USMLE Step 2 Quiz
Practice Acute Neurologic Emergencies in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
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A 60-year-old man presents with acute-onset confusion and right-sided weakness. He is unable to provide a history. His wife states his symptoms started approximately 1 hour ago. In the emergency department, his blood pressure is 180/100 mm Hg. What is the most appropriate initial diagnostic test to guide immediate management?
What is the most appropriate initial diagnostic test to guide immediate management?
This quiz focuses on Acute Neurologic Emergencies, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 60-year-old man presents with acute-onset confusion and right-sided weakness. He is unable to provide a history. His wife states his symptoms started approximately 1 hour ago. In the emergency department, his blood pressure is 180/100 mm Hg. What is the most appropriate initial diagnostic test to guide immediate management?
What is the most appropriate initial diagnostic test to guide immediate management?
Explanation: In any patient presenting with acute focal neurologic deficits suggestive of a stroke, the most critical initial step is to differentiate between ischemic and hemorrhagic stroke, as their management is drastically different. A non-contrast CT scan of the head is the fastest and most widely available imaging modality to reliably detect acute intracranial hemorrhage. While MRI with DWI is more sensitive for early ischemia, it takes longer to perform and is not the first-line test. The immediate priority is to rule out a bleed before considering therapies like thrombolysis. Carotid ultrasound and lumbar puncture are not indicated for the initial evaluation of acute stroke.
A 68-year-old man with a history of hypertension and atrial fibrillation, for which he takes metoprolol and apixaban, is brought to the emergency department by his wife. She states that he was watching television when he suddenly complained of the "worst headache of his life," followed by vomiting and a decreased level of consciousness over several minutes. On examination, his blood pressure is 190/110 mm Hg, heart rate is 95/min and irregular, and respirations are 12/min. He withdraws from painful stimuli and has nuchal rigidity. A non-contrast CT scan of the head is ordered.
Which of the following is the most likely finding on the head CT scan?
Explanation: This patient's presentation with a sudden-onset, severe "thunderclap" headache, vomiting, nuchal rigidity, and decreased level of consciousness is classic for a subarachnoid hemorrhage (SAH). The most common cause of non-traumatic SAH is a ruptured saccular (berry) aneurysm. A non-contrast head CT is the initial diagnostic test of choice and would show hyperdense (bright) blood in the subarachnoid space, including the basilar cisterns and sulci. If the CT is negative but clinical suspicion remains high, a lumbar puncture should be performed to look for xanthochromia.
A 72-year-old woman is brought to the emergency department 90 minutes after the sudden onset of left-sided facial droop, left arm weakness, and slurred speech. Her medical history is significant for type 2 diabetes mellitus and hypertension. Her blood pressure is 175/95 mm Hg. A non-contrast CT scan of the head shows no evidence of hemorrhage or acute ischemic changes. The patient's symptoms are not improving.
Which of the following is the most appropriate next step in management?
Explanation: This patient presents with classic signs of an acute ischemic stroke within the 3-hour window for thrombolysis (and up to 4.5 hours in eligible patients). The non-contrast head CT has appropriately ruled out hemorrhage. Her blood pressure is below the 185/110 mm Hg contraindication threshold for alteplase (tPA). Therefore, the most appropriate next step is to administer intravenous alteplase to attempt reperfusion. CT angiography is useful for identifying large vessel occlusion for potential thrombectomy but should not delay tPA administration. Aggressively lowering blood pressure to <140/90 mm Hg is not indicated and could worsen cerebral perfusion. Aspirin should be administered, but not until 24 hours after tPA administration to reduce the risk of hemorrhagic conversion.
A 44-year-old man is brought to the emergency department after being found actively seizing by his roommate. The seizure has been continuous for the past 10 minutes. It is described as a generalized tonic-clonic seizure. Emergency medical services established intravenous access en route. The patient has no known medical history. His temperature is 38.1°C (100.6°F), blood pressure is 150/90 mm Hg, heart rate is 120/min, and oxygen saturation is 93% on a non-rebreather mask.
Which of the following is the most appropriate initial pharmacologic treatment?
Explanation: This patient is in status epilepticus, defined as a continuous seizure lasting more than 5 minutes or recurrent seizures without a return to baseline. The initial management priority is to terminate the seizure. First-line therapy is an intravenous benzodiazepine, such as lorazepam, diazepam, or midazolam. These medications enhance the effect of the neurotransmitter GABA, causing widespread CNS inhibition. If the seizure persists after an adequate dose of a benzodiazepine, a second-line agent such as fosphenytoin, valproic acid, or levetiracetam should be administered. Phenobarbital is typically reserved for refractory status epilepticus.
A 59-year-old woman with a history of metastatic breast cancer to the brain is brought to the emergency department with a worsening headache, nausea, and increasing lethargy over the past 24 hours. On examination, she is drowsy but arousable to voice. Her blood pressure is 160/70 mm Hg, heart rate is 55/min, and respirations are 10/min and irregular. Papilledema is noted on funduscopic examination.
In addition to arranging for urgent neuroimaging and neurosurgical consultation, which of the following is the most appropriate immediate intervention?
Explanation: This patient's presentation, including the triad of hypertension, bradycardia, and irregular respirations (Cushing's triad), along with papilledema, is highly suggestive of acutely increased intracranial pressure (ICP). Given her history of brain metastases, this is likely due to vasogenic edema surrounding the tumors. The most appropriate immediate intervention is to administer high-dose intravenous corticosteroids, such as dexamethasone, which rapidly reduces vasogenic edema and can alleviate symptoms of increased ICP. Antibiotics are not indicated. A lumbar puncture is contraindicated due to the risk of uncal herniation. Sodium bicarbonate is not a primary treatment for increased ICP.
A 25-year-old man is brought to the emergency department following a motorcycle crash. He was not wearing a helmet. On arrival, he is comatose with a Glasgow Coma Scale (GCS) score of 6 (E1, V2, M3). His right pupil is 6 mm and nonreactive, while his left pupil is 3 mm and reactive. His blood pressure is 170/90 mm Hg, and his heart rate is 50/min.
Which of the following interventions should be performed most urgently?
Explanation: This patient has a severe traumatic brain injury (GCS < 8) with clinical signs of uncal herniation (anisocoria with a fixed, dilated pupil). This is a neurosurgical emergency due to rapidly increasing intracranial pressure (ICP). The most urgent intervention is to secure the airway via endotracheal intubation and initiate controlled hyperventilation. Hyperventilation causes cerebral vasoconstriction by lowering PaCO2, which transiently reduces cerebral blood volume and ICP. This serves as a critical bridge to more definitive treatments like osmotic therapy (hypertonic saline or mannitol) or surgical intervention (e.g., craniotomy, EVD placement). Prophylactic antibiotics are not the most urgent step.
A 77-year-old man is being considered for intravenous thrombolysis for an acute ischemic stroke that began 2 hours ago. He has a significant right-sided hemiparesis and aphasia. His medical history includes hypertension, hyperlipidemia, and a total knee replacement performed 4 weeks ago. His current medications are lisinopril and atorvastatin. A non-contrast head CT shows no hemorrhage. His blood pressure is 165/90 mm Hg.
Which of the following is a contraindication to administering alteplase in this patient?
Explanation: The administration of intravenous alteplase (tPA) has strict inclusion and exclusion criteria to minimize the risk of bleeding. A major surgery, such as a total knee replacement, within the preceding 3 months is an absolute contraindication to tPA due to the high risk of severe bleeding at the surgical site. While advanced age was previously a relative contraindication, current guidelines support its use in older adults. The patient's blood pressure is below the 185/110 mm Hg threshold. A history of hypertension is not a contraindication, although uncontrolled hypertension at the time of administration is.
A 30-year-old woman with a history of epilepsy, well-controlled on lamotrigine, is brought to the emergency department. She had a generalized tonic-clonic seizure that lasted approximately 3 minutes and self-resolved. She is now postictal but easily arousable. Her boyfriend states she ran out of her medication 3 days ago. After initial stabilization and a normal neurologic exam except for drowsiness, an intravenous line is placed and labs are drawn.
Which of the following is the most appropriate next step in management?
Explanation: This patient had a single, self-limited breakthrough seizure in the context of a known seizure disorder and medication nonadherence. Since the seizure has terminated and she is returning to baseline, she is not in status epilepticus. The most appropriate management is to address the underlying cause, which is the missed medication. She should be given a dose of her home antiepileptic drug (lamotrigine) and provided with a prescription refill. Administering a loading dose of a different antiepileptic like fosphenytoin is unnecessary as she is not actively seizing and could cause adverse effects. Urgent neuroimaging and continuous EEG are not indicated for a simple breakthrough seizure with a clear precipitant.
A 35-year-old woman presents to the emergency department with a sudden, severe headache and neck stiffness. She denies trauma. A non-contrast head CT is negative for hemorrhage. Given the high clinical suspicion for subarachnoid hemorrhage, a lumbar puncture is performed. The opening pressure is 22 cm H2O.
Which of the following cerebrospinal fluid findings would be most diagnostic of a subarachnoid hemorrhage in this patient?
Explanation: When a non-contrast head CT is negative in a patient with a high suspicion for subarachnoid hemorrhage (SAH), the next step is a lumbar puncture (LP). The most specific finding for SAH on LP is xanthochromia, which is the yellow discoloration of the CSF due to bilirubin from the breakdown of red blood cells. Xanthochromia takes several hours to develop and distinguishes a true hemorrhage from a traumatic tap (where the RBC count would be high but no xanthochromia would be present). Lymphocytic pleocytosis suggests viral meningitis, low glucose suggests bacterial meningitis, and albuminocytologic dissociation (high protein, normal cells) is seen in Guillain-Barré syndrome.
A 50-year-old woman with a history of hypertension presents with acute onset of vertigo, nausea, vomiting, and difficulty walking. On examination, she has nystagmus, dysmetria on the left side, and gait ataxia. She has no significant motor weakness or sensory loss. Her symptoms began 2 hours ago.
Which of the following is the most likely diagnosis?
Explanation: This patient's constellation of acute-onset vertigo, nystagmus, dysmetria, and gait ataxia points strongly to a cerebellar lesion. These are the classic signs of a posterior circulation stroke affecting the cerebellum. Acute labyrinthitis typically presents with vertigo and nystagmus but not with focal neurologic signs like dysmetria or ataxia. A basal ganglia hemorrhage would cause contralateral hemiparesis. A carotid territory TIA would cause symptoms like transient monocular blindness (amaurosis fugax) or unilateral weakness/numbness, not cerebellar signs.
A 75-year-old man is found at home by his son, who last spoke to him 10 hours ago. The patient is awake but has dense right-sided hemiplegia and global aphasia. The exact time of symptom onset is unknown. A non-contrast head CT is negative for hemorrhage. An MRI of the brain is performed.
Which of the following MRI findings would suggest that this patient might still be a candidate for reperfusion therapy?
Explanation: In patients with an unknown time of stroke onset ('wake-up stroke'), MRI can help determine eligibility for thrombolysis or thrombectomy. A diffusion-weighted imaging (DWI) sequence becomes positive within minutes of an ischemic event, while the fluid-attenuated inversion recovery (FLAIR) sequence typically takes 4.5-6 hours to become positive. A 'DWI-FLAIR mismatch' (positive DWI, negative FLAIR) indicates that the stroke likely occurred within the past 4.5 hours, making the patient a potential candidate for intravenous thrombolysis. If both DWI and FLAIR are positive, the stroke is likely older than 4.5-6 hours. Normal signals would not explain the deficit, and periventricular hyperintensities are chronic small vessel ischemic changes.
A 45-year-old woman is treated with intravenous alteplase for an acute ischemic stroke. Three hours into the infusion, she complains of a severe headache and begins to vomit. The nurse notes that her blood pressure has risen to 200/110 mm Hg and her neurologic exam has worsened, with a decreased level of consciousness.
What is the most appropriate immediate action?
Explanation: The patient's clinical deterioration with severe headache, vomiting, hypertension, and worsening neurologic status during or after alteplase administration is highly concerning for symptomatic intracerebral hemorrhage, the most feared complication of thrombolysis. The most appropriate immediate action is to stop the alteplase infusion and obtain an emergent non-contrast head CT to confirm or rule out bleeding. Increasing the infusion would be catastrophic. While mannitol and labetalol might be needed, diagnosing the hemorrhage is the absolute first priority that will guide all subsequent management.
A 66-year-old woman with a history of severe preeclampsia during her last pregnancy is admitted with headache, visual disturbances, and a seizure. Her blood pressure on admission is 220/120 mm Hg. An MRI of the brain shows bilateral, symmetric areas of vasogenic edema, predominantly in the parietal and occipital lobes.
What is the most likely diagnosis?
Explanation: This patient's presentation of headache, visual changes, and seizures in the setting of a hypertensive emergency, along with MRI findings of posterior vasogenic edema, is classic for Posterior Reversible Encephalopathy Syndrome (PRES). PRES is a clinicoradiologic syndrome caused by failed cerebral autoregulation in the setting of severely elevated blood pressure or other triggers (e.g., eclampsia, immunosuppressive drugs). Management involves treating the underlying cause, primarily by carefully lowering the blood pressure. Bilateral PCA strokes would show restricted diffusion, not vasogenic edema. Herpes encephalitis typically affects the temporal lobes. CJD is a rapidly progressive dementia and is not associated with these acute findings.
A 55-year-old man with a history of alcohol use disorder is admitted to the intensive care unit for pneumonia and septic shock. On day 3 of his admission, after being weaned off sedation, he is noted to have persistent, subtle twitching of his eyelids and fingers. He remains unresponsive to verbal or painful stimuli. His vital signs are stable. An EEG is performed.
This patient's clinical presentation is most concerning for which of the following neurologic emergencies?
Explanation: This critically ill patient's presentation of unexplained coma with subtle motor phenomena (myoclonic jerks of the eyelids and fingers) is highly concerning for nonconvulsive status epilepticus (NCSE). NCSE is a state of continuous seizure activity without the overt convulsions seen in generalized tonic-clonic status epilepticus. It is a common cause of altered mental status in ICU patients and requires EEG for diagnosis. While the other conditions are in the differential for altered mental status in a patient with alcohol use disorder, the subtle motor activity strongly points toward NCSE as the most likely acute neurologic emergency.
A 62-year-old man is brought in by ambulance with generalized seizure activity that has not stopped for 20 minutes. He was given two doses of intravenous lorazepam by paramedics without cessation of the seizure. In the emergency department, he is intubated for airway protection. He continues to have tonic-clonic movements.
Which of the following is the most appropriate next medication to administer?
Explanation: This patient has benzodiazepine-refractory status epilepticus. After initial treatment with adequate doses of a benzodiazepine fails, the next step is to administer a non-benzodiazepine intravenous antiepileptic drug. The three recommended second-line agents are fosphenytoin, valproic acid, and levetiracetam. Fosphenytoin is a common and appropriate choice. Administering more lorazepam is unlikely to be effective and increases the risk of respiratory depression (though the patient is already intubated). A continuous infusion of an anesthetic agent like propofol or midazolam is third-line therapy for refractory status epilepticus. Magnesium sulfate is used for eclamptic seizures.
An 80-year-old resident of a nursing home is brought to the emergency department for altered mental status. For the past two days, he has been confused and lethargic. He has a history of dementia and atrial fibrillation, for which he takes donepezil and dabigatran. On examination, he is somnolent and does not follow commands. There is no clear focal deficit. Laboratory studies show a creatinine of 2.5 mg/dL (baseline 1.2 mg/dL). A non-contrast head CT shows no acute intracranial process.
The patient's acute neurologic decline is most likely a complication of which of the following?
Explanation: Dabigatran is a direct thrombin inhibitor that is primarily cleared by the kidneys. In the setting of acute kidney injury, the drug can accumulate to toxic levels, leading to a profound anticoagulant effect and increased risk of bleeding, including intracranial hemorrhage. Even without overt bleeding on CT, supratherapeutic levels can cause encephalopathy. The patient's acute decline in the setting of new renal failure makes dabigatran toxicity the most likely cause. Donepezil overdose is less likely to cause this presentation. While NCSE is possible, the medication toxicity is a more direct explanation given the labs. A rapid two-day decline is too acute for typical dementia progression.
A 70-year-old woman on warfarin for atrial fibrillation is brought to the emergency department with a GCS of 10. She reportedly fell and hit her head 2 hours ago. A non-contrast head CT reveals a large acute subdural hematoma with 8 mm of midline shift. Her most recent INR was 3.5.
In addition to emergent neurosurgical consultation, which of the following is the most important immediate step in her medical management?
Explanation: This patient has a life-threatening traumatic intracranial hemorrhage (subdural hematoma) complicated by supratherapeutic anticoagulation with warfarin. The most critical step is to urgently reverse the coagulopathy to prevent further bleeding. This is achieved by administering intravenous vitamin K along with a rapid-acting reversal agent. Prothrombin complex concentrate (PCC) is the preferred rapid agent; if unavailable, fresh frozen plasma (FFP) is an alternative. Mannitol is used for increased ICP but does not address the underlying coagulopathy. Protamine sulfate reverses heparin, not warfarin. Seizure prophylaxis may be considered but is not as immediately life-saving as reversing the anticoagulation.
A 65-year-old man with poorly controlled hypertension presents to the emergency department with the acute onset of left-sided weakness and sensory loss. His symptoms began approximately 2 hours ago. His blood pressure is 210/120 mm Hg. A non-contrast CT of the head is performed, which shows a 3-cm intraparenchymal hemorrhage in the right basal ganglia.
Which of the following is the most critical immediate step in this patient's management?
Explanation: This patient has an acute intracerebral hemorrhage (ICH) associated with severe hypertension. The most critical immediate step is to rapidly but carefully lower his blood pressure to prevent ongoing bleeding and hematoma expansion, which is a major cause of early neurologic deterioration. The current guidelines recommend lowering the systolic blood pressure to a target of 140-160 mm Hg using a titratable intravenous agent like nicardipine or labetalol. While mannitol and neurosurgical consultation may be necessary if there are signs of increased ICP or mass effect, blood pressure control is the first priority. Alteplase is absolutely contraindicated as it would worsen the hemorrhage.
An 81-year-old man presents to the emergency department 6 hours after the onset of right-sided weakness and aphasia. A non-contrast head CT is negative for hemorrhage. A subsequent CT angiogram reveals an occlusion of the M1 segment of the left middle cerebral artery. The patient's NIH Stroke Scale score is 18. He has a history of coronary artery disease and had a coronary stent placed 2 months ago.
Which of the following is the most appropriate management for this patient?
Explanation: This patient has a severe ischemic stroke (NIHSS 18) due to a large vessel occlusion (left M1) and presents within the extended window for mechanical thrombectomy (up to 24 hours in selected patients). He is outside the 4.5-hour window for intravenous alteplase. Therefore, the most appropriate management is mechanical thrombectomy, which has been shown to improve functional outcomes in patients with large vessel occlusions. Heparin infusion is not indicated for acute ischemic stroke and may increase the risk of hemorrhagic conversion. Dual antiplatelet therapy is used for secondary prevention but is not the primary acute treatment for a severe stroke of this nature.
A 22-year-old collegiate basketball player collapses during practice. He is brought to the emergency department awake but confused, complaining of a severe headache. A non-contrast CT of the head is performed and is normal. A subsequent CT angiogram of the head and neck is performed, which shows a dissection of the left internal carotid artery.
Which of the following is the most appropriate initial management for this patient's condition?
Explanation: Carotid artery dissection is an important cause of stroke in young adults, often precipitated by trauma or strenuous activity. The primary goal of treatment is to prevent thromboembolic stroke from the site of the dissection. This is typically achieved with either anticoagulation (e.g., with heparin followed by warfarin) or antiplatelet therapy (e.g., aspirin). The choice between the two is debated, but one must be started. Surgical intervention is reserved for rare cases. tPA is not indicated as there is no evidence of an established ischemic stroke on imaging, and it could worsen the intramural hematoma of the dissection. While blood pressure control is important, it is not the primary treatment, unlike in aortic dissection.