Cerebrovascular Disease
Majaz Moonis
Richard P. Goddeau Jr
Muhib Khan
John P. Weaver
I. GENERAL PRINCIPLES
A. Cerebrovascular disease includes the following:
1. Stroke caused by arterial thrombotic or embolic ischemia (IS).
2. Intracerebral hemorrhage (ICH) and extracerebral hemorrhage (EH) into the subarachnoid, subdural, and epidural spaces.
B. Admission to the intensive care unit (ICU) is often warranted because of the severity of the disease or institution of newer therapies.
C. This chapter focuses on ischemic cerebrovascular disease (ICVD) and ICH.
II. ICVD
A. Prognosis.
1. Altered sensorium (state of consciousness), conjugate gaze paresis, and early radiologic signs of large infarction predict a poor outcome.
2. Lacunar stroke has a better prognosis (70% to 80% recovery).
3. Transient ischemic attack (TIA) patients have a 5.5% chance of stroke within 48 hours and 10% risk of stroke within 30 days.
B. Etiology.
1. ICVD results from restriction of blood flow to the brain, usually because of arterial occlusion.
2. Cardioembolic stroke is due to ischemic/valvular heart disease, atrial fibrillation, or cardiomyopathy.
3. Atherothrombotic stroke is caused by occlusion of a large intra-/extracranial portion of the carotid/vertebrobasilar system from progressive stenosis and occlusion.
4. Lacunar stroke is due to small blood vessel occlusion.
5. Watershed territory strokes result from systemic hypotension, with resulting border zone infarction (areas between anterior and middle cerebral artery [MCA], or middle and posterior cerebral artery distributions).
C. Diagnosis.
1. History—helps to determine the type of stroke.
a. Cardioembolic more common during the day with acute onset.
b. Atherothrombotic more often during sleep.
c. Intracranial hemorrhage often starts with a headache, and deficit may progress for a considerable time.
d. TIA is defined as a neurologic/retinal deficit due to IS, followed by full recovery and lack of infarction on imaging studies.
2. Examination.
a. Aphasia, hemiparesis or hemiparesthesia, and monocular visual loss suggest carotid system IS.
b. Vertigo, cerebellar ataxia, and crossed deficits (ipsilateral cranial nerve and contralateral hemiparesis or hemianesthesia) suggest involvement of the vertebrobasilar system.
c. Pure motor hemiparesis, pure sensory stroke, ataxic hemiparesis, and dysarthria—clumsy hand syndrome—suggest the diagnosis of lacunar stroke.
3. Laboratory and radiologic evaluation.
a. Neuroimaging: An essential procedure!
i. To exclude ICH or subarachnoid hemorrhage.
ii. To select patients for acute thrombolytic therapy.
iii. Noncontrast head computed tomography (CT) usually does not demonstrate the region of infarction in the acute period (within 12 hours of onset). Diffusion-weighted magnetic resonance imaging (DW-MRI) can demonstrate ischemic lesions within minutes of onset, whereas perfusion imaging (PI) demonstrates the area at risk of eventual infarction. A diffusion-weighted perfusion imaging (DW-PI) mismatch demonstrates the penumbra (salvageable tissue). Perfusion computed tomography (CTP) and CT angiography (CTA) are accurate, faster, and, therefore, more practical when thrombolytic therapy is anticipated.
b. An electrocardiogram (ECG) and telemetry in all patients with IS: A 30-day cardiac event monitor/implantable long-term cardiac monitor at discharge in cryptogenic stroke, to look for atrial fibrillation.
c. Echocardiography, transesophageal echocardiogram in selected cases.
d. Carotid ultrasound and transcranial Doppler ultrasound are used in patients with contraindications to CTA or magnetic resonance angiography (MRA).
e. Blood studies, at a minimum, should include the following: a complete blood count (CBC), fasting lipids, blood glucose, and sCRP. Hypercoagulable workup and anticardiolipin antibodies may be obtained in younger patients or those with prior venous thrombosis, recurrent abortions, thrombocytopenia, and migraine (lupus antiphospholipid antibody anticoagulant syndrome).
D. Treatment.
1. Identify patients who are candidates for thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) (Table 123-1). Thrombolysis: 33% greater probability of being free of any disability; at 3 months, 10-fold relative increased risk of intracranial bleeding.
a. Patients presenting within 4.5 hours of onset of ischemic stroke should have an urgent CT scan to rule out hemorrhage and large
infarcts (greater than one-third of the MCA territory). CTA should be considered to evaluate for large vessel occlusion amenable to endovascular thrombectomy. CTP or MRI (DW-PI) may be helpful to define extent of ischemic penumbra.
infarcts (greater than one-third of the MCA territory). CTA should be considered to evaluate for large vessel occlusion amenable to endovascular thrombectomy. CTP or MRI (DW-PI) may be helpful to define extent of ischemic penumbra.
TABLE 123-1 Intravenous Thrombolytic Therapy for Acute Ischemic Stroke | |
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