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SCRN practice questions

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Question 1Anatomy, Physiology, and Pathophysiology of Stroke

Which vessel connects the anterior circulation to the posterior circulation in the Circle of Willis?

  1. Posterior communicating artery Correct answer.
  2. Ophthalmic artery
  3. Middle cerebral artery
  4. Anterior communicating artery

Explanation

The posterior communicating artery links the internal carotid artery to the posterior cerebral artery, joining the anterior and posterior circulations. The anterior communicating artery instead joins the two anterior cerebral arteries within the anterior circulation.

Question 2Anatomy, Physiology, and Pathophysiology of Stroke

Normal cerebral blood flow in gray matter is approximately:

  1. 300 mL/100 g/min
  2. 10 mL/100 g/min
  3. 150 mL/100 g/min
  4. 50 mL/100 g/min Correct answer.

Explanation

Gray matter normally receives about 50 mL/100 g/min, while white matter receives roughly 20 mL/100 g/min. Flow falls to symptomatic levels near 20 and to infarction near 10 mL/100 g/min.

Question 3Anatomy, Physiology, and Pathophysiology of Stroke

The most common site of hypertensive intracerebral hemorrhage is the:

  1. Frontal lobe
  2. Cerebellar hemisphere
  3. Basal ganglia Correct answer.
  4. Pons

Explanation

Hypertensive hemorrhage classically occurs in the putamen and other basal ganglia structures because small penetrating arteries there are exposed to high pressures. The thalamus, pons, and cerebellum follow in frequency.

Question 4Anatomy, Physiology, and Pathophysiology of Stroke

Ruptured berry aneurysms are most frequently located at the:

  1. Basilar artery tip
  2. Ophthalmic artery origin
  3. Anterior communicating artery Correct answer.
  4. Middle cerebral artery bifurcation

Explanation

The anterior communicating artery complex is the single most common site of berry aneurysms, followed by the middle cerebral bifurcation and the posterior communicating artery origin. Aneurysms arise at branch points where the vessel wall is weakest.

Question 5Anatomy, Physiology, and Pathophysiology of Stroke

The Monro-Kellie doctrine describes the fixed-volume relationship among which three intracranial compartments?

  1. Blood, cerebrospinal fluid, and bone
  2. Brain, blood, and cerebrospinal fluid Correct answer.
  3. Brain, cerebrospinal fluid, and extracellular fluid
  4. Brain, skull, and meninges

Explanation

The doctrine holds that brain parenchyma, intravascular blood, and cerebrospinal fluid share a rigid container, so an increase in one compartment must be offset by a decrease in another. Once compensation is exhausted, intracranial pressure rises.

Question 6Anatomy, Physiology, and Pathophysiology of Stroke

A patient has weakness of the right face and right arm with relative sparing of the right leg. The lesion most likely involves the:

  1. Left anterior cerebral artery
  2. Right posterior cerebral artery
  3. Right anterior cerebral artery
  4. Left middle cerebral artery Correct answer.

Explanation

The middle cerebral artery supplies the lateral convexity, including the motor cortex areas for the face and arm. The anterior cerebral artery supplies the medial cortex where the leg is represented.

Question 7Anatomy, Physiology, and Pathophysiology of Stroke

Infarction of the left anterior cerebral artery most typically produces weakness of the:

  1. Right face
  2. Left arm
  3. Right leg Correct answer.
  4. Left leg

Explanation

The anterior cerebral artery supplies the medial frontal and parietal cortex, which contains the motor representation of the contralateral leg. A left-sided lesion therefore weakens the right leg.

Question 8Anatomy, Physiology, and Pathophysiology of Stroke

A transient ischemic attack is best defined as:

  1. Transient dysfunction without tissue infarction Correct answer.
  2. Reversible brain injury visible on MRI
  3. Transient symptoms caused by seizure activity
  4. A stroke with complete recovery within 30 days

Explanation

The classic definition of transient ischemic attack is a brief episode of focal neurologic dysfunction caused by ischemia without permanent infarction. Modern imaging shows that some patients have small infarcts, but the defining feature remains absence of persistent tissue damage.

Question 9Anatomy, Physiology, and Pathophysiology of Stroke

Occlusion of the left posterior cerebral artery at its origin most commonly causes:

  1. Right hemiparesis
  2. Left hemineglect
  3. Left homonymous hemianopia
  4. Right homonymous hemianopia Correct answer.

Explanation

The posterior cerebral artery supplies the occipital cortex, so a left-sided occlusion produces a right homonymous hemianopia, often with macular sparing. Motor weakness and neglect are features of anterior circulation lesions.

Question 10Anatomy, Physiology, and Pathophysiology of Stroke

A patient with lateral medullary syndrome has loss of pain and temperature sensation on the right face and the left body. The lesion is located in the:

  1. Left medial medulla
  2. Right medial pons
  3. Right lateral medulla Correct answer.
  4. Left lateral pons

Explanation

Lateral medullary syndrome results from posterior inferior cerebellar artery or vertebral artery occlusion. The spinal trigeminal nucleus carries ipsilateral face sensation and the spinothalamic tract carries contralateral body sensation, placing the lesion on the side of the face symptoms.

Question 11Anatomy, Physiology, and Pathophysiology of Stroke

A patient is fully awake and aware but can move only the eyes vertically. This locked-in syndrome results from infarction of the:

  1. Cervical spinal cord
  2. Bilateral medial frontal lobes
  3. Ventral pons Correct answer.
  4. Midbrain tectum

Explanation

Infarction of the ventral pons interrupts the corticospinal and corticobulbar tracts while sparing the reticular activating system, leaving consciousness intact. Vertical eye movements persist because the midbrain oculomotor nuclei are spared.

Question 12Anatomy, Physiology, and Pathophysiology of Stroke

A small infarct of the internal capsule caused by lenticulostriate artery occlusion typically produces:

  1. Cortical sensory loss
  2. Global aphasia
  3. Pure motor hemiparesis Correct answer.
  4. Homonymous hemianopia

Explanation

Lenticulostriate perforators supply the internal capsule where the corticospinal tract is tightly packed, so a lacune there causes weakness without cortical signs. Cortical deficits such as aphasia, neglect, or hemianopia require larger cortical or visual pathway lesions.

Question 13Anatomy, Physiology, and Pathophysiology of Stroke

A patient who becomes profoundly hypotensive develops weakness that is most severe proximally in both arms. The most likely pattern is:

  1. Bilateral cerebellar infarction from vertebral disease
  2. Bilateral thalamic infarction from basilar occlusion
  3. Border-zone infarction between ACA and MCA Correct answer.
  4. Lacunar infarction in both lenticulostriate territories

Explanation

Watershed infarcts occur at the junctions between major arterial territories when systemic pressure falls, most often between the anterior and middle cerebral artery territories. Because the arm area lies at this junction, proximal arm weakness is characteristic.

Question 14Anatomy, Physiology, and Pathophysiology of Stroke

The ischemic penumbra is best described as:

  1. Edema surrounding a hematoma
  2. Brain tissue that is already irreversibly infarcted
  3. Hemorrhagic transformation of an infarct
  4. Hypoperfused but salvageable tissue Correct answer.

Explanation

Penumbral tissue is hypoperfused enough to lose function but retains enough flow to remain viable for a period. Restoring perfusion can rescue this tissue, which is the rationale for reperfusion therapy.

Question 15Anatomy, Physiology, and Pathophysiology of Stroke

In the ischemic cascade, excessive extracellular glutamate injures neurons primarily by:

  1. Direct blockade of sodium channels
  2. Calcium influx with protease activation Correct answer.
  3. Reduced nitric oxide production
  4. Rapid depletion of ATP stores

Explanation

Glutamate overactivates NMDA and AMPA receptors, allowing calcium to flood the cell. The calcium surge activates proteases, lipases, and endonucleases and stimulates nitric oxide synthase, leading to cell death.

Question 16Anatomy, Physiology, and Pathophysiology of Stroke

In a patient with chronic hypertension, the cerebral autoregulation curve is:

  1. Shifted right, with a higher lower limit Correct answer.
  2. Shifted left, with a lower lower limit
  3. Flat with no identifiable limits
  4. Unchanged from normotensive patients

Explanation

Chronic hypertension remodels cerebral arterioles so the autoregulatory range shifts toward higher pressures. Such patients tolerate high pressures better but are vulnerable to ischemia if pressure is lowered too quickly.

Question 17Anatomy, Physiology, and Pathophysiology of Stroke

Cerebral perfusion pressure is calculated as:

  1. Mean arterial pressure minus intracranial pressure Correct answer.
  2. Systolic pressure minus intracranial pressure
  3. Mean arterial pressure minus central venous pressure
  4. Intracranial pressure minus mean arterial pressure

Explanation

Cerebral perfusion pressure equals mean arterial pressure minus intracranial pressure, using central venous pressure instead when it is higher. It represents the pressure gradient driving blood flow to the brain.

Question 18Anatomy, Physiology, and Pathophysiology of Stroke

Cerebral amyloid angiopathy most characteristically causes:

  1. Subarachnoid hemorrhage from a berry aneurysm
  2. Recurrent lobar hemorrhages in older adults Correct answer.
  3. Bilateral thalamic infarction
  4. Deep hemispheric hemorrhage in young smokers

Explanation

Beta-amyloid deposition in cortical and leptomeningeal vessels makes them fragile, causing lobar hemorrhages that often recur in older patients. Deep hemorrhages are more typical of hypertension.

Question 19Anatomy, Physiology, and Pathophysiology of Stroke

Angiographic vasospasm after aneurysmal subarachnoid hemorrhage most often occurs:

  1. Between days 3 and 14 Correct answer.
  2. Between days 1 and 2
  3. After 4 weeks
  4. Within the first 6 hours

Explanation

Vasospasm usually begins around day 3, peaks between days 7 and 10, and resolves by about day 14. This timing drives the use of nimodipine and delayed ischemia monitoring.

Question 20Anatomy, Physiology, and Pathophysiology of Stroke

After a large middle cerebral artery infarct, maximal cerebral edema and herniation risk occur at approximately:

  1. 2 hours
  2. 24 hours
  3. 3 to 5 days Correct answer.
  4. 12 hours

Explanation

Cytotoxic edema begins early, but vasogenic edema and mass effect peak around 3 to 5 days after a large infarct. This is the period of greatest risk for midline shift and herniation.

Question 21Anatomy, Physiology, and Pathophysiology of Stroke

A single small deep infarct produces contralateral hemiplegia, hemianesthesia, and homonymous hemianopia. The affected vessel is most likely the:

  1. Anterior choroidal artery Correct answer.
  2. Recurrent artery of Heubner
  3. Posterior communicating artery
  4. Superior cerebellar artery

Explanation

The anterior choroidal artery supplies the posterior limb of the internal capsule, the optic tract and lateral geniculate body, and part of the medial temporal lobe. Occlusion therefore combines motor, sensory, and visual pathway deficits in one small deep territory.

Question 22Anatomy, Physiology, and Pathophysiology of Stroke

A patient has sudden coma, bilateral thalamic infarction, and vertical gaze palsy. This top of the basilar syndrome is caused by occlusion of the:

  1. Distal basilar artery Correct answer.
  2. Proximal vertebral arteries
  3. Both posterior inferior cerebellar arteries
  4. Left internal carotid artery

Explanation

Distal basilar occlusion at the posterior cerebral artery bifurcation infarcts the rostral midbrain and both thalami. The result is impaired consciousness, vertical gaze abnormalities, and often pupillary and oculomotor signs.

Question 23Anatomy, Physiology, and Pathophysiology of Stroke

Hemorrhagic transformation of an ischemic infarct is most strongly associated with:

  1. Large infarct with reperfusion Correct answer.
  2. Small lacunar infarcts
  3. Hypotension during the hospital stay
  4. A previous transient ischemic attack

Explanation

Large infarcts injure the blood-brain barrier over a wide area, and reperfusion of that damaged tissue allows blood to extravasate. Anticoagulation and thrombolysis further increase this risk.

Question 24Anatomy, Physiology, and Pathophysiology of Stroke

The cerebral blood flow threshold below which tissue becomes irreversibly infarcted, forming the ischemic core, is approximately:

  1. 15 mL/100 g/min
  2. 10 mL/100 g/min Correct answer.
  3. 30 mL/100 g/min
  4. 20 mL/100 g/min

Explanation

Neurons lose function at about 20 mL/100 g/min but remain viable in the penumbra until flow falls near 10 mL/100 g/min, when membrane failure and infarction occur. The core is therefore defined by flow at or below roughly 10 mL/100 g/min.

Question 25Anatomy, Physiology, and Pathophysiology of Stroke

A patient with a cerebellar infarct becomes drowsy with irregular respirations. The most urgent concern is:

  1. Extension of the infarct into the occipital lobe
  2. Hemorrhagic transformation of the cerebellum
  3. Bilateral leg weakness from pyramidal involvement
  4. Cerebellar swelling compressing the brainstem Correct answer.

Explanation

The posterior fossa is a rigid compartment, so cerebellar edema can obstruct the fourth ventricle and compress the brainstem, causing hydrocephalus and respiratory depression. Urgent decompression may be required.

Question 26Anatomy, Physiology, and Pathophysiology of Stroke

Saccular (berry) aneurysms of the circle of Willis most commonly arise at which location?

  1. Midportion of the basilar artery trunk
  2. Junction of the anterior communicating and anterior cerebral arteries Correct answer.
  3. Intracavernous segment of the internal carotid artery
  4. Origin of the posterior inferior cerebellar artery

Explanation

Saccular aneurysms arise at arterial branch points where the media is deficient, and the anterior communicating complex is the single most frequent site, followed by the middle cerebral bifurcation and the posterior communicating artery origin. This distribution explains why ruptured berry aneurysms typically produce blood in the basal cisterns and interhemispheric fissure.

Question 27Anatomy, Physiology, and Pathophysiology of Stroke

In a patient with long-standing hypertension, spontaneous intracerebral hemorrhage most characteristically occurs in which location?

  1. Midbrain tegmentum
  2. Putamen and adjacent basal ganglia Correct answer.
  3. Frontal lobe white matter
  4. Cerebellar hemisphere

Explanation

Chronic hypertension produces lipohyalinosis and Charcot-Bouchard microaneurysms in small deep perforating arteries such as the lenticulostriates, so the putamen and basal ganglia account for roughly half of hypertensive hemorrhages. The thalamus, pons, and cerebellum follow in frequency.

Question 28Anatomy, Physiology, and Pathophysiology of Stroke

A patient develops sudden numbness of the right face, arm, and leg with no weakness, and imaging shows a small left thalamic infarct. Which vessel is most likely occluded?

  1. Left thalamogeniculate arteries Correct answer.
  2. Left recurrent artery of Heubner
  3. Left anterior choroidal artery
  4. Left lenticulostriate arteries

Explanation

A pure sensory stroke from a thalamic lacune reflects damage to the ventral posterolateral nucleus, which is supplied by the thalamogeniculate arteries arising from the P2 segment of the posterior cerebral artery. Occlusion of these small perforators removes sensory input to the thalamus without involving motor pathways.

Question 29Anatomy, Physiology, and Pathophysiology of Stroke

A woman in the first week postpartum develops worsening headache followed by weakness that is greater in both legs than in the arms, and imaging shows bilateral parasagittal hemorrhagic infarcts. Which vascular structure is most likely thrombosed?

  1. Superior sagittal sinus Correct answer.
  2. Straight sinus
  3. Cavernous sinus
  4. Transverse sinus

Explanation

The superior sagittal sinus drains the parasagittal cortex, where the leg motor representation sits on the medial hemispheric surface, so thrombosis produces bilateral leg-predominant venous infarction that is frequently hemorrhagic. Pregnancy and the puerperium are classic hypercoagulable triggers.

Question 30Anatomy, Physiology, and Pathophysiology of Stroke

A 35-year-old develops sudden neck pain, a drooping right eyelid with a small pupil, and transient loss of vision in the right eye. Which diagnosis best explains these findings?

  1. Giant cell arteritis
  2. Right posterior communicating artery aneurysm
  3. Right vertebral artery dissection
  4. Right internal carotid artery dissection Correct answer.

Explanation

An intimal tear in the cervical internal carotid artery stretches the perivascular sympathetic fibers to produce a painful ipsilateral Horner syndrome, and emboli from the dissection site reach the ophthalmic artery to cause transient monocular visual loss. Neck pain in a young adult after minor trauma is the typical clue.

Question 31Anatomy, Physiology, and Pathophysiology of Stroke

Which neuronal populations are most vulnerable to injury after global cerebral ischemia from cardiac arrest?

  1. Oligodendrocytes of the corpus callosum
  2. Spinal motor neurons and dorsal root ganglion cells
  3. Astrocytes of the brainstem
  4. Hippocampal CA1 and cerebellar Purkinje cells Correct answer.

Explanation

Neurons with the highest metabolic demand and the densest glutamate receptor expression, notably CA1 pyramidal cells of the hippocampus and Purkinje cells of the cerebellum, die first after global ischemia. This selective vulnerability underlies the memory and coordination deficits that follow cardiac arrest.

Question 32Anatomy, Physiology, and Pathophysiology of Stroke

In the first hour after an acute ischemic stroke, the predominant mechanism of tissue swelling is movement of water into cells driven by which process?

  1. Venous congestion from impaired cerebral outflow
  2. Failure of the sodium-potassium pump with cellular swelling Correct answer.
  3. Obstruction of cerebrospinal fluid outflow at the arachnoid granulations
  4. Leakage of plasma proteins across a disrupted blood-brain barrier

Explanation

Loss of ATP during ischemia stops the Na+/K+ ATPase, so sodium accumulates intracellularly and water follows, producing cytotoxic edema within minutes to hours. Vasogenic edema from blood-brain barrier breakdown appears later and peaks over days.

Question 33Anatomy, Physiology, and Pathophysiology of Stroke

Three days after carotid endarterectomy for a 90% stenosis, a patient has an ipsilateral throbbing headache, confusion, and a seizure, with blood pressure 190/100 and CT showing edema without a new infarct. Which mechanism best explains this picture?

  1. Contrast-induced disruption of the blood-brain barrier
  2. Vasospasm of the intracranial arteries
  3. Failure of autoregulation in chronically hypoperfused tissue Correct answer.
  4. Thrombosis of the endarterectomized internal carotid artery

Explanation

In chronic severe stenosis the distal arterioles are maximally dilated to preserve flow, so autoregulatory reserve is exhausted; restoring normal perfusion pressure then delivers excessive flow, causing headache, seizures, and edema that may progress to hemorrhage. Tight postoperative blood pressure control is the key preventive measure.

Question 34Anatomy, Physiology, and Pathophysiology of Stroke

A patient has a right third-nerve palsy with a dilated, nonreactive pupil and left-sided hemiparesis. The infarct most likely involves which structure?

  1. Right lateral medulla
  2. Left posterior limb of the internal capsule
  3. Right midbrain cerebral peduncle Correct answer.
  4. Right pons at the level of the abducens nucleus

Explanation

Fascicles of the third nerve and the corticospinal tract travel together in the cerebral peduncle, so a midbrain infarct there causes an ipsilateral pupil-involving oculomotor palsy with contralateral hemiparesis, known as Weber syndrome. The responsible vessel is typically a paramedian branch of the posterior cerebral artery or basilar tip.

Question 35Stroke Assessment and Diagnosis

Which stroke subtype accounts for the majority of all strokes?

  1. Ischemic stroke Correct answer.
  2. Subarachnoid hemorrhage
  3. Intracerebral hemorrhage
  4. Cerebral venous sinus thrombosis

Explanation

Ischemic stroke results from arterial occlusion and accounts for roughly 87% of all strokes. Hemorrhagic strokes, including intracerebral and subarachnoid hemorrhage, make up the minority. Cerebral venous sinus thrombosis is a rare cause.

Question 36Stroke Assessment and Diagnosis

What is the maximum possible score on the NIHSS?

  1. 24
  2. 42 Correct answer.
  3. 31
  4. 15

Explanation

The NIHSS contains 15 items, and the highest possible total score is 42. Higher scores indicate greater neurologic deficit and often more severe stroke. A score of 0 indicates no measurable deficit.

Question 37Stroke Assessment and Diagnosis

Which imaging study is typically obtained first in the emergency department to distinguish ischemic stroke from intracranial hemorrhage?

  1. CT angiography
  2. Carotid duplex ultrasound
  3. MRI with gadolinium
  4. Noncontrast head CT Correct answer.

Explanation

Noncontrast head CT is fast and widely available and reliably identifies acute intracranial hemorrhage. It helps determine eligibility for reperfusion therapy. CT angiography and MRI may provide additional vascular or tissue information afterward.

Question 38Stroke Assessment and Diagnosis

Intravenous alteplase for acute ischemic stroke is generally administered within what time window from symptom onset in eligible patients?

  1. 6 hours
  2. 24 hours
  3. 12 hours
  4. 4.5 hours Correct answer.

Explanation

The standard approved window for intravenous alteplase in eligible patients is up to 4.5 hours from symptom onset. Selected patients may be considered for other reperfusion strategies beyond that window. Time is brain, so rapid evaluation is essential.

Question 39Stroke Assessment and Diagnosis

Which factor is the most common cause of spontaneous intracerebral hemorrhage?

  1. Hypertension Correct answer.
  2. Arteriovenous malformation
  3. Anticoagulant use
  4. Cerebral amyloid angiopathy

Explanation

Chronic hypertension causes small-vessel changes that predispose to spontaneous intracerebral hemorrhage, especially in the basal ganglia, thalamus, pons, and cerebellum. Cerebral amyloid angiopathy is an important cause in older adults but is less common overall. Anticoagulation and vascular malformations account for a smaller proportion.

Question 40Stroke Assessment and Diagnosis

A patient has sudden right-sided weakness and expressive aphasia. Which vascular territory is most likely involved?

  1. Right middle cerebral artery
  2. Right anterior cerebral artery
  3. Left middle cerebral artery Correct answer.
  4. Left posterior cerebral artery

Explanation

The left middle cerebral artery supplies the left frontal and parietal regions, including Broca area and the motor cortex controlling the right face and arm. Expressive aphasia with right hemiparesis is therefore a classic left MCA syndrome. The posterior cerebral artery primarily affects vision and memory.

Question 41Stroke Assessment and Diagnosis

Which bedside test is essential in every patient with suspected acute stroke because hypoglycemia can mimic stroke?

  1. Urine drug screen
  2. Blood glucose Correct answer.
  3. Lumbar puncture
  4. Serum magnesium level

Explanation

Hypoglycemia can cause focal neurologic deficits that resemble stroke and must be corrected immediately. Bedside blood glucose testing is therefore part of the initial assessment for every suspected stroke. Other laboratory tests may be obtained but do not replace glucose measurement.

Question 42Stroke Assessment and Diagnosis

During NIHSS motor arm testing, the patient's right arm holds at 90 degrees briefly, then drifts downward but does not hit the bed. What score is assigned to the right arm?

  1. 1 Correct answer.
  2. 3
  3. 0
  4. 2

Explanation

A score of 1 is assigned when the arm drifts downward but does not hit the bed within the 10-second test period. A score of 0 indicates no drift. Higher scores indicate greater weakness, such as inability to hold the arm against gravity or no movement.

Question 43Stroke Assessment and Diagnosis

A 68-year-old with diabetes has a 30-minute episode of unilateral arm weakness and a blood pressure of 160/95 mm Hg. Using the ABCD2 score, what is the total?

  1. 6 Correct answer.
  2. 4
  3. 7
  4. 5

Explanation

ABCD2 assigns 1 point for age 60 years or older, 1 for blood pressure at least 140/90 mm Hg, 2 for unilateral weakness, 1 for duration of 10 to 59 minutes, and 1 for diabetes. This patient scores 1 + 1 + 2 + 1 + 1, for a total of 6. Higher scores indicate greater short-term stroke risk after TIA.

Question 44Stroke Assessment and Diagnosis

Which of the following is one of the five TOAST etiologic subtypes of ischemic stroke?

  1. Hemorrhagic transformation
  2. Small-vessel occlusion Correct answer.
  3. Lacunar syndrome
  4. Watershed infarction

Explanation

The TOAST classification includes large-artery atherosclerosis, cardioembolism, small-vessel occlusion, stroke of other determined etiology, and stroke of undetermined etiology. Small-vessel occlusion is therefore a recognized TOAST subtype. Watershed infarction and lacunar syndrome describe mechanisms or clinical patterns rather than TOAST categories.

Question 45Stroke Assessment and Diagnosis

A patient has pure motor hemiparesis without cortical signs. Which location most commonly produces this lacunar syndrome?

  1. Cerebellar hemisphere
  2. Occipital lobe
  3. Internal capsule Correct answer.
  4. Cerebral cortex

Explanation

Pure motor lacunar syndromes are commonly caused by small infarcts in the internal capsule, corona radiata, or basis pontis. The internal capsule carries descending motor fibers in a compact area, so a small lesion can produce marked hemiparesis without cortical signs. Cortical involvement would more often cause aphasia, neglect, or visual field deficits.

Question 46Stroke Assessment and Diagnosis

Bilateral weakness and cortical blindness after prolonged hypotension most likely reflect which process?

  1. Cardioembolic occlusion of a single MCA
  2. Lacunar infarction of the thalamus
  3. Cerebellar hemorrhage
  4. Border-zone infarction Correct answer.

Explanation

Severe hypotension can cause hypoperfusion in the distal regions between major arterial territories, producing border-zone or watershed infarcts. Bilateral border-zone injury can affect the motor cortex and occipital regions, causing weakness and cortical blindness. Single-vessel embolic occlusion usually affects one territory rather than multiple border zones.

Question 47Stroke Assessment and Diagnosis

A patient reports a sudden severe thunderclap headache. Noncontrast CT is negative. What is the most appropriate next step to evaluate for subarachnoid hemorrhage?

  1. Intravenous alteplase
  2. Lumbar puncture Correct answer.
  3. Carotid duplex ultrasound
  4. Reassurance and discharge

Explanation

When subarachnoid hemorrhage is suspected but noncontrast CT is negative, lumbar puncture is performed to assess for xanthochromia. Xanthochromia reflects breakdown of red blood cells in the cerebrospinal fluid. Discharging the patient without further evaluation risks missing a sentinel hemorrhage.

Question 48Stroke Assessment and Diagnosis

Which condition is a recognized risk factor for cerebral venous sinus thrombosis?

  1. Long-standing atrial fibrillation
  2. Pregnancy and postpartum state Correct answer.
  3. Recent uncomplicated viral rhinitis
  4. Well-controlled type 2 diabetes

Explanation

Pregnancy and the postpartum period are well-recognized hypercoagulable states associated with cerebral venous sinus thrombosis. Other risk factors include oral contraceptive use, thrombophilia, dehydration, and adjacent infection. Atrial fibrillation predisposes mainly to arterial cardioembolic stroke.

Question 49Stroke Assessment and Diagnosis

Which feature most strongly suggests a stroke mimic rather than acute ischemic stroke?

  1. Abrupt onset of focal deficit
  2. Maximal deficit at onset
  3. Expressive aphasia
  4. Postictal confusion Correct answer.

Explanation

Postictal confusion after a seizure suggests a mimic such as Todd paresis or prolonged postictal deficits. Acute ischemic stroke typically presents with sudden focal neurologic deficits that are maximal at onset. Aphasia and abrupt onset are common in true stroke.

Question 50Stroke Assessment and Diagnosis

The hyperdense middle cerebral artery sign on noncontrast CT indicates:

  1. Old infarction of the MCA territory
  2. Acute thrombus in the MCA Correct answer.
  3. A patent MCA with high flow
  4. Hemorrhagic transformation

Explanation

A hyperdense MCA sign reflects acute thrombus within the artery and is an early sign of large-vessel occlusion. It appears before frank infarction is visible on noncontrast CT. Old infarction would typically appear as hypodensity or volume loss.