What are the next steps for a patient with nausea, poor balance, and subtle left side weakness, potentially indicating a neurological issue like stroke or TIA?

Immediate Emergency Evaluation Required for Suspected Posterior Circulation Stroke

This patient requires immediate emergency department evaluation with brain imaging (CT or MRI) and vascular imaging within 24 hours, as the combination of nausea, poor balance, and subtle left-sided weakness strongly suggests a posterior circulation stroke or high-risk TIA. 1

Clinical Reasoning for Urgency

The symptom triad presented indicates VERY HIGH risk for recurrent stroke requiring immediate action:

• Nausea with poor balance (ataxia) are classic posterior circulation (vertebrobasilar) symptoms 1
• Subtle left-sided weakness represents unilateral motor involvement, which places this patient in the highest risk category 1
• The combination of posterior circulation symptoms (nausea, imbalance) with motor weakness suggests either a brainstem stroke affecting crossed pathways or multiple territory involvement 1, 2, 3

Critical time window: 43% of strokes following TIA occur within 7 days, with 17% occurring the same day and 9% the next day 4. The risk is as high as 13% in the first 90 days 1.

Immediate Actions Required

1. Emergency Department Transfer

• Send immediately to an ED with on-site brain imaging and stroke treatment capability 1
• Do not delay for outpatient workup 1
• Time from symptom onset to treatment directly impacts outcomes 5

2. Initial Diagnostic Studies (Within 24 Hours)

Brain imaging - Priority #1:

• CT head without contrast (fastest to exclude hemorrhage) OR MRI with diffusion-weighted imaging (DWI) (more sensitive for posterior circulation strokes, which can be as small as 4mm) 1, 3
• MRI-DWI is superior for detecting acute pontine and cerebellar infarcts that CT may miss 3

Vascular imaging - Must be completed within 24 hours:

• CTA or MRA from aortic arch to vertex to evaluate both extracranial and intracranial vessels 1
• Vertebrobasilar system must be visualized given the posterior circulation symptoms 1

Immediate laboratory tests:

• Blood glucose (to exclude hypoglycemia as stroke mimic) 1, 6
• Complete blood count with platelets 1
• Electrolytes and renal function 1
• PT/INR and aPTT 1
• 12-lead ECG (to detect atrial fibrillation or other cardioembolic sources) 1

3. Specific Examination Considerations

Assess for brainstem localization:

• Check for ipsilateral facial sensory loss with contralateral body weakness (suggests brainstem lesion affecting crossed pathways) 3
• Evaluate cranial nerve function, particularly looking for diplopia, dysarthria, or dysphagia 1
• Perform HINTS examination (Head Impulse, Nystagmus, Test of Skew) if cerebellar symptoms predominate - this is more sensitive than early MRI for cerebellar stroke 6

Document precise symptom characteristics:

• Exact time of symptom onset or last known well (critical for thrombolysis eligibility) 5
• Whether symptoms are transient, fluctuating, or persistent 1
• Progression or improvement of weakness 1

Risk Stratification Based on Presentation

This patient meets VERY HIGH risk criteria per Canadian Stroke Best Practice guidelines 1:

• Unilateral weakness (even if subtle) within 48 hours = highest risk category
• Requires immediate ED evaluation and imaging within 24 hours 1

The vertebrobasilar symptomatic disease carries a 2.4-13.1% annual stroke rate, among the highest risk territories 2.

Common Pitfalls to Avoid

Do NOT delay imaging for outpatient scheduling - the benefit of intervention (carotid endarterectomy for symptomatic stenosis) is greatly diminished beyond 2 weeks, and essentially lost after 4-12 weeks 1

Do NOT dismiss subtle weakness - 77% of acute stroke patients have upper-limb motor deficits, and subtle findings can represent evolving stroke 1

Do NOT assume TIA if symptoms persist - with modern imaging, many patients with symptoms <24 hours have cerebral infarction on DWI, meeting the tissue-based definition of stroke 1

Do NOT miss posterior circulation strokes - nausea and imbalance are frequently attributed to benign causes, but when combined with any focal neurological sign, they mandate stroke evaluation 1, 2

Consider stroke mimics but err on side of caution: hypoglycemia, seizure with Todd's paralysis, migraine with aura, and peripheral nerve lesions can mimic stroke, but these are excluded through the emergency evaluation, not by delaying imaging 7

Treatment Implications of Timely Diagnosis

If imaging confirms acute ischemic stroke:

• IV alteplase within 3-4.5 hours improves functional outcomes (OR 1.6 within 3 hours; OR 1.3 within 3-4.5 hours) 5
• Mechanical thrombectomy within 6-24 hours for large vessel occlusion dramatically improves independence rates (OR 2.49-4.92) 5
• Dual antiplatelet therapy (aspirin + clopidogrel) within 24 hours for minor stroke/high-risk TIA reduces 90-day stroke risk from 7.8% to 5.2% 5

The window for maximum benefit is measured in hours, not days - immediate action is non-negotiable 4.