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Flashcards in Peripheral Vascular Disease Deck (41):
1

What is an aneurysm? 

What is an arterial dissection?

Aneurysm:

  • Localized dilatation of a blood vessel (aorta) or heart
  • Types:
    • True: involves all three layers of wall
    • False (pseudoaneurysms): Wall defect leading to extravascular hematoma

Arterial dissection:

  • blood enters the wall of the artery

2

What are the two pathologic processes that can cause an aneurysm?

  • Inadequate or abnormal syntheses of collagen

or

  • Excessive connective tissue degradation

3

What syndromes are caused by inadequate or abnormal syntheses of collagen?  

What is the pathogenesis for each?

  1. Marfan syndrome
    • 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
  2. Ehlers-Danlos syndrome
    • One variant has defective synthesis of Type III collagen
    • Leads to aneurysm formation

4

How can excessive connective tissue degradation lead to anuerysm formation?

  • Occurs with increased matrix metalloproteinase (MMP) or decreased tissue inhibitors of metalloproteinase (TIMP)
  • In the setting of inflammation (atherosclerosis) polymorphisms of MMP &/or TIMP genes may predispose to aneurysm formation

5

What can loss of smooth muscle cells lead to in the vascular wall?

  • Loss of smooth muscle cells
    • Thickening of intima (due to atherosclerosis)
  • Leads to ischemia of inner media
    • Systemic hypertension
  • Narrows vasa vasorum ⇒ ischemia of outer media
    • Morphologic results is cystic medial degeneration

6

What are the most common causes of aneurysms?

  1. Atherosclerosis – abdominal aorta
  2. Hypertension – ascending aorta

7

What are some uncommon causes of aneurysms?

  • Congenital defects
  • Infections (bacteria, fungi)
  • Trauma – AV (fistula) aneurysm
  • Vasculitis
  • Genetic defects in collagen (Marfan’s & Ehlers-Danlos)

8

  1. What congenital defects lead to aneurysm formation?
  2. What infections lead to aneurysm formation?

  1. Congenital defects
    • Berry aneurysm: bifurcation of cerebral arteries, subarachnoid hemorrhage
  2. Infections (bacteria, fungi)
    • Mycotic aneurysm: septic emboli, direct extension, direct infection by circulating organisms
    • Syphilis (Treponema pallidum)

9

  • What is the most common location of arotic aneuryms?  
  • What are some less common locations?  
  • What is the most common etiology of aortic anuerysms?  
  • What is the most common association of aortic aneurysms?

 

  • Abdominal aortic aneurysm (AAA): MOST COMMON LOCATION
    • Below renal arteries and above bifurcation
  • Less common: Arch of aorta, thoracic aorta and iliac arteries 
  • Most common cause – atherosclerosis
  • More common in men & smokers

10

Describe the morphology of aortic aneurysms: 

  • Up to 15 cm diameter
  • Thinning & destruction of media
  • Mural thrombus
  • Saccular or fusiform
  • Variants:
    • inflammatory – unknown etiology
    • mycotic – secondary infection (salmonella gastroenteritis) of an atherosclerotic wall

11

What is the classic clinical presentation of AAA?

What complications can arise from AAA?

  • More common in men over 50
  • Present as pulsatile abdominal mass

​Complications:

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

12

Risk of rupture is directly proportional to ____.

size

  • Aggressive management for large aneurysms (> 5 cm)

13

What are causes of thoracic arotic aneurysms?

  1. Hypertension
  2. Marfan’s syndrome
  3. Syphilis (tertiary)

14

What are clinical features associated with thoracic aortic aneurysms?

  1. Mediastinum encroachment
    • Tracheal compression
    • Esophageal compression
    • Bone erosion
    • Cough due to irritation of recurrent laryngeal nerve 
  2. Cardiac Symptoms
    • Heart failure due to aortic valve insufficiency
  3. Aortic rupture

15

What causes an aortic dissection?

What is the pathogenesis of aortic dissections?

  • Blood between and along laminar planes of media
    • Causes a blood-filled channel that easily ruptures
  • Pathogenesis/etiology
    • Hypertension (40-60 years of age):
      • > 90% of cases
    • Connective tissue abnormality (younger ages): in association with Marfan’s syndrome or Ehlers-Danlos syndrome
    • Ascending aorta most commonly involved
    • Rare causes:
      • post-procedural – arterial cannulation 
      • pregnancy

16

What is the morphology of aortic dissection?

What patients have a pre-existing condition to aortic dissection?

  • Intimal tear within 10 cm of aortic valve
  • Dissection plane between middle and outer thirds of wall, in media
    • Usually extends anterograde
    • Usually ruptures “out”
    • May reenter and form a double-barreled lumen
  • In hypertensive patients
    • Vasa vasorum: hyaline arteriolosclerosis
    • Media: loss of smooth muscle cells
  • Pre-existing pathology of cystic medial degeneration in patients with connective tissue disorder (Marfan syndrome)

17

What is responsible for aortic dissection in Marfan's Syndrome?

  • Cystic medial necrosis causes connective tissue weakness
  • Pools of blue mucinous ground substance disrupt elastic fibers

18

What is the clinical course of an aortic dissection?

  • Dependent on level of aorta involved
  • Sharp pain of anterior chest, uneven pulses and widened mediastinum
  • Types A and B
  • Classic clinical symptoms:
    • Sudden onset of tearing
    • Stabbing pain in anterior chest radiating to back

19

What are complications associated with aortic dissection?

  • Hemopericardium occurs when blood dissects through media, proximally
    • causes tamponade
  • May also rupture into pleural or peritoneal cavities

20

What is vasculitis?

What general pathologic processes can cause it?

  • Inflammation of vessel walls; may affect any size vessel
  • Pathogenesis
    1. Immune-mediated processes
    2. Infectious origin
    3. Unknown

21

Pathogenesis of Immune-mediated Vasculitis:

Immune-compex mediated

  1. SLE (Systemic Lupus Erythematosis): DNA – anti-DNA complexes
  2. Hypersensitivity to drugs
  3. Viral infections
    • HBsAg – anti-HBSsAg

22

Pathogenesis of Immune-mediated Vasculitis:

Anti Neutrophil Cytoplasmic Antibodies (ANCA) associated

  • Autoantibodies against enzymes in granules of neutrophils
    • Ab titers mirror clinical severity
  • Two main patterns:
    1. Antiproteinase-3 (PR3-ANCA) – Wegener Granulomatosis
      1. Target antigen: PR3 (neutrophil granule constituent)
      2. FYI PR3-ANCA = c-ANCA
    2. Anti-myeloperoxidase (MPO-ANCA) – Microscopic polyangiitis and Churg-Strauss syndrome
      • Target antigen: myeloperoxidase
      • FYI MPO-ANCA = p-ANCA

23

What disease is associated with antibodies to endothelial cells?

Kawasaki disease

24

Vasculitis of infectious origin & unknown origin:

  1. Infectious
    1. Direct invasion
      • Syphilis
      • Aspergillus & mucormycosis
    2. Indirect
      • Immune mechanisms triggering cross-reactivity
  2. Unknown
    • Giant cell arteritis
    • Takayasu arteritis
    • Polyarteritis nodosa

25

  1. Large vessel vasculitis: 
  2. Medium vessel vasculitis: 
  3. Small vessel vasculitis: 

  1. Large vessel vasculitis: Granulomatous disease
    • Giant cell arteritis
    • Takayasu arteritis
  2. Medium vessel vasculitis:  
    • Polyarteritis nodosa - immune complex mediated
    • Kawasaki disease - anti-endothelial antibodies
  3. Small vessel vasculitis: 
    • Microscopic polyangitis
    • Wegener granulomatosis
    • Churg-Strauss syndrome

26

Giant Cell (Temporal) Arteritis:

  • What does it affect?
  • What is the etiology?
  • What is the clinical presentation, diagnosis and treatment?

  • Most common form of systemic vasculitis in adults
  • Affects aorta and its major branches 
    • temporal artery, ophthalmic, and vertebral arteries
  • Pathogenesis: uncertain
  • Clinical:
    • > 50 y, often with painful superficial temporal artery, diplopia, visual loss, headache
    • Increased ESR 
    • Diagnosis: biopsy
    • Treatment: steroids

27

What is the morphology of temporal (giant cell) arteritis?

  • Nodular thickenings of artery with narrowed lumen
  • Patchy (discontinuous) segments affected
  • Biopsy requires 2-3 cm
    • Multiple levels examined

28

What is the histology of temporal arteritis?

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

29

Describe what is seen in Takayasu Arteritis:

  • Pulseless disease (upper extremities), ocular disturbances
  • Japanese women younger than 40 yrs
  • Granulomatous inflammation of aortic arch and its branches
  • Pulmonary arterties are involved 50%
    • coronary and renal arteries may be involved
  • Pathogenesis: autoimmune etiology
  • Histology: lymphocytes, giant cells, collagenous fibrosis

30

What is polyarteritis nodosa?  What is the pathogensis? How is it treated?

  • Systemic segmental transmural necrotizing inflammation of small or medium-sized muscular arteries
  • Renal and visceral arteries affected, spares lung
  • Focal, random, episodic
  • All stages of inflammation and fibrosis co-exist
  • Aneurysms
    • Necrosis with karyorrhexis
  • Young adults (30% Hep B antigen), no ANCA
  • Acute, chronic, subacute, or remittent course
  • 90% remission or cure - corticosteroids, cyclophosphamide

31

What is the classic presentation of polyarteritis nodosa?

  1. Rapidly accelerating hypertension (renal artery involvement)
  2. Abdominal pain & bloody stools
  3. Peripheral neuritis

32

Kawasaki Syndrome:

  • Where is endemic?
  • What vessels are affected?
  • What is the most common demographic?

  • Endemic in Japan
  • Rare, but increasing in the US
  • Large, medium and small arteries
    • often coronaries with aneurysm formation
  • With mucocutaneous lymph node syndrome
    • Mucous membrane inflammation
    • Enlarged lymph nodes
  • 80% are < 4 yrs 
  • Leading cause of acquired heart disease in children (in Japan)

33

What does Kawasaki syndrome resemble on histology?

What is the etiology of Kawasaki syndrome?

  • Histology: Necrosis and inflammation, aneurysms, resembles polyarteritis nodosa
  • Etiology:
    • ? autoantibodies to endothelial cells and smooth muscle cells
    • ? Infectious agent (virus) trigger

34

Microscopic Polyangitis

  • What vessels are affected?
  • What type of ANCA? (if any)
  • How will it appear on histology?

  • Arterioles, capillaries, venules
    • Skin, mucous membranes, lungs, brain, heart, GIT, kidneys, muscles
  • Necrotizing glomerulonephritis (90%) and pulmonary capillaritis
  • MPO-ANCA + in 70%
    • Immunologic reaction to antigens- drug, Strep, tumor proteins
  • Histology: fibrinoid necrosis, neutrophils, nuclear dust (karyorrhexis)
     

35

What determines the major clinical features in microscopic polyangitis?

  • Major clinical features are dependent on vascular bed involved:
    1. hemoptysis
    2. hematuria
    3. proteinuria
    4. abdominal pain or bleeding
    5. muscle pain or bleeding
    6. cutaneous purpura

36

Wegener Granulomatosis

  • What areas are affected?
  • What type of ANCA? (if any)

  • Necrotizing vasculitis
    • Granulomas of lung &/or upper respiratory tract (ear, nose, sinuses, throat)
    • Vasculitis of small to medium sized vessels in lungs & upper respiratory tract
    • Glomerulonephritis
  • PR3-ANCAs present in >95%
    • Likely cell-mediated hypersensitivity response against inhaled infections or environmental antigen
       

37

What is the most common demographic affected by Wegener granulomatosis?

What is the prognosis and associated symptoms?

  • M > F, ~40 years of age
  • Prognosis:
    • Without treatment: 1 yr – 80% mortality
  • Symptoms:
    • Pneumonitis (95%)
    • Sinusitis (90%)
    • Nasopharyngeal ulcerations (75%)
    • Renal disease (80%)

38

What type of vasculitis is Churg-Strauss syndrome?

allergic granulomatosis and angiitis

39

Churg-Strauss Syndrome:

  • What is it associated with?
  • What are the clinical symptoms?
  •  Is there ANCA association?

  • Small vessel vasculitis associated with
    • Asthma
    • Allergic rhinitis
    • Lung infiltrates
    • Peripheral eosinophilia & infiltration of vessels by eosinophils
    • Extravascular necrotizing granulomas
  • Clinical symptoms
    • Palpable purpura
    • GI bleeding
    • Renal impairment
    • Cardiomyopathy
  • Possible hyper-responsiveness to allergic stimulus
  • MPO-ANCAs – present in minority

40

Thromboangiitis Obliterans (Buerger disease): 

  • What areas are affected?
  • What are the clinical features?

  • Inflammation and thrombosis of medium to small sized muscular arteries and secondarily the veins and nerves
    • Tibial and radial arteries
    • Smokers*
      • < 35 yrs, Israeli, Indian subcontinent, & Japanese
    • Painful ischemic disease
    • Gangrene of limbs, requiring amputation
    • Etiology unknown
      • Direct endothelial cell toxicity by a component of tobacco

41

What is Raynaud's phenomena?

What is the difference between primary and secondary?

Paroxysmal pallor or cyanosis of fingers, toes, nose or ears

  • 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
    • Can be due to SLE, SS (Systemic sclerosis – Scleroderma), atherosclerosis, Buerger disease