Stroke Condition characterized by rapidly developing signs and symptoms of a focal brain lesion with symptoms lasting for more than 24hrs with no apparent cause other that of vascular origin

Risk Factors Age (>65 y/o) Gender (M>F) Family History Prior strokes or MI HPN Diabetes atrial fibrillation (AF) and other specific cardiac conditions High blood cholesterol Arterial disease obesity lifestyle (exposure to cigarette smoke, excessive alcohol use, physical inactivity and unhealthy diet)

StrokeHemorrhagicIntracerebralSubarachnoid Ischemic (85%)

Hemorrhagic Stroke

Intracerebral hemorrhage ( bleeding within the brain) – Accts for 20% of stroke – Usually results from chronic high blood pressure that weakens the arteries causing it to break – Sudden onset of severe headache, vomiting, focal neurologic deficits that progress over minutes – May present with agitation and lethargy  stupor and coma – Other causes: trauma, ruptured aneurysm, AV malformation, anticoagulant, thrombolytic agts, CV amyloidosis, bleeding disorders

Hemorrhagic Stroke Subarachnoid hemorrhage (bleeding between the inner and outer layers of the tissue covering the brain) – 10% of stroke – Most common cause is ruptured aneurysm – Other cause: AV malformation – Symptoms: sudden, severe headache that peaks within seconds followed by a brief loss of consciousness but others remain coma or unconscious – stiff neck as well as continuing headaches, often with vomiting, dizziness, and low back pain – Weakness/paralysis and loss of sensation on one side of the body, aphasia

Ischemic Stroke death of an area of brain tissue (cerebral infarction) resulting from an inadequate supply of blood and oxygen to the brain due to blockage of an artery most commonly a branch of one of the internal carotid arteries

Pathophysiology In situ thrombosis of intracranial vessels affecting small penetrating arteries that arise from major intracranial arteries Occlusion by an embolus (cardiogenic sources such as atrial fibrillation or artery-to artery emboli from carotid atherosclerotic plaque; often affecting large intracranial vessels Hypoperfusion- flow limit stenosis of major extracranial (internal carotid) or intracranial vessel

Ischemic Stroke

Etiology Ischemic stroke Atherosclerosis Hypoperfusion Arteriogenic emboli Small vessel “lacunes” 25% Cardiogenic Embolism 20% Others 35% (cryptogenic, dissection, arteritis,Prothrombotic state etc) Illustration of different clinical courses of MS.(Adapted from Lublin FD, Reingold SC. Defining the clinical course of multiple sclerosis: results of an international survey. Neurology 1996;46: )

Cardioembolism 20 % of all ischemic strokes Embolism of thrombotic material forming on the atrial or ventricular wall or the left heart valves  may fragment or lyse producing TIA or occlude arteries producing stroke Sudden in onset with maximum neurologic deficit at once Emboli most often lodge in the MCA,PCA or their other branches Most common cause: atrial fibrillation Others:MI, prosthetic heart valve, rheumatic heart dse, ischemic cardiomyopathy

Artery-Artery Embolism Thrombus formation on atherosclerotic plaques may embolize to intracranial arteries Carotid Atherosclerosis – Carotid bifurcation is the most common source – RF for carotid disease: Male gender, old age, HPN, Diabetes, hypercholesterolemia, smoking – Produces 10% of ischemic stroke

Other Causes Lacunar infarction one of the small arteries deep in the brain becomes blocked by a mixture of fat and connective tissue—a blood clot is not the cause This disorder is called lipohyalinosis and tends to occur in older people with diabetes or poorly controlled high blood pressure Only a small part of the brain is damaged in lacunar infarction.

Clinical manifestations depends on which artery is blocked and thus which part of the brain is deprived of blood and oxygen branch from the internal carotid artery are affected, the ff are most common: – Blindness in one eye – Inability to see out of the same side in both eyes – Abnormal sensations, weakness, or paralysis in one arm or leg or on one side of the bo branch from the vertebral arteries: – Dizziness and vertigo – Double vision – Generalized weakness on both sides of the body

Clinical manifestations Others: – difficulty speaking (for example, slurred speech) – impaired consciousness (such as confusion) – loss of coordination – urinary incontinence – Severe strokes may lead to stupor or coma. – behavioral problems (depression or an inability to control emotions)