What is the appropriate diagnostic work‑up and initial management for a patient presenting with hand numbness and pain that has progressed to inability to move the arm?

Diagnostic Work-Up for Hand Numbness Progressing to Arm Paralysis

This presentation demands immediate emergency department evaluation within hours to rule out acute stroke, spinal cord compression, or acute arterial occlusion—all of which require intervention within minutes to hours to prevent permanent disability or death. 1, 2

Immediate Life-Threatening Conditions to Exclude

Acute Stroke Assessment

• Check for stroke symptoms immediately: facial weakness, speech disturbance, or contralateral symptoms, as the combination of arm numbness with these features carries a 72% probability of stroke 1
• Isolated arm numbness alone still represents high stroke risk and requires urgent evaluation 1
• Patients presenting within 48 hours have a 10% risk of completed stroke within the first week, with highest risk in the first 48 hours 1
• Obtain brain MRI with diffusion-weighted imaging immediately as the preferred modality to detect acute ischemic changes 1
• If MRI unavailable, perform CT head without contrast to rule out hemorrhage 1
• CT angiography or MR angiography from aortic arch to vertex is essential to evaluate carotid and vertebral artery disease 1

Acute Arterial Occlusion

• Assess the "6 P's" immediately: Pain, Pallor, Pulselessness, Paresthesias (numbness), Poikilothermia (cool limb), Paralysis 1
• Check radial pulse on the affected arm and measure blood pressure in both arms 1
• If pulse is absent or blood pressure unmeasurable, this is acute arterial occlusion requiring immediate vascular surgery consultation for thrombectomy/embolectomy 1
• Outcome depends entirely on time to reperfusion 1

Spinal Cord Compression

• Obtain full spinal column MRI immediately if there is bilateral weakness, sensory level, bowel/bladder dysfunction, or back pain 3
• MRI with both T1- and T2-weighted images is required to demonstrate spinal metastases and epidural compression 3
• MRI should be performed within 12 hours if there is clinical suspicion of myelum or cauda compression 3
• Look for alarm symptoms: decreased leg strength, difficulty controlling limbs, very wobbly gait, numbness radiating from chest/stomach/groin, or inability to walk 3

Peripheral Nerve Injury Evaluation

Guillain-Barré Syndrome

• Consider GBS in patients with rapidly progressive bilateral weakness of legs and/or arms in the absence of CNS involvement 3
• Classic presentation includes distal paresthesias followed by ascending weakness starting in legs and progressing to arms and cranial muscles 3
• Reflexes are decreased or absent in most patients at presentation and in almost all patients at nadir 3
• Disease onset is acute or subacute, with patients typically reaching maximum disability within 2 weeks 3
• If maximum disability occurs within 24 hours or after 4 weeks, consider alternative diagnoses 3
• Dysautonomia is common and includes blood pressure/heart rate instability, pupillary dysfunction, and bowel/bladder dysfunction 3

Focal Nerve Injury

• Obtain high-resolution ultrasound of the affected nerve from proximal to distal to identify the exact site and nature of injury 4
• MRI with dedicated neurography sequences (diffusion-weighted imaging) provides superior soft-tissue detail if ultrasound is equivocal 4
• Isolated wrist drop without upper motor neuron signs points to peripheral radial nerve injury rather than central causes 4

Critical Diagnostic Algorithm

Step 1: Time-Sensitive Triage (Within Minutes)

• Assess airway, breathing, circulation first 2
• Check for signs of elevated intracranial pressure and herniation 2
• Perform focused neurologic examination to localize the lesion 2

Step 2: Urgent Imaging (Within Hours)

• Brain imaging must be performed immediately to differentiate ischemic from hemorrhagic stroke, as this fundamentally changes treatment 1
• If stroke excluded and weakness is ascending or bilateral, obtain full spinal MRI within 12 hours 3
• If unilateral and pulse absent, obtain CT angiography of the affected limb emergently 1

Step 3: Specialist Consultation (Same Day)

• Patients with unilateral or bilateral neurological symptoms presenting within 48 hours require same-day assessment at a stroke prevention clinic or emergency department with advanced stroke capacity 1
• Vascular surgery consultation if acute arterial occlusion suspected 1
• Neurosurgery consultation if spinal cord compression identified 3

Immediate Medical Management

If Stroke Suspected

• Initiate aspirin 75-325 mg daily immediately unless contraindicated, as the patient has symptomatic cerebrovascular disease 5
• Start high-intensity statin therapy (atorvastatin 80 mg daily) regardless of cholesterol levels 5
• Consider dual antiplatelet therapy (aspirin + clopidogrel 75 mg) for the first 21 days in patients with symptomatic carotid stenosis 1

If Guillain-Barré Syndrome Diagnosed

• Intravenous immunoglobulin (0.4 g/kg daily for 5 days) or plasma exchange (200-250 ml/kg for 5 sessions) 3
• Monitor respiratory function closely for neuromuscular respiratory failure 2

If Peripheral Nerve Injury

• Initiate aggressive physical therapy immediately focusing on affected muscle groups 4
• Wrist splinting in neutral position (20-30 degrees extension) to prevent contractures 4
• Topical NSAIDs for localized pain and inflammation 4

Common Pitfalls to Avoid

• Do not dismiss isolated numbness as benign—it still represents high stroke risk requiring urgent evaluation 1
• Do not rely on conventional x-rays, CT scans, or bone scintigraphy to exclude spinal metastases—full spinal MRI is required 3
• Do not delay imaging for "observation" in patients presenting within 48 hours—this is the highest-risk period 1
• Do not assume normal reflexes exclude Guillain-Barré Syndrome—patients with pure motor variant and AMAN subtype may have normal or exaggerated reflexes 3
• Do not perform lumbar puncture before neuroimaging if elevated intracranial pressure or spinal cord compression is suspected 2