What is the recommended treatment for a 57-year-old female experiencing intermittent twitching around the mouth for the past 6 months?

Hemifacial Spasm: Evaluation and Management

A 57-year-old woman with 6 months of intermittent twitching around the mouth most likely has hemifacial spasm and requires neuroimaging with MRI to exclude structural causes, followed by botulinum toxin injection as first-line treatment if imaging is negative.

Initial Diagnostic Approach

The clinical presentation strongly suggests hemifacial spasm, which is characterized by unilateral, involuntary, irregular clonic or tonic movements of muscles innervated by the facial nerve. 1 The 6-month duration and intermittent nature are typical features. 1

Key Clinical Features to Confirm

• Unilaterality is essential - hemifacial spasm is always unilateral, typically starting around the eye and progressing to involve the lower face 1
• Pattern of spread - movements typically begin in the orbicularis oculi and spread downward to involve the lower facial muscles 1
• Absence during sleep - symptoms should disappear during sleep 2
• Triggers - stress, fatigue, and voluntary facial movements may exacerbate symptoms 1

Critical Red Flags Requiring Urgent Evaluation

Perform immediate neurological examination to exclude:

• Facial weakness or paralysis - suggests facial nerve palsy rather than spasm, requiring urgent imaging within 2-4 months if symptoms persist 3
• Other cranial nerve involvement - suggests brainstem pathology 3
• Recent onset after trauma or surgery - suggests secondary causes 3
• Associated hearing loss or tinnitus - suggests cerebellopontine angle lesion 3

Mandatory Neuroimaging

MRI with contrast of the brain and internal auditory canals must be obtained to exclude secondary causes. 3 This is critical because approximately 19% of cases have identifiable secondary causes including:

• Vascular compression at the facial nerve root exit zone (most common primary cause) 1
• Posterior fossa tumors (facial schwannomas, meningiomas, epidermoid cysts) 3
• Demyelinating disease (multiple sclerosis) 1
• Brainstem lesions (infarcts, vascular malformations, tumors) 3
• Inflammatory conditions (sinusitis, mastoiditis in rare cases) 4

High-resolution temporal bone CT may be added if MRI shows temporal bone pathology or if infection is suspected. 3

Differential Diagnosis to Exclude

Facial Dystonia

• Involves sustained muscle contractions rather than clonic twitching 2
• Often bilateral and involves jaw muscles (oromandibular dystonia) 2
• May worsen with hormonal changes (menses, pregnancy) 2

Hemifacial Seizures

• Stereotyped contractions every few seconds with possible eye deviation 5
• Requires EEG and EMG showing no "lateral spread" response 5
• Associated with brainstem lesions on MRI 5

Facial Myokymia

• Fine, rippling movements rather than gross twitching 1
• Often associated with multiple sclerosis or brainstem pathology 1

Post-Bell's Palsy Synkinesis

• History of prior facial paralysis is essential 1
• Movements occur with voluntary facial expressions (e.g., eye closure with smiling) 1
• Accounts for 11% of cases referred for hemifacial spasm 1

Treatment Algorithm

If MRI Shows Vascular Compression (Primary Hemifacial Spasm)

Botulinum toxin injection is the first-line treatment:

• Inject into affected facial muscles under EMG guidance if available 1
• Provides symptom relief in most patients for 3-4 months 1
• Repeat injections are necessary as effects are temporary 1

Microvascular decompression surgery is definitive treatment:

• Reserved for patients who fail or refuse botulinum toxin 1
• Provides permanent cure in 85-90% of cases when vascular compression is confirmed 1

If MRI Shows Secondary Cause

Treatment depends on the underlying etiology:

• Tumors require neurosurgical consultation for possible resection 5
• Inflammatory conditions (sinusitis, mastoiditis) require appropriate antimicrobial therapy 4
• Demyelinating disease requires neurology referral for disease-modifying therapy 1

If MRI is Normal

Proceed with botulinum toxin as for primary hemifacial spasm while considering rare mimickers 1

Common Pitfalls to Avoid

• Do not delay imaging - 19% of cases have secondary causes requiring specific treatment 1
• Do not confuse with facial tics - tics are suppressible and associated with premonitory urge 1
• Do not miss bilateral involvement - true hemifacial spasm is never bilateral; bilateral cases suggest other diagnoses 1
• Do not perform microvascular decompression without confirming vascular compression on high-quality MRI 5
• Do not attribute symptoms to psychogenic causes without thorough organic workup - only 18% of referred cases are non-organic 1