Atherosclerosis

Question 1

What is atherosclerosis?

Answer 1

Dual meaning:

The accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries.

The thickening and hardening of arterial walls as a consequence of atherosclerosis

Question 2

What is arteriosclerosis?

Answer 2

The thickening of the walls of arteries and arterioles usually as a result of hypertension or diabetes mellitus.

Question 3

What are the macroscopic features of atherosclerosis?

Answer 3

• Fatty streak
• Simple plaque
• Complicated plaque

Question 4

What is a fatty streak?

Answer 4

• Earliest lesion in atherosclerosis
• Flat and do not cause a disturbance to blood flow
• Occur in early life
• Consist of:
  
  • intimal foam cells
  • smooth muscle cells
  • extracellular lipid

As they grow they turn into plaques….

Question 5

What is a plaque?

Answer 5

• Fatty streaks that have grown
• white/yellow
• impinge on the lumen of the artery
• partly circumferential
• 0.3-1.5cm in diameter
• Microscopically:
  
  • fibrosis and necrosis
  • cholesterol clefts
  • distruption to internal elastic lamina
  • extension into the media

Question 6

How can plaques become complicated?

Answer 6

• Ulceration
• Thrombosis
• Spasm
• Embolisation
• Calcification
• Haemorrhage
• Aneurysm formation

Question 7

When does rupture of an atherosclerotic artery normally occur?

Answer 7

In cerebral arteries when the patient has hypertension as well as atherosclerosis. This is caused by weakening of the media.

Question 8

Where does atherosclerosis normally occur?

Answer 8

• Aorta - espeically abdominla
• Coronary arteries
• Carotid arteries
• Cerebral arteries
• Leg arteries

Question 9

What is an aneurysm?

Answer 9

A localised widening of an artery, vein or heart often presetning as a bulge. The wall of a vessel becomes weakened and is prone to rupture.

In large arteries aneurysms normally occur secondary to atherosclerosis.

Question 10

What are dilitations of veins called?

Answer 10

Varices

Question 11

What are saccular aneurysm?

Answer 11

An aneurysm that is shaped like a sac. Commonly occur in the abdominal aorta and are 10-15cm in diameter. Generally lined or filled with a thrombus.

Question 12

What is a fusiform aneurysm?

Answer 12

An aneurysm shaped like a spindle

Question 13

What are the two main complications of aortic aneurysms?

Answer 13

• large aneurysms may rupture and thrombus
• plaque material within them may embolism

Question 14

What is the normal arterial structure?

Answer 14

In order of layers from the lumen:

• TUNICA INTIMA
  
  • Endothelium
  • Sub-endothelium
• TUNICA MEDIA
  
  • Internal elastic lamina
  • Muscular media
• TUNICA ADVENTITIA
  
  • External elastic lamina
  • Adventitia

Arteries closer to the heart contain more elastin and therefore have more elastic capability to deal with high pressure.

Question 15

What are the early microscopic changes in atherosclerosis?

Answer 15

• Proliferation of smooth muscle cells
• Accumulation of foam cells
• Extracellular lipid

Question 16

What are the later macroscopic features of atherosclerosis?

Answer 16

• Fibrosis
• Necrosis
• Cholesterol clefts
• Possible inflammatory cells

The internal elastic lamina gets disrupted and can form bridges of damage to the intermedia. Ingrown angiogenesis can by leaky and lead to the haemorrhaging of the plaque. Plaque may fissure.

Question 17

What are the clinical consequences of ischaemic heart disease?

Answer 17

• sudden death
• myocardial infarction
• angina pectoris
  
  • normally caused by exercise and relieved on rest
• arrhythmias
• cardiac failure
  
  • shortness of breath
  • pulmonary oedema

Question 18

What are the clinical consequences of cerebral ischaemia?

Answer 18

• Transient ischaemic attack (TIA)
  
  • symptoms of a stroke but resolves in <24 hours
• Cerebral infarction (Stroke)
  
  • from thrombus or embolus from diseased carotid artery
• Multi-infarct dementia

Question 19

What is a dissecting aneurysm?

Answer 19

• Mainly occur in the aorta and the major branches
• Form within a few minutes
• Low survival rate
• Inner layer of the wall tears open and blood enters the tear separating the media into two layers
  
  • artery becomes occluded

Question 20

What are the consequences of mesenteric ischaemia?

Answer 20

• Ischaemic colitis
  
  • decreased blood flow through superior mesenteric artery
• Malabsorption
• Intestinal infarction

Question 21

What is peripheral vascular disease?

Answer 21

Arteriosclerosis of arteries or veins particularly in the legs causing pain especially during exercise. Pain improves with rest. Can also affect the arms, stomach and kidneys but this is uncommon

Question 22

What is Leriche syndrome?

Answer 22

A type of peripheral artery/vascular disease caused by a build-up of plaque in the iliac arteries. This causes a hypoxia in the legs. Symptoms:

• pain, fatigue, cramping in legs and buttocks during exercise
• pale, cold legs
• erectile dysfunction
• impotence

Question 23

What is ischaemic rest pain?

Answer 23

*

Question 24

What is an atheroma?

Answer 24

A degeneration of the walls of the arteries caused by the accumulated fatty deposits and scar tissue. The build-up of plaque/ fatty deposits in arteries.