What is the differential diagnosis for a patient with sudden onset weakness and strange feelings in the left hand that progressed to bilateral arms and hands?

Differential Diagnosis for Sudden Onset Bilateral Arm and Hand Weakness with Strange Sensations

This patient requires immediate emergency department evaluation for acute ischemic stroke, which is the most critical diagnosis to rule out given the sudden onset and progression from unilateral to bilateral symptoms. 1

Immediate Life-Threatening Diagnoses

Acute Ischemic Stroke (Primary Concern)

• Sudden onset unilateral weakness that progresses to bilateral involvement places this patient at VERY HIGH risk for stroke, with up to 10% risk of recurrent stroke within the first week. 2
• The initial left-sided weakness with "strange feelings" (likely sensory disturbance) followed by bilateral progression suggests either:
  • Progressive thrombotic stroke affecting bilateral motor pathways 1
  • Multiple embolic events in rapid succession 3
  • Basilar artery territory involvement affecting bilateral descending motor tracts 1
• Patients presenting within 48 hours with unilateral weakness (face, arm, and/or leg) are considered highest risk and require immediate ED transfer with advanced stroke capabilities 1

Guillain-Barré Syndrome (GBS)

• GBS classically presents with ascending weakness starting distally in the legs, but can present atypically with arm-predominant or simultaneous limb involvement. 1
• The bilateral nature and progression pattern fits GBS, particularly if accompanied by:
  • Decreased or absent reflexes (present in most patients at presentation) 1
  • Sensory symptoms (distal paresthesias or "strange feelings") 1
  • Acute or subacute onset reaching maximum disability within 2 weeks 1
• Approximately two-thirds of GBS patients report preceding infection within 6 weeks (Campylobacter jejuni, cytomegalovirus, hepatitis E, Mycoplasma pneumoniae, Epstein-Barr virus, Zika virus) 1
• Critical distinguishing feature: GBS typically causes bilateral weakness that is relatively symmetric, whereas stroke causes contralateral deficits from a unilateral brain lesion. 1, 4

Hemorrhagic Stroke

• Intracerebral hemorrhage can present identically to ischemic stroke with progressive weakness 2
• Cannot be differentiated clinically from ischemic stroke—requires urgent brain imaging 2

Other Neurological Emergencies

Spinal Cord Pathology

• Acute cervical myelopathy (cord compression, epidural abscess, transverse myelitis) can cause bilateral arm weakness if the lesion is at C5-T1 level 1
• Look for: sensory level, bowel/bladder dysfunction, bilateral leg involvement, preserved reflexes or hyperreflexia (unlike GBS) 1

Post-Ictal (Todd's) Paralysis

• Transient focal weakness following seizure activity can mimic stroke 2
• Distinguished by witnessed seizure activity and gradual resolution over hours (not progression to bilateral involvement) 2

Hemiplegic Migraine

• Can present with unilateral weakness and sensory symptoms 2
• Typically younger patients with history of similar episodes, gradual onset over minutes, and complete resolution 2
• Does not explain progression to bilateral involvement 2

Metabolic Causes (Must Rule Out Immediately)

Hypoglycemia

• Can cause focal neurological deficits mimicking stroke and must be ruled out immediately with bedside glucose testing. 2
• Rapidly reversible with glucose administration 2

Severe Electrolyte Abnormalities

• Rarely cause focal neurological symptoms but should be checked with basic laboratory investigations 2

Critical Immediate Actions Required

Time-sensitive evaluation protocol:

1. Activate emergency medical services (9-1-1) immediately—only 53% of stroke patients currently use EMS despite clear mortality benefit. 2

2. Establish exact time of symptom onset or last known normal time to determine eligibility for IV tPA (within 4.5 hours) or endovascular thrombectomy (within 24 hours for selected patients) 3, 2

3. Check blood glucose immediately at bedside to rule out hypoglycemia 2

4. Transfer to emergency department with advanced stroke capabilities:

   • On-site brain imaging (CT or MRI) 1
   • Access to IV tPA and endovascular thrombectomy 1, 3
   • Stroke team availability 1

5. Urgent brain imaging (non-contrast CT or MRI) within 24 hours to differentiate ischemic from hemorrhagic stroke 1, 2

6. Non-invasive vascular imaging (CTA or MRA from aortic arch to vertex) within 24 hours to identify large vessel occlusion requiring endovascular thrombectomy 1, 3, 2

7. 12-lead electrocardiogram without delay to assess for atrial fibrillation or acute cardiac event 1, 2

8. Complete blood count, serum electrolytes, creatinine, and fasting blood glucose 2

Key Clinical Distinctions

Stroke vs. GBS differentiation:

• Stroke: Sudden onset (seconds to minutes), contralateral deficits from unilateral brain lesion, preserved or normal reflexes initially, vascular risk factors 1, 4
• GBS: Acute/subacute onset (hours to days), bilateral relatively symmetric weakness, decreased/absent reflexes, preceding infection history 1

The progression from unilateral to bilateral involvement in this case is atypical for stroke but possible with:

• Basilar artery thrombosis affecting bilateral motor pathways 1
• Multiple embolic events 3
• Recurrent stroke in opposite hemisphere 1

This progression pattern is more consistent with GBS if accompanied by areflexia and ascending pattern. 1

Critical Pitfalls to Avoid

• Do not assume symptoms are "too mild" to be stroke—even transient symptoms carry 10% risk of completed stroke within one week. 2
• Do not delay imaging for laboratory results—brain imaging takes priority over all other testing. 2
• Do not treat hypertension aggressively in acute stroke unless BP >185/110 mmHg for tPA candidates or >220/120 mmHg otherwise, as cerebral perfusion depends on elevated BP. 3
• Do not dismiss bilateral symptoms as "non-stroke"—basilar artery territory strokes can cause bilateral deficits. 1
• In patients reaching maximum disability within 24 hours or after 4 weeks, consider alternative diagnoses to GBS. 1