Recurrent Stroke (Most Likely Diagnosis)
This patient is most likely experiencing a recurrent ischemic stroke affecting the same vascular territory as their prior CVA. The combination of dizziness with worsening left-sided weakness in someone with established cerebrovascular disease strongly suggests new ischemic injury rather than simple progression of old deficits 1.
Clinical Reasoning
Why Recurrent Stroke is Most Likely:
- New symptom onset: Dizziness is a new complaint that wasn't part of the original presentation
- Worsening of existing deficits: The patient reports "body weakness" suggesting progression beyond baseline hemiparesis
- High recurrence risk: Patients with prior stroke face 13% risk of recurrent stroke within 90 days and up to 30% within 5 years 2
- Dizziness as a stroke symptom: While often dismissed, dizziness can indicate posterior circulation involvement or even hemispheric stroke 1, 3
Critical Anatomical Considerations:
The left-sided symptoms could arise from:
Right hemisphere involvement (most common for left-sided deficits): Right internal carotid or middle cerebral artery territory causing left-sided weakness, left-sided sensory loss 1
Posterior circulation stroke: Vertebrobasilar system involvement can cause dizziness, imbalance, and incoordination, potentially with associated weakness 1, 4
Supratentorial stroke with vestibular symptoms: Right hemispheric lesions (particularly involving insula, temporal regions) can present with dizziness and contralateral weakness 5, 6
Immediate Diagnostic Approach
Urgent Imaging Required:
Brain MRI with DWI is the gold standard - CT misses up to 89% of acute posterior circulation strokes and many small cortical infarcts 3. However, if MRI unavailable:
- Non-contrast CT head immediately to exclude hemorrhage
- CT angiography (CTA) from arch to vertex to assess vascular patency 7
- MRI brain with DWI as soon as available for definitive diagnosis 3
Key Clinical Examination Points:
Look specifically for:
- HINTS examination (Head Impulse, Nystagmus, Test of Skew) if dizziness is prominent - helps distinguish peripheral from central causes 3
- New focal deficits beyond baseline hemiparesis
- Ataxia, cranial nerve deficits, visual field cuts suggesting posterior circulation 1
- Vital signs - blood pressure, cardiac rhythm
Common Pitfalls to Avoid
Attributing symptoms to old stroke: Don't assume worsening weakness is just "progression" of prior CVA - this represents new pathology until proven otherwise
Dismissing dizziness: Isolated dizziness with prior stroke history warrants full stroke workup. Up to 75% of posterior circulation strokes may lack obvious focal deficits initially 3
Relying on CT alone: Non-contrast CT has very low sensitivity for acute posterior circulation and small cortical infarcts 3
Waiting for "classic" stroke symptoms: The NIHSS underemphasizes posterior circulation findings - patients can have NIHSS of 0 with significant posterior circulation stroke 4
Alternative Diagnoses to Consider (Less Likely)
- Seizure with Todd's paralysis: Would expect more acute onset, typically resolves within 48 hours
- Metabolic derangement: Check glucose, electrolytes, but wouldn't explain focal progression
- Vertebrobasilar dolichoectasia: Rare cause of recurrent symptoms 8, but imaging would show characteristic vascular changes
- Hemorrhagic transformation of old infarct: Would need imaging to exclude
Time-Critical Management
Treat as acute stroke until proven otherwise:
- Activate stroke protocol immediately
- Check time of symptom onset (last known well time)
- Assess for thrombolysis eligibility if within appropriate window
- Consider mechanical thrombectomy if large vessel occlusion identified 4
The presence of prior stroke with residual deficits does NOT exclude acute treatment eligibility - each new event should be evaluated independently for intervention 1.