What is the initial management for a patient presenting with a posterior circulation stroke?

Initial Management of Posterior Circulation Stroke

Administer IV alteplase (0.9 mg/kg) immediately within 4.5 hours if eligible, followed by urgent consideration for endovascular thrombectomy—but recognize that these strokes are frequently missed because symptoms like isolated vertigo, nausea, or headache can mask devastating basilar artery occlusion even with NIHSS score of 0. 1

Immediate Recognition and Triage

Critical Diagnostic Pitfall

• Posterior circulation strokes present with non-specific symptoms (dizziness, vertigo, nausea, vomiting, headache, loss of consciousness) that cause significant diagnostic delays compared to anterior circulation strokes 1, 2
• The NIHSS significantly underestimates severity because it focuses on limb weakness and speech rather than cranial nerve deficits and ataxia 1
• A patient can have NIHSS of 0 with only headache and vertigo yet harbor life-threatening basilar artery occlusion 1

Key Physical Examination Findings

• Ataxia (especially truncal ataxia), nystagmus, visual field defects, cranial nerve palsies, binocular diplopia, dysarthria, dysphagia 3, 1
• Transient, fluctuating, or persistent symptoms without motor weakness or language disturbance (hemibody sensory symptoms, monocular vision loss, hemifield vision loss) indicate moderate-to-high risk 3

Rapid Assessment Protocol

Initial Stabilization (First 10 Minutes)

• Assess airway, breathing, and circulation immediately 3
• Conduct neurological examination using standardized stroke scale (NIHSS), recognizing its limitations in posterior circulation 3, 1
• Measure heart rate and rhythm, blood pressure, temperature, oxygen saturation, hydration status, and assess for seizure activity 3
• Obtain acute blood work as part of initial evaluation 3

Urgent Imaging (Within 25 Minutes)

• Complete non-contrast CT within 25 minutes of arrival for thrombolysis candidates 1
• Look for hyperdense basilar artery sign (sensitivity 71%, specificity 98% for basilar occlusion; optimal density 40-42 Hounsfield units) which predicts poor 6-month outcome (mRS >2, OR 5.6) 1
• Perform CTA immediately at time of brain CT from aortic arch to vertex to assess both extracranial and intracranial circulation 3, 1
• Do not delay IV tPA for vascular imaging—begin thrombolysis before transport for additional imaging or endovascular therapy 1

Blood Pressure Management Before Thrombolysis

For Thrombolysis Candidates

• Target: systolic ≤185 mmHg and diastolic ≤110 mmHg 3, 1
• If systolic >185 mmHg or diastolic >110 mmHg:
  • Labetalol 10-20 mg IV over 1-2 minutes (may repeat once) OR 1
  • Nitropaste 1-2 inches OR 1
  • Nicardipine drip 5 mg/h, titrate up by 2.5 mg/h at 5-15 minute intervals (maximum 15 mg/h) 1
• Do not administer tPA if blood pressure cannot be reduced and maintained at target levels 1

For Non-Thrombolysis Candidates

• Lower blood pressure only when systolic >220 mmHg or diastolic >120 mmHg 3
• Aggressive blood pressure reduction may decrease perfusion pressure and worsen ischemia 3

Acute Reperfusion Therapy

Intravenous Thrombolysis

• Administer IV alteplase 0.9 mg/kg (10% bolus over 1 minute, remainder over 59 minutes) within 4.5 hours of symptom onset 1
• Posterior circulation strokes have similar benefits and lower hemorrhage risks compared to anterior circulation 4
• Approximately one-fifth of ischemic strokes occur in posterior circulation, and randomized trials included these patients despite focusing on anterior circulation 3, 2
• Do not withhold thrombolysis for mild or rapidly improving symptoms—one-third of patients with rapid improvement develop severe subsequent deterioration 3

Endovascular Thrombectomy

• Recent ATTENTION and BAOCHE trials demonstrate thrombectomy benefits basilar artery occlusion 4
• Intravenous alteplase may be equally beneficial as endovascular approaches for basilar artery occlusion (22% vs 24% good outcomes) 3
• The intravenous approach prevents unavoidable delays from invasive procedures and is best option in centers lacking endovascular expertise 3
• Consider thrombectomy for eligible patients, but do not delay IV tPA while arranging transfer 3, 1

Prognostic Awareness

High-Risk Features

• Mortality in basilar artery occlusion ranges from 45% to 86% without recanalization 1
• Predictors of poor outcome: older age, higher NIHSS score, lack of recanalization, atrial fibrillation, intracranial hemorrhage, pc-ASPECTS ≤8 1
• Door-to-needle time is often significantly longer for posterior circulation strokes due to difficulty in timely recognition 1

Follow-up Imaging

• Perform repeat CT or MRI at 24 hours after thrombolytic therapy regardless of clinical stability 5
• This 24-hour scan is required before starting anticoagulants or antiplatelet agents for secondary prevention 5
• For posterior circulation strokes, follow-up MRI may be appropriate to confirm diagnosis even when initial MRI is negative 5

Acute Neurological Complications

Cerebellar Edema

• Brain edema peaks at 3-5 days after stroke but can occur within 24 hours with large cerebellar infarctions 3
• Space-occupying cerebellar strokes can benefit from decompressive craniectomy 4
• Less than 10-20% of patients develop clinically significant edema warranting medical intervention 3

Aspiration Prevention

• Assess swallowing ability before allowing oral intake—persons with brain stem infarctions are at greatest risk 3
• Water swallow test at bedside is useful screening; videofluoroscopic modified barium swallow if indicated 3
• Insert nasogastric or nasoduodenal tube when necessary for feedings and medications 3