Peripheral Vascular Disease Pathology Flashcards by Meghan May

What type of aneurysm involves all three layers of wall?

True aneurysm

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Wall defect leading to extravascular hematoma

◦ False (pseudoaneurysms):

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Arterial dissection is when

blood enters the wall of the artery

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Understand the difference between true and false aneurysms

◦ True: involves all three layers of wall
◦ False (pseudoaneurysms): Wall defect leading to extravascular
hematoma

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Defective synthesis of fibrillin
Fibrillin is “scaffolding” for deposition of elastic tissue
Results in cystic medial necrosis of aorta
Leads to aneurysm formation & aortic dissection

Marfan syndrome

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Factors affecting ______ function or structure can lead to aneurysms

collagen

*inadequate or abnormal syntheses of collagen

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One variant has defective synthesis of Type III collagen
Leads to aneurysm formation

Ehlers-Danlos syndrome

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Excessive connective tissue degradation can lead to aneurysm formation:
– Occurs with increased ________or decreased ___________

matrix metalloproteinase (MMP)

tissue inhibitors of metalloproteinase (TIMP)

(if inflammation (atherosclerosis) polymorphisms of MMP &/or TIMP genes may predispose to aneurysm formation)

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Patho of aneurysms:

Loss of smooth muscle cells leads to what three things?

Thickening of intima (due to atherosclerosis) –> ischemia of inner media
Systemic hypertension–> Narrows vasa vasorum, leading to ischemia of outer media
Morphologic results is cystic medial degeneration

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Two common underlying causes of aneurysms

– Atherosclerosis – abdominal aorta
– Hypertension – ascending aorta

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Uncommon causes of aneurysms:

Congenital defects
• Berry aneurysm: bifurcation of cerebral arteries, subarachnoid hemorrhage
Infections (bacteria, fungi)
• Mycotic aneurysm: septic emboli, direct extension, direct infection by circulating organisms
• Syphilis (Treponema pallidum)
Trauma – AV (fistula) aneurysm
Vasculitis
Genetic defects in collagen (Marfan’s & Ehlers-Danlos)

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Most common location of aortic aneurysm?

Abdominal aortic aneyrsm located BELOW renal arteries and ABOVE bifurcation

(arch of aorta/thoracic arota and iliac arteries less common)

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What population is most commonly associated with aneurysms?

what is most common cause?

Men and smokers

cauase = atherosclerosis

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Morphology of aneurysm
– Up to _____ diameter
– Thinning & destruction of______
– Mural thrombus
– Saccular or fusiform

15 cm

media

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Two variants of aneurysms include inflammatory and mycotic. What are their causes?

inflammation = unknown

mycotic = secondary infection of an atherosclerotic wall

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AAA is more common in:

how do they present on exam?

how do we manage them?

men over 50

present at pulsatile abdominal mass

if aneurysms is >5cm we do aggressive management (risk of rupture is proportional to the size)

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Complications of AAA

– Rupture into peritoneum or retroperitoneum
– Vascular obstruction – renal, mesenteric, spinal arteries
– Embolism of atheroma or mural thrombus to kidneys or
lower extremities
– Impingement of ureter(s)

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What are our two options for repair of an aneurysm?

open repair with graft sewn into place

stent-graft insterted through right and left common femoral arteries

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Three common causes of thoracic aortic aneurysms

▫ Hypertension
▫ Marfan’s syndrome
▫ Syphilis (tertiary)

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What clinical features do we see in pts with thoracic aortic aneurysms?

In regards to mediastinum encroachment:
▫ Tracheal compression ▫ Esophageal compression ▫ Bone erosion ▫ Cough due to irritation of recurrent laryngeal nerve

Cardiac symptoms: Heart failure due to aortic valve insufficiency

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Blood between and along laminar planes of media
– Causes a blood-filled channel that easily ruptures

aortic dissection

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Two main causes of aortic dissection

– Hypertension (40-60 years of age): > 90% of cases
– Connective tissue abnormality (younger ages): in association with Marfan’s syndrome or Ehlers-Danlos syndrome

– Rare causes: post-procedural – arterial cannulation; pregnancy

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Most commonly involved vasculature in aortic dissection

Ascending aorta

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Morphology of Aortic dissection
• Intimal tear within ______of aortic valve
• Dissection plane between middle and outer thirds of wall, in the _____
– Dissection usually extends _____
–Usually ruptures_____

10 cm

media

anterograde

“out”

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If aortic dissection reenters it can form:

double-barreled lumen

In hypertensive patients with aortic dissection we see – Vasa vasorum with : –In the media:

hyaline arteriolosclerosis : loss of smooth muscle cells

What's the reasoning for people with Marfans to get aortic dissection?

pre-exsisting pathology of cystic medial degernation in pts with CT disorder such as marfans the cycsitc medial necrosis cause CT tissue weakness and get pools of blue mucinous ground substance disrupting the elastic fibers

Clincal presentation of aortic dissection is dependent on : What are the classic symptoms

level of aorta involved --Sharp pain of anterior chest, uneven pulses and widened mediastinum –Sudden onset of tearing or stabbing pain in anterior chest radiating to back

This is a complication of an aortic dissection and occurs when blood dissects through media, proximally • May also rupture into pleural or peritoneal cavities

Hemopericardium

Inflammation of vessel walls; may affect any size vessel Caused by:– Immune-mediated processes– Infectious origin– Unknown

Vasculitis

Vasculitis can be immune complex mediated, how so?

– SLE (Systemic Lupus Erythematosis): DNA – anti-DNA complexes – Hypersensitivity to drugs – Viral infections: HBsAg – anti-HBSsAg

ANCA: anti Neutrophil Cytoplasmic Antibodies assoicated What is this?

cause of vasculitis. autoantiBs against enZ in granules of neutrophils and we see as Ab titers get higher; the vasculitis get worse

What is the disease associated with and target of Antiproteinase-3 or ANCA3

Wegener Granulomatosis target antigen is PR3 (neutrophil granule consituent)

What is the vasculitis associated with Anti-myeloperoxidase (MPO-ANCA)

Microsocpic polyangiitis and Churger Strauss syndrome target antiG is myeloperoxidase

Vasculitis of infectious origin & unknown origin Infectious can be direct or indirect. – Direct invasion: – Indirect via :

Direct is: syphilis, aspergillus, mucormycosis Indirect: immune mechanisms triggering cross-reactivity

Origin of the following vasculitities -Giant cell arteritis – Takayasu arteritis – Polyarteritis nodosa

Unknown origin

Most common form of systemic vasculitis in adults • Affects aorta and its major branches, especially temporal artery, ophthalmic, and vertebral arteries

Giant Cell (temporal) arteritis--\> affects LARVE VESSELS

\> 50 y, often with painful superficial temporal artery, diplopia, visual loss, headache – Increased ESR (Erythrocyte Sedimentation Rate) What do you suspect and how do you diagnosis it?

Suspect Giant Cell Arteritis (above is the classic presentation) Diagnosis done via biopsy

Pt comes in complaning of headachesm vision loss and diploplia. You note this little nug on his head... You order a biopsy of 2-3 cm (bc its required for this disease!!!) and what do you expect to see?

Pt has Temporal giant cell arteries: Nodular thickenings of artery with narrowed lumen  Patchy (discontinuous) segments affected

You dx your pt with temporal arteritis... what do you see on histology? How do you tx this?

* Granulomatous inflammation of inner half of media around internal elastic lamina * Destruction of internal elastic lamina * Multinucleated giant cells (but not always!)

``` Pulseless disease (upper extremities), ocular disturbances •See in Japanese women younger than 40 yrs ```

Takayasu Arteritis

In Takayasu Arteritis we see granulomatous inflammation of : • Pulmonary arterties are involved \_\_\_\_\_% of the time

aortic arch and its branches 50%

What causes Takayasu Arteritis? What do we see on histology?

autoimmune etiology • Histology: lymphocytes, giant cells, collagenous fibrosis

Systemic segmental transmural necrotizing inflammation of small or medium-sized muscular arteries

Polyarteritis Nodosa (classic) \*Medium vessel vasculitities\*

What arteries are affected and spared in polyarteritis nodosa?

Renal and visceral arteries affected, spares lung

Describe the inflamation and fibrosis we see in polyarteritis nodosa... is this a episodic or chronic disease?

Focal, random, episodic • All stages of inflammation and fibrosis co-exist The episodes are focal, random, episodic but the disease itself can be acute, chronic, subacute, or remittent course

Polyarteritis nodosa is seen in Young adults specfically with this:

(30% Hep B antigen), no ANCA

Young patient comes to clinic, she has rapidly accelerating hypertension (renal artery involvement), acute Abdominal pain & bloody stools Your attending says she also has peripheral neuritis These is a classical clinical picture of which medium vessel vasculitity?

Polyarteritis Nodosa

What do we see histologically in pts with polyarteritis nodosa?

Necrosis with karyorrhexis (broken down fragments of nuclei) there is transmural or full thickness involvement with lots of neutrophils and inflammation

• Endemic in Japan/ Rare, but increasing in the US Affects: Large, medium and small arteries, often coronaries with aneurysm formation

Kawasaki Syndrome

Kawasaki can present with which other sysdrome?

With mucocutaneous lymph node syndrome – Mucous membrane inflammation and Enlarged lymph nodes

Age distribution of Kawasakis and histology

* 80% are \< 4 yrs; leading cause of acquired heart disease in children (in Japan) * Histology: Necrosis and inflammation, aneurysms \*\*\*\*resembles polyarteritis nodosa

Vasculitis that affects arterioles, capillaries, venules as well as kkin, mucous membranes, lungs, brain, heart, GIT, kidneys, muscles

Microscopic Polyangiitis (Leukocytoclastic Vasculitis)

In Microscopic Polyangiitis (Leukocytoclastic Vasculitis) we see * _________ + in 70% * Immunologic reaction to\_\_\_\_\_, _______ and \_\_\_\_\_

MPO-ANCA+ antigens- drug, Strep, tumor proteins

If kidney and lung are involved in Microscopic Polyangitis, what do we worry about?

Necrotizing glomerulonephritis (90%) and pulmonary capillaritis

Histology of a arteriole shows fibrinoid necrosis, neutrophils and nuclear dust. Dx?

microscopic polyangiitis (leukocytoclastic vasculitis)... this is in arterioles/capillaries/ venules simular histology to polyartieritis nodosa and kawasaki but po,yarteritis affects meduim musclar vesses and Kawasaki affects large/medium/small arteries (often coronies)

Major clinical features of pts with Microscopic polyangiitis

Major clinical features are dependent on vascular bed involved: • Hemoptysis, hematuria, proteinuria, abdominal pain or bleeding, muscle pain or bleeding, & cutaneous purpura

Wegener Granulomatosis is a Necrotizing vasculitis, it causes – Granulomas of: – Vasculitis : – Glomerulonephritis

Granulomas of lung &/or upper respiratory tract (ear, nose, sinuses, throat) Vasculitis of small to medium sized vassels in lungs & upper respiratory tract

In Wegener Granulomatosis\_\_\_\_\_\_ present in \>95% – Likely cell-mediated hypersensitivity response against inhaled infections or environmental antigen

PR3-ANCAs

Who more commonly gets Wegener Granulomatosis? What is their outcome?

M \> F, ~40 years of age – Without treatment: 1 yr – 80% mortality

– Symptom profile for • Pneumonitis (95%) • Sinusitis (90%) • Nasopharyngeal ulcerations (75%) • Renal disease (80%)

Wegener granulomatosis

Small vessel vasculitis associated with – Peripheral EOSINOPHILIA & infiltration of vessels by eosinophils – Asthma – Allergic rhinitis – Lung infiltrates – Extravascular necrotizing granulomas

Churg-Strauss Syndrome: allergic granulomatis and angiitis

Whats a key difference in Wegeners granulomatosis vs Churg-Strauss?

Wegener: Granulomas of lung &/or upper respiratory tract (ear, nose, sinuses, throat) so focused around vessels Churg-Strass has Extravascular necrotizing granulomas

Clincal symptoms of Churg-Strauss syndrome

– Palpable purpura – GI bleeding – Renal impairment – Cardiomyopathy

Are ANCAs present in both Wegener and Churg-Stauss?

PR3-ANCA present in 95% of Wegener, but ANCA present in minority in Churg-Strauss; its more of a hypersensitivity or allergic stimulus

Inflammation and thrombosis of medium to small sized muscular arteries and secondarily the veins and nerves

Thromboangiitis Obliterans | (Buerger disease)

What arteries are usually involved in Thromboangiitis Obliterans(Buerger disease)? What population is it more common in?

Tibial and radial arteries (limb involvement) SMOKERS, \<35, Israeli, Indian and Japanese

Clincal presentation of Thromboangiitis Obliterans(Buerger disease) and etiology

Painful ischemic disease – Gangrene of limbs, requiring amputation – Etiology unknown • Direct endothelial cell toxicity by a component of tobacco

Raynaud Phenomenon = • Paroxysmal pallor or cyanosis of fingers, toes, nose or ears Primary causes: Secondary causes:

• Primary – Recurrent vasospasm of unknown cause (exaggerated response to cold) – Young, healthy women – No structural changes in the arterial walls (until late in disease) • Secondary – Arterial insufficiency due to narrowing and can be due to SLE, SS (Systemic sclerosis – Scleroderma), atherosclerosis, Buerger disease