What is the recommended workup for acute unilateral arm numbness?

Acute Unilateral Arm Numbness Workup

Acute unilateral arm numbness requires immediate stroke protocol activation with urgent non-contrast head CT and CT angiography from aortic arch to vertex, performed within 30-60 minutes of arrival, as this presentation represents a high-risk stroke symptom that demands time-sensitive evaluation and treatment. 1, 2

Immediate Actions (First 5-10 Minutes)

Activate stroke code immediately for any patient presenting with acute unilateral arm numbness, as arm weakness or numbness is present in 88-100% of stroke presentations and places the patient in the highest risk category. 3, 1

• Document exact time of symptom onset or last known normal to determine eligibility for IV thrombolysis (3-4.5 hour window) and endovascular thrombectomy 1, 2
• Perform bedside capillary glucose measurement immediately to exclude hypoglycemia as a stroke mimic 1, 2
• Apply the National Institutes of Health Stroke Scale (NIHSS) to quantify deficits, infer likely vessel occlusion, and guide treatment eligibility 1
• Assess for additional stroke symptoms including facial asymmetry, speech difficulties, visual changes, or other focal neurological deficits using the FAST assessment 2, 3

Essential Neuroimaging (Within 30-60 Minutes)

Non-contrast head CT is the mandatory first imaging study to exclude intracranial hemorrhage before any thrombolytic therapy can be administered. 1, 2

CT angiography from aortic arch to vertex must be performed concurrently to:

• Detect large-vessel occlusion qualifying the patient for endovascular thrombectomy 1
• Visualize intracranial and extracranial circulation 1
• Identify significant carotid stenosis 2
• Assess posterior circulation and aortic arch pathology 1

Laboratory Evaluation (Immediate)

Order the following tests stat to confirm thrombolysis eligibility and identify stroke etiology: 1, 2

• Complete blood count
• Electrolytes and renal function panel
• Coagulation studies (aPTT, INR)
• Blood glucose
• Troponin
• 12-lead electrocardiogram to detect atrial fibrillation or other cardioembolic sources 1, 2

Risk Stratification

Patients presenting within 48 hours with unilateral arm numbness are classified as VERY HIGH risk for stroke, requiring same-day assessment at a stroke-ready facility. 1, 2 This is particularly true when numbness is accompanied by:

• Motor weakness 3, 1
• Speech or language disturbance 3, 2
• Other focal neurological symptoms 2

Critical Pitfalls to Avoid

Do not postpone transfer for extensive ancillary testing – each minute of delay worsens neurological outcome and reduces treatment options. 1

Do not dismiss isolated sensory symptoms – while less common than motor deficits, isolated arm numbness can still represent acute ischemic stroke and requires the same urgent evaluation. 1, 4

Do not assume peripheral nerve pathology without first excluding stroke – while conditions like carpal tunnel syndrome or radial tunnel syndrome can cause arm numbness, these typically have gradual onset and bilateral risk factors (diabetes, hypothyroidism). 5 Acute unilateral presentation mandates stroke workup first.

Ongoing Monitoring (First 24-48 Hours)

Once stroke is confirmed or excluded:

• Repeat neurological assessments (NIHSS) at baseline and hourly for 24 hours 1
• Monitor blood pressure every 15 minutes until stable, then every 30-60 minutes 1
• Maintain continuous cardiac monitoring to detect paroxysmal atrial fibrillation 1, 2

Special Considerations for Trauma

If the patient has a history of limb trauma with acute numbness, consider vascular injury workup with CT angiography if there is proximity to a major vascular axis, non-pulsatile extremity, or isolated neurological deficit. 3 However, in the absence of clear trauma history, stroke protocol takes precedence.