From the Research
Posterior circulation stroke and Posterior Reversible Encephalopathy Syndrome (PRES) are distinct neurological conditions with different causes, presentations, and outcomes, and the key distinction lies in their reversibility and management approaches. The main difference between the two conditions is that posterior circulation stroke results from a sudden interruption of blood flow to the posterior brain regions, causing permanent damage to brain tissue, whereas PRES is characterized by reversible vasogenic edema in the posterior brain regions, usually triggered by severe hypertension, certain medications, eclampsia, or autoimmune disorders 1.
Causes and Presentation
Posterior circulation stroke typically presents with symptoms like vertigo, ataxia, visual field defects, diplopia, dysarthria, and crossed sensory or motor deficits, whereas PRES manifests with headache, altered mental status, seizures, visual disturbances, and often hypertension 2. The underlying causes of posterior circulation stroke include atherosclerosis, cardioembolism, and small vessel disease, whereas PRES is often associated with severe hypertension, renal failure, autoimmune disorders, eclampsia, or immunosuppressant medications 3.
Imaging and Diagnosis
Imaging also differs between the two conditions: stroke shows restricted diffusion on MRI indicating cytotoxic edema, while PRES demonstrates vasogenic edema on T2/FLAIR sequences without diffusion restriction 4. Early detection of PRES is key for a rapid recovery and good prognosis, and frequent neurological evaluations and neuroimaging examinations by computed tomography or magnetic resonance imaging are required for both the diagnosis and assessment of the condition 2.
Management and Outcomes
Treatment approaches reflect the fundamental difference between the two conditions, with stroke management focusing on reperfusion and secondary prevention, while PRES management centers on removing the trigger and controlling blood pressure 5. The key to managing PRES is prompt treatment of the underlying cause and blood pressure management, which can lead to reversal of the condition, whereas posterior circulation stroke requires acute interventions like thrombolysis or thrombectomy if eligible.
Some studies have reported atypical forms of PRES, which can make diagnosis and management more challenging 3. Additionally, there have been reports of an association between PRES and essential thrombocythemia, highlighting the importance of considering multiple potential causes and triggers in patients with PRES 5. Overall, a thorough understanding of the differences between posterior circulation stroke and PRES is essential for providing optimal care and improving outcomes for patients with these conditions.