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Isolated Seventh Cranial Nerve Palsy

URGENT — Neuro

Symptoms

sudden onset of unilateral facial weakness or total paralysis

inability to close the eye (lagophthalmos) with secondary irritation

drooling, slurred speech, and food collecting in the cheek

altered taste (anterior 2/3 of tongue) or hyperacusis

retro-auricular pain (behind the ear) often precedes the weakness

blurred vision or foreign body sensation from corneal exposure

Clinical Findings

Central VS. peripheral

  • central (umn/stroke): spares the forehead due to bilateral innervation
  • peripheral (lmn/bell): involves the forehead (unable to wrinkle brow)

Ocular signs

  • lagophthalmos: incomplete eyelid closure on the affected side
  • positive bell phenomenon: the eye rotates upward during attempted closure
  • exposure keratopathy: ranges from punctate staining to stromal melting
  • lower lid ectropion and epiphora (tearing) due to lacrimal pump failure

Systemic & chronic signs

  • ramsay hunt (vzv): vesicles on the pinna, ear canal, or soft palate
  • synkinesis: aberrant regeneration (e.g., eye closes when smiling)
  • crocodile tears: tearing while eating (gustolacrimal reflex)

Etiology

Idiopathic & viral

  • bell palsy: most common; idiopathic (likely hsv-1 reactivation)
  • ramsay hunt syndrome: varicella-zoster virus (vzv) of the geniculate ganglion

Other causes

  • infectious: lyme disease (suspect if bilateral), hiv, or syphilis
  • trauma: temporal bone fractures or parotid/mastoid surgery
  • neoplasm: acoustic neuroma (cpa mass) or parotid gland tumors
  • inflammatory: sarcoidosis

Red Flags

forehead sparing (suggests a central umn lesion like stroke or tumor)

bilateral simultaneous palsy (suspect lyme, sarcoidosis, or guillain-barré)

multiple cranial nerve deficits (v, vi, viii) (localizes to cpa or brainstem)

vesicles in the ear or mouth (requires immediate antiviral for ramsay hunt)

progressive worsening >3 weeks or no recovery by 3 months (rule out cancer)

Investigations

Clinical exam

  • bedside: test forehead movement and orbicularis strength
  • slit-lamp: evaluation for exposure-related corneal thinning
  • ear/oropharynx: check for vesicles or parotid masses

Laboratory & imaging

  • bilateral workup: lyme titers, ace level, and rpr/fta-abs
  • mri brain/cpa with contrast: if other cn involved or no recovery at 3 months
  • ct temporal bone: if history of head trauma

Treatment

Medical

  • corticosteroids (prednisone) and antivirals (valacyclovir) for acute phase

Corneal protection

  • preservative-free artificial tears, lubricating ointments, and moisture goggles
  • bandage contact lens for persistent epithelial defects

Surgical & procedural

  • upper lid weight (gold/platinum) or tarsorrhaphy for severe lagophthalmos
  • botulinum toxin to manage synkinesis or induce protective ptosis

Clinical Pearl

Facial palsy with vesicles in the ear canal is Ramsay-Hunt — start antivirals and steroids within 72 hours to maximize recovery; the ENT consult is for the hearing, not the nerve.

Differential Diagnosis

  • bell palsy (idiopathic lmn)
  • ramsay hunt syndrome
  • lyme disease
  • pontine stroke or tumor (forehead spared)
  • parotid gland neoplasm

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