Q41

How do platelets adhere at the site of a vascular injury?

Von Willebrand’s factor on endothelium most important, * bridging platelet surface receptors (Gplb) and collagen

Also collagen direct to platelet collagen receptors, and interaction with extracellular fibronectin.

How is a primary haemostatic plug formed?

Mass of aggregated platelets formed under influence of released ADP and TXA2

Detail…thrombin etc to follow on


Q42

What is aortic dissection?

Aortic dissection is the dissection of blood along the laminar planes of the aortic media, with the formation of a blood filled channel within the aortic wall, which often ruptures, causing massive haemorrhage.

There is usually an intimal tear that extends into but not through the media of the ascending aorta, usually within 10 cm of the aortic valve. The dissection can extend proximally into the heart, as well as distally along the aorta into the iliac and femoral arteries. Sometime, the blood re-ruptures into the lumen of the aorta, producing a second intimal tear. There is usually no marked dilatation of the

aorta. The dissection does not affect the aorta that is affected by substantial atherosclerosis.
Pass: adequate definition

What are the predisposing factors for aortic dissection?

Hypertension

Connective tissue diseases (eg: Marfan) Iatrogenic

Pass: 1

What are the complications of aortic dissection?

Death

–              rupture 3 body cavities

Extension/Obstruction

–              Carotid, renal, mesenteric arteries

Retrograde to aortic valvular apparatus (root)

–              Cardiac tamponade

–              Aortic insufficiency

–              Coronary ostia (AMI)

–              Spinal arteries

Pass: Need 3 specifics


Q43

What are the morphological features of an abdominal aortic aneurysm?

An aneurysm is a localised dilatation of the abdominal aorta. It is usually between the renal arterial and the bifurcation of the aorta into iliac vessels. The aneurysm often contains atheromatous ulcers covered with mural thrombi, with thinning and destruction of the media.

List the common causes of abdominal aortic aneurysm.

  • Atherosclerosis
  • Congenital (cystic medial degeneration)
  • Mycotic
  • Syphilis
  • Trauma
  • Immunological
  • (Salmonella)

Pass: 2

What are the complications of an abdominal aortic aneurysm?

  • Rupture
  • Occlusion of branch – iliac, mesenteric, vert.
  • Embolism of atheroma/thrombi
  • Impingement adj. Structure (ureter, erosion vert.)
  • Presentation abdominal mass
  • Rupture Risk (2% <4cm) (5-10% each year >5cm)
  • Operative mortality (unruptured 5%) (ruptured >50%)

Pass: 3


Q44

What are the causes of calcific aortic stenosis?

–              Senile calcific aortic stenosis

–              Calcification of congenitally deformed valve

Pass: 1

What are the complications of aortic stenosis?

Increasing obstruction to left ventricular outflow

Cardiac output maintained (left ventricular hypertrophy)

Angina (? ? microcirculatory myocardium) Syncope (? Poorly understood)

Cardiac decompensation – congestive failure

Pass: 2


Q45

Define Shock

  1. Tissue hypoperfusion
  2. Reduced Cardiac Output OR
  3. Reduced effective Blood volume

Describe the stages of haemorrhagic shock

  1. Non-progressive
  2. Progressive
  3. Irreversible

Can you draw a graph showing the relationship between proportion of blood loss and cardiac output in haemorrhagic shock?

Something like the picture (turns down around 20%, dead at 45%)


Q46

What are the criteria for systemic hypertensive heart disease?

  1. Left Ventricular Hypertrophy
  2. Absence of another cause
  3. Systemic Hypertension

What are the gross morphology findings in hypertensive heart disease?

  1. Thick L ventricular wall
  2. No dilation
  3. L atrial enlargement
  4. Increased weight of heart

Pass: 3 of 4

What are the pathological consequences?

  1. Stiffness
  2. Impaired diastolic filling
  3. Atrial dilation/fibrillation
  4. Heart failure
  5. Sudden Cardiac Death

Q47

Define Oedema
Prompt: Increased fluid WHERE?

Increased fluid in interstitial space

What mechanisms contribute to oedema?

  1. Increased Hydrostatic pressure
  2. Reduced Plasma Osmotic Pressure
  3. Impaired Lymph flow
  4. Renal Retention Salt & water
  5. Inflammation

Pass: 4 of 5

How do these mechanisms contribute to development of oedema in congestive cardiac failure?

  1. Decreased cardiac output
  2. Increased Venous pressure
  3. Renal Retention of salt & fluid (renin-Angiotensin)

Pass: 2 of 3


Q48

Draw a typical atheromatous plaque.

  1. Endothelium
  2. Fibrous Cap
  3. Necrotic Centre
  4. Foam Cells
  5. Cholesterol crystals
  6. Calcium

Pass: 4 of 6

What are the pathological consequences?
(Prompt for process and consequence)

  1. Weakening wall -Rupture of Vessel, aneurysm
  2. Gradual Occlusion – Ischaemia
  3. Disruption – Acute Occlusion
  4. Embolisation – Distal occlusion
  5. Calcification

Pass: 3 of 5

Which arteries are commonly affected?

  1. Large elastic – aorta
  2. Medium sized muscular
  3. Lower Limbs more than Upper
  4. Coronary
  5. Circle of Willis
  6. Carotids

Q49

How are the causes of anaemia classified?

  1. Blood loss
    • Acute
    • Chronic
  2. Increased red cell destruction
    • Inherited genetic
      • Hereditary Spherocytosis
      • G6PD
      • Thalassaemia
      • Sickle cell
    • Acquired genetic
      • Paroxysmal noctural haemoglobinuria
    • Antibody mediated
      • Transfusion
      • Drugs
      • Rhesus disease
    • Mechanical trauma
      • Haemolytic Uraemic Syndrome
      • Disseminated Intravascular Coagulation
      • Thrombotic Thrombocytopaenic Purpura
      • Cardiac valves
      • Runners
    • Infectious
      • Malaria
    • Toxic
      • Envenom
      • Clostridia
      • Lead
  3. Decreased red cell production
    • Inherited genetic
      • Fanconi’s
      • Thalassaemia
    • Nutritional
      • B12/folate
      • Iron
    • Erythropoietin deficit
      • Renal failure
      • Chronic disease
    • Immune
      • Aplastic anaemia

Pass Criteria:

  • Bold main headings
  • 1 example of each

Describe the pathogenesis of iron deficiency and anaemia.

  • Causes
    • Chronic blood loss
    • Poor diet
    • Impaired absorption
    • Increased requirements
  • Iron stores used up first – ferritin, haemosiderin
  • Once reserves depleted, serum iron and transferrin decrease
  • Erythroid activity increases, no iron in marrow macrophages
  • Red cells become hypochromic and microcytic

Pass Criteria:

  • Bold to pass

Please give examples of anaemias that are more common in specific ethnic groups.

  • Hereditary spherocytosis: Northern Europe
  • G6PD: 10% African American, Africa, Middle Eastern, Mediterranean
  • Sickle cell: African descent, up to 30%
  • Thalassaemia trait: Africa, Asia, Mediterranean, India
  • Pernicious: Scandinavian, Caucasian

Pass Criteria:

  • 1 correct with example

Q50

What are the predisposing factors for calcific aortic stenosis?

  • Age: normal valve 70-90 years, bicuspid 50-70
  • Bicuspid valve or other congenital abnormality
  • Wear and tear
  • Chronic injury
  • Hyperlipidaemia
  • Hypertension
  • Inflammation
  • Other factors associated with atherosclerosis

Pass Criteria:

  • Bold and one other

What are the clinical consequences of aortic stenosis?

  • Gradual obstruction of left ventricular outflow leads to concentric left ventricular hypertrophy – pressure overload
  • Ischaemia/angina
  • Can get systolic and diastolic dysfunction
  • Congestive heart failure and syncope herald decompensation

Pass Criteria:

  • 3 out of 4 concepts in bold to pass

What are the potential complications of a congenital bicuspid aortic valve?

  • Calcification
  • Stenosis
  • Regurgitation
  • Infective endocarditis
  • Aortic dilatation
  • Dissection

Pass Criteria:

  • Bold and 2 others

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