Cerebrovascular Disorders Part 1

Author(s): Nneka L. Ifejika-Jones, MD MPH

Originally published:7/30/2012

Last updated:4/19/2016

1. DISEASE/DISORDER:

Definition

Cerebrovascular disease refers to an abnormality of the brain, resulting from a pathologic process of the blood vessels. The terms stroke or cerebrovascular accident refer to the abrupt onset of a focal neurologic deficit caused by cerebrovascular disease.

Etiology

Strokes can be classified as ischemic (85%) or hemorrhagic (15%).

The Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system1 for ischemic stroke is based on the underlying stroke mechanisms:

  1. Large artery atherosclerosis: Intracranial, extracranial (carotid, aortic arch)
  2. Cardioembolic: Atrial fibrillation, segmental wall akinesis, paradoxical embolus, patent foramen ovale, and congestive heart failure
  3. Small vessel: Lacunar infarction
  4. Other: Vessel dissection, venous thrombosis, drugs
  5. Cryptogenic

Hemorrhagic strokes are most often caused by hypertension, with lesions typically located in the basal ganglia, thalamus, pons, and cerebellum. Amyloid angiopathy is the second most common cause, with lesions more often in cortical locations. Other cause of stroke include medications (either iatrogenic, e.g., warfarin, novel oral anticoagulant (NOAC) agent, or drugs of abuse, e.g., cocaine), vascular malformations, cerebral venous thromboses, or tumors.

Epidemiology including risk factors and primary prevention

Stroke is the most common neurologic emergency, and it is the leading cause of disability in the United States.

Modifiable risk factors include hypertension, hyperlipidemia, poorly controlled diabetes mellitus, obesity, substance abuse, and atrial fibrillation.

Hypertension is the greatest risk factor for both ischemic and hemorrhagic stroke; the higher the blood pressure (BP), the greater the risk. This is why even in prehypertensive individuals (systolic BP of 120-139 mm Hg), lifestyle modifications (diet, exercise) to reduce BP are recommended.

Multiple epidemiologic studies have found an association between hyperlipidemia and an increased risk of ischemic stroke. Individuals with diabetes have a greater susceptibility to atherosclerosis and proatherogenic risk factors (hypertension and hyperlipidemia). The presence of hyperglycemia, or elevated blood sugars, can enlarge eventual stroke size and increase the risk of brain hemorrhage.2

Obesity is associated with an increased incidence of all listed modifiable risk factors. Excessive alcohol consumption, tobacco use, and other substance abuse leads to stroke predisposition. Atrial fibrillation is associated with a 4 to 5-fold increased risk of ischemic stroke because of embolism of stasis-induced thrombi.

Nonmodifiable risk factors include a family history of cerebrovascular disease, sickle cell disease, or hypercoaguable states. Ethnic populations, such as African-Americans and Hispanics, are more likely to have cerebrovascular disease than Caucasians. Advanced age and male sex are also other nonmodifiable risk factors.

Patho-anatomy/physiology

There are signs and symptoms characteristic of vascular lesions in the various arterial territories of the brain.1

  1. Middle cerebral: Contralateral loss of strength and sensation in the face, upper limb, and to a lesser extent, the lower limb. Aphasia characterizes dominant hemisphere lesions, while neglect accompanies nondominant hemisphere lesions.
  2. Anterior cerebral: Contralateral loss of strength and sensation in the lower limb and, to a lesser extent, in the upper limb.
  3. Posterior cerebral: Contralateral visual field deficit, possibly confusion and aphasia if present in the dominant hemisphere.
  4. Penetrating branches (lacunar syndrome): Contralateral weakness or sensory loss (usually not both) in the face, arm, and leg. Dysarthria or ataxia may be present. Aphasia, neglect, or visual loss are not characteristic of lacunar syndromes.
  5. Basilar: Combinations of limb ataxia, dysarthria, dysphagia, facial and limb weakness, and sensory loss. Pupillary asymmetry, dysconjugate gaze, decreased responsiveness, and visual field loss may be present.
  6. Vertebral (or posterior inferior cerebellar): Truncal ataxia, dysarthria, dysphagia, ipsilateral sensory loss on the face, and contralateral sensory loss below the neck.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

Presentation of ischemic strokes varies according to the underlying etiology.4

Thrombotic/atherosclerotic strokes typically occur with a slow fluctuating clinical course, with deficits progressing over 24 to 48 hours. Thrombotic strokes are more likely to be preceded by transient ischemic attacks.

In contrast, cardioembolic stroke has a sudden onset. Although the neurologic deficits can be severe with cardioembolism, as the embolus fragments into smaller pieces, these deficits can rapidly resolve.

Hypertensive hemorrhages have a variable progression ranging from minutes to days. Symptoms include headache, nausea, or vomiting because of increased intracranial pressure.

Specific secondary or associated conditions and complications

The most common neurologic complications of cerebrovascular disease include recurrent stroke, with a 12 to 15% incidence in the first year, followed by hemorrhagic transformation, hydrocephalus, cerebral edema, and seizure.5 Cardiac complications include arrhythmia, acute coronary syndrome, and heart failure. Infectious complications include urinary tract infections and aspiration pneumonias. Thrombotic complications include deep venous thrombosis, pulmonary embolus, and thrombophlebitis.

2. ESSENTIALS OF ASSESSMENT

History

At initial evaluation, patients with ischemic stroke who present within the 0- to 4.5-hour time window may be eligible for intravenous thrombolysis with tissue plasminogen activator.6,7 Stroke distribution, type, and etiology should be documented.

For patients with a large vessel occlusion of the anterior circulation (i.e., the M1 branch of the middle cerebral artery), intra-arterial therapy with a clot retriever device is a second treatment in ischemic stroke within 6 hours from symptom onset 8,9,10. Used in conjunction with intravenous tissue plasminogen activator therapy, thrombectomy with a stent retriever in the anterior circulation improved functional outcomes at 90 days 11.

A significantly higher proportion of patients who received intra-arterial therapy achieved a good functional outcome compared to medical management alone, without an increase in the incidence of symptomatic intracranial hemorrhage. In the MR CLEAN study, there were 13.5% absolute risk difference points in rates of functional independency between patients who received intra-arterial therapy compared to medical management alone8.

On admission to a rehabilitation unit, acute interventions, such as hemicraniectomy, carotid revascularization, or ventriculostomy placement should be listed. The patient’s hospital course and complications should also be reviewed. Medical history should focus on stroke risk factors. A thorough social history should discuss family support, home environment, and alcohol, tobacco, or drug use.

Physical examination

Vital signs should focus on temperature, pulse, respiratory rate, pulse oximetry with supplemental oxygen requirements, and blood pressure for the previous 24 hours. The patient’s level of arousal and responsiveness should always be documented. Head, ears, eyes, nose, and throat examination includes evaluation of incision sites, extraocular musculature and pupils, and the presence of a nasogastric tube.

Cardiovascular examination includes auscultation for the presence of a murmur, distant heart sounds, irregular rhythm, and a carotid bruit. The pulmonary examination includes careful auscultation both anteriorly and at the lung bases. The abdominal examination should document bowel sounds, abdominal tenderness, and the presence of a percutaneous endoscopic gastrostomy tube and urinary catheter.

A careful neurologic examination can often localize the region of brain dysfunction. The exam includes evaluation of mental status, cranial nerve, motor, cerebellar, and sensory function. Motor control, strength, balance, coordination, and gait should be evaluated. Examination of cortical function includes testing for aphasia, apraxia, neglect, and cortical sensation. Presence and severity of spasticity should be assessed. The extremity examination should include check for distal pulses, edema, color changes, and calf pain.

Functional assessment

The functional history documents the patient’s prestroke baseline and current status in order to aid in determining the prognosis.

This includes the prestroke ability to perform basic activities of daily living, ambulatory status, and use of durable medical equipment. Physical therapy and occupational therapy assessments are valuable for poststroke functional status.

Premorbid cognitive impairments, such as psychiatric disease, dementia, and learning disability, should be documented.

Speech/language pathologists can provide valuable input when managing any cognitive and communication deficits after stroke. A swallow assessment may include a bedside swallow evaluation, in addition to either a modified barium swallow or a fiberoptic endoscopic evaluation of swallow to evaluate dysphagia and to screen for aspiration risk.

If caregiver services were required prior to admission for either physical or cognitive impairments, the duration and frequency of this level of care should be documented.

Laboratory studies

Laboratory studies focus on both identification of stroke etiology and evaluation for acute treatments.3 Serum electrolytes, cholesterol panel, liver function tests, complete blood count, and hemoglobin A1c are a part of standard practice.

If coagulopathy is suspected, a coagulation panel, D-dimer, and fibrinogen are performed. Hypercoaguable testing for arterial thromboses includes antiphospholipid antibody panel, lupus anticoagulant, Russell viper venom, and hemoglobin electrophoresis. Additional tests for venous thromboses are protein C and S, antithrombin III, Factor V Leiden, and Factor II G20210A. Autoimmune testing, such as erythrocyte sedimentation rate, antinuclear antibody, Complement components 3 and 4, SS-A, SS-B, and high-sensitivity C-reactive protein, should be performed.

In patients with a concern for hereditary stroke, testing for mutations of the Notch 3 gene on chromosome 19 can help with the diagnosis of Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL)12.

Imaging

Computed tomography (CT) scan of the brain without contrast will identify a hemorrhagic stroke, because blood is radiopaque (bright). However, CT may not show obvious changes in patients with acute ischemic stroke within the first 24 hours. Signs to look for on the CT in patients with ischemic stroke include loss of grey/white differentiation, sulcal effacement, slit-like ventricles, and midline shift.

Magnetic resonance imaging of the brain allows for identification of ischemic lesions. A set protocol includes T1, T2, fluid-attenuated inversion-recovery (FLAIR), diffusion-weighted imaging (DWI), and apparent-diffusion coefficient sequences. T1 shows possible subtle changes (appears dark) because of a decreased signal. On T2, ischemic lesions and cerebral edema appear white. With FLAIR, ischemic lesions appear white; the suppression of the cerebrospinal fluid (CSF) (dark) makes it easier to find pathology at the CSF/brain junction.

Ischemic lesions with DWI appear white, with maximal intensity at 40 hours13.  On apparent diffusion coefficient, ischemic lesions appear dark where the DWI is bright. It is maximally dark at 28 hours.

Supplemental assessment tools

Magnetic resonance angiography (MRA) evaluates the intracranial vessels and the extracranial vessels of the neck. MRA can detect arterial stenosis, aneurysms, and arteriovenous malformations.

Magnetic resonance venography can be used to identify venous sinus thrombosis. It can also detect atypical hemorrhagic infarcts located high in the convexity, with more associated edema.

Transcranial Doppler ultrasound detects left to right shunt (most common is the patent foramen ovale), emboli monitoring, diagnosis of intracranial stenosis or acute occlusion, and monitoring of acute thrombolytic therapy14.

Early predictions of outcomes

Risk factors for disability after stroke include severe stroke with minimal motor recovery at 4 weeks, evidenced by either a prolonged flaccidity, or a late return of the proprioceptive facilitation (>9d) of the proximal traction response in the arm (>13d). Other risk factors are bilateral lesions, low level of consciousness, previous stroke or functional disability, poor sitting balance, severe neglect, sensory and visual deficits, global aphasia, urinary or fecal incontinence (lasting >1-2wk), and delay in medical care.

Environmental

Environmental factors can significantly impact morbidity. In patients with limited bed mobility, a stage I pressure ulcer can form in as little as 2 hours. Turning/positioning schedules are integral to maintain skin integrity.

Orientation cues are important for patients with confusion or neglect. Dry-erase boards that are updated daily with the day, month, and year, as well as names of the care providers and scheduled test/procedures provide additional environmental support.

Social role and social support system

After a cerebrovascular event, it is common to see changes to the patient’s social role, both at home and in their community. There is a sense of loss, and it is appropriate for patients to grieve this loss. During this time, the support of family and friends is extremely important.

Professional Issues

The goal of providing acute stroke treatment and stroke rehabilitation is to restore as much independence as possible by improving physical, mental, and emotional function. This must be done in a way that preserves the dignity of the patient and motivates the patient to adjust and regain functional abilities.

3. REHABILITATION MANAGEMENT AND TREATMENTS

See Cerebrovascular Disorders Part 2.

4.CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE

See Cerebrovascular Disorders Part 2.

5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE

See Cerebrovascular Disorders Part 2.

REFERENCES

  1. Adams HP Jr, Bendixen BH, Kappelle LJ, et al. Classification of subtype of acute ischemic stroke. Definitions for use in a multicenter clinical trial. TOAST. Trial of Org 10172 in Acute Stroke Treatment. Stroke. 1993;24:35-41.
  2. Guide to Clinical Preventative Services: Report of the U.S. Preventative Servies Task Force. Baltimore, MD: Williams and Wilkins; 1996.
  3. Uchino K, Pary JK, Grotta JC. Acute Stroke Care: A Manual from the University of Texas-Houston Stroke Tteam. New York, NY: Cambridge University Press; 2007.
  4. Garrison SJ. Handbook of Physical Medicine and Rehabilitation. Philadelphia, PA: Lippincott Williams and Wilkins; 2003.
  5. Pendlebury ST, Rothwell PM. Risk of recurrent stroke, other vascular events and dementia after transient ischaemic attack and stroke. Cerebrovasc Dis. 2009;27 Suppl 3:1-11.
  6. Hacke W, Donnan G, Fieschi C. Association of outcome with early stroke treatment: pooled analysis of ATLANTIS, ECASS and NINDS rt-PA stroke trials. Lancet. 2004;363:768-774.
  7. Hacke W, Kaste M, Bluhmki M. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke. N Engl J Med. 2008;359:1317-1329.
  8. Berkhemer OA, Fransen PS, Beumer D, van den Berg LA, Lingsma HF, Yoo AJ et al; for the MR CLEAN investigators.  A randomized trial of intraarterial treatment for acute ischemic stroke.  N Engl J Med. 2015; 372:11-20.
  9. Goyal M, Demchuk AM, Menon BK, Eesa M, Rempel JL, Thornton J et al; ESCAPE trial investigators.  Randomized assessment of rapid endovascular treatment of ischemic stroke.  N Engl J Med. 2015; 372:1019-1030.
  10. Campbell BC, Mitchell PJ, Kleinig TJ, Dewey HM, Churilov L et al; for the EXTEND-IA investigators.  Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging Selection.  N Engl J Med. 2015; 372:1009-1018.
  11. Saver JL, Goyal M, Bonafe A, Diener HC, Levy EI, Pereira VM et al; for the SWIFT PRIME investigators.  Stent-Retriever Thrombectomy after Intravenous t-PA vs. t-PA Alone in Stroke.  N Engl J Med. 2015; 372:2285-2295.
  12. Meschia JF, Brott TG, Brown RD Jr. Genetics of cerebrovascular disorders. Mayo Clin Proc. 2005; 80:122-32.
  13. Eastwood JD, Engelter ST, MacFall JF, Delong DM, Provenzale JM. Quantitative assessment of the time course of infarct signal intensity on diffusion-weighted images. AJNR Am J Neuroradiol. 2003;24:680-687.
  14. Caplan LR. Diagnosis and treatment of ischemic stroke. JAMA. 1991;266:2413-2418.

Original Version of the Topic:

Nneka L. Ifejika-Jones, MD MPH. Cerebrovascular Disorders Part 1 (Disease/Disorder, Principles of Assessment). Publication Date: 2012/07/30.

*Nneka L. Ifejika-Jones, MD MPH – Disclosure Information:

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