Hard Multiple Choice Questions on Regional Brain Syndromes Relevant to Neurosurgery
Question 1: Posterior Circulation Stroke Presentation
A 62-year-old patient presents to the emergency department with acute onset vertigo, diplopia, and ataxia. MRI reveals an acute infarct in the territory of the posterior inferior cerebellar artery (PICA). Which of the following management steps should be prioritized FIRST?
A) Obtain carotid duplex ultrasonography B) Initiate aspirin 160-300 mg within 48 hours (after excluding hemorrhage on CT) C) Perform immediate CT head without contrast followed by vascular imaging with CTA or MRA D) Schedule outpatient neurology follow-up within 2 weeks E) Start physical therapy for ataxia
Correct Answer: C
Explanation: Patients presenting with symptoms suggestive of posterior circulation ischemia (vertigo, diplopia, ataxia) require immediate neuroimaging with CT head without contrast to exclude hemorrhage, followed by vascular imaging with CTA or contrast-enhanced MRA to evaluate for vertebrobasilar stenosis or occlusion 1, 2. High-grade stenosis of the inferior cerebellar arteries represents a vascular emergency with high risk of recurrent stroke 2. The American Heart Association guidelines emphasize that symptoms associated with vertebral artery and inferior cerebellar artery disease include dizziness, vertigo, diplopia, ataxia, and bilateral sensory deficits 2. CTA or contrast-enhanced MRA have higher sensitivity and specificity than ultrasonography for vertebral artery stenosis 2. While aspirin should be initiated within 48 hours for ischemic stroke 1, the immediate priority is diagnostic imaging to confirm the diagnosis and assess vascular anatomy. Delaying evaluation of these symptoms in the setting of suspected vascular stenosis can lead to preventable strokes 2.
Question 2: Guillain-Barré Syndrome Recognition
A 45-year-old woman presents with 5 days of progressive bilateral leg weakness that has now ascended to involve her arms. She reports a respiratory infection 3 weeks ago. On examination, she has areflexia in all extremities and distal paresthesias. Which of the following is the MOST appropriate initial management?
A) Discharge home with outpatient neurology referral B) Admit for monitoring with assessment of respiratory function and consideration of IVIG or plasma exchange C) Start high-dose corticosteroids D) Obtain lumbar puncture before any other intervention E) Wait 2 more weeks to see if symptoms progress further
Correct Answer: B
Explanation: This patient presents with classic Guillain-Barré syndrome (GBS): rapidly progressive bilateral ascending weakness, areflexia, distal paresthesias, and preceding infection within 6 weeks 3, 4. The American Academy of Neurology emphasizes that GBS is characterized by rapidly progressive bilateral weakness typically starting in the legs and ascending to the arms and cranial muscles, accompanied by decreased or absent reflexes 4. Patients typically reach maximum disability within 2 weeks 3, 4. Immediate admission is required because respiratory failure develops in approximately 20% of patients with GBS 4. Treatment options include intravenous immunoglobulin (0.4 g/kg daily for 5 days) or plasma exchange (200-250 ml/kg for 5 sessions) 3. Mortality is estimated at 3-10% even with best medical care 4. Corticosteroids are not indicated for GBS 3. While lumbar puncture can support the diagnosis (showing albuminocytologic dissociation), treatment should not be delayed for this test 3. The monophasic clinical course with acute or subacute onset distinguishes GBS from other neuropathies 3, 4.
Question 3: Brain Metastases Management
A 58-year-old man with non-small cell lung cancer presents with headache and mild right-sided weakness. MRI brain reveals 2 brain metastases: one 4 cm left frontal lesion with significant surrounding edema and one 1 cm right parietal lesion. What is the MOST appropriate initial treatment approach?
A) Whole brain radiation therapy (WBRT) alone B) Stereotactic radiosurgery (SRS) alone for both lesions C) Surgical resection of the large frontal lesion followed by individualized radiotherapy D) Chemotherapy with temozolomide E) Observation with repeat MRI in 3 months
Correct Answer: C
Explanation: Patients with significant brain edema, neurologic symptoms, or large space-occupying brain metastases (>3 cm) should undergo surgical resection if they are surgical candidates 3. This patient has a 4 cm lesion with significant edema causing neurologic symptoms (right-sided weakness), making him an ideal surgical candidate 3. The American College of Chest Physicians guidelines specifically recommend neurosurgical evaluation for patients with significant edema, neurologic symptoms, large metastasis (>3 cm), or resectable solitary lesions 3. After gross total resection with no evidence of residual intracranial disease, patients can be observed, with radiotherapy tailored to individual needs 3. For the smaller 1 cm parietal lesion, SRS can be considered as adjuvant therapy 3. SRS alone is recommended for patients with 1-3 brain metastases who do NOT have large lesions or significant mass effect 3. WBRT is reserved for patients with 5 or more brain metastases 3. The benefit of delaying WBRT in patients with low burden disease outweighs potential risks, but this patient's large symptomatic lesion requires surgical intervention first 3.
Question 4: Altered Mental Status Imaging
A 72-year-old woman presents to the ED with acute confusion and disorientation that started 6 hours ago. She has no focal neurologic deficits on examination. Vital signs show temperature 38.5°C, BP 165/95 mmHg. Which imaging study should be obtained FIRST?
A) MRI brain without contrast B) CT head without contrast C) CT head with contrast D) MRI brain with and without contrast E) No imaging needed; treat as urinary tract infection
Correct Answer: B
Explanation: For patients presenting with altered mental status (AMS) and suspected intracranial pathology, CT head without contrast is recommended as the initial imaging modality 3. The American College of Radiology emphasizes that identifying patients with AMS or delirium secondary to acute intracranial pathology is extremely important to guide management and ensure early appropriate triage 3. CT head without contrast can demonstrate treatable structural lesions such as subdural hematomas, intracranial hemorrhage, or mass lesions that may result in clinical symptoms 3. In a large study of over 708,145 adult ED encounters, CT head examinations performed for AMS had a critical result yield of 9.8% 3. While MRI provides superior detail for many conditions, CT is faster, more readily available, and does not require the same level of patient cooperation—critical factors in confused patients 3. This patient has fever and hypertension, which could indicate infection or intracranial hemorrhage 3. Lower Glasgow Coma Scale, presence of lateralizing signs, and higher systolic blood pressure are significantly associated with abnormal brain imaging 3. Once hemorrhage is excluded, further evaluation for infection, metabolic derangements, or other causes of delirium can proceed 3.
Question 5: Alzheimer's Disease Atypical Presentation
A 54-year-old right-handed woman presents with 18 months of progressive difficulty with visual-spatial tasks, getting lost in familiar places, and difficulty reading, but relatively preserved memory. Neuropsychological testing confirms posterior cortical dysfunction. Which imaging study provides the HIGHEST diagnostic accuracy for confirming Alzheimer's disease pathology in this atypical presentation?
A) MRI brain without contrast showing hippocampal atrophy B) CT head without contrast C) Brain amyloid PET/CT D) Brain perfusion SPECT E) MR spectroscopy
Correct Answer: C
Explanation: Brain amyloid PET/CT has the highest sensitivity for diagnosing Alzheimer's disease (AD) and is particularly useful in patients with atypical presentations who are less likely to manifest typical atrophy patterns on MRI 3. The American College of Radiology states that brain amyloid PET/CT has higher sensitivity than brain MRI and brain FDG-PET/CT for the diagnosis of AD 3. The Society of Nuclear Medicine and Molecular Imaging's 2024 Appropriate Use Criteria specifically state that brain amyloid PET/CT is appropriate in patients presenting with MCI or dementia that could be consistent with AD pathology but has atypical features such as a nonamnestic clinical presentation 3. This patient has posterior cortical atrophy (PCA) variant of AD, characterized by visual-spatial dysfunction with relatively preserved memory—a classic atypical presentation 3. Patients undergoing brain amyloid PET/CT require fewer follow-up imaging studies and are more likely to benefit from definitive diagnosis, especially young patients and those with atypical presentations 3. While MRI can show regional atrophy patterns and FDG-PET/CT can show hypometabolism in the parieto-temporo-occipital cortex characteristic of PCA 3, amyloid PET/CT directly demonstrates AD pathology with sensitivity up to 96% and specificity up to 100% 3.
Question 6: Spontaneous Intracranial Hypotension
A 38-year-old woman presents with severe orthostatic headache that began 2 weeks ago after a yoga class. The headache is dramatically worse when upright and improves when lying flat. She is unable to care for herself without assistance. Brain MRI shows diffuse pachymeningeal enhancement and brain sagging. What is the MOST appropriate next step in management?
A) Discharge with oral analgesics and outpatient neurology follow-up in 4 weeks B) Urgent referral (within 48 hours) to neurology with access to epidural blood patch expertise C) Immediate lumbar puncture to measure opening pressure D) Start high-dose corticosteroids E) Refer to psychiatry for conversion disorder
Correct Answer: B
Explanation: Patients with suspected spontaneous intracranial hypotension (SIH) who are not able to care for themselves but have help should be referred urgently within 48 hours to a neurologist with access to practitioners skilled in performing epidural blood patches (EBPs) 3. This patient has classic SIH: orthostatic headache (provoked by posture rather than movement), brain MRI showing pachymeningeal enhancement and brain sagging, and significant functional impairment 3. The multidisciplinary consensus guideline from the Journal of Neurology, Neurosurgery and Psychiatry provides specific referral urgency criteria: if the patient can care for themselves, referral should be within 2-4 weeks; if unable to care for themselves but has help, within 48 hours; if unable to care for themselves without help, emergency admission 3. Early referral to a specialist center is indicated if first-line treatments fail or there is rapid clinical deterioration 3. A specialist neuroscience center should have neuroradiological investigations (CT myelography and/or digital subtraction myelography), practitioners skilled in epidural blood patching, expertise in targeted patching, and surgical expertise to repair spinal CSF leaks 3. Lumbar puncture would worsen the CSF leak and is contraindicated 3. The presence of normal brain and spine MRI does not rule out SIH, though this patient has classic findings 3.
Question 7: Carotid Territory TIA Workup
A 68-year-old man with hypertension presents with 20 minutes of right arm weakness and aphasia that completely resolved 2 hours ago. He is now neurologically normal. What is the MOST appropriate initial diagnostic imaging study?
A) Carotid duplex ultrasonography B) Transthoracic echocardiography C) CT angiography of head and neck D) Conventional catheter angiography E) MRI brain with diffusion-weighted imaging
Correct Answer: A
Explanation: Duplex ultrasonography is recommended to detect carotid stenosis in patients who develop focal neurological symptoms corresponding to the territory supplied by the left or right internal carotid artery 3. This patient had a left hemispheric transient ischemic attack (TIA) with right arm weakness and aphasia, indicating left carotid territory ischemia 3. The American Heart Association/American College of Cardiology guidelines state that the initial evaluation of patients with transient retinal or hemispheric neurological symptoms of possible ischemic origin should include noninvasive imaging for detection of extracranial carotid and vertebral artery disease 3. TIA is an important predictor of stroke; the risk is highest in the first week, as high as 13% in the first 90 days after the initial event 3, 1. Early recognition and risk stratification are critical stroke prevention measures 3. Duplex ultrasonography is the appropriate first-line test because it is noninvasive, widely available, and highly accurate for detecting carotid stenosis 3. If ultrasonography cannot be obtained or yields equivocal results, MRA or CTA should be performed 3. The benefit of carotid endarterectomy in preventing stroke is greatly diminished beyond 2 weeks after symptom onset, making urgent evaluation essential 3. Echocardiography should be performed when extracranial or intracranial cerebrovascular disease is not severe enough to account for symptoms, to search for cardioembolic sources 3.
Question 8: Complex Regional Pain Syndrome with Brain Involvement
A 54-year-old man develops burning pain, swelling, and vasomotor changes in his right hand 2 months after a fall with head trauma. Brain MRI at the time of injury was normal. Three-phase bone scan shows increased uptake in the right wrist. What additional neuroimaging finding would BEST explain the development of CRPS in this patient?
A) Hippocampal atrophy on volumetric MRI B) Traumatic axonal injury of the left corticospinal tract on diffusion tensor tractography C) Increased perfusion in the motor cortex on arterial spin labeling D) Pachymeningeal enhancement suggesting CSF leak E) Periventricular white matter lesions suggesting demyelination
Correct Answer: B
Explanation: Traumatic axonal injury of the corticospinal tract (CST) contralateral to the affected limb can be demonstrated on diffusion tensor tractography (DTT) in patients who develop CRPS following mild traumatic brain injury 5. A case report in Diagnostics documented a patient with identical presentation: direct head trauma from a fall, development of CRPS symptoms (burning pain, swelling, vasodilation, skin temperature asymmetries, motor weakness) in the right hand 2 months after injury, normal conventional brain MRI, positive three-phase bone scan, and DTT showing partial tearing of the left CST at the subcortical white matter with significantly decreased fiber number 5. The CRPS appeared to be related to traumatic axonal injury of the left CST following mild traumatic brain injury 5. This demonstrates that conventional MRI may appear normal while DTT can reveal microstructural white matter injury affecting the CST 5. Brain plasticity changes in CRPS include structural and functional alterations in areas associated with spatial body perception, somatosensory cortex, motor cortex, and pain processing 6, 7. At early stages of CRPS, patients show reduced gray matter volume and perfusion in somatosensory cortex and limbic system, while late-stage patients exhibit increased perfusion in motor cortex 6. Understanding the central nervous system involvement in CRPS is important for treatment planning 6.
Question 9: Multiple Sclerosis Initial Presentation
A 34-year-old woman presents with 5 days of numbness isolated to the left side of her chin and lower lip. Brain MRI shows a lesion involving the pontine trigeminal fibers and multiple periventricular T2-hyperintense white matter lesions. CSF analysis reveals oligoclonal IgG bands (CSF only) and elevated IgG index. What is the MOST appropriate management?
A) Reassure and discharge without treatment B) Start prophylactic interferon-beta therapy C) High-dose IV methylprednisolone for acute relapse only D) Obtain follow-up MRI in 4 months to assess for new lesions before starting treatment E) Refer to maxillofacial surgery for chin numbness
Correct Answer: D
Explanation: In patients presenting with a clinically isolated syndrome (CIS) suggestive of multiple sclerosis, prophylactic immunomodulatory treatment should be started after the suspicion of inflammatory/demyelinating activity is confirmed with follow-up imaging demonstrating dissemination in time 8. This patient has "numb chin syndrome" as the initial presentation of CIS suggestive of MS 8. The case report in Deutsche Medizinische Wochenschrift documented an identical patient: 34-year-old woman with subacute onset numb chin, brain MRI showing pontine trigeminal fiber lesion and multiple periventricular T2-hyperintense white matter lesions, CSF with oligoclonal IgG bands and elevated IgG index 8. Follow-up MRI after 4 months demonstrated new supratentorial brain lesions, confirming a syndrome highly suggestive of MS, after which prophylactic treatment with interferon-beta was started 8. The facial sensory disturbance resolved spontaneously 8. This approach follows the principle of confirming dissemination in time (new lesions on follow-up MRI) before initiating disease-modifying therapy 8. Research shows that lesion location characteristics, particularly in the corona radiata, optic radiation, and splenium of the corpus callosum, are associated with progression from CIS to clinically definite MS after long-term follow-up 9. Starting treatment immediately without confirming dissemination in time would be premature, while waiting indefinitely without follow-up imaging would miss the opportunity for early intervention 8.
Question 10: Dementia Evaluation with Atypical Features
A 62-year-old man presents with 2 years of progressive cognitive decline, prominent visual hallucinations, parkinsonism, and fluctuating cognition. MRI brain shows mild generalized atrophy. Which imaging study would BEST distinguish between Alzheimer's disease and dementia with Lewy bodies in this patient?
A) Brain FDG-PET/CT showing temporoparietal hypometabolism B) Brain striatal SPECT or SPECT/CT showing abnormal striatal uptake C) MR spectroscopy showing decreased NAA/Cr ratio in posterior cingulate D) Brain amyloid PET/CT showing diffuse cortical uptake E) Brain perfusion SPECT showing bilateral posterior hypoperfusion
Correct Answer: B
Explanation: A normal pattern of radiotracer uptake in the striatum on brain striatal SPECT or SPECT/CT can help distinguish patients with Alzheimer's disease from those with dementia with Lewy bodies (DLB); abnormal striatal uptake indicates DLB or coexistent AD in patients with suspected DLB 3. This patient has classic features of DLB: visual hallucinations, parkinsonism, and fluctuating cognition 3. The American College of Radiology guidelines emphasize that brain striatal SPECT or SPECT/CT is specifically useful for this differential diagnosis 3. DLB is characterized by dopaminergic neuronal loss in the substantia nigra, which results in decreased striatal dopamine transporter uptake on SPECT imaging 3. While brain FDG-PET/CT can show patterns of hypometabolism that differ between AD and DLB (with DLB showing hypometabolism in the association visual cortex while sparing the posterior cingulate gyrus, the "cingulate island sign") 3, striatal SPECT directly assesses the dopaminergic system pathology that is the hallmark of DLB 3. Brain amyloid PET/CT would not distinguish between AD and DLB, as both conditions can have amyloid deposition 3. Brain perfusion SPECT showing bilateral posterior hypoperfusion is more characteristic of AD than DLB 3. The presence of abnormal striatal uptake on SPECT has high specificity for distinguishing DLB from AD 3.