Vascular - Pathophysiology

Question 1

Pathophysiology of DVT

Answer 1

• blood clot forms on the wall of a vein & partially / completely occludes the flow of venous blood back to the heart
• causes the wall of the vein to become inflamed, this promotes platelet aggregation and thrombus can propagate or grow
• may lead to pain or redness, usually not accompanied by symptoms due to the depth of the vein
• usually seen in venous system due to slower movement of blood - intravascular conditions promote activation of coagulation cascade causing platelets to adhere readily
• in severe obstruction, pressure behind clot may lead to oedema or it being disloded, most thrombi do dissolve

Question 2

Describe effects of altered peripheral circulation

Answer 2

• decreases blood / oxygen that gets to extremities, can lead to temperature issues, circulatory stasis and hypoxia
• hypoxia leads to inflammatory reactions in vessels and tissues, circulation can become so sluggish that needs for oxygen, nutrients and waste removal are barely met
• ischemia in lower extremities due to obstruction of arterial blood flow by atherosclerosis results in pain on ambulation called intermittent claudication, pulses can cease in extremities & skin colour changes occur

Question 3

Describe anaemia

Answer 3

• function of RBCs is to carry oxygen, anemia occurs when there is a dysfunction in the ability of RBCs to carry oxygen around the body, leads to systemic effects
• production of RBSs is regulated by erythropoietin, occurs in bone marrow and requires iron, vitB12 and folate
• rate of haemoglobin production is determined by levels of iron in the body

Question 4

Describe pathophysiology of three main types of aneurisms

Answer 4

• aneurysm is a localized dilation or out pouching of a vessel wall
• form when there is a disruption of the wall in the vessel due to changes in collagen & elastin, increases vulnerability of vessels to intravascular pressures
• atherosclerosis is a common cause because plaque formation erodes the vessel wall & contributes to inflammation which further weakens the vessel.
• plaque deposits + degenerative changes = loss of elasticity, weakening & eventual dilation
• Berry
  
  • usually congenital abnormalities, leads to a sac-like out-pouching from the vessel wall, grows & weakens over time
• Fusiform
  
  • involve circumference of the vessel, usually found in ascending aorta & abdominal aorta due to atheroscloritc changes
• Dissecting
  
  • tear in the intima of the aorta - most common in ascending aorta where pressures are highest
  • aorta is largest artery in body, blood is pumped through at high force, vessel walls can break down, lead to ballooning out and damage to the intima leads to blood passing through into media layer causing a weaker false channel for blood flow