From the Guidelines
A posterior cerebrovascular accident (CVA) assessment should prioritize immediate neuroimaging with CT angiography or MRI, as these strokes can rapidly deteriorate and may require different treatment approaches than anterior circulation strokes. The assessment should focus on identifying symptoms specific to the posterior circulation, which supplies the brainstem, cerebellum, and occipital lobes. Begin by evaluating for vertigo, ataxia, and visual field defects, which are hallmark signs of posterior circulation involvement, as recommended by the American Heart Association/American Stroke Association guideline 1. Check for nystagmus, diplopia, and dysarthria, which indicate brainstem dysfunction. Assess for limb coordination using finger-to-nose and heel-to-shin tests to detect cerebellar involvement. Evaluate visual fields by confrontation testing to identify homonymous hemianopia from occipital lobe damage. Also, examine for altered consciousness, which may occur with brainstem involvement. The National Institutes of Health Stroke Scale (NIHSS) should be supplemented with these specific assessments as it may underestimate posterior stroke severity. According to the ACR Appropriateness Criteria, surveillance imaging after the initial ischemic injury is defined should focus on identifying complications such as hemorrhagic conversion or associated mass effect 1. Time is critical, so if posterior stroke is suspected, immediate action is necessary to prevent further deterioration. Some key points to consider in the assessment of a posterior CVA include:
- Evaluating for symptoms specific to the posterior circulation
- Using immediate neuroimaging with CT angiography or MRI
- Assessing for brainstem dysfunction and cerebellar involvement
- Evaluating visual fields to identify homonymous hemianopia
- Examining for altered consciousness
- Supplementing the NIHSS with specific assessments for posterior stroke severity.
From the Research
Assessment for Posterior Cerebrovascular Accident (CVA)
The assessment for a posterior cerebrovascular accident (CVA) involves various factors, including the use of recombinant tissue-type plasminogen activator (rt-PA) thrombolytic therapy.
- The efficacy of intravenous alteplase thrombolytic therapy for posterior circulation stroke (PCS) has been rarely described 2.
- Studies have shown that patients with acute PCS who received rt-PA thrombolytic therapy within 3 hours after stroke onset had better outcomes compared to those treated within 3-4.5 hours 2.
- The National Institutes of Health Stroke Scale (NIHSS) score is used to assess the severity of stroke, and patients with mild stroke (NIHSS score ≤3 points) who received alteplase thrombolysis therapy within 3 hours after stroke onset benefited more from the therapy 2.
- Other studies have investigated the safety and efficacy of tissue plasminogen activator (tPA) in patients with acute ischemic stroke, including those with posterior circulation stroke 3, 4, 5, 6.
- A systematic review and meta-analysis found that IV tPA is associated with a better functional outcome at 90 days in patients with wake-up stroke, despite an increased risk of symptomatic intracranial hemorrhage 5.
- Another study found that patients with posterior circulation stroke had a higher rate of small vessel disease and lacunar stroke, but the outcome was similar to those with anterior circulation stroke in terms of complications and mortality 6.
- The use of imaging-based treatment algorithms, such as MRI or CT-based imaging, can help identify patients with wake-up stroke who may benefit from IV tPA 5.