Isolated Facial palsy, CN VII

Diseases, , , , , ,

Upper motor neuron lesion:

Diagnosis:

This is a clinical diagnosis. The underlying cause is determined by investigations and clinical correlation.

Clinical features:

  • Sparing of the forehead muscles
  • Asymmetry of face at rest or on movement: smile, puffing the cheeks and on wincing
  • The palpebral fissure may be widened on the affected side

Investigations to consider:

MRI brain
RPR, HbA1c

Treatment:

Treat the underlying cause
Protect the eye

Lower motor neuron lesion:

Diagnosis:

This is a clinical diagnosis. The underlying cause is determined by investigations and clinical correlation.

Clinical features:

  • Involvemen of the forehead muscles
  • Asymmetry of face at rest or on movement: smile, puffing the cheeks and on wincing
  • Usually palpebral fissure is widened on the affected side
  • Assess VII, VIII, Weber test, otoscopy, parotid
  • Ramsey Hunt syndrome ‘VZV’ a.k.a. herpes zoster oticus:
  • Ear pain, vesicular rash, LMN VII palsy, VIII may also be involved
  • Impaired lacrimation implies lesion involving or proximal to the geniculate ganglion

Investigations to consider:

VZV serology and VZV PCR
ACE levels
ESR, CRP, ANA screen, ENA panel (anti- dsDNA, anti-Sm, anti-RNP, SSA, SSB, anti-Jo-1, antitopoisomerase ‘formerly anti Scl-70’, antinucleolar, anticentromere), ANCA (c-ANCA, p-ANCA), Complement C3, C4 and CH50
HIV testing
CSF analysis
Guillain Barre Syndrome antibodies
MRI brain with and without contrast: if atypical for Bell’s palsy

Treatment:

Treat the underlying cause
Protect the eye
If VZV a.k.a. Ramsay Hunt syndrome:

  • Acyclovir immediately

If traumatic or due to acute/chronic otitis media:

  • Urgent ENT referral

Cerebellopontine angle syndrome CPA syndrome:

  • MRI T2, & T1 +contrast:
  • T2: Filling defects in CSF spaces in CPA
  • T1 +gadolinium:
    • Enhancing: vestibular schwannoma, meningioma ‘dural tail’
    • Nonenhancing: arachnoid cyst with hypointense ring, cholesteatoma (epidermoids),

Causes of isolated facial nerve palsy (CN VII):

Upper motor neuron lesion:

  • Stroke, most common
  • Vasculitis
  • Syphilis
  • HIV

Lower motor neuron lesion:

  • Bell’s palsy a.k.a. Idiopathic (but HSV-1 is implicated), most common
  • VZV a.k.a. Herpes zoster, Ramsay Hunt Syndrome
  • Otitis media
  • Cholesteatoma
  • Tumours:
    • Cerebellopontine angle, acoustic or facial neuroma
    • Glomus tumour
    • Parotid tumour
  • Temporal bone fracture
  • Diabetes mellitus
  • Lyme disease
  • Sarcoidosis
  • Amyloidosis
  • AIDS
  • Sjogren’s syndrome
  • Lesions of the facial nucleus (usually affects other nerves as well)

Recurrent or bilateral lower motor neuron facial palsy:

  • Base of the skull tumour e.g. Lymphoma
  • Lyme disease
  • Sarcoidosis
  • Gullian-Barre syndrome
  • If immunocompromised, VZV
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