34. Cerebrovascular disease - classification, etiology, pathogenesis, clinical manifestations.

Cerebrovascular disease - classification, etiology, pathogenesis, and clinical manifestations.

Cerebrovascular disease refers to any disorder of the brain caused by abnormal blood supply, leading to ischemia, infarction, or hemorrhage.

Classification

1. 1 Ischemic (occlusive) cerebrovascular disease

Cerebral infarction (ischemic stroke).

Transient ischemic attacks (TIA).

1. 2 Hemorrhagic cerebrovascular disease

Intracerebral hemorrhage (e.g., hypertensive hemorrhage ).

Subarachnoid hemorrhage (e.g., ruptured aneurysm).

Etiology (Causes)

Ischemic disease

Thrombosis (usually on atherosclerotic plaque).

Embolism (cardiac sources — atrial fibrillation, valvular disease; artery-to-

artery emboli).

Hypoperfusion (e.g., severe hypotension, cardiac arrest).

Hemorrhagic disease

Hypertension (most common cause of intracerebral hemorrhage ).

Aneurysm rupture (berry aneurysms in subarachnoid hemorrhage ).

Arteriovenous malformations (AVMs).

Coagulopathies (e.g., anticoagulant therapy, hemophilia ).

Pathogenesis

Ischemic cerebrovascular disease

1. Vessel occlusion (thrombus or embolus).
2. Reduced blood flow → brain ischemia → energy failure.
3. Failure of Na /K -ATPase pump → cytotoxic edema → neuronal injury.
4. If prolonged (>5 minutes), irreversible infarction (neuronal death).
5. In "penumbra" region (area around core infarct), partial perfusion → potentially salvageable with reperfusion.

Hemorrhagic cerebrovascular disease

1. Vessel rupture → bleeding into brain parenchyma or subarachnoid space.
2. Mass effect → increased intracranial pressure.
3. Compression of adjacent brain tissue → secondary ischemia.
4. Toxic effects of blood breakdown products on neurons.