What is the diagnosis and treatment for a patient experiencing facial numbness and spasm for 2 weeks?

Facial Numbness and Spasm for 2 Weeks: Diagnosis and Management

Immediate Diagnostic Priority

You must perform a comprehensive history and physical examination to exclude dangerous secondary causes before assuming this is benign hemifacial spasm—approximately 30% of facial nerve disorders have identifiable underlying pathology including tumors, stroke, or demyelinating disease. 1

Critical Red Flags Requiring Urgent Imaging

The combination of facial numbness WITH spasm is atypical and demands immediate investigation, as numbness is NOT a feature of typical hemifacial spasm and may represent the earliest sign of malignancy or serious neurologic disease. 2, 3

Order MRI head and MRI orbits/face/neck with and without contrast immediately if ANY of the following are present: 1

• Facial numbness (the hallmark of trigeminal neuropathy and a red flag for tumor or demyelinating disease) 2
• Progressive weakness beyond the expected timeline 4
• Other cranial nerve involvement (diplopia, dysphagia, dizziness) 1
• Bilateral facial symptoms 4
• Isolated branch paralysis 4
• History of malignancy, particularly head/neck or parotid tumors 1
• Recent trauma or skull base pathology 5

Differential Diagnosis Algorithm

Primary Hemifacial Spasm (if NO numbness present)

• Unilateral involuntary clonic/tonic contractions of CN VII-innervated muscles 6, 3
• Typically starts around eye, spreads to lower face 6
• Caused by vascular compression at facial nerve root exit zone in 62% of cases 6
• Key distinguishing feature: NO sensory symptoms 3

Secondary Causes (MUST exclude when numbness present)

• Cerebellopontine angle tumors (schwannomas, meningiomas, epidermoid cysts) causing both CN V and CN VII dysfunction 5
• Brainstem pathology (stroke, demyelination, tumor) affecting facial nerve nucleus or fascicles 5, 7
• Perineural tumor spread from skull base or parotid malignancy 1
• Post-Bell's palsy synkinesis (history of prior facial weakness) 8, 6
• Hemifacial seizures (stereotyped contractions with possible eye deviation, refractory to typical treatments) 7

Other Mimickers to Consider

• Psychogenic facial spasm (18% of referrals in one series) 6
• Facial tics (suppressible, preceded by premonitory urge) 6, 3
• Blepharospasm (bilateral eye involvement) 3
• Hemimasticatory spasm (jaw-closing muscles, may have trigeminal involvement) 9, 6

Diagnostic Workup

Imaging Protocol (for atypical features including numbness)

MRI is the primary modality and should include: 1

• MRI head without and without IV contrast (rating 8/9) 1
• MRI orbits/face/neck with and without contrast (rating 8/9) 1
• Use thin-cut high-resolution sequences through CN V and CN VII pathways 1
• 3D heavily T2-weighted sequences and MRA to characterize vascular loops if hemifacial spasm suspected 1, 8

Note: MRI has 73-100% sensitivity for detecting perineural tumor spread and >95% sensitivity for identifying vascular compression in true hemifacial spasm. 1

Clinical Examination Specifics

Assess the following systematically: 1

• All cranial nerves (CN V sensory function in all three divisions, CN VII motor function, CN VIII hearing, CN IX/X palate/swallow) 1
• Timing of symptom onset (sudden vs. gradual—neoplastic/infectious causes progress gradually) 1
• Character of spasms (clonic vs. tonic, distribution pattern, presence during sleep) 9, 6
• Associated symptoms (hyperacusis, taste disturbance, dry eye—suggest CN VII involvement) 4
• Skin examination (head/face for malignancy) 1
• Parotid examination (masses suggesting parotid tumor) 1

Treatment Algorithm

If Imaging Reveals Secondary Cause

• Treat underlying pathology (tumor resection, treatment of demyelinating disease, etc.) 5
• Refer to neurosurgery or appropriate specialist based on etiology 8

If Primary Hemifacial Spasm Confirmed (NO numbness, vascular compression identified)

First-Line Treatment: Botulinum Toxin Injections 8, 3

• Effective treatment with few disabling side effects 3
• Provides temporary improvement for months 8
• Repeat injections every 3-4 months as needed 8

Pharmacologic Options (if botulinum toxin fails or not tolerated): 8

• Gabapentin: Start 300 mg at bedtime, titrate to 900-1600 mg daily in divided doses 8
• Pregabalin: 75-300 mg every 12 hours 8
• Baclofen: Try if gabapentin/pregabalin fail 8

Surgical Option: Microvascular Decompression 8

• Consider for patients who fail botulinum toxin or cannot tolerate repeated injections 8
• Success rate approximately 85%, with 70% remaining symptom-free at 10 years 8
• Requires referral to experienced neurosurgeon 8
• Complications: 2-4% hearing loss, 0.4% mortality 8
• Obtain MRI with 3D T2-weighted sequences and MRA before surgery to characterize vascular anatomy 8

If Trigeminal Neuropathy (numbness predominant)

• Urgent imaging mandatory to exclude malignancy or autoimmune disease 2
• Periodic re-evaluation required even if initial workup negative, as numbness may represent earliest sign of progressive disease 2
• Consider neurophysiologic testing and laboratory evaluation for autoimmune markers 2

Common Pitfalls to Avoid

• Assuming benign hemifacial spasm when numbness is present—numbness is NOT a feature of typical hemifacial spasm and mandates investigation for secondary causes 2, 3
• Delaying imaging in atypical presentations—progressive numbness may represent malignancy requiring urgent diagnosis 2
• Misdiagnosing hemifacial seizures as hemifacial spasm—look for stereotyped contractions, eye deviation, and lack of EMG lateral spread 7
• Using botulinum toxin before excluding structural lesions—always image first when red flags present 3
• Failing to examine all cranial nerves—other CN involvement suggests brainstem or skull base pathology 1