FACIAL NERVE FACIAL NERVE

Supranuclear control (UMN)Supranuclear control (UMN) of the facial of the facial nerve is by the contra lateral precentral nerve is by the contra lateral precentral gyrus, cross over to the facial nerve ucleus gyrus, cross over to the facial nerve ucleus in the in the ponspons..

Cortical control of VII nerveCortical control of VII nerve

BELLS PALSYBELLS PALSYDefinitionDefinition

Bells palsy is idiopathic unilateral lower Bells palsy is idiopathic unilateral lower motor type of facial nerve palsy.motor type of facial nerve palsy.

PathophysiologyPathophysiology Reactivation of herpes simplex type 1 in the Reactivation of herpes simplex type 1 in the geniculate ganglion causing swelling of facial geniculate ganglion causing swelling of facial nerve resulting in facial nerve palsy.nerve resulting in facial nerve palsy. The lesion is believed to be at the stylomastoid The lesion is believed to be at the stylomastoid foramen foramen

Clinical featuresClinical features It affects men and women equally and is seen It affects men and women equally and is seen

at all ages.at all ages.

Onset is abrupt and is unilateral and worsens Onset is abrupt and is unilateral and worsens quicklyquickly

Maximal weakness usually is attained by 48 Maximal weakness usually is attained by 48 hours. hours.

Features of LMN facial palsy will be there Features of LMN facial palsy will be there The corner of the mouth droops, the creases and The corner of the mouth droops, the creases and

skin folds are effaced, the forehead is unfurrowed, skin folds are effaced, the forehead is unfurrowed, and the eyelids will not close. and the eyelids will not close.

Upon attempted closure of the lids, the eye on the Upon attempted closure of the lids, the eye on the paralyzed side rolls upward (paralyzed side rolls upward (Bell's phenomenonBell's phenomenon).).

The lower lid sags also, and the punctum falls The lower lid sags also, and the punctum falls away from the conjunctiva, permitting tears to away from the conjunctiva, permitting tears to spill over the cheek. spill over the cheek.

Food collects between the teeth and lips, and Food collects between the teeth and lips, and saliva may dribble from the corner of the mouth.saliva may dribble from the corner of the mouth.

Taste is lost over the anterior two-thirds of the tongue on the Taste is lost over the anterior two-thirds of the tongue on the same side due to damage to chorda tympani nervesame side due to damage to chorda tympani nerve

There may be hyperacusis and rarely tearing from the eyeThere may be hyperacusis and rarely tearing from the eye

Loss of corneal reflex on side of facial palsyLoss of corneal reflex on side of facial palsy

May have subjective numbness on side of facial weakness, but May have subjective numbness on side of facial weakness, but no true sensory deficit on testing (fifth cranial nerve spared) no true sensory deficit on testing (fifth cranial nerve spared)

Rest of neurological examination is normal.Rest of neurological examination is normal.

LMN lesion

Differential DiagnosisDifferential Diagnosis Ramsay Hunt syndromeRamsay Hunt syndrome Facial palsy associated with a vesicular eruption of Facial palsy associated with a vesicular eruption of

the pharynx, external auditory canal, the pharynx, external auditory canal,

Often the eighth cranial nerve is affected as well.Often the eighth cranial nerve is affected as well.

Acoustic neuromaAcoustic neuroma

Tumors that invade the temporal boneTumors that invade the temporal bone

lesion in the brain (upper motor neuron)lesion in the brain (upper motor neuron)

InvestigationsInvestigations Diagnosis can usually be made Diagnosis can usually be made clinically clinically

Investigations like MRI, ESR, HIV testing are Investigations like MRI, ESR, HIV testing are

required only if presentation is atypical like required only if presentation is atypical like

bilateral, involvement of other cranial nerve bilateral, involvement of other cranial nerve

and pyramidal tract.and pyramidal tract.

Electromyography (EMG) has only Electromyography (EMG) has only

prognostic valueprognostic value

TreatmentTreatment1) Symptom management1) Symptom managementPaper tape or patch to depress the upper eyelid Paper tape or patch to depress the upper eyelid during sleep and prevent corneal drying and during sleep and prevent corneal drying and abrasionsabrasions2) Medical treatment2) Medical treatment a) Prednisolonea) Prednisolone Oral prednisolone60 to 80 mg daily during the Oral prednisolone60 to 80 mg daily during the

first 5 days then tapered over the next 5 days first 5 days then tapered over the next 5 days To be initiated in first 48–72 hours of To be initiated in first 48–72 hours of

symptoms.symptoms.

Treatment (cont.)Treatment (cont.)b) Acyclovirb) Acyclovir Combined with prednisone should be started Combined with prednisone should be started

within 3 days of symptom onsetwithin 3 days of symptom onset Dose - 400 mg 5 times daily for 10 daysDose - 400 mg 5 times daily for 10 days..

ComplicationsComplications Corneal drying and injury (abrasion, ulceration)Corneal drying and injury (abrasion, ulceration) Incomplete recovery with partial or permanent Incomplete recovery with partial or permanent

nerve impairmentnerve impairment

PrognosisPrognosis Approximately 80–90% of patients recover Approximately 80–90% of patients recover

fully within a few weeks or monthsfully within a few weeks or months Evidence of denervation by EMG after 10 Evidence of denervation by EMG after 10

days indicates bad prognostic sign. days indicates bad prognostic sign.

DON’T FORGETDON’T FORGET UMNUMN lesions cause lesions cause opp. side loweropp. side lower

half facial nerve palsy.half facial nerve palsy.

LMNLMN lesions cause lesions cause same side one halfsame side one half facial palsy.facial palsy.

Don’t forgetDon’t forget Bell’s palsy is Bell’s palsy is LMNLMN facial palsy. facial palsy.

Onset is acute and is Onset is acute and is unilateral.unilateral.

Diagnosis is clinicalDiagnosis is clinical

Treatment – steroids + acyclovirTreatment – steroids + acyclovir