The following cases and commentary, which address stroke, are excerpted from ACP's Medical Knowledge Self-Assessment Program (MKSAP14).
Case 1: Sudden trouble with speech
A 72-year-old man is brought to the emergency department because of sudden trouble with speech and word finding that has persisted for one hour. He has a history of hypertension and atrial fibrillation. His medications include warfarin, lisinopril and atenolol.
On physical examination, the patient's temperature is normal, pulse rate is 70 beats/min and irregular and blood pressure is 150/95 mm Hg; his BMI is 35.5 kg/m2. Cardiac examination shows an irregularly irregular rhythm with variable intensity of S1 and no murmurs or extra sounds. His lungs are clear to auscultation. Neurologic examination reveals paraphasic errors, an impaired ability to repeat sentences verbatim and mild weakness of the right side of the face and the right arm; no leg weakness is detected. Reflexes are brisker in the right than the left limbs, and there is a Babinski's sign on the right. Testing of the patient's level of consciousness, visual fields and sensory function in the fingers and toes shows no abnormalities.
Which of the following diagnostic tests should be done immediately?
A. Carotid duplex ultrasonography
B. CT of the head
Case 2: Weakness and vision loss
A 71-year-old woman is evaluated in the emergency department because of a six-hour history of left-sided weakness and left visual field loss. She has a history of hypertension for which she takes lisinopril. The patient has no history of atrial fibrillation. She has smoked one pack of cigarettes daily for the past 50 years.
Physical examination shows a pulse rate of 72 beats/min and a blood pressure of 170/100 mm Hg. Results of her cardiopulmonary examination are normal. Neurologic examination reveals left homonymous hemianopia; severe weakness of the left arm, left leg and left side of the face; and neglect of the left side of space. She has a normal level of consciousness and speech.
Platelet count, INR, creatinine concentration and electrolyte levels are all within normal limits. Electrocardiography shows a normal sinus rhythm without evidence of ischemia or infarction. A CT scan shows a hyperdense right middle cerebral artery that is associated with low density in the right middle cerebral artery territory. Echocardiography is pending.
Which of the following is the best immediate treatment?
A. Aspirin, orally
B. Enoxaparin, subcutaneously
C. Labetalol, intravenously
D. Recombinant tissue plasminogen activator, intravenously
E. Warfarin, orally
Case 3: Sudden onset of moderate neck pain
A 22-year-old man is evaluated in the emergency department eight hours after the sudden onset of moderate neck pain followed by vertigo, ataxia, slurred speech and difficulty swallowing. His medical history is unremarkable and he is not taking any medications. Physical examination shows left ptosis, anisocoria with the left pupil smaller than the right, nystagmus, left-sided dysmetria and decreased pain and temperature sensation on the left side of the face and right side of the body. CT scan of the brain is normal.
Which of the following is the most appropriate next step in the evaluation of this patient?
A. Repeat noncontrast CT scan of the brain in 24 hours
B. Carotid ultrasound
C. MRI and magnetic resonance angiography of the brain and neck
D. Lumbar puncture
Case 4: Vertigo, ataxia and headache
A 58-year-old man is evaluated in the emergency department after awakening with vertigo, ataxia and headache. He has hypertension and stable angina, and his medications are aspirin, a beta-blocker and a statin.
On examination, his blood pressure is 170/92 mm Hg. Physical examination reveals bidirectional nystagmus and gait ataxia. CT scan of the brain is normal. Examination the following day reveals lethargy alternating with agitation, intractable hiccups, bidirectional horizontal nystagmus, normal strength, and dysmetria of the right upper and lower extremities.
Which of the following is the most likely diagnosis?
A. Vestibular neuronitis
B. Benign positional vertigo
C. Vestibular migraine
D. Ménière's disease
E. Cerebellar infarction
Case 5: Worsening left hemiparesis
A 78-year-old woman is evaluated in the emergency department for worsening of left hemiparesis, which was caused by a stroke two years earlier. The stroke involved the right middle cerebral artery territory and was attributed to atrial fibrillation. Initially, she had a very severe left hemiparesis, but gradually improved with three months of rehabilitation. At her most recent office evaluation, she had a very mild left central facial palsy, a left pronator drift and a left foot drop.
Today, she awoke and realized that she could not walk due to the increased weakness, which has now persisted for several hours. Her current medications are warfarin and metoprolol.
On examination, blood pressure is 110/70 mm Hg, heart rate is 80 beats/min, respiration rate is 18 breaths/min, and temperature is 38.1°C (100.5°F). Physical examination reveals an irregularly irregular heart rhythm but is otherwise normal. Neurologic examination reveals normal mental status, normal visual fields, a moderate left central facial palsy and moderate left hemiparesis. INR is 2.3. Electrolytes and glucose are normal. CT scan of the brain shows a chronic hypodensity in the right middle cerebral artery territory.
Which of the following is the most likely diagnosis?
A. Acute cerebral infarction
B. Postictal paresis
C. Unmasking of chronic deficit due to infection
D. Hemorrhage into previous infarction
Case 6: Aphasia and right-sided weakness
A 79-year-old man is evaluated in the emergency department 65 minutes after the witnessed onset of aphasia and mild right-sided weakness. His medical history includes localized prostate cancer. He has had no recent bleeding, surgery, or trauma.
His blood pressure is 170/100 mm Hg, heart rate is 90 beats/min, and respiration rate is 16 breaths/min. Physical examination is normal. Neurologic examination reveals severe global aphasia, without any understandable speech or ability to follow commands, a prominent right central facial palsy and very mild right pronator drift. Strength and sensation are normal. Complete blood count and serum electrolytes and glucose are normal. CT of the brain is normal.
Which of the following is the most appropriate therapy for this patient?
A. Intravenous tissue plasminogen activator
B. Intra-arterial tissue plasminogen activator
C. Intravenous abciximab
D. Intravenous heparin
Answers and commentary
Correct answer: B. CT of the head.
The patient presents with a syndrome of aphasia and right hemiparesis that suggests acute stroke in the left middle cerebral artery territory. Further, the patient is seen within the three-hour window during which intravenous recombinant tissue plasminogen activator (rtPA) is indicated. It is essential to establish through brain imaging the presence and mechanism (ischemic versus hemorrhagic) of stroke as quickly as possible (within 30 minutes of arrival in the emergency department, if possible) before rtPA is initiated. Thrombolytic therapy with rtPA can reverse neurologic dysfunction in patients with acute ischemic stroke: The number of patients who recover complete independence after stroke increases from approximately 35% to approximately 50% after thrombolytic therapy. All subtypes of ischemic stroke respond to intravenous thrombolytic therapy.
CT of the head without radiocontrast is initially indicated for patients with suspected stroke and can reliably distinguish acute intracerebral hemorrhage from ischemia. Because CT is relatively insensitive to ischemic changes in the first few hours after stroke, early findings may be subtle, such as hyperdense vessels (suggestive of acute intraluminal thrombus), loss of boundaries between gray and white matter and effacement of cerebral sulci. CT is nearly 100% sensitive for detecting intracerebral hemorrhage and approximately 90% sensitive for detecting subarachnoid hemorrhage.
MRI is also an option for the evaluation of patients with acute stroke. A recent prospective comparison of MRI and CT in the emergency department setting found that MRI is more sensitive than CT for diagnosing ischemic stroke and as sensitive as CT for diagnosing hemorrhagic stroke. However, MRI is generally more expensive, usually more time consuming and often less available compared with CT. Acquiring results from MRI should never delay the initiation of rtPA therapy in potential candidates. Therefore, MRI currently is not the standard of care in this setting.
Carotid duplex scanning and echocardiography may be useful for establishing the most likely reason for ischemic stroke and in guiding treatment for secondary prevention. However, they do not have a role in the acute management of stroke.
Electroencephalography is not indicated in this case because the history strongly suggests a stroke and not a seizure. A postictal focal neurologic syndrome is also an unlikely explanation for the patient's signs and symptoms.
- CT is currently the standard of care for ruling out hemorrhage before administering intravenous tissue plasminogen activator to patients seen within three hours of exhibiting stroke-like symptoms.
- MRI with diffusion imaging and gradient echo imaging is superior to CT for diagnosing ischemic stroke in the emergency department setting but is not more sensitive than CT for diagnosing hemorrhagic stroke in that setting.
Correct answer: A. Aspirin, orally.
This patient has had an acute infarction involving the right middle cerebral artery territory. Aspirin administered within 48 hours of stroke onset results in a small but significant reduction of the risk for recurrent stroke during the first two weeks after the stroke and improves outcome at six months.
Anticoagulation with unfractionated heparin or low-molecular-weight heparin does not benefit patients who have had a hemispheric ischemic stroke and is associated with an increased risk of secondary hemorrhage. Therefore, providing anticoagulation with heparin or low-molecular-weight heparin (such as enoxaparin) in most ischemic strokes is inappropriate, except for subcutaneous heparin for prophylaxis against deep venous thrombosis.
A mean arterial pressure (approximated by the following equation: diastolic pressure + 1/3 [systolic pressure – diastolic pressure]) of up to 140 mm Hg is acceptable in acute ischemic stroke. This patient's mean arterial pressure is 123 mm Hg. Rapid lowering of blood pressure with agents such as labetalol may compromise cerebral blood flow and result in more extensive cerebral infarction.
The patient is not eligible for acute thrombolytic therapy with recombinant tissue plasminogen activator (rtPA) because she could not be treated within three hours of symptom onset. Early treatment with rtPA increases the likelihood of benefit; after three hours, however, the risk of intracerebral bleeding exceeds the benefit of reduced disability or death.
Orally administered warfarin provides no immediate benefit and is only superior to aspirin for secondary prevention of ischemic stroke in patients with overt sources of cardioembolism. Its use in this case is not indicated because the presence of an embologenic lesion has not been established. High-risk cardioembolic causes of stroke and transient ischemic attack that are treated with anticoagulation include atrial fibrillation, left atrial appendage thrombus, left ventricular thrombus and dilated cardiomyopathy with a significant reduction in ejection fraction.
- Aspirin administered within 48 hours of stroke onset results in a small but significant reduction of the risk for recurrent stroke during the first two weeks after the stroke and improves outcome at six months.
- A mean arterial pressure of up to 140 mm Hg is acceptable in acute ischemic stroke.
Correct answer: C. MRI and magnetic resonance angiography of the brain and neck.
This patient has an ischemic stroke (cerebral infarction). The symptoms and signs involve multiple lower cranial nerves (dysphagia, dysarthria), crossed sensory deficits and cerebellar ataxia, which suggest a left lateral medullary localization, possibly also involving the left cerebellum. The sudden onset of symptoms suggests that stroke is the cause. The normal CT rules out a parenchymal intracerebral hemorrhage, which would be unlikely in the medulla. Blood is supplied to this area by the posterior inferior cerebellar artery, a major branch of the vertebral artery. In a previously healthy young person, the less common causes of stroke must be considered, such as vertebral artery dissection, which often occurs spontaneously without trauma or typical vascular risk factors. Typical symptoms of vertebral dissection include neck or posterior head pain, Horner's syndrome (ptosis and miosis), dysarthria, dysphagia, decreased pain and temperature sensation of the face and contralateral body, dysmetria, ataxia and vertigo. Magnetic resonance angiography is an excellent tool in diagnosing dissection. Noncontrast CT scan in 24 hours will only reveal the evolving stroke, not its cause. Carotid ultrasound studies do not reliably characterize abnormalities in the vertebral artery other than reversal of flow. Lumbar puncture is used to evaluate suspected subarachnoid hemorrhage in a patient who has a severe headache with a normal CT scan, but such localized medullary symptoms would be atypical for subarachnoid hemorrhage.
- Vertebral artery dissection typically presents with neck or head pain, Horner's syndrome, dysarthria, dysphagia, decreased pain and temperature sensation, dysmetria, ataxia and vertigo.
- Magnetic resonance angiography is the most sensitive diagnostic test for vertebral artery dissection as a cause of stroke.
Correct answer: E. Cerebellar infarction.
This patient presents with headache, vertigo, and ataxia, which are the classic presenting symptoms of ischemic or hemorrhagic cerebellar stroke. Although CT scan can exclude hemorrhage, infarcts may not be well visualized early, especially in the brainstem and cerebellum. The patient's deterioration the following day with signs of brainstem compression (altered level of consciousness and intractable hiccups) indicates a dire situation, and urgent neurosurgical decompression is required. Peripheral vertigo may be a result of many disorders of the ear, including vestibular neuronitis, benign positional vertigo, vestibular migraine, acoustic neuroma and Ménière's disease, but none of these causes unilateral limb ataxia, dysarthria or hiccups. Headache may accompany vestibular migraine but is not a feature of the other peripheral disorders.
- The classic symptoms of cerebellar stroke are headache, vertigo and ataxia.
Correct answer: C. Unmasking of chronic deficit due to infection.
This patient presents with right hemispheric dysfunction, but these symptoms are similar to and less severe than the previous stroke in that area. The normal CT excludes hemorrhage into the old infarction. Recurrent stroke in the same territory as the previous stroke with identical symptoms is not likely to occur with atrial fibrillation, which can send emboli to any part of the brain. Seizure cannot be refuted or confirmed with the existing information, but the lack of any other signs of seizure and the duration of several hours make postictal paresis less likely. Unmasking of a chronic deficit due to infection is highly likely because of the fever; the patient should be carefully evaluated for an occult infection, such as a urinary tract infection.
- Infection with fever can temporarily exacerbate a chronic neurologic defect in a patient with a previous stroke.
Correct answer: A. Intravenous tissue plasminogen activator.
This patient has an acute infarction in the left middle cerebral artery territory. He can be treated within three hours after the onset of his stroke and meets all eligibility criteria for intravenous tissue plasminogen activator. Intra-arterial tissue plasminogen activator is not approved for acute stroke, nor is abciximab, though they are being studied for stroke treatment up to six hours after onset in patients not eligible for tissue plasminogen activator. Intravenous heparin is not effective for acute ischemic stroke. Aspirin is useful in the early treatment of stroke because it prevents early recurrences, but does not have a major impact on clinical outcome.
- In acute ischemic stroke, tissue plasminogen activator is indicated if therapy is started within three hours of onset of symptoms, if there is no hemorrhage on CT scan and if all other eligibility criteria are met.