L4: Arteritis, atherosclerosis & diseases of arteries

Question 1

What is the definition of arteritis?

Answer 1

• Inflammation of arteries

Question 2

What are the types of arteritis?

Answer 2

1- Infective

2- Non-infective

Question 3

What causes infective arteritis?

Answer 3

• due to microorganisms e.g. (staph aureus). It may be:
  Acute as in arteries passing in area of acute inflammation or,Chronic as in arteries passing in area of chronic inflammation (endarteritis obliterans).

Question 4

What are the types of non-infective arteritis?

Answer 4

• Polyarteritis nodosa.
• Systemic lupus erythematosus.
• Thromboangitis obliterans.
• Giant cell arteritis.

Question 5

What is non infective arteritis mediated by?

Answer 5

• These inflammatory and often necrotizing vascular lesions are usually mediated by immune mechanism (immune complex deposition).

“Type III hypersensitivity reaction”

Question 6

What is the definition of polyarteritis nodosa?

Answer 6

• It is a necrotizing inflammation of small and medium sized arteries caused by immune complex hypersensitivity reaction. It is marked by destruction of arterial media and internal elastic lamina resulting in aneurysmal nodules.
• Mostly affects kidney, heart, GIT, CNS and musculoskeletal vessels. “Biopsy is taken for diagnosis”

Question 7

What are the complications of polyarteritis nodosa?

Answer 7

• Ischemia: It may be chronic due to fibrosis or acute due to thrombosis.
• Rupture due to fibrinoid necrosis leading to heamorrhage. “Acute”
• Aneurysms due to weak fibrosed media. “Chronic”

Question 8

What is the definition of systemic lupus erythrematous?

Answer 8

• Multi-system disease, type III hypersensitivity (immune complex).

“Mainly affects females in middle age”

Question 9

What are the affected blood vessels in SLE?

Answer 9

• Small arteries, arterioles or even venules are affected nearly all-over the body.

Question 10

What is the fate of SLE?

Answer 10

• Death is usually due to:
  1. Hypertension
  2. Renal failure

Question 11

What is giant cell arteritis? (Temporal arteritis)

Answer 11

• It seen in medium to large sized arteries with granuloma formation.

“Mainly affects males, especially in temporal artery”

Question 12

What is Thromboangitis obliterans? (Buerger’s disease)

Answer 12

• It is an acute inflammation (followed by chronic) involving small to medium-sized arteries of the extremities extending to adjacent vein and nerve.

Question 13

What is the cause of Thromboangitis obliterans?

Answer 13

• Hypersensitivity to tobacco products with hereditary predisposition.

“More in Jewish”

Question 14

What are The complications of Thromboangitis obliterans?

Answer 14

• Ischemia which may lead to intermittent claudication (chronic ischemia) and gangrene (acute ischemia).

“Pain after walking for some time”

Question 15

What is the definition of atherosclerosis?

Answer 15

• Chronic degenerative disease characterized by formation of intimal fibro- fatty plaques

Question 16

What is the most common arterial disease?

Answer 16

• Atherosclerosis

Question 17

where is atherosclerosis more common?

Answer 17

• More common in developed countries

Question 18

What is the pathogenesis of atherosclerosis?

Answer 18

1- Reaction to injury formulation

Injury (or dysfunction) of endothelium leads to…
• Entry of monocytes and lipids (hyperlipoproteinemia) to subendothelium.
• Platelet adhesion and aggregation.

2- Release of mitogenic factors from platelets and
macrophages…..proliferation and migration of smooth muscle fibers.

3- Monocytes and smooth muscle cells engulf lipid and
cause lipid deposition into the lesion.

4- Necrosis in the deeper part.

Question 19

What is the N/E of atherosclerosis?

Answer 19

• Sites: Small, medium, and large arteries
• Aorta, especially descending *Coronaries and cerebrals
• Femoral , renal, superior mesenteric and internal carotids.
• Uncomplicated atheroma: “unit lesion for atherosclerosis”
  disc-like patches. Color ranges from yellow to white according to relative amount of fat covered by glistening intima. more around the mouths of the branches.
• Complicated atheroma: calcification, ulceration, thrombosis

Question 20

What is the M/E of atherosclerosis?

Answer 20

• Intimal lesions:
  Subendothelial fibrous cap, formed of proliferated smooth muscle cells, foam cells and extra cellular matrix, Central core of cholesterol and cholesterol esters, lipid laden macrophages (foam cells), necrotic debris and calcification.
• Medial lesions:
  Internal elastic lamina: disrupted
  Media: atrophy “due to pressure”
  Vascularisation of plaque
• Adventitia: lymphocytic infiltrate “to fight infection”

Question 21

What are the complications of atherosclerosis?

“ACUTE”

Answer 21

1- Narrowing of vascular lumen…chronic ischemia.

2- Superimposed thrombosis…acute ischemia.

3- Ulceration with liberation of fatty core … acute ischemia, athero emboli, DIC.

4- Pressure atrophy of the media with fibrosis….weakening of the wall …. Aneurysm.

5- Dystrophic calcification.