What is the management approach for a patient presenting with symptoms of a posterior stroke?

Management of Posterior Circulation Stroke

Patients presenting with posterior circulation stroke symptoms require immediate emergency department evaluation with the same priority as anterior circulation stroke, focusing on rapid determination of thrombolytic eligibility within 3 hours of symptom onset, airway protection, and cautious blood pressure management. 1

Immediate Recognition and Triage

Clinical Presentation

Posterior circulation (vertebrobasilar) stroke presents with distinct symptoms that differ from anterior circulation events:

• Ataxia, cranial nerve deficits, visual field loss, dizziness, imbalance, and incoordination are characteristic of vertebrobasilar ischemia 1
• Binocular diplopia, dysarthria, dysphagia indicate posterior circulation involvement 1
• Patients may present with non-focal symptoms that overlap with anterior circulation strokes, making diagnosis challenging 2, 3

Critical Time Assessment

• The single most important piece of information is time of symptom onset - defined as when the patient was last known to be at baseline or symptom-free 1
• For patients who awaken with symptoms, onset time is when they were last awake and normal 1
• Patients presenting within 48 hours with posterior circulation symptoms (ataxia, binocular diplopia, dysarthria, dysphagia) are at VERY HIGH risk for recurrent stroke 1

Urgent Diagnostic Evaluation

Immediate Imaging

Non-contrast head CT must be performed immediately to exclude intracranial hemorrhage, though it has poor sensitivity (~10%) for detecting posterior fossa ischemic strokes 1

• CT should be completed within 25 minutes of arrival, with interpretation within 45 minutes 4
• MRI head without contrast is the preferred imaging modality for suspected posterior circulation stroke due to superior sensitivity for posterior fossa lesions 1
• CTA or MRA from aortic arch to vertex should be performed urgently within 24 hours to evaluate for large vessel occlusion and determine thrombectomy eligibility 1, 4

Laboratory Studies

Do not delay neuroimaging or acute treatment while waiting for laboratory results except for patients on warfarin requiring INR 4

Essential labs include:

• Complete blood count, electrolytes, glucose, renal function, coagulation studies, troponin 4
• ECG should be completed without delay due to high incidence of cardiac disease 1, 4

Acute Treatment

Thrombolytic Therapy

Intravenous rtPA (0.9 mg/kg; maximum 90 mg) is strongly recommended for carefully selected patients who can receive medication within 3 hours of symptom onset 1

• Posterior circulation strokes have similar benefits and lower hemorrhage risks compared to anterior circulation when treated with thrombolysis 5, 6
• Safe use requires strict adherence to NINDS selection criteria, close observation, and careful ancillary care 1
• Intravenous streptokinase or other thrombolytic agents cannot be safely substituted for rtPA 1

Mechanical Thrombectomy

Recent evidence from ATTENTION and BAOCHE trials demonstrates that thrombectomy benefits basilar artery occlusion 6

• CTA/MRA should be performed to identify patients eligible for mechanical thrombectomy 1
• Effectiveness for other posterior circulation occlusion sites beyond basilar artery remains uncertain 6

Supportive Care

Urgent treatment must include measures protecting airway, breathing, and circulation, especially in seriously ill or comatose patients 1

• Elevated blood pressure should be lowered cautiously 1
• Temperature should be verified at least four times daily for three days, treating if >37.5°C 4
• Oxygen saturation should be monitored, with supplemental oxygen only if <94% 4
• Blood glucose should be monitored at least four times daily for the first three days 4

Antiplatelet and Anticoagulation

Aspirin can be administered within the first 48 hours due to reasonable safety and small benefit 1

• Urgent anticoagulation cannot be recommended routinely as it increases risk of brain hemorrhage, especially in moderately severe strokes, without proven benefit in preventing early recurrent stroke 1
• Short-term dual antiplatelet therapy is appropriate for secondary prevention 6

Common Pitfalls

Diagnostic Challenges

• Commonly used prehospital stroke scales do not adequately represent posterior circulation symptoms, leading to delayed recognition 2
• HINTS examination requires special training - most emergency physicians cannot perform it with sufficient accuracy as a first-line test before MRI 1
• CT has very low sensitivity (~10%) for acute posterior fossa stroke - do not rely on negative CT to exclude diagnosis 1

Treatment Delays

• Onset to treatment time is typically longer in posterior circulation stroke compared to anterior circulation 5
• Patients with posterior circulation symptoms presenting within 48 hours should be immediately sent to an ED with advanced stroke care capacity including on-site brain imaging and access to acute stroke treatments 1

Specialized Stroke Unit Care

Comprehensive stroke unit care, including rehabilitation, should be provided to a broad spectrum of patients 1

• Organized stroke care increases the number of patients who can be treated 1
• Subsequent hospital treatment should include measures to prevent medical/neurological complications and evaluation to determine stroke etiology for secondary prevention 1

Neurosurgical Considerations

Ischemic and hemorrhagic space-occupying cerebellar strokes can benefit from decompressive craniectomy 6

• Monitor for signs of cerebellar edema causing brainstem compression, which can decrease level of consciousness 1