Thrombosis results from the pathologic activation of the hemostatic pathways, leading to the accumulation of polymerized fibrin and platelet aggregates (a thrombus). If the thrombus breaks off and travels distally in the circulation it is considered and embolus.
Virchow's triad outlines the 3 factors that promote thrombosis: endothelial injury, abnormal blood flow, and hypercoagulability.
Atherosclerotic damage to arteries is a major cause of thrombosis. The plaques of atherosclerosis disrupt blood flow and cause endothelial injury (fulfilling 2 of Virchow's criteria).
Hemorrhagic strokes account for about 10-15% of all strokes (ischemic strokes make up the bulk of the rest). Patients with hypertension are at particular risk for hemorrhagic strokes because the increased arterial pressure can undermine weaken arterial walls. Things such as aneurysms (e.g. congenital berry aneurysms) or atherosclerosis can sufficiently undermine the arterial wall predisposing patients to hemorrhagic strokes.
The layman's term "Stroke" or "Brain Attack" refers to a rapid loss of brain function. Its etiology can be divided into 2 general categories.
Ischemic strokes result from the occlusion of a cerebral vessel by a thrombus or embolus. Alternatively ischemia can be the result of generalized hypoperfusion of the brain (e.g. due to hypoxia, hypoxemia, or hypotension).
Hemorrhagic strokes are the result of bleeding within the cranial vault which results in compression injury due to the space occupied by the escaped blood (hematoma).
Use the 4 blue buttons above to navigate through 3 cases of stroke: thrombotic, hypoperfusion related, and hemorrhagic. Can you distinguish between the 3 stroke types?
A few general questions:
What is the difference between a thrombus and and embolus?
What are thrombi composed of?
What are the 3 major predisposing causes of thrombosis (a.k.a Virchow's triad)?
What is the most common cause of thrombosis?
What are the predisposing conditions that lead to hemorrhagic strokes?
ischemia, hypoxia, hypoxemia, anoxia, and hypotension are overlapping conditions, but what does each term mean specifically?
