Cerebrovascular Diseases

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Ischemic Stroke - Brain Attack Basics

  • Pathophysiology:
    • Core Infarct: Irreversible neuronal death due to severe ischemia.
    • Ischemic Penumbra: Potentially salvageable tissue surrounding core; target for reperfusion.
    • Cytotoxic Edema: Intracellular swelling due to Na+/K+ pump failure; early sign.
  • CT (NECT - Non-Enhanced CT):
    • Early Signs (often subtle, within 6 hrs):
      • Hyperdense MCA sign (clot in MCA).
      • Loss of insular ribbon.
      • Sulcal effacement.
      • Obscuration of lentiform nucleus.
    • ASPECTS (Alberta Stroke Program Early CT Score): 0-10 scale (10 regions: M1-M6, Insula, Caudate, Lentiform, Internal Capsule). 📌 Score < 6 indicates poor outcome. ASPECTS score areas diagram
  • MRI:
    • DWI/ADC Mismatch:
      • DWI: Bright (restricted diffusion) within minutes.
      • ADC: Dark (confirms true restriction). DWI-ADC mismatch in acute ischemic stroke
    • FLAIR: Detects subacute infarcts (hyperintense after ~6 hrs).
    • PWI (Perfusion-Weighted Imaging): Identifies penumbra (mismatch between PWI and DWI).
  • Vascular Imaging:
    • CTA/MRA: Detects large vessel occlusion (LVO).

⭐ Diffusion-Weighted Imaging (DWI) is the most sensitive sequence for detecting acute ischemic stroke within minutes of onset.

Hemorrhagic Stroke - When Vessels Burst

  • Intracerebral Hemorrhage (ICH): Bleeding within brain parenchyma.
    • Causes: Hypertension (commonest), amyloid angiopathy (lobar, elderly), AVM, tumor.
    • Locations: Basal ganglia, thalamus, pons, cerebellum.
  • Subarachnoid Hemorrhage (SAH): Bleeding into subarachnoid space.
    • Causes: Ruptured berry aneurysm (~85%), AVM, trauma.
      • 📌 Aneurysm sites (Circle of Willis): ACOM > PCOM > MCA.
    • Symptom: "Thunderclap headache".
  • Imaging:
    • NECT: Primary for acute blood (hyperdense).

      ⭐ Non-contrast CT (NECT) is the initial imaging modality of choice for suspected acute stroke to rapidly differentiate ischemic from hemorrhagic stroke.

    • CTA: Identifies aneurysms, vascular lesions.
    • MRI (FLAIR, GRE/SWI): Subacute blood, hemosiderin.
  • Grading (SAH):
    • Hunt & Hess: Clinical severity (Grades 1-5).
    • Fisher Scale: CT appearance, vasospasm risk (Grades 1-4).

Vascular Malformations - Brain's Tangled Plumbing

  • Arteriovenous Malformation (AVM)
    • Nidus, direct artery-to-vein shunting.
    • Feeding arteries, early draining veins.
    • Angio: 'bag of worms'. High hemorrhage risk.
  • Cavernous Malformation (Cavernoma)
    • MRI: 'popcorn'/'berry' (T2WI).
    • Hemosiderin rim (dark T2/GRE/SWI). No AV shunting. MRI brain Cavernoma popcorn appearance hemosiderin rim
  • Developmental Venous Anomaly (DVA)
    • 'Caput medusae'/'palm tree': trans-cortical draining vein.
    • Usually incidental, benign.
  • Capillary Telangiectasia
    • Often pontine; 'brush-like' enhancement.
    • Usually incidental, benign.

⭐ Developmental Venous Anomalies (DVAs) are the most common cerebral vascular malformation and are typically benign 'leave-me-alone' lesions, often associated with cavernomas.

Beyond Strokes - Veins, Smoke, Fire

  • Cerebral Venous Thrombosis (CVT)
    • Thrombus in dural sinuses/cortical veins.
    • NECT: 'dense clot sign'/'cord sign'.
    • CECT: 'empty delta sign'.
    • MRI/MRV: Loss of flow void, thrombus signal, venous infarcts (often hemorrhagic, non-arterial territories).

    ⭐ The 'empty delta sign' on contrast-enhanced CT or MR venography is a characteristic finding of dural venous sinus thrombosis, particularly of the superior sagittal sinus.

  • Moya Moya Disease
    • Progressive stenosis/occlusion of terminal ICA & proximal ACA/MCA.
    • Angiography: 'puff of smoke' collaterals. 📌 "Moya Moya" = "puff of smoke" in Japanese.
    • Moya Moya vs normal vasculature cerebral angiography
  • CNS Vasculitis
    • Inflammatory; segmental narrowing/beading of vessels.
    • Multifocal infarcts of varying ages on MRI.

High‑Yield Points - ⚡ Biggest Takeaways

  • MCA territory infarcts are most common; hyperdense MCA sign on NCCT is an early sign.
  • MRI (DWI) is most sensitive for acute ischemic stroke, detecting it within minutes.
  • Lacunar infarcts (<1.5 cm) are deep, often linked to hypertension or diabetes.
  • Watershed infarcts affect arterial border zones due to systemic hypoperfusion.
  • For SAH, CT is initial; LP if CT negative. Ruptured berry aneurysms are a key cause.
  • Cerebral Amyloid Angiopathy (CAA) causes recurrent lobar hemorrhages in the elderly_._

Practice Questions: Cerebrovascular Diseases

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A 45-year-old man presents with weakness in his right arm and slurred speech that started suddenly 2 hours ago. Which diagnostic test is most appropriate to confirm the diagnosis?

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Flashcards: Cerebrovascular Diseases

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The investigation of choice for stroke is a _____.

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The investigation of choice for stroke is a _____.

NCCT

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