic observations

Clinical and mediator observations

Granulomatous arterial inflammation

Association with some MHC class II haplotypes

T-cell and macrophage infiltrates

Steroid responsiveness

Proinflammatory cytokines

Possible antiendothelial antibodies

Multiple observations converge on immune mediation; No specific antigen is proven.

Slide 25 · Active giant cell arteritis: Core microscopy

Inflammation often predominates in the arterial media.

Classic lesions form granulomatous reactions around the internal elastic membrane.

An inflammatory infiltrate includes T cells and macrophages.

Slide 26 · Internal elastic lamina injury is central

Medial inflammatory infiltrate

Damage around internal elastic membrane

Elastic lamina fragmentation

Wall and intimal remodeling

A structure-specific lesion links inflammation to the characteristic arterial histology.

Microscopic recognition requires seeing the actual elastic boundary—not merely “granulomas.”

Slide 27 · Giant cells are characteristic but not mandatory

Multinucleated giant cells are described in many adequate biopsy specimens.

Granulomas and giant cells can be scarce or absent despite giant cell arteritis.

The full distribution and wall injury pattern matter in histologic interpretation.

Slide 28 · Patchy involvement produces skip lesions

Segment A

Inflamed wall

Diagnostic segment

Segment B

Relatively spared wall

Possible negative section

Segment C

Inflamed wall

Additional involved area

Schematic segments illustrate sampling heterogeneity, not measured lesion length.

Slide 29 · Intimal thickening and thrombosis may compound ischemia

Involved segments show intimal thickening that reduces vessel diameter.

Thrombi are occasionally present in the described lesions.

Either obstruction mechanism can impair flow in a vulnerable arterial bed.

Slide 30 · Active versus healed giant cell arteritis

Active lesion

Healed lesion

Medial inflammatory infiltrate

Granulomatous reaction may be present

Elastic lamina fragmentation

Medial attenuation and scarring

Persistent intimal thickening

Adventitial fibrosis

The diagnostic architecture changes as inflammation becomes scar.

Slide 31 · Headache and tenderness reflect cranial arteritis

Localized headache or facial pain may track the superficial temporal artery.

The involved artery can be painful on palpation.

Symptoms should be linked to a specific inflamed cranial vascular territory.

Slide 32 · Constitutional symptoms may be the only initial clues

Fever, fatigue and weight loss may accompany the disease.

Symptoms of systemic inflammation may precede recognizable local ischemia.

Absence of an obvious focal arterial symptom does not rule out vasculitis.

Slide 33 · Giant cell arteritis: Ocular clinicopathologic chain

Ophthalmic artery involvement

Inflammatory arterial compromise

Ocular ischemic disturbance

Diplopia or visual loss

Abrupt visual dysfunction can reflect arterial disease beyond the temporal biopsy site.

Slide 34 · Temporal artery biopsy assesses a patchy disease

Histologic diagnosis relies on obtaining an adequately sampled artery segment.

Skip lesions create a risk that a sampled portion is not representative.

Biopsy should be interpreted together with the clinical presentation.

Slide 35 · A negative temporal artery biopsy is not absolute exclusion

Even adequate samples may miss patchy arterial inflammation.

The posterior probability depends on the compatible clinical and vascular findings.

A negative section cannot erase a strong clinical suspicion by itself.

Histology is important; Sampling error must be understood.

Slide 36 · Giant cell arteritis: Consolidate pathology and presentation

Immune arterial inflammation

Granulomatous/elastic wall injury

Intimal narrowing ± thrombosis

Cranial symptoms ± ocular ischemia

Inflammation and ischemia each contribute to the symptom complex.

Clinical urgency comes from the threatened ophthalmic circulation.

Slide 37 · Takayasu arteritis: Defining features

TAKAYASU ARTERITIS

Granulomatous arteritis affecting medium and large arteries.

Predominant involvement of aorta, especially the arch and its great branches.

Commonly manifests with attenuated upper-extremity pulses—“pulseless disease.”

Slide 38 · Takayasu arteritis: The aortic arch pattern

Aorta / great vessels

Aortic wall

Transmural fibrous thickening

Arch branches

Severe narrowing / occlusion

Upper limbs

Reduced pulses and blood pressure

The pattern explains why upper-extremity vascular findings are conspicuous.

Slide 39 · Transmural thickening is a major gross feature

The aortic wall becomes irregularly thickened.

Involvement can be distributed through the full wall thickness.

Intimal hyperplasia contributes to critical branch-vessel stenosis.

Slide 40 · Age pattern and geography are clinical context

Age

Geography

Usually presents before age 50 years classification

Compared with giant cell arteritis, patients are typically younger

Age assists classification but does not define histology

Historically associated with Japanese populations

Occurs across the world

Associated with some HLA haplotypes

Slide 41 · Takayasu pathogenesis is likely T-cell mediated

A probable autoimmune mechanism mediated by T cells.

Some HLA associations support immune susceptibility.

The textbook does not identify a definitive initiating antigen.

Slide 42 · Takayasu: Wall thickening can obliterate large branches

Uninvolved segment

Patent lumen

Intimal hyperplasia

Reduced lumen

Severe disease

Critical obstruction

Schematic shapes illustrate luminal change; No numeric stenosis estimates.

Slide 43 · Takayasu disease may extend beyond the arch

Aorta / great vessels

Renal vessels

Systemic hypertension

Coronary ostia

Myocardial ischemia / infarction

Pulmonary arteries

Pulmonary hypertension

Distal aorta

Lower-limb claudication

The phenotype broadens when other aortic branches are involved.

Slide 44 · Early Takayasu histology: Adventitial inflammation

Adventitial mononuclear infiltrates may surround vasa vasorum.

Perivascular cuffing is one described early/active pattern.

Inflammation is not restricted to a single mural layer.

Slide 45 · Media: Granulomas and focal injury in Takayasu

Intense mononuclear inflammation may extend through the media.

Granulomatous inflammation may include multinucleated giant cells.

Patchy medial necrosis is described within the active injury pattern.

Slide 46 · Takayasu: Progression to fibrous remodeling

Early inflammatory

Adventitial cells; Vasa vasorum cuffing

Outer-wall inflammation

Active transmural

Medial mononuclear cells ± granulomas

Wall damage + intimal hyperplasia

Chronic fibrotic

Collagenous scar in all wall layers

Fixed luminal narrowing

Schematic stages represent patterns, not a fixed timeline.

Slide 47 · Pulseless disease: An anatomic explanation

Aortic arch arteritis

Great-vessel luminal obstruction

Less flow into upper limb

Diminished pulse / pressure

Marked stenosis or luminal obliteration is the structural correlate.

Peripheral pulse abnormalities can arise from proximal large-artery lesions.

Slide 48 · Systemic symptoms may precede vascular insufficiency

Early fatigue, fever and weight loss are nonspecific.

As arterial lesions progress, ischemic vascular symptoms increasingly dominate.

A systemic-to-vascular clinical evolution is described, but course varies.

Slide 49 · Ocular and neurologic consequences in Takayasu

Ocular disturbances include visual defects and retinal hemorrhages.

Severe disease can be associated with complete visual loss.

Neurologic deficits arise as major arterial territories become compromised.

Slide 50 · Renal arterial stenosis contributes to hypertension

Renal artery involvement

Renovascular perfusion compromise

Systemic hypertension

Systemic hypertension in many affected patients.

A proximal arterial inflammatory lesion can produce a secondary blood-pressure phenotype.

Slide 51 · Coronary ostial narrowing threatens the myocardium

Aortic-root / ostial disease

Narrowing of coronary entry

Myocardial ischemia

Possible infarction

This mechanism differs anatomically from primary coronary plaque obstruction.

Slide 52 · Pulmonary arterial involvement affects pressure

Pulmonary artery arteritis

Flow-limiting vessel disease

Pulmonary hypertension

Pulmonary circulation may also participate in large-vessel arteritis.

Slide 53 · Aortic-root involvement may lead to valve insufficiency

Aortic root disease

Dilation of proximal aorta

Aortic valve insufficiency

Dilation is an occasional complication, not the dominant branch-vessel pattern.

Not all large-vessel complications result from stenosis.

Slide 54 · Distal aortic disease produces leg symptoms

Disease distal to arch

Reduced downstream arterial flow

Lower-extremity claudication

The same inflammatory disease can produce different limb findings by site.

Slide 55 · Takayasu clinical course is heterogeneous

More progressive presentation

Less progressive / quiescent period

Early constitutional symptoms

Increasing vascular abnormalities

Potential end-organ sequelae

Some patients enter a quieter interval

Previous injury may leave lasting deficits

Long-term survival remains possible

Clinical inactivity does not necessarily reverse established structural injury.

Slide 56 · The histology of GCA and Takayasu overlaps

Giant cell arteritis

Takayasu arteritis

Medial granulomatous reaction

Elastic lamina fragmentation

Intimal narrowing and healed scars

Mononuclear ± granulomatous medial inflammation

Intimal hyperplasia

Transmural fibrosis and scarring

Robbins explicitly describes the two histologic patterns as essentially indistinguishable.

Slide 57 · Demographics and distribution resolve histologic overlap

Older age and cranial/temporal symptoms favor giant cell arteritis.

Younger age and aortic-arch branch obstruction favor Takayasu arteritis.

Neither granulomas nor giant cells alone reliably distinguishes the two.

Slide 58 · Systemic inflammation and focal ischemia coexist

Systemic inflammatory features

Arterial territory–specific features

Fever or malaise

Fatigue and weight loss

Manifestations may be nonspecific

Headache and visual loss

Upper-limb pulse deficit

Hypertension, claudication or organ ischemia

Slide 59 · Localize the arterial lesion from the clinical clue

Clue

Probable involved arterial bed

Pathologic consequence

Temple pain

Superficial cranial arteries

Focal arterial inflammation

Reduced arm pulse

Aortic arch branches

High-grade stenosis

Renal hypertension

Renal arteries

Perfusion compromise

Claudication

Distal aorta / limb arteries

Flow limitation

Visual loss

Ocular-supplying arteries

Threatened ocular perfusion

Slide 60 · Clinical application: Cranial arteritis

HYPOTHETICAL TEACHING CASE

A patient older than 50 years develops new temporal-region headache, scalp-region arterial tenderness, systemic fatigue, and abrupt diplopia.

Which vascular complication is most urgent to recognize, and why?

Slide 61 · Case interpretation: Giant cell arteritis

Age and cranial symptoms support the giant cell arteritis pattern.

Ocular dysfunction raises concern for ophthalmic arterial involvement.

Granulomatous arteritis and elastic lamina injury are expected pathology, but biopsy sampling may miss skip lesions.

Clinical consequences must inform interpretation of a potentially negative biopsy.

Slide 62 · Clinical application: Pulseless disease

HYPOTHETICAL TEACHING CASE

A younger adult has fever and fatigue followed by asymmetric weak upper-extremity pulses, low arm blood pressure, and new exertional arm symptoms.

Where should the arterial lesion be localized, and what structural change explains the pulses?

Slide 63 · Case interpretation: Takayasu arteritis

The aortic arch and its major branches are the favored anatomic pattern.

Intimal hyperplasia and mural fibrosis can produce severe branch-vessel narrowing.

Granulomatous histology alone would not separate Takayasu from giant cell arteritis.

Use age, distribution, hemodynamics and histology together.

Slide 64 · Etiologic safeguard: Exclude direct infectious arteritis

Not every inflamed large artery has an immune-mediated vasculitis.

Direct invasion by bacterial or fungal pathogens as an alternative.

The immune-versus-infectious distinction matters because immunosuppression can aggravate infection.

Slide 65 · Synthesis: From immune injury to clinical pattern

Granulomatous / mononuclear arteritis

Elastic + mural injury

Stenosis or fibrous remodeling

Territory-specific ischemic effects

Giant cell arteritis: Cranial ischemic threat in older adults.

Takayasu arteritis: Arch-branch obstruction in younger adults.

The arterial wall is the lesion; Vascular territory determines the clinical phenotype.

Slide 66 · Further reading and source figures

Robbins, Cotran & Kumar

Pathologic Basis of Disease

Large Vessel Vasculitis and the immediately following sections on Giant Cell Arteritis and Takayasu Arteritis

Refer to the original textbook images for specimen morphology; the drawings in this lecture are explanatory schematics.