7.4 Cranial Nerve VII (Facial) Palsy

Cranial Nerve VII palsies may require the candidate to determine:

1. The location of the neurological lesion, and exclude life-threatening causes
2. The oculoplastic management to a multi-factorial problem

Examination Outline

Examination Structure

1. Visual Acuity (Best Corrected)

2. Inspection

  1. Facial asymmetry
    1. Loss of forehead wrinkles (upper motor neurone CNVII palsy)
    2. Brow ptosis (not blepharoptosis) / Lid retraction & Superior sclera [iii]
    3. ↓ Blink “Please blink” Twitch of mouth = aberrant regeneration
    4. Ectropion (paralytic) / Inferior scleral show / Red eye
    5. Loss of nasolabial fold
    6. Drooping angle of the mouth
  2. Scars / masses (behind ear, parotid, lymphadenopathy)
  3. Esotropia (CNVI

Check MRD1 if considering a gold weight

Figure 7.4.1 Right Lower Motor Neurone CNVII Palsy

Figure 7.4.1
Right Lower Motor Neurone CNVII Palsy

Note the loss of forehead wrinkles (hence LMN palsy), brow ptosis, paralytic ectropion and less prominent nasolabial fold.

3. Dynamic Testing

Branch

Instruction to Patient

Examiner Task

i. Temporal

Instruction to Patient

“Look up”

Examiner Task

Try to push down

ii. Zygomatic + Bells

Instruction to Patient

“Close your eyes as tight as you can”

Examiner Task

Try to open

iii. Buccal

Instruction to Patient

“Puff out your cheeks”

Examiner Task

Push in

iv. Mandibular

Instruction to Patient

“Grin like a gorilla / Show me your teeth”

Examiner Task

Narrow inter-palpebral fissure = aberrant regeneration

v. Cervical (platysma)

Instruction to Patient

“Stretch your neck as if shaving”

Examiner Task

Crocodile tears [iv] = aberrant regeneration

The fibres that originally innervated the submandibular / sublingual glands now innervate the lacrimal gland via the greater petrosal nerve

4. Assess Risk of Exposure

i. Bells Phenomenon
  • Firmly but gently grip both upper eyelids with your thumbs to prevent closing. Ask the patient to “Close your eyes”. With an upward Bells phenomenon, the globes rotate up and out
ii. Lagophthalmos

(2° to upper lid orbicularis dysfunction, unopposed levator)

  • Ask the patient to “Rest your head back and gently close your eyes as if you are going to sleep”. Assess whether there is an opening between the upper and lower eyelids- if so, measure this with a ruler
iii. Facial / Corneal Sensation (CN V)
  • Ask the examiner for corneal sensation - under examination conditions you will usually be told the result
iv. Dry Eye and Corneal Exposure
  • Stain the tear film with fluorescein and examine with a slit lamp for punctate stain

5. CN VI

  • Check abduction

6. CN VIII

Test hearing (use 512 Hz tuning fork):

  • Hyperacusis = loss of dampening function of stapedius
  • Deafness = consider CPA tumour

Check the ears:

  • Vesicles in external auditory canal = Ramsay-Hunt
  • SCC behind ear = infiltrate facial nerve

7. Parotid

  • Palpate for tumours
  • Check regional lymph nodes

8. Slit-Lamp Exam

  • Corneal exposure?

9. Fundoscopy

  • Papilloedema?

10. Hemiplegia

  • Strength
  • Cerebellar function – finger-nose

Summary

  • Unilateral or bilateral
  • Upper vs. lower motor neuron
  • Aberrant regeneration
  • Corneal exposure (Paralytic ectropion? Neurotrophic cornea?)
  • CNVI / VIII involvement
  • Ramsay-Hunt

Anatomy

Figure 7.4.2 CNVII Pathways

Figure 7.4.2
CNVII Pathways

Upper versus Lower Motor Neurone CNVII Palsies

  • Upper Motor Neurone (e.g. CVA)
    • Spastic paralysis of contralateral lower face
    • (Sparing of frontalis & some orbicularis- bilateral innervation)
    • Can raise eyebrows
  • Lower Motor Neurone (e.g. Bells palsy)
    • Flaccid paralysis of ipsilateral side of face
    • Can’t raise eyebrow on affected side
Figure 7.4.3 Upper versus Lower Motor Neurone CNVII Palsies

Figure 7.4.3
Upper versus Lower Motor Neurone CNVII Palsies

Upper Motor Neurone lesions produce spastic paralysis of the contralateral lower face. The forehead is unaffected because this has bi-cortical innervation.
Lower Motor Neurone lesions produce flaccid paralysis of the ipsilateral side of the face

Aetiology

1. Idiopathic

  • Bell’s palsy is a diagnosis of exclusion and may be related to viral infection (e.g. HSV)
  • ⅔ of unilateral CNVII palsy
  • Develops over hours
  • Unilateral mastoid pain is often present
  • 85% get satisfactory recovery by 3 months
  • Consider MRI if no improvement

2. Trauma / Surgery

  • e.g. parotid

3. Infection

  • Ramsay-Hunt syndrome (VZV) – external acoustic meatus (EAM) vesicles, deafness, vertigo
  • Chronic otitis media
  • Chronic meningitis (TB, Sarcoidosis)
  • HIV

4. Immunological

  • MS
  • Guillain- Barré syndrome

5. Neoplastic

  • Cerebellopontine Angle CPA (acoustic neuroma, nasopharyngeal cancer, cholesteatoma)
  • Parotid Cancer
  • SCC with perineural spread

6. Metabolic

  • Diabetes
  • Paget’s disease

Causes of Bilateral CNVII palsy

  1. Myaesthenia gravis / Guillain-Barré
  2. Sarcoidosis
  3. NF-2 (bilateral acoustic neuromas)
  4. Mobius syndrome
  5. Basilar meningitis

Causes of CNVII Palsy by Location

i. Upper Motor Neurone
  1. CVA
  2. Tumour
  3. Infection
  4. Demyelination (MS)
ii. Lower Motor Neurone

Brainstem (Pons)

Causes

  1. CVA
  2. Tumour
  3. Infection
  4. Demyelination (e.g. MS)

Associated Features

  1. CN V palsy (↓ Corneal sensation)
  2. CN VI palsy (Diplopia)
  3. Long-tract signs

Cerebellopontine Angle Syndrome

Causes

  1. Tumour (e.g. CPA)
  2. Infection
  3. Trauma
  4. Platybasia- Paget’s

Associated Features

  1. CN V palsy (↓ Corneal sensation)
  2. CN VI palsy [v] (Diplopia)
  3. CN VIII palsy (↓ Hearing)
  4. Nervus intermedius (lacrimation / taste / salivation loss & hyperacusis)
    After geniculate ganglion → Lacrimation OK
    After nerve to stapedius → Hearing OK
    After chorda tympani → Taste / Salivation OK
  5. Ramsay Hunt / VZV (Ear vesicles)
  6. Cerebellar signs

CNVII wraps around CNVI nucleus

Outside Stylomastoid Foramen

Causes

  1. Tumour (Parotid, SCC)
  2. Demyelination (e.g. Guillain-Barré)

Associated Features

Depending on location may only affect certain muscles

Causes of Epiphora in CNVII Palsy

Hyperlacrimation

Secondary to exposure
Aberrant regeneration of the lacrimal gland causing “crocodile tears”

Epiphora

Punctal ectropion
Lacrimal pump failure “functional block”

Investigations

  • Bells palsy is a diagnosis of exclusion
  • If the history or examination findings are not typical (e.g. not acute presentation, progressing after 3 weeks), then the patient should be re-examined for other causes and an MRI brain with contrast ordered

Management

The correct management of the patient depends on:

  1. Predominant problem
    1. Exposure (UL retraction, paralytic lagophthalmos, ectropion)
    2. Epiphora (dry eye, ectropion, functional block)
  2. Likelihood of recovery
  3. Neurotrophic cornea

Consider 7 days of Prednisone ± Aciclovir for Bells Palsy.

A) Exposure

  1. Conservative
    1. Lubricants (unpreserved)
    2. Tape lid shut at night (or moisture chamber)
    3. ± Punctal plugs
  2. Staged surgery - what and when will depend on potential for CNVII recovery
    1. Temporary (if CNVII function is expected to improve)
      1. Temporary lateral tarsorrhaphy
      2. Botox to upper lid (contraindicated in reverse Bells)
      ii. Definitive procedure

For Paralytic Lagophthalmos

  1. Gold weight
    Trial weights pre-op: e.g. 0.8 grams, check MRD, closure. Aim for relaxed eyelid closure and no ptosis in primary. NB: May need to manually close the eye before sleep. Risks: Extrusion, ptosis, reaction to gold, worsening of lagophthalmos when lying down (remove).
  2. Levator recession / dis-insertion
  3. Palpebra
  4. l springs

For Paralytic Ectropion

  1. Lateral tarsal strip / Canthoplasty (often insufficient in complete CNVII palsies - sags with time)
  2. (Medial canthoplasty) (shortens the vertical IPD medially, inverts the punctum)

For vertical elevation:

  1. Lower lid spacer graft: eyelid skin, hard palate
  2. Fascia lata or silicone suspension sling of the lower eyelid
  3. Cheek lift: Subperiosteal or SOOF lift
  4. Consider facial reanimation- temporalis muscle transfer, facial nerve graft - but often takes 12-18 months to grow

For Brow Ptosis

Brow lift

For Aberrant Regeneration

Botox, Muller resection

B) Epiphora

  • DCR + Jones tube [vi] (beware- tears are protective)

DCR alone won’t help because of failure of pump mechanism in the canalicular system

          

All rights reserved. No part of this publication which includes all images and diagrams may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the authors, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law.

Vitreoretinal Surgery Online
This open-source textbook provides step-by-step instructions for the full spectrum of vitreoretinal surgical procedures. An international collaboration from over 90 authors worldwide, this text is rich in high quality videos and illustrations.

© 2021 WESTMEAD EYE MANUAL

Website by WebInjection