Pathology+of+cerebrovascular+disease+dr+anim

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Pathology+of+cerebrovascular+disease+dr+anim

  1. 1. Pathology of Cerebrovascular Disease By Prof. J.T. Anim Department of Pathology
  2. 2. Cerebrovascular Disease <ul><li>Affected blood vessels </li></ul><ul><ul><li>Intracranial vessels </li></ul></ul><ul><ul><ul><li>Middle cerebral artery </li></ul></ul></ul><ul><ul><ul><li>Anterior cerebral artery </li></ul></ul></ul><ul><ul><ul><li>Basilar artery (posterior cerebral arteries) </li></ul></ul></ul><ul><ul><li>Extracranial vessels </li></ul></ul><ul><ul><ul><li>Carotid artery </li></ul></ul></ul><ul><ul><ul><ul><li>Common carotid artery </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Internal carotid artery </li></ul></ul></ul></ul><ul><ul><ul><ul><li>(external carotid artery) </li></ul></ul></ul></ul><ul><ul><ul><li>Vertebral artery </li></ul></ul></ul><ul><ul><ul><li>others </li></ul></ul></ul>
  3. 3. Brain: Blood supply
  4. 4. Brain: Blood supply
  5. 5. Arterial blood supply to the brain
  6. 6. Brain: Blood supply
  7. 7. Cerebrovascular Disease <ul><li>Transient ischaemic attack (TIA) </li></ul><ul><ul><li>A fully reversible neurological deficit often lasting for no more than a few minutes , but occasionally up to 24 hours. </li></ul></ul><ul><ul><ul><li>No structural brain damage has occurred </li></ul></ul></ul>
  8. 8. Cerebrovascular Disease <ul><li>Factors predisposing to TIA </li></ul><ul><ul><li>Atherosclerosis </li></ul></ul><ul><ul><ul><li>Superimposed hypotension </li></ul></ul></ul><ul><ul><ul><li>Spasm of diseased vessel </li></ul></ul></ul><ul><ul><li>Disorders in the neck (spondylosis) </li></ul></ul><ul><ul><li>Other extracranial vascular diseases eg. embolism </li></ul></ul>
  9. 9. Cerebrovascular Disease <ul><li>Stroke </li></ul><ul><ul><li>Rapid onset of a focal disturbance of cerebral function of presumed vascular origin and of more than 24 hours duration. </li></ul></ul><ul><ul><ul><li>Permanent brain damage has occured </li></ul></ul></ul>
  10. 10. STROKE Ischaemic/Occlusive Haemorrhagic/Disruptive Intraparenchymal Subarachnoid Mixed Thrombosis Embolism Hypotension Atherosclerosis Fibromuscular dysplasia Arteritis Dissection Cardiac Extracranial vessels Paradoxical Other emboli Pump failure Hypovolaemia
  11. 11. Stroke: Causes
  12. 12. Ischaemic Stroke <ul><li>Atherosclerosis </li></ul><ul><ul><li>Carotid artery </li></ul></ul><ul><ul><ul><li>Common carotid </li></ul></ul></ul><ul><ul><ul><li>Internal carotid </li></ul></ul></ul><ul><ul><ul><li>(external carotid) </li></ul></ul></ul><ul><ul><li>Vertebro-basilar system </li></ul></ul><ul><ul><ul><li>Posterior cerebral </li></ul></ul></ul><ul><ul><ul><ul><li>With normal BP, >90% cross sectional area reduction is necessary to impair blood flow </li></ul></ul></ul></ul>
  13. 13. Ischaemic Stroke <ul><li>Factors affecting tissue survival </li></ul><ul><ul><li>Adequacy of collateral circulation </li></ul></ul><ul><ul><li>State of systemic circulation </li></ul></ul><ul><ul><ul><li>Reduced blood flow, cardiac pump failure, hypovolaemia, hyperviscosity </li></ul></ul></ul><ul><ul><li>Serological factors </li></ul></ul><ul><ul><ul><li>Low blood sugar, high blood sugar, hypoxia, elevated serum calcium, high blood alcohol </li></ul></ul></ul>
  14. 14. Ischaemic Stroke <ul><li>Factors affecting tissue survival contd . </li></ul><ul><ul><li>Changes within obstructing vascular lesion </li></ul></ul><ul><ul><ul><li>Fragmentation and advancing of embolus </li></ul></ul></ul><ul><ul><ul><li>Reactive vasoconstriction (spasm) </li></ul></ul></ul><ul><ul><ul><li>Reperfusion – stunned cells may recover </li></ul></ul></ul><ul><ul><ul><li>Propagation of thrombus – collateral occlusion </li></ul></ul></ul><ul><ul><ul><li>Embolisation from previous thrombus </li></ul></ul></ul>
  15. 15. Ischaemic Stroke <ul><li>Factors affecting tissue survival contd . </li></ul><ul><ul><li>Resistance within microcirculatory bed </li></ul></ul><ul><ul><ul><li>Hypertension </li></ul></ul></ul><ul><ul><ul><li>Diabetes mellitus – thickened vessel walls </li></ul></ul></ul><ul><ul><ul><li>Hyperviscosity </li></ul></ul></ul><ul><ul><ul><li>Diffuse thromboses (low microcirculatory flow) </li></ul></ul></ul><ul><ul><li>Oedema and raised ICP </li></ul></ul><ul><ul><ul><li>Increased resistance to blood flow </li></ul></ul></ul>
  16. 16. Ischaemic Stroke <ul><li>Intracranial vascular occlusion </li></ul><ul><ul><li>Effects usually confined to area of supply of affected vessel </li></ul></ul><ul><li>Extracranial vascular occlusion </li></ul><ul><ul><li>Effects may be modified by collateral circulation </li></ul></ul><ul><ul><li>Watershed infarction may be seen </li></ul></ul>
  17. 17. Brain: Distribution of cerebral infarction
  18. 18. CNS Ischaemia <ul><li>Selective vulnerability of CNS cells </li></ul><ul><ul><li>Neurons – most sensitive </li></ul></ul><ul><ul><li>Oligodendroglia </li></ul></ul><ul><ul><li>Astrocytes </li></ul></ul><ul><ul><li>Microglia </li></ul></ul><ul><ul><li>Blood vessels </li></ul></ul><ul><ul><ul><ul><li>In descending order of sensitivity </li></ul></ul></ul></ul>
  19. 19. Brain: Effect of global ischaemia
  20. 20. Consequences of global ischaemia Effects of global ischaemia
  21. 21. CNS Ischaemia <ul><li>Mild hypoxia </li></ul><ul><ul><li>Selective neuronal necrosis eg. respirator lung </li></ul></ul><ul><li>Moderate hypoxia </li></ul><ul><ul><li>Neuronal necrosis </li></ul></ul><ul><ul><li>Neuroglial necrosis </li></ul></ul><ul><ul><li>Blood vessels and microglia are spared </li></ul></ul><ul><ul><ul><ul><li>Partial cerebral infarction </li></ul></ul></ul></ul>
  22. 22. Ischaemic Stroke <ul><li>Infarction (stroke) </li></ul><ul><ul><li>Thrombotic – usually anaemic (may be haemorrhagic) </li></ul></ul><ul><ul><li>Embolic – usually haemorrhagic , often multiple. Haemorrhagic nature due to: </li></ul></ul><ul><ul><ul><li>Necrosis of vessel wall </li></ul></ul></ul><ul><ul><ul><li>Lysis of embolus with restoration of some blood flow. </li></ul></ul></ul>
  23. 23. CNS Infarction <ul><li>Vascular occlusion causes: </li></ul><ul><ul><li>Necrosis of neurons, neuroglia and blood vessels </li></ul></ul><ul><ul><li>4-6 hrs. – coagulative necrosis </li></ul></ul><ul><ul><li>12-15 hrs. – sharp demarcation (swelling of neuropil) </li></ul></ul><ul><ul><li>24 hrs. – reactive changes </li></ul></ul><ul><ul><ul><li>Proliferation of microglia, astrocytes, capillaries </li></ul></ul></ul><ul><ul><ul><li>Inflammatory reaction </li></ul></ul></ul>
  24. 24. CNS Infarction <ul><li>Infarction contd. </li></ul><ul><ul><li>1-2 weeks – Swelling resolves </li></ul></ul><ul><ul><ul><li>Softening </li></ul></ul></ul><ul><ul><ul><li>Shrunken granular grey matter </li></ul></ul></ul><ul><ul><ul><li>Accumulation of lipid-laden phagocytes (gitter cells) in infarcted area </li></ul></ul></ul><ul><ul><li>Several months – shrunken cystic lesion traversed by glial fibrils and small blood vessels </li></ul></ul>
  25. 25. Brain: Recent anaemic infarct
  26. 26. Brain: Older infarct showing cavity formation
  27. 27. Brain: Older infarct
  28. 28. Bilateral posterior cerebral infarcts
  29. 29. Brain: Recent haemorrhagic infarct
  30. 30. Brain: Haemorrhagic infarct
  31. 31. Brain: Haemorrhagic infarct
  32. 32. Brain: Multiple haemorrhagic infarcts
  33. 33. Brain: Relatively recent infarct - Histology
  34. 34. Brain: Older infarct showing ‘gitter’ cells
  35. 35. Brain: Older infarct - Histology
  36. 36. Brain: Old infarct with cavity formation - Histology
  37. 37. Brain: Laminar infarct
  38. 38. Brain: Watershed infarct
  39. 39. Brain: Very old infarct showing atrophy of hemisphere
  40. 40. CNS Infarction <ul><li>Vertebro-basilar occlusion </li></ul><ul><ul><li>Infarction of brainstem </li></ul></ul><ul><ul><li>Infarction of cerebellum </li></ul></ul><ul><ul><li>Infarction of posterior cerebral arterial territory </li></ul></ul>
  41. 41. Clinical effects of basilar artery occlusion
  42. 42. Brain: Haemorrhagic cerebellar infarcts
  43. 43. Chronic CNS Ischaemia <ul><li>Lacunae </li></ul><ul><ul><li>Small cavities located deep within cerebral hemispheres (basal ganglia) and pons </li></ul></ul><ul><ul><li>Elderly subjects - >90% with hypertension </li></ul></ul><ul><ul><li>? Small infarcts </li></ul></ul><ul><ul><li>? Expanded perivascular spaces </li></ul></ul><ul><ul><li>? Resolving haemorrhages </li></ul></ul><ul><ul><li>Associated with vascular dementia </li></ul></ul><ul><ul><ul><li>Multi-infarct dementia </li></ul></ul></ul><ul><ul><ul><li>Binswanger’s disease </li></ul></ul></ul>
  44. 44. Brain: Lacuna in pons
  45. 45. Brain: Lacunar lesions
  46. 46. CNS Infarction <ul><li>Venous thrombosis </li></ul><ul><ul><li>Primary – non-infectious </li></ul></ul><ul><ul><ul><li>Pregnancy, puerperium and oral contraceptives </li></ul></ul></ul><ul><ul><ul><li>Haematological disorders </li></ul></ul></ul><ul><ul><ul><li>Extreme dehydration </li></ul></ul></ul><ul><ul><ul><ul><li>Haemorrhagic infarction </li></ul></ul></ul></ul><ul><ul><li>Secondary – pyogenic infections </li></ul></ul><ul><ul><ul><li>Infections from sinuses, middle ear </li></ul></ul></ul><ul><ul><ul><li>Compound fracture </li></ul></ul></ul><ul><ul><ul><ul><li>Septic infarction </li></ul></ul></ul></ul>
  47. 47. Brain: Bilateral haemorrhagic infarct – Sup. Saggital sinus thrombosis
  48. 48. Haemorrhagic Stroke <ul><li>Brain and spinal cord substance (intraparenchymal) </li></ul><ul><li>Subarachnoid </li></ul><ul><li>Mixed </li></ul>
  49. 49. Haemorrhagic Stroke <ul><li>Major predisposing factors </li></ul><ul><ul><li>Hypertension </li></ul></ul><ul><ul><li>Congenital anomalies </li></ul></ul><ul><ul><li>Vascular malformations </li></ul></ul><ul><li>Minor predisposing factors </li></ul><ul><ul><li>Vasculitis </li></ul></ul><ul><ul><li>Bleeding diatheses </li></ul></ul>
  50. 50. Haemorrhagic Stroke <ul><li>Primary intraparenchmal haemorrhage </li></ul><ul><ul><li>Predisposing vascular changes include: </li></ul></ul><ul><ul><ul><li>Fibrinoid necrosis </li></ul></ul></ul><ul><ul><ul><li>Hyaline arteriolosclerosis (lipohyalinosis) </li></ul></ul></ul><ul><ul><ul><li>Microaneurysms (Charcôt-Bouchard) </li></ul></ul></ul><ul><ul><li>Sizes of haemorrhage </li></ul></ul><ul><ul><ul><li>Massive - >3cm diam. Cerebral hemisphere </li></ul></ul></ul><ul><ul><ul><ul><ul><li>> 1.5cm diam. brainstem </li></ul></ul></ul></ul></ul>
  51. 51. Brain: Charcot-Bouchard microaneurysm
  52. 52. Brain: Common sites of spontaneous haemorrhage
  53. 53. Brain: Haemorrhage into basal ganglia
  54. 54. Brain: Massive hemispheric haemorrhage
  55. 55. Brain: Haemorrhage into basal ganglia
  56. 56. Brain: Pontine haemorrhage
  57. 57. Brain: Pontine haemorrhage
  58. 58. Haemorrhagic Stroke <ul><li>Subarachnoid haemorrhage </li></ul><ul><ul><li>Saccular aneurysm 65% </li></ul></ul><ul><ul><ul><ul><li>Females = males </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Developmental medial defect </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Superimposed degenerative changes eg. atheroma </li></ul></ul></ul></ul><ul><ul><ul><ul><li>15-20% multiple </li></ul></ul></ul></ul><ul><ul><li>A-V malformations 5% </li></ul></ul><ul><ul><li>Others (blood dyscrasias) 5% </li></ul></ul><ul><ul><li>No cause found 20% </li></ul></ul>
  59. 59. Haemorrhagic Stroke <ul><li>Subarachnoid haemorrhage </li></ul><ul><ul><li>Secondary effects include: </li></ul></ul><ul><ul><ul><li>Rebleeding </li></ul></ul></ul><ul><ul><ul><li>Vasoconstriction (spasm) </li></ul></ul></ul><ul><ul><ul><li>hydrocephalus </li></ul></ul></ul>
  60. 60. Brain: Distribution of saccular (berry) aneurysms
  61. 61. Brain: Multiple berry aneurysms
  62. 62. Brain: Berry aneurysm - arrow
  63. 63. Brain: A large berry aneurysm
  64. 64. Brain: Subarachnoid haemorrhage – ruptured berry aneurysm
  65. 65. Brain: Giant atherosclerotic aneurysm
  66. 66. Haemorrhagic Stroke <ul><li>Mixed (intraparenchymal and subarachnoid) haemorrhage </li></ul><ul><ul><li>A-V malformations </li></ul></ul><ul><ul><li>Capillary angiomas </li></ul></ul><ul><ul><ul><li>Focal irritation may predispose to convulsions (epileptiform attacks) </li></ul></ul></ul>
  67. 67. Brain: Causes of mixed subarachnoid and intracerebral haemorrhages
  68. 68. Brain: Vascular malformations
  69. 69. Brain: Vascular malformation – cerebral hemisphere
  70. 70. Brain: Arterio-venous malformation
  71. 71. Brain: Vascular malformation

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