Arteriovenous malformation treatment US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Arteriovenous malformation treatment. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Arteriovenous malformation treatment US Medical PG Question 1: A 72-year-old woman comes to the physician for follow-up care. One year ago, she was diagnosed with a 3.8-cm infrarenal aortic aneurysm found incidentally on abdominal ultrasound. She has no complaints. She has hypertension, type 2 diabetes mellitus, and COPD. Current medications include hydrochlorothiazide, lisinopril, glyburide, and an albuterol inhaler. She has smoked a pack of cigarettes daily for 45 years. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 12/min, and blood pressure is 145/85 mm Hg. Examination shows a faint abdominal bruit on auscultation. Ultrasonography of the abdomen shows a 4.9-cm saccular dilation of the infrarenal aorta. Which of the following is the most appropriate next step in management?
- A. Elective endovascular aneurysm repair (Correct Answer)
- B. Adjustment of cardiovascular risk factors and follow-up ultrasound in 12 months
- C. Adjustment of cardiovascular risk factors and follow-up ultrasound in 6 months
- D. Elective open aneurysm repair
- E. Adjustment of cardiovascular risk factors and follow-up CT in 6 months
Arteriovenous malformation treatment Explanation: ***Elective endovascular aneurysm repair***
- The patient's **infrarenal aortic aneurysm** has grown from 3.8 cm to 4.9 cm in one year, approaching the **5.0 cm threshold for intervention in women** (compared to 5.5 cm for men). The **rapid growth rate of 1.1 cm/year** (normal is <0.5 cm/year) significantly increases rupture risk and is an indication for intervention even before reaching the absolute size threshold.
- Given her multiple comorbidities (hypertension, diabetes, COPD, 45 pack-year smoking history), **endovascular aneurysm repair (EVAR)** is preferred over open repair due to lower perioperative morbidity and mortality in high-risk surgical candidates.
- The combination of near-threshold size and rapid growth makes elective repair appropriate now rather than continued surveillance.
*Adjustment of cardiovascular risk factors and follow-up ultrasound in 12 months*
- While **risk factor modification** (smoking cessation, blood pressure control) is essential, it is insufficient as the primary management given the aneurysm's significant growth and imminent rupture risk.
- A 12-month follow-up interval is too long for a rapidly growing aneurysm (grew 1.1 cm in the past year), as this increases the risk of rupture without intervention.
*Adjustment of cardiovascular risk factors and follow-up ultrasound in 6 months*
- **Risk factor management** is important but does not address the immediate need for intervention due to the aneurysm's size approaching the threshold and concerning growth rate.
- While 6-month surveillance might be considered for smaller aneurysms with slower growth, this aneurysm's rapid expansion rate suggests it will exceed 5.0 cm well before the next surveillance interval, increasing rupture risk unnecessarily.
*Elective open aneurysm repair*
- **Open aneurysm repair** is an effective treatment but carries significantly higher perioperative risks (30-day mortality 3-5% vs 1-2% for EVAR) compared to endovascular repair, especially in patients with multiple comorbidities.
- Given this patient's COPD, smoking history, and cardiovascular risk factors, EVAR is the preferred approach to minimize surgical stress and improve perioperative outcomes.
*Adjustment of cardiovascular risk factors and follow-up CT in 6 months*
- **Risk factor modification** alone is insufficient given the aneurysm's proximity to intervention threshold and rapid growth rate.
- While CT provides more detailed anatomic imaging for surgical planning, continued surveillance is inappropriate when the patient already meets criteria for intervention. Additionally, CT involves radiation exposure and is typically reserved for pre-operative planning rather than routine surveillance.
Arteriovenous malformation treatment US Medical PG Question 2: A 58-year-old man presents to the clinic concerned about his health after his elder brother recently became bed-bound due to a brain condition. He has also brought a head CT scan of his brother to reference, as shown in the picture. The patient has type 2 diabetes mellitus, hypertension, osteoarthritis, and hypercholesterolemia. His medication list includes aspirin, diclofenac sodium, metformin, and ramipril. He leads a sedentary lifestyle and smokes one pack of cigarettes daily. He also drinks 4–5 cups of red wine every weekend. His BMI is 33.2 kg/m2. His blood pressure is 164/96 mm Hg, the heart rate is 84/min, and the respiratory rate is 16/min. Which of the following interventions will be most beneficial for reducing the risk of developing the disease that his brother has?
- A. Statin therapy
- B. Quit smoking
- C. Stop aspirin
- D. Blood sugar control
- E. Blood pressure control (Correct Answer)
Arteriovenous malformation treatment Explanation: ***Blood pressure control***
- The brother's CT scan shows features of **white matter hyperintensities (WMH)**, indicative of **cerebral small vessel disease**, a significant risk factor for **neurodegenerative conditions** and dementia, which can cause a patient to become bedridden.
- **Hypertension** is the most potent and modifiable risk factor for the development and progression of WMH and other forms of cerebral small vessel disease; therefore, strict **blood pressure control** is the most beneficial intervention.
*Statin therapy*
- Statins are crucial for managing **hypercholesterolemia** and reducing the risk of **atherosclerotic cardiovascular disease** and stroke.
- While beneficial for overall vascular health, **dyslipidemia** is less strongly associated with WMH and cerebral small vessel disease than hypertension.
*Quit smoking*
- **Smoking** is a significant risk factor for **stroke**, **atherosclerosis**, and several neurodegenerative disorders.
- While important for overall health, **smoking cessation** has a less direct and immediate impact on the progression of existent WMH compared to **blood pressure control**.
*Stop aspirin*
- **Aspirin** is used for **primary or secondary prevention** of cardiovascular events due to its **antiplatelet effects**.
- There is no indication that stopping aspirin would benefit in preventing further cerebral small vessel disease; rather, it could increase the risk of other vascular events in this patient with multiple risk factors.
*Blood sugar control*
- **Type 2 diabetes mellitus** is a known risk factor for **vascular dementia** and can contribute to small vessel disease.
- While important for long-term health, the impact of **blood sugar control** on WMH progression is less substantial compared to **blood pressure control**.
Arteriovenous malformation treatment US Medical PG Question 3: A 53-year-old man is brought to the emergency department for confusion. He was in his usual state of health until about 3 hours ago when he tried to use his sandwich to turn off the TV. He also complained to his wife that he had a severe headache. Past medical history is notable for hypertension, which has been difficult to control on multiple medications. His temperature is 36.7°C (98°F), the pulse is 70/min, and the blood pressure is 206/132 mm Hg. On physical exam he is alert and oriented only to himself, repeating over and over that his head hurts. The physical exam is otherwise unremarkable and his neurologic exam is nonfocal. The noncontrast CT scan of the patient's head is shown and reveals an acute intraparenchymal hemorrhage in the basal ganglia. Which of the following diagnostic tests would be most helpful in determining the underlying cause of this patient's hemorrhage?
- A. Lumbar puncture
- B. Electroencephalogram (EEG)
- C. MRI of the brain
- D. CT angiography of the neck
- E. CT angiography of the brain (Correct Answer)
Arteriovenous malformation treatment Explanation: ***CT angiography of the brain***
- Following identification of an **intracerebral hemorrhage** on noncontrast CT, **CT angiography (CTA) of the brain** is the most appropriate next diagnostic test to identify underlying vascular abnormalities such as **arteriovenous malformations (AVMs)**, **aneurysms**, **dural arteriovenous fistulas**, or **moyamoya disease**.
- While this patient has severe hypertension (a common cause of basal ganglia hemorrhage), CTA should still be performed to rule out secondary causes, particularly in patients under 70 years old or those with atypical features.
- CTA can be performed rapidly in the acute setting and has high sensitivity for detecting vascular lesions that may require specific treatment.
*MRI of the brain*
- MRI with specialized sequences (GRE, SWI, FLAIR) can provide detailed information about **chronic microhemorrhages**, **cerebral amyloid angiopathy**, **underlying tumors**, or **cavernomas**.
- However, MRI is typically performed **after CTA** in the workup of intracerebral hemorrhage, not as the immediate next step.
- MRI is less readily available in the acute setting and takes longer to perform than CTA.
*CT angiography of the neck*
- This test visualizes the **carotid and vertebral arteries** in the neck to detect **stenosis**, **dissection**, or **atherosclerotic disease**.
- It is not directly useful for identifying the cause of an **intraparenchymal hemorrhage** within the brain substance itself.
*Lumbar puncture*
- Lumbar puncture analyzes **cerebrospinal fluid (CSF)** and is primarily used for suspected **subarachnoid hemorrhage** (when CT is negative), **meningitis**, or **encephalitis**.
- It is **contraindicated** in patients with significant intraparenchymal hemorrhage due to risk of herniation from increased intracranial pressure.
*Electroencephalogram (EEG)*
- EEG measures **electrical activity in the brain** and is used to diagnose **seizure disorders** or evaluate altered mental status from metabolic or epileptic causes.
- While confusion can result from seizures, the primary pathology is the **intracerebral hemorrhage** identified on CT, which EEG cannot diagnose or characterize.
Arteriovenous malformation treatment US Medical PG Question 4: A 44-year-old female is admitted to the neurological service. You examine her chart and note that after admission she was started on nimodipine. Which of the following pathologies would benefit from this pharmacologic therapy?
- A. Thromboembolic stroke
- B. Subdural hematoma
- C. Epidural hematoma
- D. Pseudotumor cerebri
- E. Subarachnoid hemorrhage (Correct Answer)
Arteriovenous malformation treatment Explanation: ***Subarachnoid hemorrhage***
- Nimodipine is a **calcium channel blocker** specifically used to prevent and treat **cerebral vasospasm** following a subarachnoid hemorrhage.
- Vasospasm is a common and often devastating complication that can lead to delayed cerebral ischemia and poor neurological outcomes.
*Thromboembolic stroke*
- Treatment for thromboembolic stroke focuses on **reperfusion therapies** (e.g., tPA, thrombectomy) and antiplatelet/anticoagulant medications.
- Nimodipine does not play a role in the acute management or prevention of tissue damage in ischemic stroke.
*Subdural hematoma*
- Subdural hematomas are collections of blood between the dura and arachnoid mater, usually resulting from **head trauma**.
- Management typically involves **surgical evacuation** if symptomatic, and nimodipine is not indicated.
*Epidural hematoma*
- Epidural hematomas involve bleeding between the dura mater and the skull, often due to **arterial injury** from head trauma.
- These are surgical emergencies, and nimodipine has no therapeutic role.
*Pseudotumor cerebri*
- Also known as **idiopathic intracranial hypertension**, this condition involves elevated intracranial pressure without a mass lesion.
- Treatment focuses on reducing CSF pressure, often with diuretics (e.g., acetazolamide), and nimodipine is not part of the management.
Arteriovenous malformation treatment US Medical PG Question 5: A 48-year-old woman is brought to the emergency department because of a 1-hour history of sudden-onset headache associated with nausea and vomiting. The patient reports she was sitting at her desk when the headache began. The headache is global and radiates to her neck. She has hypertension. She has smoked one pack of cigarettes daily for the last 10 years. She drinks alcohol occasionally. Her father had a stroke at the age 58 years. Current medications include hydrochlorothiazide. She is in severe distress. She is alert and oriented to person, place, and time. Her temperature is 38.2°C (100.8°F), pulse is 89/min, respirations are 19/min, and blood pressure is 150/90 mm Hg. Cardiopulmonary examination shows no abnormalities. Cranial nerves II–XII are intact. She has no focal motor or sensory deficits. She flexes her hips and knees when her neck is flexed while lying in a supine position. A CT scan of the head is shown. Which of the following is the most appropriate intervention?
- A. Perform burr hole surgery
- B. Administer intravenous alteplase
- C. Administer intravenous vancomycin and ceftriaxone
- D. Perform surgical clipping (Correct Answer)
- E. Perform decompressive craniectomy
Arteriovenous malformation treatment Explanation: ***Perform surgical clipping***
- The clinical presentation of **sudden-onset severe headache** ("thunderclap headache"), **nausea, vomiting, neck stiffness (positive Brudzinski's sign)**, and the CT scan showing **blood in the subarachnoid space** strongly indicate a **subarachnoid hemorrhage (SAH)** from a ruptured cerebral aneurysm.
- Definitive treatment requires **securing the aneurysm** to prevent **rebleeding**, which carries 40-50% mortality. Modern management includes **endovascular coiling** (first-line for most cases) or **surgical clipping**.
- **Surgical clipping** involves placing a metal clip across the aneurysm neck to exclude it from circulation. It remains the preferred approach for certain aneurysm locations (MCA), wide-necked aneurysms, or when accompanied by hematoma requiring evacuation.
- Among the options provided, surgical clipping is the only definitive intervention that secures the ruptured aneurysm.
*Perform burr hole surgery*
- **Burr hole surgery** is used for draining **subdural hematomas** or accessing the brain for procedures like biopsy or external ventricular drain placement.
- While burr holes may be needed for complications of SAH (e.g., hydrocephalus requiring EVD), this is not the primary intervention for securing the ruptured aneurysm itself.
*Administer intravenous alteplase*
- **Alteplase** (tPA) is a **thrombolytic agent** used for **acute ischemic stroke** within 4.5 hours of symptom onset.
- Administering thrombolytics in **hemorrhagic stroke** (like SAH) is **absolutely contraindicated** as it would worsen bleeding and cause catastrophic neurological deterioration or death.
*Administer intravenous vancomycin and ceftriaxone*
- **Vancomycin and ceftriaxone** treat **bacterial meningitis**, which can present with headache, fever, and meningeal signs.
- Although the patient has low-grade fever (likely from blood irritating meninges, not infection) and neck stiffness, the **sudden-onset thunderclap headache** and **CT findings of SAH** make ruptured aneurysm the diagnosis, not meningitis. The fever in SAH is typically from aseptic meningeal irritation.
*Perform decompressive craniectomy*
- **Decompressive craniectomy** removes skull bone to relieve **elevated intracranial pressure** from massive brain swelling (severe TBI, malignant MCA infarction).
- While SAH can cause elevated ICP, craniectomy does not secure the aneurysm. The immediate priority is preventing **rebleeding** by securing the aneurysm source, not managing secondary complications.
Arteriovenous malformation treatment US Medical PG Question 6: A 65-year-old man presents to the emergency department for sudden weakness. He was doing mechanical work on his car where he acutely developed right-leg weakness and fell to the ground. He is accompanied by his wife, who said that this has never happened before. He was last seen neurologically normal approximately 2 hours prior to presentation. His past medical history is significant for hypertension and type II diabetes. His temperature is 98.8°F (37.1°C), blood pressure is 177/108 mmHg, pulse is 90/min, respirations are 15/min, and oxygen saturation is 99% on room air. Neurological exam reveals that he is having trouble speaking and has profound weakness of his right upper and lower extremity. Which of the following is the best next step in management?
- A. Thrombolytics
- B. Noncontrast head CT (Correct Answer)
- C. CT angiogram
- D. MRI of the head
- E. Aspirin
Arteriovenous malformation treatment Explanation: ***Noncontrast head CT***
- A **noncontrast head CT** is the most crucial initial step in managing acute stroke symptoms because it can rapidly rule out an **intracranial hemorrhage**.
- Distinguishing between ischemic stroke and hemorrhagic stroke is critical, as the management strategies are vastly different and administering thrombolytics in the presence of hemorrhage can be fatal.
*Thrombolytics*
- **Thrombolytics** can only be administered after an **intracranial hemorrhage** has been excluded via noncontrast head CT.
- Administering thrombolytics without imaging could worsen a hemorrhagic stroke, causing significant harm or death.
*CT angiogram*
- A **CT angiogram** is used to identify large vessel occlusions in ischemic stroke and is typically performed after a noncontrast CT rules out hemorrhage.
- This imaging is crucial for determining eligibility for **endovascular thrombectomy** but is not the very first diagnostic step.
*MRI of the head*
- An **MRI of the head** is more sensitive for detecting acute ischemic changes but takes longer to perform and is often not readily available in the acute emergency setting.
- It is not the initial imaging of choice for ruling out hemorrhage due to its longer acquisition time compared to CT.
*Aspirin*
- **Aspirin** is indicated for acute ischemic stroke but should only be given after an **intracranial hemorrhage** has been ruled out.
- Like thrombolytics, aspirin could exacerbate a hemorrhagic stroke and is thus deferred until initial imaging is complete.
Arteriovenous malformation treatment US Medical PG Question 7: A 54-year-old man comes to the physician because of a painful mass in his left thigh for 3 days. He underwent a left lower limb angiography for femoral artery stenosis and had a stent placed 2 weeks ago. He has peripheral artery disease, coronary artery disease, hypercholesterolemia and type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for 34 years. Current medications include enalapril, aspirin, simvastatin, metformin, and sitagliptin. His temperature is 36.7°C (98°F), pulse is 88/min, and blood pressure is 116/72 mm Hg. Examination shows a 3-cm (1.2-in) tender, pulsatile mass in the left groin. The skin over the area of the mass shows no erythema and is cool to the touch. A loud bruit is heard on auscultation over this area. The remainder of the examination shows no abnormalities. Results of a complete blood count and serum electrolyte concentrations show no abnormalities. Duplex ultrasonography shows an echolucent sac connected to the common femoral artery, with pulsatile and turbulent blood flow between the artery and the sac. Which of the following is the most appropriate next best step in management?
- A. Ultrasound-guided thrombin injection (Correct Answer)
- B. Covered stent implantation
- C. Ultrasound-guided compression
- D. Coil embolization
- E. Schedule surgical repair
Arteriovenous malformation treatment Explanation: ***Ultrasound-guided thrombin injection***
- The patient presents with a **post-catheterization pseudoaneurysm** as indicated by the pulsatile, tender mass with a bruit after recent femoral angiography, and confirmed by duplex ultrasonography showing an echolucent sac connected to the common femoral artery with pulsatile flow.
- **Ultrasound-guided thrombin injection** is the preferred treatment for pseudoaneurysms that are larger than 2-3 cm or have been present for more than 1 week, as it effectively closes the pseudoaneurysm sac with a high success rate and minimal invasiveness.
*Covered stent implantation*
- This is a treatment for arterial injury or aneurysm, but it is generally reserved for **larger or more complex pseudoaneurysms**, or those that have failed less invasive treatments, due to its greater invasiveness and potential complications.
- It involves placing a stent graft to exclude the pseudoaneurysm from the circulation.
*Ultrasound-guided compression*
- This technique involves applying sustained pressure to the pseudoaneurysm neck, which can lead to thrombosis. However, it has a **lower success rate** compared to thrombin injection, especially for larger pseudoaneurysms, and is often painful and time-consuming.
- It is often considered a first-line therapy for smaller pseudoaneurysms (<2-3 cm) before thrombin injection, but in this case, the pseudoaneurysm is 3 cm.
*Coil embolization*
- This procedure is typically used to treat **arteriovenous malformations** or high-flow bleeding rather than pseudoaneurysms.
- It involves placing coils into the vessel to induce thrombosis, but carries risks of distal embolization and might be overly aggressive for a femoral pseudoaneurysm.
*Schedule surgical repair*
- **Surgical repair** is indicated for pseudoaneurysms that are rapidly expanding, symptomatic with critical limb ischemia, infected, or those that have failed less invasive treatments.
- In this case, given the patient's stable condition and the availability of less invasive options, surgical repair is not the initial best step.
Arteriovenous malformation treatment US Medical PG Question 8: A boy with diabetic ketoacidosis is admitted to the pediatric intensive care unit for closer monitoring. Peripheral venous access is established. He is treated with IV isotonic saline and started on an insulin infusion. This patient is at the highest risk for which of the following conditions in the next 24 hours?
- A. Cerebral edema (Correct Answer)
- B. Intrinsic kidney injury
- C. Cognitive impairment
- D. Hyperkalemia
- E. Deep venous thrombosis
Arteriovenous malformation treatment Explanation: ***Cerebral edema***
- **Cerebral edema** is a severe and potentially fatal complication of **diabetic ketoacidosis (DKA)** treatment, particularly in children.
- It results from a rapid decrease in serum osmolality during treatment, causing water to shift into brain cells.
*Intrinsic kidney injury*
- While dehydration in DKA can lead to **prerenal acute kidney injury**, **intrinsic kidney injury** is less common as an acute risk directly from DKA treatment in the first 24 hours.
- Initial fluid resuscitation often improves renal perfusion, reducing the risk of intrinsic damage unless other predisposing factors are present.
*Cognitive impairment*
- Cognitive impairment after DKA is more commonly observed in the long term, potentially due to recurrent episodes or severe DKA with cerebral edema.
- It is not the most immediate and highest risk acute complication in the short-term (next 24 hours).
*Hyperkalemia*
- Patients with DKA typically present with **hyperkalemia** due to acidosis and insulin deficiency, which resolves with insulin therapy as potassium shifts back into cells.
- The more immediate risk during treatment, especially after initial fluid resuscitation and insulin, is **hypokalemia**, not hyperkalemia, due to the intracellular shift of potassium.
*Deep venous thrombosis*
- **Dehydration** and **hyperviscosity** associated with DKA can increase the risk of **thrombosis**, but **deep venous thrombosis** is not the highest or most immediate acute risk in the next 24 hours.
- **Cerebral edema** is a more specific and life-threatening complication directly related to the treatment of DKA in children.
Arteriovenous malformation treatment US Medical PG Question 9: A 68-year-old man presents for a screening ultrasound scan. He has been feeling well and is in his usual state of good health. His medical history is notable for mild hypertension and a 100-pack-year tobacco history. He has a blood pressure of 128/86 and heart rate of 62/min. Physical examination is clear lung sounds and regular heart sounds. On ultrasound, an infrarenal aortic aneurysm of 4 cm in diameter is identified. Which of the following is the best initial step for this patient?
- A. Reassurance
- B. Beta-blockers
- C. Urgent repair
- D. Surveillance (Correct Answer)
- E. Elective repair
Arteriovenous malformation treatment Explanation: **Surveillance**
- An **infrarenal aortic aneurysm** of 4 cm in diameter in an asymptomatic patient is typically managed with **regular surveillance** to monitor for growth.
- Surgical intervention is generally reserved for aneurysms larger than 5.5 cm or those that are rapidly expanding or symptomatic.
*Reassurance*
- While it's important to provide reassurance, simply doing so without a concrete plan for follow-up would be inappropriate given the potential for **aneurysm expansion** and rupture.
- The patient's **tobacco history** is a significant risk factor for aneurysm progression and warrants monitoring.
*Beta-blockers*
- Beta-blockers may be part of the medical management for **hypertension** and could theoretically slow aneurysm growth by reducing pulsatile stress.
- However, they are not the primary **initial step** for an asymptomatic aneurysm of this size and do not replace the need for surveillance.
*Urgent repair*
- **Urgent repair** is indicated for symptomatic aneurysms, those that are rapidly expanding, or those showing signs of rupture or impending rupture, none of which are present here.
- A 4 cm aneurysm in an asymptomatic patient does not meet the criteria for **urgent intervention**.
*Elective repair*
- **Elective repair** is typically considered for aneurysms exceeding 5.5 cm in diameter or those that are symptomatic or rapidly growing.
- A 4 cm aneurysm is below the threshold for **elective repair** in an asymptomatic patient without other high-risk features.
Arteriovenous malformation treatment US Medical PG Question 10: A 48-year-old woman undergoes awake craniotomy for resection of a left frontal glioma near Broca's area. Intraoperatively, cortical mapping identifies eloquent tissue, but the tumor extends into functionally critical regions. The surgeon achieves 70% resection when the patient develops expressive aphasia during mapping. Frozen section shows low-grade astrocytoma. The family previously expressed desire for maximal resection. Evaluate the intraoperative decision-making.
- A. Use awake testing to define exact limits of safe resection
- B. Obtain family consultation intraoperatively about acceptable deficits
- C. Convert to asleep anesthesia and use anatomic landmarks for resection
- D. Continue resection since low-grade tumors justify aggressive surgery
- E. Stop resection to preserve language function (Correct Answer)
Arteriovenous malformation treatment Explanation: ***Stop resection to preserve language function***
- Development of **expressive aphasia** during mapping indicates the surgical margin has reached **eloquent cortex** (Broca's area), and proceeding further risks permanent neurological deficit.
- The principle of **"maximal safe resection"** prioritizes the preservation of **quality of life** and functional status over the total removal of a low-grade tumor.
*Use awake testing to define exact limits of safe resection*
- Awake testing and **cortical mapping** have already identified the limit by triggering aphasia; additional testing at that specific site is redundant and risks seizure or further injury.
- Once a **functional boundary** is identified via intraoperative monitoring, it serves as the definitive anatomical endpoint for the resection.
*Obtain family consultation intraoperatively about acceptable deficits*
- Surrogate decision-makers cannot provide **informed consent** for new, immediate neurological deficits in the middle of a procedure when the surgeon has reached a safety limit.
- The surgeon’s primary obligation is to maintain **patient safety** and adhere to the established surgical plan of functional preservation.
*Convert to asleep anesthesia and use anatomic landmarks for resection*
- Converting to **general anesthesia** would lose the benefit of **functional monitoring**, making any further resection near Broca's area extremely dangerous and blind to functional limits.
- **Anatomic landmarks** are often unreliable for predicting function due to **neuroplasticity** or tumor displacement, making mapping essential in this region.
*Continue resection since low-grade tumors justify aggressive surgery*
- While aggressive resection improves **progression-free survival**, the prognosis for **low-grade astrocytomas** is relatively long, making a permanent, devastating deficit like **aphasia** unacceptable.
- Aggressive surgery is only justified up to the **functional boundary**; crossing it violates the core surgical principle of avoiding non-recoverable morbidity.
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