W7: Atherosclerosis I; HT; Atheroma; Thrombosis & Embolism; Ischaemia

Question 1

Describe the process of atherogenesis and understand how atheromatous plaques form

Answer 1

focal plaques in intima of large/medium arteries

1. FATTY STREAK: non-significant. fat-laden macrophage
2. ATHEROMATOUS PLAQUE: lipid core fibrous cap (inflamm cells), smc prod collagen, foamy macrophage, lipid, debris
3. FULLY DEVELOPED PLAQUE: calcification, arterial branching, large areas
4. COMPLICATED ATHEROMA: haemorrhage or rupture

Question 2

Understand the role of lipids in the aetiology of atheroma and presentation of hypercholeteraemia

Answer 2

LDL cholesterol major component of accumulation at vascular wall, which become oxidised and consumed by foam cells = toxicity = endothelial injury

• 1º familial or 2º idiopathic/acquired hypercholesterolaemia; FH ↓LDL receptors on membrane

• corneal arcus, tendon xanthoma, xanthelasmata

Question 3

Acute Complications of atherosclerosis

Answer 3

stenosis = St. Angina

severe stenosos = ischaemia, unstable ang., periph. art. disease, atrophy

acute atheromatou occlusion: coag cascade, necrosis of affected area

embolisation of distal beds

ruptured atheromatous AAA = dilatation of vessel, retroperitoneal haemorrage

Question 4

Describe the process of thrombosis.

Answer 4

thrombosis: solid mass from blood constituent in vasc. system
clot: solid blood

1. turbulent blood flow
2. endothelial injury
3. collagen exposure and interaction with plaque
4. fibrin meshwork and rbc trap

*lines of zahn: rbc then PT.

=> prophylaxis: TEDS, subcutaneous heparin

Question 5

Common emboli

Answer 5

fat, bone marrow emboli: fractures

trophpoblast, amniotic: pregnancy

Question 6

Rheumatic Heart Disease - aetiology, pathophys, and pres.

Answer 6

Predisposing rheumatic fever at early age
* males, flitting, polyarthritis, rashes, fever, sore throat
* DISORDERED IMM. RESPONSE = cardiac and joint inflamm. (+neuro)
- Ab and T-mediated dmg to heart
=> ASCHOFF BODIES (necrotic, inflamm cells)
=> pancarditis + murmurs

Question 7

RHD - valvular + chronic rheumatic heart diseases

Answer 7

VALVULAR

• MITRAL STENOSIS (common) or regurg.
• Vegetations on valve leaflets

CHRONIC
- valvular abn. 
- inflamm = fibrinoid
=> deforming fibrotic valvular disease
* leaflet thickening, commissural fusion, thickeneing and shortening of chord. tend.

Question 8

RHD - valvular + chronic rheumatic heart diseases

Answer 8

VALVULAR

• MITRAL STENOSIS (common) or regurg.
• Vegetations on valve leaflets

CHRONIC
- valvular abn. 
- inflamm = fibrinoid
=> deforming fibrotic valvular disease
* leaflet thickening, commissural fusion, thickeneing and shortening of chord. tend.

Question 9

General Process of Infarction: main events

Answer 9

1. NECROSIS
2. ENZYME RELEASE AND TISSUE DESTRUCTION
   i. COAGULATIVE NECROSIS (heart, spleen)
   ii. COLLIQUITIVE NECROSIS (brain): cystic infarct d/t small foci breakdown draw fluid to area

=> often irreversible and severe dmg.

Question 10

STAGES OF MYOCARDIAL INFARCTION

Answer 10

EARLY HOURS

• coag, haemorr., oedema
• necrosis, lymph infiltrate (24hr)
• swollen mitochondria

DAYS

• ↑Infiltrate ↓Specialised Features
• Disintegration. Immune Cell Death
• pale infarct., red (lung+liver)
• darkening of infarct

WEEKS

• Granulation at periphery
• Established gran. and collagen deposit.
• ↑Collagen + Scarring

=> scar.

Question 11

Reperfusion Injury

Answer 11

Restoration of supply but huge influx of oxidative dmg + inflamm cells.