Approach to a patient with stroke - Pathophysiology of stroke


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Etiology, risk factors and basic pathophysiology of CVAs.

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Approach to a patient with stroke - Pathophysiology of stroke

  1. 1. Approach to a patient with stroke<br />AshwinHaridas<br />Asem Ali Ashraf<br />Adam EAH Adam<br />
  2. 2. Definitions<br />Stroke<br />Clinical syndrome of rapid onset of focal deficits of brain function lasting more than 24 hours or leading to death<br />Transient Ischemic attack (TIA)<br />Clinical syndrome of rapid onset of focal deficits of brain function which resolves within 24 hours<br />
  3. 3. Definitions<br />Progressive Stroke <br />A stroke in which the focal neurological deficits worsen with time<br />Also called stroke in evolution<br />Completed Stroke<br />A stroke in which the focal neurological deficits persist and do not worsen with time<br />
  4. 4. Epidemiology<br />Third most common cause of death after cancer and ischeamic heart disease<br />Most common cause of severe physical disability<br />Prevalence of stroke in India is about 1.54 per 1000<br />Death rate is about 0.6 per 1000<br />Incidence and prevalence of stroke is on the rise due to increasing adoption of unhealthy lifestyle & an increasing life expectancy<br />
  5. 5. Stroke Risk Factors<br />Fixed<br />Age<br />Gender (Male>Female)<br />Race (Afro-Caribbean>Asian>European)<br />Heredity<br />Previous vascular event eg. MI, peripheral embolism<br />High fibinogen<br />Modifiable<br />Hypertension<br />Heart disease (Atrial fibrillation, endocarditis)<br />Diabetes mellitus<br />Hyperlipidaemia<br />Smoking<br />Excess alcohol consumption<br />Oral contraceptives <br />
  6. 6. Types of Stroke<br />Ischemic<br />Hemorrhagic<br />
  7. 7. Anterior Circulation<br />Posterior Circulation<br />
  8. 8. Middle Cerebral Artery<br />
  9. 9. Anterior Cerebral Artery<br />
  10. 10. Posterior Cerebral Artery<br />
  11. 11. Ischemic Stroke<br />80% of strokes<br />Arterial occlusion of an intracranial vessel leads to hypoperfusion of the brain region it supplies<br />
  12. 12. Etiology of ischemic stroke<br />Thrombotic<br />Lacunar stroke<br />Large vessel thrombosis<br />Hypercoagulable disorders<br />Embolic<br />Artery to artery<br />Carotid bifurcation<br />Aortic arch<br />Cardioembolic<br />Atrial fibrillation<br />Myocardial infarction<br />Mural thrombus<br />Bacterial endocarditis<br />Mitral stenosis<br />Paradoxical embolus<br />
  13. 13. Thrombotic Stroke<br />Atherosclerosis is the most common pathology leading to thrombotic occlusion of blood vessels<br />Hypercoagulable disorders – uncommon cause<br />Antiphospholipid syndrome<br />Sickle cell anemia<br />Polycythemiavera<br />Homocysteinemia<br />Vasculitis: PAN, Wegener’s granulomatosis, giant cell arteritis<br />
  14. 14. Thrombotic Stroke<br />Lacunar stroke<br />Accounts for 20% of all strokes<br />Results from occlusion of small deep penetrating arteries of the brain<br />Pathology: lipohyalinosis & microatheroma<br />Thrombosis leads to small infarcts known as lacunes<br />Clinically manifested as lacunar syndromes<br />
  15. 15. Embolic Stroke<br />Cardioembolic stroke<br />Embolus from the heart gets lodged in intracranial vessels<br />MCA most commonly affected<br />Atrial fibrillation is the most common cause<br />Others: MI, prosthetic valves, rheumatic heart disease<br />Artery to artery embolism<br />Thrombus formed on atherosclerotic plaques gets embolized to intracranial vessels<br />Carotid bifurcation atherosclerosis is the most comon source<br />Others: aortic arch, vertebral arteries etc.<br />
  16. 16. Etiology of ischemic stroke<br />
  17. 17. Blood supply to the brain is autoregulated<br />Blood flow<br />If zero leads to death of brain tissue within 4-10min <br /><16-18ml/100g tissue/min infarction within an hour<br />Ischemia leads to development of an ischemic core and an ischemic penumbra<br />Pathophysiology of Ischemic Stroke<br />
  18. 18.
  19. 19. Ischemic Penumbra<br />Tissue surrounding the core region of infarction which is ischemic but reversibly dysfunctional<br />Maintained by collaterals<br />Can be salvaged if reperfused in time<br />Primary goal of revascuralization therapies<br />
  20. 20. Thrombus/embolus<br />Hypoperfusion<br />ATP depletion<br />Failure of Na+/K+ATPase membrane ionic pump<br />Activation of pro-coagulant pathways<br />Membrane depolarization & cytotoxic cellular edema<br />Free fatty acid release<br />Calcium entry<br />Glutamate release<br />Activation of lipid peroxidases, proteases & NO synthase<br />Destruction of intracellular organelles, cell membrane & release of free radicals<br />Liquefactive necrosis<br />
  21. 21. Hemorrhagic Stroke<br />Two types<br />Intracerebral hemorrhage(ICH)<br />Subarachnoid hemorrhage(SAH)<br />Higher mortality rates when compared to ischemic stroke<br />
  22. 22. Intracerebral Hemorrhage<br /><ul><li>Result of chronic hypertension
  23. 23. Small arteries are damaged due to hypertension
  24. 24. In advanced stages vessel wall is disrupted and leads to leakage
  25. 25. Other causes: amyloidangiopathy, anticoagulant therapy, cavernous hemangioma, cocaine, amphetamines</li></li></ul><li>Subarachnoid Hemorrhage<br />Most common cause is rupture of saccular or Berry aneurysms<br />Other causes include arteriovenous malformations, angiomas, mycoticaneurysmal rupture etc.<br />Associated with extremely severe headache <br />
  26. 26. Pathophysiology Of Hemorhagic Stroke<br />Explosive entry of blood into the brain parenchyma structurally disrupts neurons<br />White matter fibre tracts are split<br />Immediate cessation of neuronal function<br />Expanding hemorrhage can act as a mass lesion and cause further progression of neurological deficits<br />Large hemorrhages can cause transtentorial coning and rapid death<br />