Key facts:
Authors: Rebecca Gray and Steven Barden
Top Tip: Start prednisolone within 72 hours
Key Differential Diagnoses
- CVA
- SOL
Key Investigations
- FBC, ESR, CRP
- U+E, LFT, Bone, Glucose
- ECG, CXR
- CT/MRI brain may be indicated to exclude other causes
Key Treatment
- PO PREDNISOLONE 60mg od
Key Management Decision
- Refer to neurology (usually not necessary)
Background
Introduction
- Bells Palsy describes the sudden paralysis of the facial (VIIth) nerve which renders the patient unable to control the facial muscles on the affected side
- Sir Charles Bell first described the anatomy and function of the facial nerve in the 1800s
- Many patients make a full recovery but some are left with residual weakness and facial pain
- The aetiology is unclear although for some cases the presumed pathophysiology of Bells Palsy is due to inflammation from a viral infection. This theory comes from the fact that during decompressive surgery the facial nerve has been observed to be swollen. These findings have also been seen on MRI scans
- The degree of swelling and the part of the facial nerve affected is variable and this gives rise to a spectrum of symptoms
- Good review articles: [Ref] ; [Ref] ; [Ref]
Definition
- Sudden unilateral facial paralysis of unknown aetiology (lower motor neurone palsy)
Epidemiology
- 11-40 cases per 100 000 pa
- Affects men and women equally
Pathology
- Thought to be due to ischaemia of nerve, cause unclear ?Viral
Risk factors
- Pregnancy increases the risk threefold – mainly seen in third trimester to first week post partum
- Diabetes
- Viruses: Herpes Simplex Virus and Herpes Zoster Virus
Erythema Migrans; suggestive of Lyme Disease 
Lyme Disease is part of the differential diagnosis of Bells Palsy (see below)
Symptoms
- Sudden onset (over hours) unilateral lower motor neurone facial paralysis – be concerned if onset greater than three weeks (see list of differential diagnoses)
- Possible loss of taste over anterior 2/3 of tongue, and inability to make tears
- Possible prodrome of ear pain and hyperacusis
Key questions
- “How long have you had the symptoms for”?
- “What have you noticed about your face?”?
Signs
- Eye brow droops on affected side
- Unable to raise affected eyebrow and wrinkle brow (NB: lower motor neurone palsy)
- Difficulty closing eye
- If the patient is asked to close their eye and show their teeth the eye ball rotates upwards and outwards: Bell’s Phenomenon
- Decreased tear production
- Mouth sags on affected side
- Unable to blow out cheeks
- Unable to whistle
- Hyperacusis if the lesion of the facial nerve extends above the point where the branch of the stapedius muscle is given off
Investigation
Blood
- FBC, ESR, CRP
- U+E, LFT, Bone, Glucose
- ECG, CXR
Key Investigations
- CT/MRI brain (normal). If atypical onset or symptoms greater than 3 weeks, do CT or MRI, looking for other causes
Specialist Investigation
- CT/MRI brain
Differential Diagnoses
Of LMN VIIth nerve palsy
Infective
- Herpes virus (type 1)
- Herpes zoster (Ramsay-Hunt syndrome)
- Lyme disease (or lyme borreliosis) is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia
- Otitis media or cholesteatoma
- Trauma - eg fractures of skull base, haematoma after acupuncture3 Multiple sclerosis
Neurological
- Guillain Barré
- Mononeurop athy - eg due to diabetes mellitus, sarcoidosis, or amyloidosis
Neoplastic
- Posterior fossa tumours, primary and secondary
- Parotid gland tumours
Other
- Sjogren's syndrome
- Hypertension and eclampsia
Of UMN VIIth nerve palsy
- CVA
- SOL, esp intracranial tumours, primary and secondary
- Syphilis
- MS
- Vasculitides
Note: Horners and third nerve palsy cause a ptosis
Treatment
Treatment
- PO PREDNISOLONE 60mg od for 10 day then tapering course – aim to start within 72 hours. Though the evidence for prednisolone in Bells Palsy is not great: [Ref]
- Eye protection if unable to fully close eye
Note: no evidence for anti-viral treatments: [Ref] ; see references below
Other
- Reassurance - the majority of cases resolve spontaneously - see prognosis.
- Eye care - ophthalmologists play an important role in preventing irreversible blindness from corneal exposure. This may be successfully achieved by using lubricating drops hourly and eye ointment at night ± eye patch
- Botulinum toxin or surgery (upper lid weighting or tarsorraphy) may also be required temporarily
- After the cornea has been protected, but recovery is thought to be unlikely, longer term management of eyelid and facial reanimation may be arranged
Prescribing issues
- Ensure prednisolone not continued at high dosage
Key management decision
- Refer to neurology or not (usually not necessary)
Admit?
- No
Bed plan
- None
Referrals
- Usually not necessary. If atypical, refer to neurology
- If patient cannot blink, refer to opthalmology
The Rest
Maxim
- "Protecting the eye will protect you"
Complications
- Partial recovery
- Irreversible blindness from corneal exposure
Follow-up
- GP
Risk stratification
- Atypical history should lead to different care pathway
Prognosis
- 75% recover normal function (higher in partial palsy)
- One sixth left with some residual weakness
- Expect recovery by three weeks or at 4-6 months (speed of nerve regeneration). Any residual deficit after this is likely to be permanent
Don't forget
- Reassurance
- Eye protection
Red flags
- Atypical history
