What is the initial workup for a patient presenting with facial numbness and tingling?

Initial Workup for Facial Numbness and Tingling

The initial workup for facial numbness and tingling should include a focused neurological examination, brain imaging (MRI with contrast), and targeted laboratory tests based on clinical suspicion rather than routine panels.

Clinical Assessment

History

• Determine onset: sudden (suggests stroke) vs. gradual (suggests other etiologies)
• Distribution of symptoms: unilateral vs. bilateral
• Associated symptoms:
  • Facial weakness (suggests Bell's palsy)
  • Visual changes (suggests stroke or demyelinating disease)
  • Headache (suggests stroke, tumor, or migraine)
  • Dizziness, trouble walking, or coordination issues (suggests stroke) 1
  • Mastication weakness (suggests trigeminal nerve involvement) 1

Physical Examination

• Perform a focused neurological examination:
  • Test facial sensation in all three trigeminal nerve distributions (V1, V2, V3)
  • Assess facial motor function (CN VII)
  • Check for other cranial nerve deficits
  • Evaluate for upper or lower motor neuron signs
  • Perform Cincinnati Prehospital Stroke Scale (facial droop, arm drift, speech) 1

Diagnostic Testing

Neuroimaging

• MRI brain with contrast is the first-line imaging study for facial numbness 1

  • Should cover the entire course of the trigeminal nerve
  • Include high-resolution sequences of the brainstem, skull base, and trigeminal nerve
  • Include MR angiography if vascular etiology is suspected 1

• CT head may be considered if:

  • MRI is contraindicated
  • Acute stroke is suspected and immediate imaging is needed
  • Bony abnormalities of the skull base are suspected 1

Laboratory Testing

• First-line tests should include 2:

  • Complete blood count
  • Electrolytes and renal function
  • Random glucose or HbA1c
  • Vitamin B12 level (deficiency can cause peripheral neuropathy and paresthesias) 3, 4

• Additional tests based on clinical suspicion:

  • ESR and CRP if inflammatory/vasculitic process suspected
  • HbA1c if diabetes suspected
  • Autoimmune panel if autoimmune disease suspected 2

Specific Scenarios

If Stroke is Suspected

• Immediate brain imaging (CT or MRI)
• Vascular imaging of head and neck (CTA or MRA)
• ECG to assess cardiac rhythm
• Urgent neurology consultation 1

If Bell's Palsy is Suspected

• Consider electrodiagnostic testing (electroneuronography, electromyography) if complete facial paralysis is present 1
• Testing should be performed 7-14 days after symptom onset for optimal results 1

If Trigeminal Neuropathy is Suspected

• MRI with attention to the full course of the trigeminal nerve
• Evaluate for neurovascular compression, demyelinating lesions, or mass lesions 1

Common Pitfalls and Caveats

• Facial pain alone is rarely caused by chronic rhinosinusitis; consider primary headache disorders when facial pain occurs without other nasal symptoms 1
• Vitamin B12 deficiency can present with neurological symptoms including paresthesias without anemia 5
• Don't miss stroke in patients with sudden-onset facial numbness, especially when accompanied by other neurological symptoms 1
• Consider that facial numbness may be part of a broader neurological disorder requiring comprehensive evaluation 6

Management Algorithm

1. Assess for red flags requiring immediate attention:

   • Sudden onset with other neurological deficits → Emergency stroke protocol
   • Progressive symptoms with headache → Urgent neuroimaging
   • Complete facial paralysis → Consider Bell's palsy and early corticosteroid treatment

2. If no red flags:

   • Order MRI brain with contrast
   • Obtain basic laboratory tests
   • Consider specialty referral based on findings:
     • Neurology for suspected central or peripheral nerve disorders
     • Otolaryngology for suspected Bell's palsy
     • Neurosurgery for mass lesions

3. Treat underlying causes once identified:

   • Corticosteroids for Bell's palsy
   • Vitamin supplementation for deficiencies
   • Appropriate management for stroke, tumors, or other identified pathologies