Atheroma

Question 0

Describe the morphological appearance of atheroma

Answer 0

Fatty streak - lipid deposits in intima, yellow, slightly raised
Simple plaque - yellow/white, raised, irregular outline, widely distributed, enlarge and coalesce
Complicated plaque - thrombosis, haemorrhage into plaque, calcification, aneurysm formation

Question 1

Define the terms ‘atheroma’, ‘atherosclerosis’, ‘arteriosclerosis’

Answer 1

Atheroma - accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries
Atherosclerosis - thickening and hardening of arterial walls as a consequence of atheroma
Arteriosclerosis - thickening of the walls of arteries and arterioles, usually as a result of hypertension or diabetes mellitus

Question 2

List some common sites of atheroma

Answer 2

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

Question 3

Describe the microscopic and macroscopic features of atheroma

Answer 3

Microscopic - proliferation of smooth muscle cells, accumulation of foam cells, extracellular lipid (early changes), disruption of internal elastic lamina, media damage, ingrowth of blood vessels, plaque fissuring
Macroscopic - fibrosis, necrosis, cholesterol clefts, inflammatory cells

Question 4

Describe the effects of severe atherosclerosis at specific anatomical sites

Answer 4

Coronary artery - ischaemic heart disease –> MI, sudden death, angina, arrhythmias, cardiac failure
Cerebral ischaemia - transient ischaemic attack, cerebral infarction (stroke), multi infarct dementia
Mesenteric ischaemia - ischaemic colitis, malabsorption, intestinal infarction, aneurysm
Peripheral vascular disease - intermittent claudication, Leriche syndrome, ischaemic rest pain, gangrene

Question 5

List some risk factors for atheroma

Answer 5

Age - slowly progressive throughout life
Gender - women protected before menopause
Hyperlipidaemia - high plasma cholesterol, LDL most significant, HDL protective, corneal arcus, xanthoma, xanthelasma
Smoking - increased platelet aggregation
Hypertension - strong link
Diabetes mellitus - doubles risk
Alcohol - >5 units, small amounts may be protective
Infection - chlamydia pneumoniae, helicobacter pylori)
Lack of exercise
Obesity
Oral contraceptives
Stress
Genetics - variations in apolipoprotein metabolism/receptors

Question 6

Discuss the unifying hypothesis of atherogenesis

Answer 6

Endothelial injury due to raised LDL, toxins (cigarette smoke), hypertension, haemodynamic stress
Endothelial injury causes platelet adhesion, PDGF release, SMC proliferation and migration, insulation of lipid, LDL, migration of monocytes into intima
Stimulated SMC produces matrix material
Foam cells secrete cytokines causing further SMC stimulation, recruitment of other inflammatory cells

Question 7

Discuss prevention methods of atheroma

Answer 7

No smoking
Reduce fat intake, regular exercise/weight control
Treat hypertension
Treat diabetes
Lipid lowering drugs
Not too much alcohol

Question 8

Describe the epidemiology of coronary heart disease (genetics, geographical, ethnic susceptibility), risk factors and markers

Answer 8

Genetics - disorders e.g. familial hyperlipidaemia
Geographical - less common in Mediterranean (diet)
Ethnic - common in Asians
Risk factors - smoking, gender (more common in men), hypertension, diabetes, alcohol, infection
Markers - apolipoprotein E genotype, angiotensin converting enzyme, genetic polymorphisms