Definition
A.A sudden interruption of blood flow to the brain.
B.Classification.
1.Thrombotic strokes—55+%.
2.Embolic strokes—10% to 30%.
3.Lacunar strokes—10%.
4.Cryptogenic strokes—10%.
Incidence
A.Approximately 800,000 strokes occur each year.
1.610,000 are first-time strokes.
2.185,000 are recurring strokes.
B.Stroke is the fifth leading cause of death.
C.Stroke is the leading cause of disability. There are approximately 7 million stroke survivors in the United States.
Pathogenesis
A.Stroke results from decreased cerebral blood flow that can be the result of an obstruction (e.g., thrombus or embolus), vasoconstriction, low blood flow states (shock), or anything that deprives oxygen or glucose to the brain.
B.Anaerobic metabolism and lactic acid production compromise surrounding brain tissue (penumbra), causing ischemia followed by infarction if blood flow is now restored.
Predisposing Factors
A.Nonmodifiable.
1.Age greater than 55 years.
2.Gender: Women greater than men.
3.Race: African Americans have a 2 to 3x increased risk compared to Caucasians.
4.Prior stroke or transient ischemic attack (TIA).
5.Family history.
B.Modifiable.
1.Hypertension.
2.Hypercholesterolemia.
3.Diabetes.
4.Atrial fibrillation.
5.Hypercoagulable states.
6.Coronary artery disease.
7.Sleep apnea.
8.Smoking.
9.Alcohol consumption.
10.Use of oral contraceptives.
11.Obesity.
12.Drug use.
Subjective Data
A.Common complaints/symptoms.
1.Depend on the location of the stroke (see section TIA
discussion).
B.Common/typical scenario.
1.Sudden, abrupt onset.
2.Typical report of family members: Patient is perfectly fine one moment and then instantly changes.
3.Relationship between typical symptoms and location of stroke (see section TIA
discussion).
C.Review of systems.
1.Ask patient about following (see Table 6.3).
a.Headaches.
b.Speech difficulties.
c.Falls.
d.Dropping objects.
e.Weakness of arms/legs/face.
f.Numbness/tingling.
g.Loss of urine/bowel control.
h.Visual changes—blurriness, double vision, loss of vision.
Physical Examination
A.Objective data.
1.Level of consciousness.
2.Visual examination.
3.Motor and sensory examination.
4.Speech assessment.
5.Cognitive test.
6.Cranial nerve examination.
B.Use the National Institute of Health Stroke Scale (NIHSS) to objectively score stroke severity. The tool uses a point range from 0 to 42, with severity increasing with score and can be accessed through the National Institutes of Health: www.ninds.nih.gov/sites/default/files/NIH_Stroke_Scale.pdf.
1.Use dynamically to assess and then reassess the patient’s condition.
TABLE 6.3 Typical Findings of Stroke Symptoms Based on Hemisphere
2.Scores greater than 13 indicate very severe stroke that may warrant surgical intervention and carry a very high probability of severe disability or death.
Diagnostic Tests
A.Initial tests to be done immediately.
1.CT head.
a.Should be done immediately if stroke is in the differential diagnosis. From the moment a stroke is suspected, a CT head should be completed within 25 minutes.
b.Do NOT delay a CT head.
2.Lab tests: Should be done simultaneously as preparing to go to CT head.
a.Minimum: Obtain a glucose done prior to CT, but if the patient is a difficult stick, obtain the rest of the lab tests after CT of the head.
b.Complete blood count (CBC), basic metabolic panel, prothrombin time (PT)/partial thromboplastin time (PTT)/international normalized ratio (INR).
3.Electrocardiogram.
B.Other tests to be considered in select patients.
1.CT angiogram (CTA)/CT perfusion (CTP): Shows blood vessels, area of occlusion, and if there is collateral circulation. It can quantify cerebral blood flow, blood volume, and the presence or absence of penumbra.
2.MRI/magnetic resonance angiography: To evaluate extent of stroke.
3.Arterial blood gas (ABG).
4.Cerebral angiography: If a candidate for thrombectomy.
5.Ultrasound of carotids: To evaluate for carotid plaque as the source of stroke.
6.EEG: If seizure suspected.
Differential Diagnosis
A.Ischemic stroke.
B.Hemorrhagic stroke.
C.Migraine.
D.Bell’s palsy.
E.Seizure.
F.Hypoglycemic/hyperglycemia episode.
G.Sepsis.
H.Vertigo.
I.Neuromuscular or neurodegenerative disease.
J.Brain tumor.
K.Meningitis.
L.Syncope.
M.Multiple sclerosis.
Evaluation and Management Plan
A.The treatment of stroke should be broken up into three main phases. In the first phase, after the stroke has been identified, the goal of treatment is to minimize the damage as quickly as possible. In the second phase of the treatment of stroke, the goal is to prevent further strokes from occurring. In the third phase of treatment, the goal is to return the patient to his or her functional baseline prior to the stroke occurring.
B.Phase I plan.
1.Medical management.
a.Blood pressure (BP) control—the goal of BP management is to avoid complications. BP that is lowered too rapidly can cause increased ischemia and BP that is too high may cause a hemorrhagic conversion.
i.If no thrombolytics are given, treat the following BP.
1)Diastolic BP >140 mmHg: Intravenous infusion.
2)Systolic BP >220 mmHg, diastolic BP 121 to 40 mmHg: Intravenous push medications.
3)Systolic BP <220 mmHg or diastolic BP <120 mmHg: Monitor in the absence of other compelling indications.
ii.If thrombolytics are to be given or have been given, treat the following BP.
1)Systolic BP >180 mmHg.
2)Diastolic BP >105 mmHg.
b.Glucose monitoring.
i.The brain requires glucose for energy. Persistent hyperglycemia is associated with poor neurological outcomes. Hypoglycemia can cause worsening of ischemia.
ii.Goal of glucose monitoring: Maintain euglycemia less than 180 mg/dL.
c.Intravenous tissue plasminogen activator (tPA) administration.
i.Given to patients with the diagnosis of ischemic stroke where intracranial hemorrhage has been ruled out who present within a 3-hour time frame for treatment from symptom onset.
ii.Some patients may qualify for treatment with intravenous tPA up to 4.5 hours. However, this is not Food and Drug Administration (FDA) approved.
2.Surgical management.
a.Endovascular intervention.
b.Intra-arterial tPA administration.
i.Intra-arterial delivery directly into the clot via endovascular intervention.
ii.Given within 6 hours of symptom onset.
iii.Delivered directly into the clot.
iv.Often used with mechanical clot extraction in large vessel strokes.
c.Carotid endarterectomy: Rarely done as an emergency.