Anterior circulation strokes (MCA territory) are usually obvious: hemiparesis, aphasia, facial droop. But posterior circulation strokes — involving the brainstem, cerebellum, and occipital lobes — are far trickier. Rookies often miss them because symptoms are subtle, nonspecific, or mimic benign conditions like vertigo. Missing them is dangerous: these strokes can cause rapid deterioration, respiratory arrest, or locked-in syndrome.
Why They’re Missed
- Symptoms are non-classic: dizziness, nausea, imbalance rather than facial droop or limb weakness.
- Often fluctuate and appear “minor.”
- CT head is frequently normal early.
- Rookies may label patients as “vestibular neuritis” or “vertigo” and discharge.
Key Symptoms & Signs of Posterior Circulation Stroke
1. Dizziness / Vertigo
- Most common presenting symptom.
- Unlike benign vertigo, often associated with other neuro deficits.
2. Nausea & Vomiting
- Severe, disproportionate to exam.
3. Ataxia
- Gait unsteady, cannot walk without support.
- Limb ataxia on finger-to-nose or heel-to-shin.
4. Cranial Nerve Deficits
- Diplopia, dysarthria, dysphagia, facial numbness or weakness.
- Hearing loss, nystagmus.
5. Visual Symptoms
- Homonymous hemianopia (occipital lobe).
- Cortical blindness in severe cases.
6. Altered Consciousness
- Brainstem involvement → drowsiness, coma.
The HINTS Exam (For Acute Vertigo)
- Head-Impulse: normal (stroke), abnormal corrective saccade (vestibular neuritis).
- Nystagmus: direction-changing (stroke), unidirectional (peripheral).
- Test of Skew: vertical ocular misalignment suggests stroke.
Rookie pearl: HINTS is more sensitive than MRI in first 48 hrs — but only if performed correctly.
Imaging Pitfalls
- CT head is often normal early in posterior circulation strokes.
- MRI (DWI) is gold standard but may also miss very early lesions.
- CTA/MRA can show large vessel occlusion (basilar, vertebral).
ED Approach
- Suspect posterior stroke in any patient with acute vertigo + neuro symptoms (ataxia, CN deficits).
- Do HINTS if trained — otherwise escalate to neuro consult.
- Obtain CT/CTA head and neck — even if CT brain is normal.
- Admit for observation if diagnosis uncertain — posterior strokes can deteriorate suddenly.
Common Rookie Mistakes
- Discharging “vertigo” without neuro exam.
- Assuming normal CT = no stroke.
- Ignoring severe ataxia as “just vestibular.”
- Missing subtle cranial nerve findings.
Rookie Pearls
- “Dizziness + one neuro sign = stroke until proven otherwise.”
- If patient cannot walk unassisted, don’t call it benign vertigo.
- MRI/CTA should be pursued liberally if suspicion high.
- Early neurology involvement is essential.
Take-Home Message
Posterior circulation strokes are easy to miss but deadly if overlooked. For rookies:
- Always examine gait, cranial nerves, and coordination in “dizzy” patients.
- Don’t rely on CT alone — consider MRI/CTA.
- When in doubt, admit and monitor — these patients can crash.
Remember: Anterior strokes are loud. Posterior strokes whisper — rookies must learn to listen.
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