5 – Vascular System Flashcards
Vascular lesions can cause:
- Edema, congestion
- Hemorrhages
- Thrombosis
- Ischemia
- Infarction in affected tissues and organs
Degenerative disease of arteries
- Arteriosclerosis
- Artherosclerosis (predispose to arterial rupture)
- Arterial hypertrophy
- Aneurysms (predispose to arterial rupture)
- Arterial medial calcification
Arteriosclerosis and atherosclerosis
- DISTINCT degenerative diseases that are manifested by
o Hardening of arterial wall
o Loss of elasticity
o Reduced vascular lumen
Arteriosclerosis
- ‘hardening’ of an artery
- Loss of arterial elasticity, hardening and luminal narrowing
- Mainly found in elastic arteries (ex. arterial branching sties)
- *raised corrugated whit plaques, may have calcium deposits
- Usually an incidental finding
Plaques in arteriosclerosis
- Fibrous tissue and smooth muscle proliferation
- Sometimes mineralization
Atherosclerosis
- Major cause of mortality in humans
- *Excessive circulating cholesterol is deposited in arterial walls
- Rare in domestic animals
Major risk factors of atherosclerosis in humans
- Familial hypercholesterolemia
- High blood pressure
- Poor diet habit
- Sedentary life-cycle
- Cigarette smoke
Lesions that form with atherosclerosis
- Atheromas
Atheromas
- Cholesterol plaques in intima and media of arteries
- Particularly common in the coronary arteries (heart attacks) and cerebral arteries (stroke)
- Reduce lumen and cause blockage
- Can lead to thrombosis
Atherosclerosis steps
- Early cholesterol deposits in intima
- Accumulation of cholesterol and lipid-laden macrophages in arterial wall
- Large lipid plaques occlude the arterial lumen and cause ischemia
Atherosclerosis is most commonly reported in
- Hypothyroid dogs with hypercholesterolemia or diabetes mellitus
- Pigs
- Psittacine birds and pigeons feed a high lipid diet
Atherosclerosis grossly
- Prominent thick arteries
- Yellow plaques
Atherosclerosis microscopically
- Plaques containing foamy, lipid-laden macrophages
- Cholesterol clefts
- Fibroblasts
- Smooth muscle proliferation
Arterial hypertrophy
- Occurs in muscular arteries
- Hypertrophy and hyperplasia
- *hypertension=common cause
- Ex. high altitude (Brisket disease)
Hypertrophy and hyperplasia in arterial hypertrophy results in
- Loss of elasticity
- Narrowing of arterial lumen
- Increased resistance
Muscular hypertrophy is frequently seen in the LUNG of cats
- Past: associated with Aelurostrongylus abstrusus
- Now: Dirofilaria immitis (hypertrophy and proliferation/inflammation)
Aneurysm
- Localized weakening and dilation of blood vessels
o Elastic arteries (less extent in veins) - Prone to rupture
2 main anatomic types of aneurysm
- Saccular (or fusiform) aneurysm
- Dissecting aneurysm (arterial dissection)
Saccular (or fusiform) aneurysm
- Spherical or ovoid dilation of blood vessel resembling a ballon filled with blood
Dissecting aneurysm (arterial dissection)
- Tear of intima allowing blood to enter into potential space between intima and media
o Progressively dissecting the wall of the vessel - Ex. hematoma separating the tunic intima from tunica media
Aneurysm prone to rupture and cause
- Hemothroax
- Hemoabdomen
- Hemopericardium
- Brain hemorrhage
Common cause of aneurysm in domestic animals:
- Strongylus vulgaris in horses
- Spirocerca lupi in dogs
- Copper deficiency in mares and pigs
- Trauma
- Atherosclerosis and hypertension (humans)
- Genetic diseases
Fusiform aneurysm in dog
- Died due to massive hemothorax caused by rupture of an aortic aneurysm
- Caused due to larval migration of Spirocerca lupi=PARASITIC AORTITIS
- Mature S. lupi parasitize the esophagus
Common causes of arterial calcification
- Hypervitaminosis D (or ingestion of toxic plants containing Vitamin D analogs)=metastatic calcification
- Chronic granulomatous diseases (ex. Johnes, TB)
- Age-related arteriosclerosis
- Aortic lesions associated with migrating larvae of Spirocerca lupi in dogs
Aortic calcification grossly (ex. cow with Johne’s disease)
- Confluent, raised, rectangular plaques on intima surface