Facial nerve palsies and their differential diagnosis References - Harrisons, Davidsons, ENT text of Dhingra, Internet and Slide share.

1. TOPIC
DISCUSSION:
FACIAL
NERVE
PARALYSIS
-Dr. Sreekari

2. Introduction
Facial nerve is the seventh of twelve paired
cranial nerves, it is a mixed nerve with motor and
sensory roots.
It emerges from the brain stem between the pons
and the medulla, controls the muscles of facial
expression
It functions in the conveyance of taste
sensations from the anterior two thirds of the
tongue and oral cavity.
It also supplies preganglionic parasympathetic
fibres to several head and neck ganglia.

3. Facial nerve is developmentally derived from the hyoid
arch, which is the second branchial arch.
The facial nerve is formed mainly of two parts:
1- Facial nerve proper (motor): arising from facial
motor nucleus in pons.
2- Nervus intermedius: it is the sensory root of facial
nerve lies between the facial nerve proper and
vestibulcochlear nerve in the pontocerebellar angle.
Carrying para-sympathetic fibers (from superior salivary
nucleus) and taste fibers ( to the solitary nucleus).

4. COURSE OF FACIAL NERVE
Origin: the motor fibres passes dorsally and medially
forming a loop around the abducent nucleus in the
floor of the 4th ventricle forming facial colliculus
and comes out at the pontomedullary angle above the
inferior cerebellar peduncle.
I- Intracranial (intrapetrosal) course
II- Extracranial course

6. I- The intrapetrous course:
The nerve passes laterally with the vestibulocochlear
nerve (CN VIII) to the internal auditory meatus. At the
bottom of the meatus the nerve enters the facial bony canal
where it runs laterally above the vestibule of inner ear.
Reaching the medial wall of the middle ear, it bends sharply
backwards above the promontory (forming its genu) where
the geniculate ganglion is found
It then arches downwards in the medial wall of the middle ear
to reach the stylomastoid foramen.

10. II- Extracranial course:
As it emerges from the stylomastoid foramen, it runs
forwards in the substance of the parotid gland crosses the
styloid process and it divides behind the neck of the
mandible into its terminal branches which come out of the
surface of the gland.

11. Branches of
Distribution
Facial canal
A.Greater Petrosal
nerve
B.Nerve to stapedius
C.Chorda tympani
Stylomastoid
foramen
A.Posterior auricular
B.Nerve to
stylohyoid
C.Nerve to digastric
(posterior belly)
In face
A.Temporal
B.Zygomatic
C.Buccal
D.Marginal
mandibular
E.Cervical

14. Testing of Facial Nerve
Branches
Testing the temporal branches of the facial nerve
To test the function of the temporal branches of the facial
nerve, a patient is asked to frown and wrinkle his or her
forehead.
Testing the Zygomatic branches of the facial nerve
The patient is asked to close their eyes tightly.

15. Testing the buccal
branches of the
facial nerve
•Puff up cheeks
(buccinator)
•Smile and show teeth
(orbicularis oris)
•Tap with finger over
each cheek to detect
ease of air expulsion
on the affected side.

17. Disorders of Facial Nerve

21. Central Facial Paralysis – Caused by CVA, tumour or an
abscess. Causes paralysis of only the lower half of face on the
contralateral side. Forehead movements are retained due to
bilateral innervation of frontalis muscle. Involuntary
emotional movements and tone of facial muscles is also
retained.
Peripheral Facial Paralysis - All the muscles of the face on
the involved side are paralysed.
Lesion at the level of nucleus – identified by associated
paralysis of 6th cranial nerve.

22. Lesion at cerebellopontine angle- presence of
vestibular and auditory defects – involvement of other
cranial nerves 5th
, 9th
, 10th
and 11th
.
Lesion in the bony canal – identified by
topodiagnostic tests.
Lesion outside the temporal bone in the parotid
area, affects only motor functions of nerve .

24. BELLS PALSY
Bells palsy is the most common cause of facial paralysis.
Effects both sexes and all ages. Incidence increases with
increasing age.
It is associated with HSV type 1 DNA in endoneurial fluid
and posterior auricular muscle suggesting reactivation of
virus in the geniculate ganglion.

27. Bell's phenomenon ( also
known as Palpebral
Oculogyric Reflex) is the
upward rolling of the eye
ball on attempted closure
of the lid.

28. Diagnosis of Bells palsy
By exclusion
Criteria
•Paralysis or paresis of all muscle groups of one side of
the face
•Sudden onset
•Absence of signs of CNS disease
•Absence of signs of Ear disease

29. Management of Bells palsy
Paper tape to depress eyelid during sleep.
Massage of weekend muscles.
Medical treatment
Corticosteroids :
•Prednisolone 60-80 mg/day for first 5 days and then
tapered over next 5 days
•Acyclovir 400 mg 5 times/day
•Famciclovir and valacyclovir 500 mg bid

30. Surgical treatment
Facial nerve decompression
Indication:
•Complete paralysis
•ENoG less than 10% in 2 weeks
•Appropriate time for surgery is 2-3 weeks after
paralysis

31. Evaluation of Facial paralysis
Clinical features
•Central VS Peripheral facial paralysis
•Cranial nerve evaluation.

32. • TOPOGNOSTIC TESTING
1. Schirmer test for lacrimation (GSPN)
2. Stapedial reflex test (Stapedial branch)
3. Taste testing (Chorda tympani nerve)
4. Salivary flow rates & pH (Chorda tympani)
• ELECTROPHYSIOLOGIC TESTS
1.Nerve excitability test (NET)
2.Electromyography(EMG)
3.Maximal stimulation test (MST)
4. Electroneuronography (ENoG)
•

34. Schirmer's Test
• Geniculate ganglion & petrosal nerve function test
• Schirmer’s test +ve when
• Affected side shows less than half the amount of
lacrimation seen on the normal side
• Sum of the lengths of wetted filter paper for both eyes less
than 25 mm
• Lesion at or proximal to the geniculate ganglion.

36. Stapedius reflex
• Nerve to stapedius muscle test
• Impedence audiometry can record the presence or
absence of stapedius muscle contraction to sound
stimuli 70 to 100 db above hearing threshold
• An absence reflex or a reflex less than half the
amplitude is due to a lesion proximal to stapedius
nerve

37. Taste (Electrogustometry)
• Chorda tympani nerve test
• Solution of salt, sugar, citrate, quinine or Electrical
stimulation
• Compares amount of current required for a response each side
of tongue.

38. Nerve Excitability Test
The nerve is stimulated at steadily increasing intensity till
facial twitch is just noticeable and compared with the
normal side.
When the difference between 2 sides exceeds 3.5
milliamps, the test is positive for degeneration.

39. Maximum stimulation Test: MST
Similar to nerve excitability test, but instead of measuring
the threshold of stimulation , the current level which gives
maximum facial movement is determined and compared
with the normal side.
Reduced or absent response indicates degeneration and is
followed by incomplete recovery.

40. Electroneurography: ENoG
Facial nerve is stimulated at the
stylomastoid foramen and
compound muscle action
potentials are picked up by the
surface electrodes. Response of
action potentials are compared
with that on the normal side.
% of degenerating fibres is
calculated
>90% ---- indicates poor prognosis
This test is most useful between
14-21 days of the onset of
complete paralysis .

41. Electromyography: EMG
Tests the motor activity of facial muscles by direct
insertion of needle electrodes (usually in
orbicularis oculi & orbicularis oris) – record at rest
and voluntary contraction of muscle.
Biphasic and Triphasic potentials - Normal resting
muscle
Fibrillation potentials – Denervated muscle
Polyphasic potentials – Regeneration of the nerve

42. DIFFERENTIAL
DIAGNOSIS

43. Herpes zoster oticus
Ramsay Hunt syndrome type II
Geniculate ganglion involves
•Symptoms:
Facial paralysis
Ear pain
Vesicles
Sensorineural
hearing loss
Vertigo

44. Lyme DiseaseIt is caused by a
bacteria Borrelia
burgdorferi.Transmitt
ed by tick bites. Most
common neurological
complication is Facial
Palsy usually on one
side.

45. Acute and chronic otitis media
Otitis media is an infection in the middle ear, which can
spread to the facial nerve and inflame it, causing
compression of the nerve in its canal.

46. Melkersson Rosenthal Syndrome
• Idiopathic disorder consisting of a triad of facial paralysis,
swelling of lips and fissured tongue. Paralysis – recurrent
and bilateral.

47. Guillain Barre Syndome
• It is a post infectious, autoimmune disorder affecting the
peripheral nerves. Facial paralysis is often bilateral.

48. Neoplasms
Carcinoma of external and middle ear, glomus tumour,
rhabdomyosarcoma and metastatic tumours of temporal
bone all result in facial paralysis. Facial nerve neuromas
occur anywhere along the course of the nerve and produce
paralysis. It is treated by excision and nerve grafting.
Neurosarcoidosis
Facial nerve paralysis, bilateral, is a common
manifestation of neurosarcoidosis (sarcoidosis of the
nervous system). It is a rare condition.

49. Congenital Facial nerve palsy
Moebius syndrome (congenital facial diplegia)
Abnormal VI ,VII,XII Nerve nuclei
Facial Nerve absent / smaller
Congenital Extra ocular muscle & facial palsy

50. Treacher collins syndrome
(mandibulo facial dysostosis)
• There is a set of typical symptoms within Treacher
Collins Syndrome
• The OMENS classification was developed as a
comprehensive and stage-based approach to
differentiate the diseases.
• O; orbital asymmetry
• M; mandibular hypoplasia
• E; auricular deformity
• N; nerve development and
• S; soft-tissue disease

51. Complications
Incomplete Recovery – Facial asymmetry persists.
Exposure Keratitis – Eye cannot be closed, tear film from the
cornea evaporates causing dryness, exposure keratitis and corneal
ulcer.
Synkinesis – Mass Movement – Attempts to move one group of
facial muscles may result in contraction of all .
Tics and Spasms – Involuntary movements are seen on the
affected side of the face. They are the result of faulty regeneration
of fibres .

52. Contractures – They result from
fibrosis of atrophied muscles or fixed
contraction of a group of muscles. They
affect movements of the face.
Hemifacial Spasms – see pic
Crocodile tears – Gustatory
Lacrimation – There is unilateral
lacrimation with mastication. Caused by
faulty regeneration of parasympathetic
fibres which supply the lacrimal gland
instead of the salivary glands.