125 Cerebrovascular Part 2 & Exciting things in January

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Anterior Circulation Strokes

Blood Supply:

• Internal carotid artery branches:
  • Middle cerebral artery (MCA): Supplies the lateral aspects of the frontal, parietal, and temporal lobes.
  • Anterior cerebral artery (ACA): Supplies the medial frontal and parietal lobes.

Clinical Features:

• MCA Stroke (Most Common):
  • Contralateral weakness and sensory loss (face and arm > leg).
  • Aphasia if the dominant hemisphere (usually left) is involved.
  • Hemineglect if the non-dominant hemisphere (usually right) is involved.
  • Gaze preference toward the side of the lesion.
• ACA Stroke:
  • Contralateral weakness and sensory loss (leg > face and arm).
  • Behavioral changes or personality disturbances (e.g., apathy, disinhibition).
  • Urinary incontinence (due to involvement of the medial frontal lobe).

Posterior Circulation Strokes

Blood Supply:

• Vertebrobasilar system:
  • Vertebral arteries join to form the basilar artery.
  • Supplies the brainstem, cerebellum, occipital lobes, and thalamus.

Clinical Features:

• Brainstem Strokes:
  • Cranial nerve deficits (e.g., dysphagia, dysarthria, facial weakness).
  • Contralateral motor or sensory deficits.
  • Vertigo, nystagmus, ataxia.
  • Decreased level of consciousness or coma in severe cases.
• Cerebellar Strokes:
  • Ataxia, dysmetria, intention tremor.
  • Vertigo and nystagmus.
• Posterior Cerebral Artery (PCA) Stroke:
  • Contralateral homonymous hemianopia (loss of the same visual field in both eyes).
  • Visual agnosia or cortical blindness in bilateral PCA strokes.
  • Thalamic involvement can cause contralateral sensory loss.

Cerebral Aneurysms

A weak area in a blood vessel wall that enlarges over time, creating a bulging or ballooning effect. A ruptured cerebral aneurysm is a common cause of subarachnoid hemorrhage (SAH).

Types:

• Berry Aneurysms (Saccular Aneurysms):
  • The most common type of cerebral aneurysm, accounting for ~75% of nontraumatic SAH.
  • Typically small and round, creating a “berry-like” appearance.
  • Frequently found in the Circle of Willis.
• Fusiform Aneurysms:
  • Less common, involving circumferential widening of a segment of the artery.
  • Found more often in larger arteries like the basilar or vertebral arteries.

Risk Factors:

• Smoking
• Alcohol (ETOH) use
• Hypertension (HTN)
• Obesity
• Polycystic ovary syndrome (PCOS)
• Marfan syndrome
• Ehlers-Danlos syndrome

Clinical Presentation:

• Unruptured Aneurysms: Often asymptomatic or cause visual disturbances, headaches, or cranial nerve palsies.
• Ruptured Aneurysms: Severe headache, nausea, vomiting, neck stiffness, photophobia, altered mental status, seizures.

Labs, Studies, and Physical Exam Findings:

Physical Exam:

• May reveal signs of increased ICP or cranial nerve palsies in larger aneurysms.

Bloodwork:

• PT/PTT and INR: Assess coagulation status before interventions.
• CBC: Rule out anemia or infection.

Imaging:

• CT Angiography (CTA): Preferred
• MR Angiography (MRA): Alternative, especially in patients unable to tolerate contrast.
• Cerebral Angiogram: Gold standard for definitive diagnosis and precise localization.
• Non-contrast CT: First-line for suspected rupture to identify SAH.
  • Look for hyperdensity in the subarachnoid spaces.
• Lumbar Puncture:
  • Xanthochromia: Yellow discoloration of CSF confirms SAH.
  • Elevated opening pressure: Suggests increased ICP.

Treatment:

Management of unruptured aneurysm:

• Blood pressure control: Target <140/90 mmHg.
• Cholesterol control.
• Regular imaging follow-up for small, stable aneurysms.

Management of ruptured aneurysm:

• Emergency Interventions:
  • Prevent rebleeding: Strict blood pressure control.
  • Treat increased ICP: Mannitol or hypertonic saline.
• Surgical Options:
  • Clipping: Open surgical procedure to place a clip at the aneurysm base, preventing rupture or rebleeding.
  • Endovascular coiling: Minimally invasive approach to induce clotting within the aneurysm.

Arteriovenous Malformation (AVM)

An abnormal tangle of blood vessels where arteries connect directly to veins without the normal capillary bed in between, leading to high-pressure blood flow in veins, increasing the risk of rupture. These are usually congenital defects.

Clinical Presentation:

• Typically asymptomatic until complications develop

Pathophysiology:

• Direct artery-to-vein connection
  • Leads to increased venous pressure and potential venous rupture
• Steal phenomenon
  • Blood is diverted away from surrounding normal brain tissue, causing ischemic symptoms

Symptoms of an Unruptured AVM:

• Headache: May be localized or resemble migraines
• Seizures: Partial or generalized seizures are common presenting symptoms
• Focal Neurological Deficits:
  • Weakness, sensory loss, or visual field deficits, depending on location

Symptoms of a Ruptured AVM:

• Sudden, severe headache: “Worst headache of life” (similar to subarachnoid hemorrhage)
• Nausea and vomiting
• Altered mental status: Confusion to coma
• Focal neurologic deficits: Weakness, numbness, or aphasia, depending on location
• Seizures
• Loss of consciousness in severe cases

Common Locations:

• Can occur anywhere in the central nervous system, but most are found in the brain
• Supratentorial regions (cerebral hemispheres):
  • Frequently located in the frontal, temporal, or parietal lobes
• Infratentorial regions:
  • Less common, but AVMs here can affect the brainstem or cerebellum, leading to significant deficits

Treatment:

Medical Management:

• Anticonvulsants for seizures
• Blood pressure control to reduce rupture risk in ruptured AVMs (target systolic BP <140 mmHg)

Interventional/Surgical Options:

• Surgical Resection: Preferred for accessible AVMs with low surgical risk
• Endovascular Embolization: Blocks blood flow to the AVM; often used preoperatively or for inoperable AVMs
• Stereotactic Radiosurgery: Focused radiation to shrink the AVM over months to years

Post-Treatment:

• Regular imaging to monitor for residual AVM or recurrence

Intracranial Hemorrhage

Bleeding that occurs within the skull, either inside the brain tissue (intra-axial) or outside the brain tissue but within the skull (extra-axial).

Causes:

• Aneurysm
• Head trauma
• Chronic hypertension (HTN)
• Blood vessel abnormalities, including arteriovenous malformations (AVMs)
• Brain tumors
• Bleeding disorders

Classification:

Intra-axial Hemorrhage:

• Bleeding occurs within the brain itself; more dangerous and difficult to treat
  • Intraparenchymal Hemorrhage: Bleeding within the brain tissue
  • Intraventricular Hemorrhage: Bleeding within the brain’s ventricles

Extra-axial Hemorrhage:

• Bleeding occurs within the skull but outside the brain tissue
  • Epidural Hemorrhage: Bleeding between the dura mater and the skull; most commonly caused by trauma
  • Subdural Hemorrhage: Bleeding in the subdural space between the dura and arachnoid mater
  • Subarachnoid Hemorrhage: Bleeding between the arachnoid and pia mater; often caused by a ruptured cerebral aneurysm

Clinical Presentation:

• Key Presentation of Subarachnoid Hemorrhage (SAH):
  • Severe headache: “The Worst Headache of My Life!” (thunderclap headache)
  • Nausea and vomiting
  • Neck stiffness and photophobia
  • Altered mental status: Ranges from lethargy to coma
  • Seizures with no prior history
• Other Possible Symptoms Across Hemorrhage Types:
  • Weakness in an arm or leg
  • Tingling or numbness
  • Changes in vision
  • Difficulty speaking, understanding speech, or swallowing
  • Loss of coordination or balance
  • Loss of fine motor skills (e.g., hand tremors)
  • An abnormal sense of taste
  • Loss of consciousness

Labs, Studies, and Physical Exam Findings:

• Neurological Examination: Assess for focal deficits or altered mental status
• Eye Examination: May reveal bleeding in the optic nerve (papilledema)

Imaging:

• Non-contrast CT (gold standard):
  • Crescent-shaped hemorrhage: Suggests subdural hematoma
  • Biconcave hemorrhage: Suggests epidural hematoma
  • Hyperdensity in subarachnoid space: Indicates subarachnoid hemorrhage
• Angiography: Evaluates vascular abnormalities (e.g., aneurysms, AVMs)
• MRI with contrast / MRA: Used for further evaluation when CT is inconclusive
• Lumbar Puncture (SAH only):
  • Xanthochromia: Confirms SAH if CT is negative
  • Elevated opening pressure: Indicates increased intracranial pressure

Treatment:

• Goals:
  • Reduce intracranial pressure (ICP)
  • Proper blood pressure management to prevent rebleeding
• Medications:
  • Painkillers for symptom management
  • Corticosteroids to reduce swelling
  • Anti-seizure medications
  • Mannitol and hypertonic saline: To reduce ICP
• Neurosurgery:
  • Craniotomy: Removes clot and relieves pressure