Test yourself: stroke


Case 1

A 71-year-old man presents to the emergency department at the instruction of his primary care physician. The patient felt well when he went to bed at midnight but awoke at 8:00 a.m. with left upper-extremity weakness and numbness. He called his physician, who told him to go to the emergency department. He arrives at the emergency department at 9:00 a.m.

The patient's medical history includes hypertension and hyperlipidemia for which he takes a thiazide diuretic and a statin. His blood pressure is 178/92 mm Hg; physical examination reveals mild left-sided neglect, a mild left central facial palsy, mild left upper- and lower-extremity weakness and a mild left hemisensory deficit. Complete blood count and serum electrolytes and plasma glucose levels are normal. CT scan of the head is normal.

Which of the following is the most appropriate next step in this patient's management?

A. Start aspirin
B. Start intravenous heparin
C. Start clopidogrel
D. Start intravenous tissue plasminogen activator
E. Lower blood pressure to 140/90 mm Hg

View correct answer for Case 1

Case 2

A 62-year-old woman is evaluated in the emergency department for sudden loss of vision in one eye. Her symptoms resolved while she was in transit to the emergency department and lasted a total of 25 minutes. She had a similar, less severe episode 1 week ago. She has a history of hypertension and hyperlipidemia, and she is a former smoker. Her current medications are aspirin, a thiazide diuretic and a statin.

On examination, her temperature is 37 °C (98.6 °F) and blood pressure is 136/88 mm Hg. She has a normal cardiac rhythm, with no murmurs and normal distal pulses. There are no carotid bruits. Neurologic evaluation is normal. Complete blood count and serum electrolytes and plasma glucose levels are normal. CT scan of the brain is normal.

Which of the following tests would have the greatest effect on this patient's therapy?

A. Carotid artery ultrasonography
B. Transcranial Doppler ultrasonography
C. MRI of the head
D. Electroencephalography
E. Lumbar puncture

View correct answer for Case 2

Case 3

A 55-year-old woman is evaluated in the emergency department for mild weakness of the right face and arm that began about 1 hour ago; she has normal sensation, vision and cognition. About 7 days ago she bent over and felt a “pop” in her head, followed by a very severe headache that dissipated over the next 3 days. She has no significant medical history and is not taking any medications. She smokes one pack of cigarettes daily.

On physical examination, her blood pressure is 135/82 mm Hg. Neurologic examination reveals only a mild right central facial palsy and mild right arm weakness. CT scan of the head is normal.

Which of the following is the most appropriate next step in the evaluation of this patient?

A. Magnetic resonance angiography of the head
B. Carotid duplex ultrasonography
C. Transcranial Doppler ultrasonography
D. Lumbar puncture
E. Echocardiography

View correct answer for Case 3

Case 4

A 61-year-old man is evaluated in the emergency department for mild left-sided weakness and left visual field loss that began about 6 hours ago. He has a history of diet-controlled hypertension.

On physical examination, the blood pressure is 160/75 mm Hg and the heart rate is 110/min and irregular. Cardiac examination reveals an irregularly irregular cardiac rhythm but is otherwise normal. Neurologic examination reveals a partial left homonymous hemianopsia, a left central facial palsy, mild left upper-extremity weakness and mild left sensory loss. Complete blood count and serum electrolytes and glucose are normal. Electrocardiography reveals atrial fibrillation. CT scan of the head shows early hypodensity of the right basal ganglia and insula.

Which of the following is the most appropriate therapy for this patient?

A. Warfarin
B. Enoxaparin
C. Clopidogrel
D. Adenosine

View correct answer for Case 4


Answers and commentary

Case 1

Correct answer: A

This patient had an acute ischemic stroke in the right middle cerebral artery territory. The time of onset is unknown, but he was last known to be well at midnight; he is therefore not eligible for intravenous thrombolytic therapy, which is indicated if therapy is started within 3 hours of onset of stroke symptoms or when the patient was last known to be well. Early administration of aspirin, 160 to 325 mg daily, modestly reduces both the short-term risk of recurrent stroke and the long-term risk of stroke-related death and disability.

Early administration of parenteral anticoagulants has no net benefit for patients with acute stroke. Clopidogrel is also not beneficial as acute stroke therapy. Early blood pressure lowering is not recommended for most patients with acute stroke unless they are being considered for thrombolytic therapy or are suffering from a concomitant myocardial infarction or aortic dissection. In such cases, some experts aim for a target mean arterial pressure of 140 mm Hg, although without definitive evidence that this is beneficial.

Key points

  • In patients with stroke not eligible for thrombolytic therapy, aspirin modestly reduces both the short-term risk of recurrent stroke and the long-term risk of stroke-related death and disability.
  • In patients with acute stroke, thrombolytic therapy must be started within 3 hours of the onset of symptoms or of the time the patient was last known to be well.

Return to the next case

Case 2

Correct answer: A

This patient had a transient ischemic attack with monocular blindness, most likely in the left middle cerebral artery territory. If she has a more than 50% stenosis of the left internal carotid artery on carotid artery ultrasonography, she may be considered for carotid endarterectomy, which would be a dramatic change in her therapy.

The other tests might be valuable, although their effect on therapy is generally much less clear. Intracranial stenosis can be detected noninvasively with transcranial Doppler ultrasonography and magnetic resonance angiography, but the mainstay of therapy for intracranial stenosis is antiplatelet therapy and risk factor modification, which she is already receiving. Intracranial angioplasty and stenting are experimental. MRI is more sensitive than CT in detecting acute infarction, and can determine whether there is evidence of prior cerebrovascular disease or other disorders, but will not usually affect treatment for most patients with a transient ischemic attack. Electroencephalography is useful in the evaluation of seizures, but seizures cannot cause monocular visual loss. Lumbar puncture is used to evaluate subarachnoid hemorrhage or central nervous system infections, but these disorders are distinctly uncommon causes of transient ischemic attack.

Key points

  • In a patient with a transient ischemic attack, carotid artery ultrasonography showing a more than 50% stenosis of the left internal carotid artery may be an indication for carotid endarterectomy.

Return to the next case

Case 3

Correct answer: D

This patient had a very severe headache 1 week before presentation with left hemispheric dysfunction, findings that are suggestive of subarachnoid hemorrhage (SAH). CT scan is only about 90% sensitive for detecting SAH, which is most likely to be missed when there is a delay in the presentation as in this patient. In such cases, lumbar puncture is required to look for xanthochromic staining of the cerebrospinal fluid, which can be detected up to 14 days after the hemorrhage, or gross blood in the fluid.

This patient's symptoms 7 days after the so-called “sentinel” hemorrhage are due to SAH-induced vasospasm with localized cerebral ischemia. Magnetic resonance angiography might detect an aneurysm, but would not detect subarachnoid blood as accurately as lumbar puncture. Carotid duplex ultrasonography and echocardiography would not be helpful in diagnosing the SAH. Transcranial Doppler ultrasonography can detect whether there are elevated velocities of the intracranial arteries, which would suggest vasospasm, but it is not a specific test and would not identify the underlying SAH.

Key points

  • CT scan may miss subarachnoid hemorrhage, especially when there is a delay in presentation after the initial hemorrhage.
  • Focal neurologic symptoms 3 to 7 days after a subarachnoid hemorrhage may be due to vasospasm with cerebral ischemia.

Return to the next case

Case 4

Correct answer: A

The patient has an acute infarction involving the right middle cerebral artery territory. Although he has no history of atrial fibrillation, it was likely present but previously undiagnosed. He is not eligible for acute thrombolytic therapy because he could not be treated within 3 hours of the onset of symptoms; however, the patient would benefit from early intervention of secondary prevention measures. He is at high risk for future cardioembolic strokes and would achieve substantial risk reduction with warfarin therapy to maintain an INR between 2.0 and 3.0.

Early use of either unfractionated or low-molecular-weight heparin is dangerous in acute ischemic stroke, and therefore enoxaparin is inappropriate. Clopidogrel has not been shown to be effective in either acute stroke or in the prophylaxis of stroke due to atrial fibrillation, although such therapy is effective in secondary prevention of non-cardioembolic stroke. Adenosine does not effectively treat atrial fibrillation, nor does it prevent stroke.

Key points

  • Secondary prevention of cardioembolic stroke consists of warfarin with a target INR of 2.0 to 3.0.
  • Heparin has no established role in the acute treatment of stroke.