Page 2395 - Hematology_ Basic Principles and Practice ( PDFDrive )

Chapter 145 Stroke 2137

Ischemic Stroke versus Intracerebral Hemorrhage Cardiac Workup

Ischemic stroke and ICH can have similar presentations. Although An electrocardiogram can identify atrial fibrillation/flutter or evidence
some clinical features are more typically associated with ICH (e.g., of previous myocardial infarction whereas in-hospital telemetry can
coma, neck stiffness, seizures, vomiting, and headache) than ischemic identify a larger proportion of patients with paroxysmal atrial fibril-
stroke, neuroimaging is required to discriminate between them. lation. Based on the results of the recent CRYSTAL AF and
Therefore emergent CT or MRI of brain is mandatory in all patients EMBRACE trials, extended cardiac rhythm monitoring using loop
presenting with suspected acute stroke. recorders increases detection rates of paroxysmal atrial fibrillation in
patients with cryptogenic ischemic stroke older than 55 years. Longer
durations of cardiac monitoring result in higher diagnostic yield, but
Measuring Stroke Severity the optimal duration is uncertain. Transthoracic echocardiography
has a low yield in patients with no previous cardiac history and a
Many scales are available for measuring stroke severity, including the normal cardiac examination. The routine use of transesophageal
Scandinavian Stroke Scale, the Canadian Stroke Scale, and the echocardiography is controversial; however, this is an essential inves-
National Institutes of Health Stroke Scale (NIHSS). The NIHSS is tigation in patients with suspected endocarditis. A PFO can be identi-
the scale most widely used in clinical practice. Other scales (e.g., fied with a bubble study when performing transthoracic or
Hunt and Hess, Fisher) are used to measure stroke severity in patients transesophageal echocardiography. Although transesophageal echo-
with SAH. cardiography identifies potential etiologies of ischemic stroke in a
relatively large proportion of patients, such as PFO, atrial septal
aneurysm, or aortic arch disease, the treatment implications of these
Risk of Stroke After Transient Ischemic Attack findings are less certain. All patients presenting with stroke should
have vascular risk factor profiling, including measurement of blood
The ABCD2 score is a validated clinical prediction score for risk of pressure, fasting lipids, blood glucose, and glycated hemoglobin
stroke in patients with TIA. Points are score for each of the following (HbA1c). All patients should have a complete blood count, troponin,
risk factors: age >60 years (1); blood pressure ≥140/90 mmHg on and coagulation profile. Other useful tests, depending on clinical
first evaluation (1); clinical symptoms of focal weakness (2) or speech suspicion, may include erythrocyte sedimentation rate, antiphospho-
impairment without weakness (1); duration of 10–59 minutes (1) or lipid antibody panel, blood cultures, antineutrophilic cytoplasmic
≥60 minutes (2); and diabetes mellitus (1). In combined validation antibodies, antinuclear antibodies, homocysteine, and lipoprotein A.
cohorts, the 2-day risk of stroke was 0% for scores of 0 or 1, 1.3%
for scores of 2 or 3, 4.1% for scores of 4 or 5, and 8.1% for scores
of 6 or 7. THERAPY

A complete review of the management of stroke is beyond the scope
INVESTIGATIONS of this chapter. Instead we provide an overview of the acute and
chronic management of stroke.
Computed Tomography of the Brain
Reperfusion Therapy for Acute Ischemic Stroke
Neuroimaging is required to distinguish between ischemic and
hemorrhagic stroke. On CT of the brain, early features of ischemia
include loss of distinction between the gray and white matter border, Thrombolysis for Acute Ischemic Stroke
sulcal effacement, loss of definition of the insula, and evolving
areas of hypodensity. Scoring systems (e.g., ASPECT score) may Intravenous tissue plasminogen activator (t-PA) is the most rigorously
be used to quantify the burden of ischemia, which predicts the evaluated thrombolytic intervention in acute ischemic stroke. Current
risk of ICH in patients receiving thrombolysis. SAH is not reli- guidelines recommend administration of t-PA in patients with acute
ably excluded by CT alone. If there is a high index of suspicion ischemic stroke presenting within 3 hours of symptom onset. Based
for SAH, a lumbar puncture is needed to reliably exclude this on the results of the ECASS III trial, current guidelines recommend
diagnosis. administration of t-PA to eligible patients up to 4.5 hours after
symptom onset, provided none of the following additional exclusion
criteria are met: age >80 years, NIHSS >25, history of both prior
Magnetic Resonance Imaging stroke and diabetes mellitus, use of oral anticoagulant therapy at the
time of acute stroke, or imaging evidence of ischemic injury involving
MRI is superior to CT for detecting acute ischemia. In the acute more than one-third of the middle cerebral artery territory. The main
setting, however, its use is limited by patient contraindications and complication of t-PA is ICH. In the Third International Stroke Trial
availability. Diffusion-weighted imaging (DWI) may identify acute (IST-3), which enrolled patients up to 6 hours after symptom onset,
ischemia within 3–6 hours of symptom onset. For diagnosis of ICH, there was an increased risk of spontaneous ICH and death at 7 days
MRI with gradient-related echo or susceptibility-weighted imaging compared with the control group, although total mortality was
has been reported to provide results similar to those provided by CT similar between the two groups at 6 months. Currently t-PA is not
of the brain (96% concordance). approved by the European Medicines Agency (EMA) beyond 4.5
hours after symptom onset (Table 145.2).
Neurovascular Imaging
Intraarterial Fibrinolysis
Extracranial and intracranial stenosis may be detected using ultra-
sound, CT angiography, magnetic resonance angiography, or conven- Current guidelines recommend intraarterial fibrinolysis in carefully
tional angiography. Ultrasound is a noninvasive, relatively inexpensive, selected patients with major ischemic strokes caused by middle
and widely available imaging modality, but is dependent on ultraso- cerebral artery occlusion if the duration of symptoms is less than 6
nographer experience and skill. Transcranial Doppler may be used hours and they are ineligible for intravenous t-PA. Rescue intraarterial
to detect intracranial large vessel stenosis, and has also been shown fibrinolysis is an option for recanalization in patients with large-artery
to risk-stratify patients with carotid stenosis with microembolic occlusion who have not responded to intravenous t-PA. Use of
signals. intraarterial t-PA is currently not FDA approved. Limited access to