Diseases of Blood Vessels Flashcards
Define arteriosclerosis.
This is the thickening, hardening, and loss of elasticity of the walls of arteries.
What are three forms of arteriosclerosis?
Atherosclerosis
Medial calcific sclerosis
Arteriolosclerosis
Define atherosclerosis.
Atherosclerosis is a chronic condition characterized by the buildup of plaque within the walls of arteries, leading to the narrowing and hardening of these blood vessels.
Discuss the pathogenesis of atherosclerosis.
◾ Factors such as hypertension, high cholesterol, smoking, and diabetes cause damage to the endothelial lining of the arteries.
◾ The damaged endothelium allows low-density lipoprotein (LDL) particles to infiltrate and accumulate in the intimal layer of the artery.
◾ LDL particles become oxidized, attracting macrophages to the site of injury. These macrophages engulf the oxidized LDL particles and transform into foam cells, leading to local inflammation.
◾ The accumulation of foam cells, lipids, and other cellular debris forms a fatty streak within the arterial wall.
◾ Smooth muscle cells from the arterial media proliferate and migrate to the intima, where they synthesize extracellular matrix components, creating a fibrous cap over the lipid core.
◾ The fibrous cap stabilizes the plaque, but as the plaque grows, it narrows the arterial lumen, restricting blood flow.
◾ Plaques can be either stable or unstable. Stable plaques have a thick fibrous cap and are less likely to rupture.
◾ Unstable plaques have a thin fibrous cap and are prone to rupture. When an unstable plaque ruptures, it exposes the underlying thrombogenic material, leading to the formation of a blood clot (thrombosis).
◾ Thrombosis can obstruct blood flow, resulting in a heart attack or stroke.
◾ Over time plaques may calcify, further stiffening the arteries and contributing to cardiovascular disease.
◾ [Image 1] [Image 2]
Define aneurysm.
This is a localized, blood-filled bulge in the wall of a blood vessel.
Define true aneurysm.
This type of aneurysm involves all three layers of the blood vessel wall (intima, media, and adventitia). The vessel wall bulges outward, but remains intact.
Define false aneurysm.
This is a vessel wall defect that occurs when blood leaks out of the vessel and is contained by the surrounding extravascular tissue, forming a hematoma that mimics an aneurysm.
Define dissection.
This is a vessel wall defect that occurs when there is a tear in the inner layer of the blood vessel wall, causing blood to flow between the layers and separate them.
State two types of aortic aneurysms.
(1) Thoracic aortic aneurysm
(2) Abdominal aortic aneurysm
List causes of aortic aneurysms.
◾ Atherosclerosis
◾ Hypertension
◾ Genetic conditions that affect connective tissue e.g. Marfa syndrome, Ehlers-Danlos syndrome
◾ Trauma e.g. from car accidents
◾ Infections e.g. syphillis or endocarditis can cause the aorta to weaken [though this is rare]
◾ Inflammatory diseases e.g. vasculitis
◾ Smoking
◾ Age
symptoms of aortic aneurysm
Often asymptomatic.
When symptoms are present:
◾ back pain
◾ chest pain
◾ pulsating sensation in the abdomen, especially with abdominal aortic aneurysms
Clinical consequences of untreated aortic aneurysms
◾ Rupture: risk of life-threatening haemorrhage, leading to rapid exsanguination
◾ Chronic pain and discomfort in the chest, back or abdomen
◾ Thromboembolism: potential for blood clots to form, leading to stroke or other organ damage
◾ Compression of adjacent structures: may cause difficulty swallowing, or respiratory issues due to pressure on adjacent structures
◾ Heart failure: in some cases, untreated aortic aneurysms can lead to heart failure due to the increased workload on the heart as it tries to pump blood through the weakened and dilated aorta
Two types of aortic dissections.
(a) Stanford Type A: involves the ascending aorta
(b) Stanford Type B: involves the descending aorta
Outline the clinical consequences commonly associated with aortic dissections.
(1) Cardiovascular complications: possible aortic rupture, leading to massive internal bleeding
(2) Organ ischemia: reduced blood flow to vital organs can cause ischemia, potentially leading to orgain failure
(3) Stroke: increased risk of stroke due to dissection-related emboli
(4) Aortic regurgitation: damage to aortic valves
(5) Cardiac tamponade: blood can accumulate in the pericardial sac around the heart, causing cardiac tamponade, which impairs the heart’s ability to pump blood effectively
(6) Death: if not promptly diagnosed and treated
Define vasculitis.
Inflammation of blood vessels.
List types of vasculitis.
(1) Giant cell arteritis
(2) Takayasu arteritis
(3) Kawasaki disease
(4) Polyarteritis nodosa
(5) Bechet’s disease
(6) Granulomatosis with polyangiitis
Briefly discuss Giant Cell Arteritis.
◾ This is a systemic vasculitis affecting large and medium-sized arteries, primarily the temporal arteries.
◾ It is most common in people above the age of 50 and is more prevalent in women.
◾ The exact cause is unknown, though it is believed to be as a result of an autoimmune response.
Briefly discuss the autoimmune response thought to be involved in the development of GCA.
◾ CD4+ T cells activate and infiltrate arterial walls.
◾ Release of pro-inflammatory cytokines (e.g. IL-6, IL-1β) exacerbates inflammation.
◾ Fusion of macrophages leads to multinucleated giant cells in arterial walls.
◾ Inflammation damages endothelium, causing arterial narrowing or occlusion.
◾ Vascular injury results in symptoms like headaches, vision loss, and possible complications e.g. stroke.
What are varicose veins?
Varicose veins are twisted, enlarged veins that are visible just under the surface of the skin. They often appear blue or dark purple and can be bulging or twisted in appearance.
Which veins are more prone to becoming varicose?
Varicose veins most commonly affect the veins in the legs.
What is the primary cause of varicose veins?
The primary cause of varicose veins is increased pressure in the veins of the lower body. This pressure can result from standing or walking for long periods.
What are the symptoms of varicose veins?
Symptoms of varicose veins can include aching pain, heaviness in the legs, swelling, and itching around the affected veins.
Risk factors for developing varicose veins
age, gender (more common in women), family history, obesity, pregnancy, prolonged standing or sitting
Briefly discuss the etiology of varicose veins.
The valves in the veins, which normally prevent blood from flowing backward, become weak or damaged. This leads to retrograde blood flow and pooling in the superficial veins.
Treatment of varicose veins
◾ Wearing compression stockings
◾ Sclerotherapy
◾ Laser treatment
◾ Catheter-based procedures using radiofrequency or laser energy
◾ High ligation and vein stripping
Initial event in atherosclerosis
(a) intimal injury
(b) fibrosis
(c) plaque rupture
(d) thrombosis
(a) intimal injury
Macrophages in atherosclerosis ingest cholesterol using
(a) oxidised LDL receptors
(b) scavenger receptors
(c) Apo E receptors
(d) Clathrin coated pits
(e) Toll-like receptors
(a) oxidised LDL receptors
Further notes:
Oxidised LDL receptors are a type of scavenger receptors.
Which of the following is not a major risk factor for atherosclerosis?
(a) Family history
(b) Hyperlipidemia
(c) Physical inactivity
(d) Diabetes
(e) Hypertension
(c) Physical inactivity
