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Martinson Arnan, M.D. and Rebecca Gottesman, M.D., Ph.D.
11-09-2010
- Results from any disruption of blood flow to the brain, prolonged enough to cause cell death and manifesting as focal neurological symptoms.
- Hemorrhagic strokes caused by blood leaking from blood vessels into brain tissue.
- Ischemic strokes caused by an occlusion of a blood vessel.
- Ischemic strokes further subcategorized by mechanism or etiology of the stroke. Subcategories include strokes due to large vessel atherosclerosis, cardio-embolism, and small-vessel disease.
- Other causes of strokes include hypercoagulability, dissection, sickle cell disease, as well as some undetermined causes (Adams).
- Stroke is the third leading cause of death in the U.S. (American Heart Association).
- Stroke is the leading cause of disability in the U.S.
- More than 700,000 strokes diagnosed in the U.S. every year, more than 160,000 of these result in death (American Heart Association).
- Diabetes is a predisposing factor for atherosclerosis and small-vessel disease, both of which can cause strokes.
- Persons with diabetes may also have other cardiovascular risk factors such as hypertension, obesity and hyperlipidemia that predispose to stroke.
- Diabetes is an independent risk factor for strokes (US Preventive Services Task Force). There is a 2- to 5-fold increased risk for stroke in patients with type 2 diabetes compared to those without diabetes (Manson, Stamler).
- About 15-33% of patients with ischemic strokes have diabetes (Karapanayiotides, Megherbi, Woo). Although diabetes is often associated with small vessel, lacunar-type strokes (Karapanayiotides), the presence of diabetes is associated with increased risk of other stroke subtypes, including cardioembolic and other nonlacunar types (Abbott).
- Hemorrhagic strokes are less frequent in persons with diabetes compared to those without diabetes (Jorgensen). Aspirin use in diabetes is not associated with an increased risk of hemorrhagic strokes, although it may be in persons without diabetes (The ETDRS Investigators).
- A history of diabetes mellitus is associated with poorer outcomes after a stroke (Lindsberg).
- On average ~1/3 of patients admitted with an acute stroke are found to be hyperglycemic (Williams, Scott). The presence of hyperglycemia is associated with poorer outcomes among patients with ischemic strokes (Bruno, 1999, Bruno, 2002, Alvarez-Sabin). Hyperglycemia may be a marker of the severity of a stroke (Candelise).
- Based on patient history, physical examination (including the NIH stroke score) and confirmatory diagnostic tests.
- Brain imaging confirms location, type, size and age of stroke. Typically, a non-contrast head CT is obtained during initial evaluation. Brain MRIs are obtained in most patients since it has a higher sensitivity/specificity for identifying strokes.
- Vascular imaging is done with CT Angiography, MR Angiography, or ultrasound to ascertain the presence of vessel occlusion.
- Perfusion images are also obtained with CT or MRI to acutely detect salvageable at-risk brain.
- Echocardiogram is obtained to rule out a cardiac source for a clot. Usually a transthoracic echocardiogram is an appropriate first test.
- Blood tests are performed to identify conditions that can mimic strokes, or increase risk of stroke. Routine tests include: serum glucose, electrolytes, EKGs, markers of cardiac ischemia, platelet counts, and coagulation profile.
- Often an infectious work-up can be completed if warranted.
- Further testing should exclude other conditions that predispose patients to having strokes [i.e. lipid profile, blood pressure measurement, continuous telemetry to rule out paroxysmal atrial fibrillation (Christensen)].
- Depend on the part of the brain that is involved.
- However, in all strokes, symptom onset is almost always sudden.
- Common symptoms include: 1) numbness and/or weakness over face, arm and/or leg; 2) trouble speaking or understanding people; 3) dizziness, gait instability or unsteadiness, and loss of coordination; 4) visual disturbance (Lloyd-Jones) including diplopia, unilateral vision loss, or a visual field cut.
- Hemorrhagic strokes more often associated with headache, nausea, and vomiting; otherwise, strokes rarely cause pain.
- Reappearance of old neurological deficits in the setting of an infection or glucose abnormalities (both hypoglycemia and hyperglycemia) can be mistaken for a stroke.
- Rarely, hypoglycemia can cause focal neurologic signs and symptoms, and can mimic stroke-like symptoms (Wallis), even in the absence of prior history of clinical stroke.
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Glycemic control: Similar to other forms of macrovascular disease, long-term follow-up of the UK Prospective Diabetes Study and the Diabetes Control and Complications Trial (EDIC) suggest that glycemic control is important to reduce risk.
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Hypertension: high blood pressure directly related to risk of ischemic stroke (Rodgers). Risk of stroke decreases by 30-40% with blood pressure lowering (Lawes). Among persons with diabetes, those with well-controlled blood pressure have 44% reduced risk of stroke compared to those who do not (UKPDS 38).
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Hyperlipidemia: goal LDL <70mg/dL (Grundy). In the Heart Protection Study, statin use decreased risk of strokes by 28% among persons with diabetes, independent of baseline LDL, pre-existing vascular disease, type or duration of diabetes, or adequacy of glycemic control (Collins).
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Smoking cessation
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Lifestyle modification: multiple large-scale prospective studies have shown that being overweight is associated with an increased risk of stroke in a dose-response fashion (Rexrode, Kurth, Song).
- The Look AHEAD trial, a randomized trial of intensive lifestyle interventions in diabetes, will include analysis of cardiovascular outcomes including stroke, at the study completion, but has already shown reductions in cardiovascular risk factors (The Look AHEAD Research Group).
- Although stroke risk calculators are not typically used in clinical practice, these engines may be useful in some patients who need to fully understand their risk for stroke before implementing lifestyle changes. Available risk engines include the UKPDS 60.
- Decision to safely administer thrombolytics depends on duration of symptoms so knowing exact time of symptom onset is important. If a patient awakes from sleep with symptoms, the time of symptom onset is assumed to be the last time patient was seen normal.
- Administration of intravenous (IV) tissue plasminogen activator (tPA) within 4.5 hours of symptom onset significantly decreases the devastating effects of ischemic strokes (Hacke).
- Patients with an anterior circulation territory stroke who are ineligible for IV tPA but are within a 6 hour window may be candidates for intraarterial (IA) tPA (Chalela, Choi). For posterior circulation strokes, window for IA tPA may even be extended to 24 hours (Ogawa). Both treatments require coordination with interventional radiology and involvement of vascular neurologists.
- Clot retrieval devices are actively being studied as a means of re-establishing flow in an artery that is occluded by a clot (Yu, Schumacher). The MERCI device from the Mechanical Embolus Removal in Cerebral Embolism (MERCI) trial is used at some centers for clot removal, although the utility of the device in improving post-stroke outcomes remains unclear (Smith).
- Most patients with acute ischemic stroke do not require anticoagulation during hospitalization. Individuals with apical thrombus or a mechanical heart valve may require anticoagulation soon after admission.
- Initiation of aspirin 325 mg within 24-48h of acute ischemic stroke (Coull) is recommended. Aspirin may not significantly limit the consequences of the acute stroke but can help prevent recurrent strokes.
- For acute ischemic stroke, aggressive blood pressure management is associated with poorer outcomes (Castillo). Only intervene if blood pressure is >220 mmHg systolic, or >120 mmHg diastolic. A reasonable goal is to decrease the blood pressure by 15-25% within the first day (Grossman). However, administering tPA is contraindicated if SBP >185 mmHg or DP >110 mmHg (The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group).
- Blood glucose should be kept in the normoglycemic range during stroke management.
- Persistent hyperglycemia in the first 24 hours of a stroke is an independent predictor of stroke volume expansion (Baird). Because hyperglycemia increases the metabolic needs of the brain and may therefore worsen any brain edema, glycemic control is particularly important in the early period after stroke.
- Because IV contrast may be needed for CT angiography or conventional angiography, metformin should be held on admission to decrease risk of lactic acidosis.
- Detailed interim history to exclude complications of strokes such as seizures, pain syndromes, contractures, or depression.
- Detailed physical examination can help determine the rate of recovery; most patients will regain some, if not all, function, up to 1-1.5 years after their initial event.
- Optimize glycemic control.
- Check routine labs needed for risk factor modification (i.e. lipid panel).
- Antiplatelet medication such as aspirin, unless the stroke has a cardioembolic etiology, in which case warfarin is preferred.
- Ask about ongoing behavior/lifestyle modification such as: smoking cessation, physical activity, weight reduction, maintaining a low salt diet.
- Closely follow progress in physical, occupation and/or speech therapies.
- Stroke risk increased in individuals with history of previous stroke. Patients with prior history of stroke need education on possible stroke symptoms, and benefit of seeking immediate emergency medical treatment if they experience any symptoms.
- Strokes in persons with diabetes are more common than the general population and are associated with poorer outcomes.
- Ischemic strokes are more common than hemorrhagic strokes in diabetes, and may be partially related to the presence of comorbidities such as hyperlipidemia and hypertension.
- Aspirin use can be safely used in diabetes and is not associated with increased risk of hemorrhagic strokes.
- Cardiovascular risk factor modification and glycemic control can reduce the risk of stroke.
- Lifestyle interventions can also decrease the risk of stroke.
- Early recognition of stroke symptoms and presentation to the hospital determines whether a patient is a candidate for thrombolytics and can affect stroke outcomes.
- Decisions about vascular or perfusion imaging approaches may be affected by presence of co-existing renal disease in individuals with diabetes due to risk for contrast nephropathy and/or nephrogenic systemic fibrosis.
- CT angiography or CT perfusion requires IV iodinated contrast, and MR perfusion or MR angiography of the neck (but not the head) requires gadolinium.
- A multidisciplinary approach including physical therapy, occupational therapy, and speech therapy is important for successful rehabilitation following stroke.
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