VII NERVE PALSY VII NERVE PALSY — EVALUATION AND MANAGEMENT

The eye cannot close and constantly weeps. The mouth dribbles, the speech is interfered with and mastication impaired. The delicate shades of continence are lost. Joy, happiness, sorrow, shock, surprise, all conditions have for their common expression the same blank stare. (Brunnell, 19279.)

Facial nerve palsy is a devastating and readily visible nerve . Loss of tone and movement is disfiguring and causes a functional disability to eye closure, chewing, speech and facial expression.

The prevalence of facial palsy in the general population is about 1:5 000, mak- ing it a common-enough clinical entity for all general practitioners to be familiar with.1,2 In most cases no definite aetiology is identified (idiopathic/Bell’s palsy). The diagnosis of an idiopathic palsy however can only be made by excluding all SHAMLAN K NAIDOO other potential causes of facial palsy. The routine assumption that all facial MB BCh, FCORL (SA) palsies are idiopathic means that many correctable causes, e.g. of otological ori- Consultant Otorhinolaryngologist gin, might be left too late to achieve any favourable outcome.

Department of Otorhinolaryngology and ANATOMY Head and Neck The leaves the brainstem and enters the internal auditory canal with Nelson Mandela School of Medicine the auditory nerve. Within the it has three branches: University of KwaZulu-Natal •greater superficial petrosal nerve — to lacrimal glands and glands within Durban nasal and palatal mucosa • chorda tympani — to taste buds and anterior two-thirds of the tongue Shamlan Naidoo is a consultant otorhino- • stapedial nerve — stapedius muscle in middle ear. laryngologist in the Department of As it exits the skull, it divides into branches within the to supply the Otorhinolaryngology and Head and Neck muscles of facial expression. Surgery at the Nelson Mandela School of Medicine, King Edward VIII and Inkosi AETIOLOGY Albert Luthuli Central hospitals. His Facial is a diagnostic challenge, with a wide differential diagnosis interests are head and neck surgery and (Table I). Nevertheless, every effort must be made to determine a treatable cause. otology. Idiopathic/Bell’s palsy Between 50% and 80% of all facial paralysis is idiopathic.2,3 There is no sex predilection but the incidence rises in pregnant women. Bell’s occurs at any age, with a slight preponderance in patients over 65 years. Ten per cent may be bilat- eral.3,4 Although idiopathic, compelling research supports an infectious cause, namely virus.5

Typically, sudden-onset unilateral facial paresis progresses to paralysis over 1 - 5 days.3 The prognosis for Bell’s is generally good, with most patients (85 - 90%) recovering completely within 1 month.2,3 The remaining 15% will not usually show signs of recovery for 3 - 6 months.2,3 A protracted recovery over a period of months increases the likelihood of sequelae such as , tics, spasms and synkinesis.

The palsy is not Bell’s if there is/are: • signs of trauma • vesicles on the head and neck • multiple cranial nerve involvement

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Table I. Differential diagnosis of facial nerve palsy

Idiopathic Tumours Systemic/metabolic Bell’s palsy Parotid mellitus Melkerson-Rosenthal Pregnancy CP angle tumour Glomus Autoimmune disorders Carcinoma (1°/2°) Porphyria Facial nerve neuroma Leukaemia

Trauma Congenital Infection Temporal bone fractures Compression injury Herpes zoster oticus Iatrogenic injury Mobius syndrome Birth trauma Dystrophia myotonica Facial Diabetic otitis externa Penetrating wounds to the ear TB Barotrauma HIV Infectious mononucleosis

• otological infection Facial paralysis as a complication of cholesteatoma, facial nerve neuroma, • other CNS lesions HIV infection has been reported, par- ear and cerebellopontine angle (CPA) • facial palsy at birth. ticularly in the early stages of HIV and tumours.2,4 Suspicious symptoms occasionally as the first manifestation include slowly developing paresis over Trauma of the infection.6 a period of more than 3 weeks, facial Trauma is the second most common twitching, other cranial nerve deficits, cause of facial nerve paralysis. These Acute otitis media with a dehiscent recurrent ipsilateral paresis and a patients may present with bloody otor- facial canal in the middle ear can parotid mass. rhoea, haemotympanum, lead to inflammation along the nerve, and deafness. Longitudinal fractures of causing paralysis. Chronic otitis media The most common malignant tumours the temporal bone comprise 80% of may also cause facial paralysis sec- causing facial paralysis are mucoepi- all temporal bone fractures and facial ondary to cholesteatoma or inflamma- dermoid and adenoid cystic carcino- nerve injuries occur in 10 - 20% of tion of the nerve. mas of the parotid. these. Transverse fractures comprise only 20% of fractures, yet the inci- Facial palsy in children is TB otitis CLINICAL EVALUATION dence of facial nerve injuries is 50%.4 media until proven otherwise. By no History Other causes of traumatic paralysis means does this infer that TB treatment include iatrogenic, birth canal should be commenced without an ENT A thorough history is paramount to trauma/forceps delivery, penetrating assessment to exclude life-threatening narrowing the differential diagnosis: parotid or middle ear trauma and causes like cholesteatoma or • onset of palsy (sudden/delayed) facial fractures. leukaemia. • duration and rate of progression • complete or incomplete palsy Infections Malignant/diabetic otitis externa is a • associated symptoms (hearing loss, The most common cause is herpes life-threatening osteitis of the temporal otorrhoea, otalgia, vertigo, vesi- zoster oticus (Ramsay-Hunt syndrome). bone, causing facial palsy and otal- cles, CNS symptoms) Reactivation of the varicella zoster gia, usually due to Pseudomonas • medical history (diabetes, pregnan- virus causes severe otalgia, deafness, aeruginosa. The diagnosis is made on cy, CVA, previous ear/parotid dis- facial paralysis and a vesicular erup- clinical suspicion in susceptible orders) tion on the ear, face, neck or oral cav- patients (diabetics, immunosuppressed, • history of trauma or previous sur- ity. Patients may also have varying patients on chemotherapy, etc.), and is gery (e.g. ear, parotid). degrees of deafness and vestibular confirmed by a positive bone scan. Examination symptoms. Only about 50% of patients regain normal facial function. Other Tumours A complete head and neck examina- infections include TB, otitis media, oti- About 5% of facial nerve palsies are tion, including assessment of the ears, tis externa, syphilis, Lyme disease, etc. due to tumours — parotid tumours, parotids, eyes (keratitis), upper aerodi-

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nerve excitability (NET), maximal provides excellent bony assessment stimulation test (MST), electroneu- of temporal bone fractures, the mid- rography (ENOG) and electromyo- dle ear and mastoid. graphy (EMG) are useful in patients • Other tests to exclude specific ill- who have complete paralysis to nesses, e.g. diabetes, sarcoidosis, determine the prognosis for return autoimmune disease, etc. of facial function. • The once popular topognostic tests MANAGEMENT (Schirmer’s, stapedial reflex, sali- Treatment of facial paralysis depends vary flow assessment) are based on on its cause. The role of the emer- the principle that lesions distal to a gency physician is to: branch of the facial nerve will •provide adequate eye protection spare the function of that branch. • exclude obvious causes These are now considered to be of • initiate appropriate therapy historical interest only and of little • seek timeous ENT referral. use in determining site of lesion, or in predicting outcome. Eye protection Fig. 1. Lower motor neuron lesion. • Radiological evaluation — per- Poor upper eyelid closure and dimin- formed in patients with a history of ished lacrimation may lead to corneal gestive tract and (cranial recurrent paralysis, CNS symptoms, dryness, punctate keratopathy, ulcera- nerves) is mandatory. The next step is suspected CPA lesions, otological tion and ultimately decreased vision. to assess whether the nerve injury is findings, history of trauma and in Patients should use artificial tears liber- complete or incomplete, upper motor patients with delayed nerve recov- ally during the day, and close the eye neuron (UMN) or lower motor neuron ery. Gadolinium-enhanced MRI is with a patch after application of an (LMN): the procedure of choice to exclude eye ointment at night. They should • UMN lesions (e.g. CVA) — upper CPA lesions or brain lesions. CT avoid dust, and wear eye protection 3rd of the face is spared • LMN lesion — weakness or paraly- sis of the entire face (Fig. 1). FACIAL PALSY

Typical findings in peripheral nerve palsy: • ONSET • At rest — less prominent wrinkles • DURATION on the affected side, eyebrow •RATE OF droop, flattened nasolabial folds, PROGRESSION and corner of the mouth turned HISTORY • RECURRENCE down. • ASSOC. • Inability to wrinkle forehead, raise SYMPTOMS eyebrows, purse lips, show teeth, • MEDICAL or whistle. Eye closure may be HISTORY incomplete. As a rule all LMN facial palsies will require an ENT referral to complete HEAD & NECK the more specialised aspects of exami- • ENT nation and investigation. • CRANIAL NERVE •PAROTID AND NECK INVESTIGATIONS EXAMINATION CNS Owing to the specialised nature of FACIAL PALSY these studies this section will deal only • UMN/LMN briefly with which investigations are • COMPLETE OR performed and why. INCOMPLETE • All patients with facial paralysis require formal audiological testing (pure tone, air and bone conduc- • AUDIOLOGY tion, speech, reflexes and tympa- • ELECTROPHYSIO- INVESTIGATION nometry). Asymmetry on the audio- LOGICAL TEST gram warrants an MRI scan to • RADIOLOGY exclude CPA lesions. • LAB. TESTS • Electrophysiological tests, e.g.

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The prevalence of facial ical regimen in altering the natural his- Immediate complete facial paralysis palsy in the general popu- tory of the palsy (85 - 90% complete with a demonstrable fracture on CT lation is about 1:5 000, recovery in 1 month) remains scan necessitates surgical exploration unproven. Despite this, experts believe and repair of the nerve as soon as making it a common that early oral prednisone (1 mg/kg/ possible, after audiological and neuro- enough clinical entity for day) may decrease degeneration, logical assessments. In incomplete or all general practitioners to reduce synkinesis (mass movement), delayed-onset palsies with temporal be familiar with. relieve pain, and promote earlier bone fractures, facial nerve testing is recovery.7 Patients should be evaluated obtained on day 4. If advanced within 5 days of starting steroid thera- degeneration has occurred the nerve The routine assumption that py. If some function is present, taper is surgically explored and decom- all facial palsies are idio- the steroids over the next 5 days. If no pressed. pathic means that many improvement is noted, the full dose correctable causes, e.g. of should be administered for 10 days, Gunshot wounds of the temporal bone tapered over the last 5 days. cause paralysis in about 50% of otological origin, might be cases. The nerve may be transected or left too late to achieve any With mounting evidence implicating secondarily injured by kinetic energy favourable outcome. the herpes simplex virus, many clini- from the bullet or by bony spicules. In cians cite the study by Adour et al., complete paralysis surgical explo- using acyclovir and prednisone, claim- ration and repair is undertaken when The prognosis for Bell’s is ing decreased neural degeneration.8 the patient is medically stable. generally good, with most Adour recommended prednisone patients (85 - 90%) recov- (1 mg/kg/day) and acyclovir (200 mg Following iatrogenic injury, the tran- ering completely within 1 5 times daily) for 10 days. sected nerve must be repaired immedi- month. ately. If paralysis occurs postoperative- Surgical decompression of the facial ly and the surgeon is confident that nerve in patients with Bell’s palsy is the nerve was intact at the end of the Facial palsy in children is controversial. It has not been shown to operation, tight ear packing is TB otitis media until proven alter the natural history of the disease removed and the patient is observed and is currently not favoured by most to allow local anaesthetic agents to otherwise. By no means clinicians. wear off. The patient is re-assessed does this infer that TB treat- and if the palsy persists, high-resolu- ment should be commenced It must be emphasised that the diagno- tion CT scan is performed to demon- without an ENT assessment sis of Bell’s can only be made when strate the nerve, and electrical testing to exclude life-threatening an otorhinolaryngologist has excluded is conducted on day 4. If advanced causes like cholesteatoma all other causes of facial palsy. May et degeneration is noted, the nerve is al., in their study of 1 675 patients explored and decompressed or or leukaemia. with ‘Bell’s palsy’, found that 13% of repaired. If there is any question patients had been incorrectly diag- about the integrity of the nerve, explo- 3 when outdoors (patch/glasses). nosed. A space-occupying lesion ration is undertaken as soon as possi- Counselling and early aggressive treat- along the course of the facial nerve ble, preferably by another surgeon. ment usually prevent complications, was discovered in 38% of patients. but if symptoms persist an ophthalmic Penetrating facial injuries with immedi- Trauma consultation is advised. These meas- ate facial paralysis are usually ures are adequate for palsies of short In temporal bone fractures it is crucial explored and repaired as soon as pos- duration. that the onset (immediate/delayed) of sible. the palsy is ascertained. A full head Infection In patients with delayed nerve recov- and neck, and neurological evaluation ery or permanent palsies, more perma- must be followed by close assessment Herpes zoster oticus is characterised nent eye protection is required. Lateral of the facial palsy (complete/incom by severe otalgia, vesicular eruptions tarsorraphy is successful in correcting plete) and inspection of the external and varying degrees of deafness. mild lagophthalmos. In severe cases, a auditory canal (EAC) and tympanic These patients require an audiogram gold weight implant or upper eyelid membrane (T/M). Common findings in to assess hearing loss. Treatment is spring is indicated. the ear are blood/laceration of the with acyclovir, 800 mg, 5 times per EAC, T/M perforation, ossicular dis- day, for 1 week, and potent anal- Bell’s palsy ruption and haemotympanum. gesics.2,3 The role of is The treatment of Bell’s remains contro- controversial, due to the risk of herpes versial. The effectiveness of any med- spread and meningoencephalitis.

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Paralysis in acute otitis media is treat- of the nerve, division and re-anastomo- The information in this article should ed with myringotomy to drain the mid- sis, interposition grafting and facial provide the appropriate first steps in dle ear space, and for nerve crossover. The misdiagnosis of a evaluation and management of facial Gram-positive cocci and Haemophilus tumour somewhere along the course of palsies, and emphasises the impor- influenzae. Facial paralysis with mas- the facial nerve, as a Bell’s palsy is tance of a specialist consultation. toiditis, however, is treated with intra- catastrophic. Findings not to miss are venous antibiotics and surgical a slowly evolving facial paresis, facial References available on request. drainage (mastoidectomy). Nerve com- twitching, middle ear mass or conduc- pression by cholesteatoma or inflam- tive deafness. A parotid mass with a mation in chronic otitis media necessi- facial nerve paralysis is malignant IN A NUTSHELL tates a CT scan. These patients until proven otherwise. undergo mastoidectomy with facial Early and adequate eye care is nerve exploration and decompression. Facial palsy in the newborn paramount. The broad differential diagnosis is Bell’s palsy — a diagnosis of exclu- Tuberculous otitis media is usually either traumatic or congenital. In con- sion! ‘Bell’s palsy’ of longer than 3 diagnosed by obtaining aspirates or genital paralysis patients are left months warrants re-evaluation. biopsies from the middle ear. Chest X- untreated until late childhood when rays often show no evidence of pul- cosmetic surgery (muscle transfer/ Diagnostic clues in facial palsy: monary tuberculosis. These patients facial slings) is performed. Trauma is vesicles — Ramsay-Hunt are treated with systemic antituberculo- usually evident by facial contusion, syndrome sis treatment. Only in some cases is ecchymoses over the mastoid, haemo- parotid mass — consider surgery indicated to remove sequestra tympanum, etc. The patient with com- malignancy and improve drainage.4 plete paralysis should undergo electri- children — TB (acute otitis cal testing of the facial nerve in the media/cholesteatoma) Malignant otitis externa causing facial first 3 days after birth to ascertain the diabetic — diabetic/malignant nerve palsy is a life-threatening condi- integrity of the nerve and to plan fur- otitis externa tion. These patients are treated with a ther treatment. trauma - fractured temporal bone. combination of intravenous Refer all facial palsies to an otorhi- piperacillin, amikacin and metronida- CONCLUSION nolaryngologist. zole until the bone scan is negative, Although Bell’s palsy is the commonest usually 6 weeks.2,4 cause of facial palsy, it is crucial that all causes are excluded to avoid over- Tumours looking life-threatening conditions. A The management of facial nerve paral- thorough history and examination is ysis caused by tumours depends on essential to narrow the differential the location, extent and malignant diagnosis. potential. It may include transposition

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