MoD 7 Atheroma Flashcards Preview

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Flashcards in MoD 7 Atheroma Deck (32):
0

What is atheroma?

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

1

What is atherosclerosis?

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

2

What is arteriosclerosis?

Thickening of walls of arteries and arterioles, usually as a result of hypertension or diabetes mellitus

3

What causes the fatty streak?

Lipid deposits in intima, yellow, slightly raised
relationship to atheroma debatable

4

What are the features of a simple plaque?

raised, yellowe/white
irregular outline
widely distributed
enlarge and coalesce(join together)

5

What are the features of complicated plaques?

Thrombosis
Haemorrhage into plaque
Calcification
Aneurysm formation

6

What are some common sites of atheroma?

Aorta- especially abdominal
Coronary arteries
Carotid arteries
Cerebral arteries
Leg arteries

7

What are the early microscopic changes in atheroma formation?

Proliferation of smooth muscle cells
Accumulation of foam cells
Extracellular lipid

8

What are the later microscopic changes in atheroma formation?

Fibrosis
Necrosis
Cholesterol clefts
+/- inflammatory cells
disruption of internal elastic lamina
damage extending into media
ingrowth of blood vessels
plaque fissuring

9

Why does the smooth muscle proliferate?

Endothelial damage leads to platelet aggregation and release of PDGF which stimulates smooth muscle proliferation

10

How do foam cells form?

Proliferation and migration of smooth muscle cells taking lipid with it.
Macrophages arriving and phagocytosing the fat

11

What are the consequences of coronary artery atherosclerosis?

Ischaemic Heart Disease-
Sudden death
MI
Angina pectoris
Arrythmias
Cardiac failure

12

What are the consequences of atherosclerosis that give cerebral ischaemia?

TIA
cerebral infarction (stroke)
multi-infarct dememntia (lots of little strokes impairing cognitive function)

13

What consequences can mesenteric ischaemia have?

Ischaemic colitis
Malabsorption
Intestinal infarction
Anneurism from high pressure, hardening and weakening

14

What can peripheral vascular disease cause?

Intermittent claudication (pain when walking from poor blood supply to leg)
Leriche syndrome (bifurcation of aorta as splits into iliac arteries)
Ischaemic rest pain (claudication of iliacartery giving gluteal pain)
Gangrene

15

What are the risk factors for atheroma?

Age
Gender (women protected before menopause)
Hyperlipidaemia (corneal arcus, xanthalasma)
Smoking
Hypertension
Diabetes mellitus
Alcohol
Infection (chlamydia, helicobacter pylori)
Lack of exercise
Obesity
Oral contraceptives
Stress

16

What is the unifying hypothesis of atherogenesis?

Endothelial injury due to: raised LDL, toxins, hypertension, haemodynamic stress
Endothelial injury causes: platelet adhesion, PDGF release, SMC proliferation and migration
Insudation of lipid, LDL oxidation, uptake of lipid by SMC and macrophages, migration, migration of monocytes into intima
Stimulated SMC make matrix material
Foam cells secrete cytokines causing further SMC stimulation and recruitment of inflam cells

17

How can atheroma be prevented?

stop smoking
modify diet
treat hypertension
treat diabetes
lipid lowering drugs

18

What can increase susceptibility to CHD?

genetic disorders like Familial hypercholesterolaemia
geographical location- less common in Mediterranean die to diet
Ethnicity- common in asians

19

What are risk factors for CHD?

smoking
gender
hypertension
diabetes
alcohol
infection e.g H. pylori

20

What do chylomicrons do?

transport lipid from intestine to liver

21

What do VLDLs do?

carry cholesterol and TG from liver
TG removed leaving LDL

22

What do LDLs do?

they are rich in cholesterol and carry cholesterol from liver to non liver cells

23

What do HDLs do?

They carry cholesterol from peripheries back to liver

24

How does apolipoprotein E link to atheroma?

Genetic variation in this protein are associated with changes in LDL levels and polymorphisms (dif phenotypes) can be used as risk markers for atheroma

25

What are some associated physical signs of hyperlipidaemia?

corneal arcus
tendon xanthomas
xanthelasma (eyelid ones)

26

How do we know hypertension isnt a sole cause of atheroma?

BP is high in arms and very uncommon for atheroma to be in arms

27

What cells are involved in atheroma formation?

endothelial cells
platelets
smooth muscle cells
macrophages
lymphocytes
neutrophils

28

What do smooth muscle cells do?

Take up LDL and lipid to become foam cells
Synthesis collagen and proteoglycans

29

What do macrophages do?

Oxidise LDL
Take up lipids to become foam cells
Secrete proteases which modify matrix
Stimulate proliferation and migration of smooth muscle cells

30

What do lymphocytes do in atheroma?

stimulate proliferation and migration of smooth muscle cells

31

What do neutrophils do in atheroma?

secrete proteases leading to continued local damage and inflammation