Onset, progression and duration

Rapidity of onset of facial palsy does not point to a specific diagnosis.5 Almost all patients demonstrate signs of recovery between 3 weeks and 3 months,23 and this course indicates a benign cause. Facial palsy that continues to progress beyond 3 weeks or lacks improvement after 3 months is suggestive of neoplastic/neurological cause and should be appropriately investigated.4 Recurrent facial nerve paralysis (RFNP) is rare, with an incidence of 6%.6 Causes of RFNP are Bell's palsy, Melkersson–Rosenthal syndrome (recurrent alternating facial palsy, fissured tongue, facial oedema, positive family history) and rarely secondary to an underlying neoplasm. Therefore, all children with RFNP should be investigated.

Laterality

Bilateral FNP is likely to be due to neurological causes such as Gullian–Barre syndrome, Moebius syndrome (bilateral facial nerve and bilateral abducens paralysis due to intrauterine brainstem necrosis) or secondary to infection (cytomegalovirus infection, Ebstein–Barr virus and Lyme disease).

Associated aural symptoms

Presence of aural symptoms indicates otitis media, cholesteatoma or tumour. Facial paralysis secondary to otitis media is rare and has incidence of 0.005%.7 Hearing loss, otalgia and facial pain may be seen in Bell's palsy and Ramsay–Hunt syndrome.

History of trauma

The lateral position of the facial nerve in children makes it more susceptible to damage. Facial nerve injury can occur in head trauma especially with longitudinal fracture of temporal bone (90%).8 FNP may also be seen following blunt cheek injury. Rarely, facial palsy occurs following parotid surgery, middle ear/mastoid surgery9 10 or following forceps delivery.4

History of immunisation

Facial nerve can rarely be affected by immunisation against polio, rabies, tetanus and influenza.11

Underlying illness

Haematological disorders, such as leukaemia,9 12 haemophilia,13 may rarely present with FNP. Acute onset FNP has also been reported in cases of malignant hypertension.14 Ear infection (otitis media, Ramsay–Hunt syndrome) and neurological infections such as meningitis, encephalitis, leprosy, botulin and tetanus may also affect the facial nerve.

Eye symptoms

History of grittiness, burning or stinging sensation in ipsilateral eye, excessive watering and blurred vision should be taken.

Assess severity of facial weakness at presentation

It is important to document the severity of facial weakness at presentation to allow assessment of recovery or progression at future visits. Clinical examination of facial function in older children is similar to an adult, allowing grading of facial function using the House-Brackmann (H.B.) scoring system (table 2).15 In younger children where examination is difficult and a meaningful grading (H.B.) score is not achievable, observation of spontaneous facial movements is important. It is useful to document which facial movements are witnessed during the consultation and which movements the parents feel that a child can achieve. Forehead movements should be particularly noted as they are affected in infranuclear palsy whereas preserved if the lesion is above the facial nucleus, ie, supranuclear.

Assessment for aetiological factors

Examination of pinna, external auditory canals, tympanic membranes and oral cavity/oropharynx should be undertaken; presence of vesicles is suggestive of Ramsay–Hunt syndrome. Signs of acute otitis media, acute mastoiditis and chronic otitis media with or without cholesteatoma should be looked for. An abnormally sited external ear, ear deformity or dysmorphism may be associated with congenital FNP. Stigmata of a temporal bone fracture should be sought in the presence of history of trauma (Battle's sign, haemotympanum and traumatic perforation).

Examination of eye

Look for degree of eyelid closure, redness of conjunctiva, frequency of blinking and excessive watering or dryness of the involved eye.

Besides focused examination, a complete general and systems examination should be carried out including remaining cranial nerves and the central nervous system. Examination of the neck must be performed to illicit a parotid neoplasm or cervical lymphadenopathy. Joints should be examined in endemic areas of Lyme disease (bilateral FNP with other cranial nerve involvement, due to borrelia spirochete). The cerebrospinal fluid (CSF) in patients with Lyme disease often shows an inflammatory response.

Investigations

The following investigations may be carried out as indicated from the history and examination.

Treatment

The medical management of a child with FNP is similar to that of an adult with FNP.

Eye care is the most important treatment in FNP. Regular use of artificial tears (eg, hypromellose eye drops) during daytime and moisturising eye ointment (eg, lacrilube) during sleep prevents dryness of eye. Glasses should be worn outdoors to protect the eye from windborne particles. If done improperly, taping of the eye can cause corneal injury and should be discouraged in children. Ophthalmological opinion should be sought if the patient has eye discomfort or redness of the sclera at any point.

If there is an obvious physical cause for the FNP (cholesteatoma or neoplasm), it should be dealt with by the involvement of appropriate teams.

Children who have FNP as a part of a syndrome or have neurological/haematological disorders should be managed in conjunction with the appropriate paediatrician.

In the absence of other causes in the history or examination, the presumptive diagnosis is Bell's palsy. Most authors believe that herpes simplex virus infection is the likely cause of Bell's palsy. Treatment for Bell's palsy with steroid or antiviral or both is controversial. Vast majority of children will recover completely, with or without treatment. Due to a paucity of randomised-control trials in children with Bell's palsy, the efficacy of steroids as well as other therapies such as acyclovir can only be extrapolated from studies done in adults.19 A double-blinded randomised-control trial conducted by Sullivan et al in Scotland showed statistically higher rate of recovery of Bell's palsy following prednisolone alone. There was no additional benefit from combining acyclovir and prednisolone compared with prednisolone alone. Acyclovir alone did not show any significant difference in the rate of facial recovery compared with placebo.20 A Cochrane review of the role of antivirals in Bell's palsy found insufficient evidence supporting their role and recommended further randomised-control trial.21

Prednisolone is typically prescribed in dose of 1 mg/kg (maximum 60 mg) for 7 days to be tapered over next few days, started within a week of onset (ideally within 72 h) provided there is no contraindication.

The prognosis of a child with Bell's palsy is generally excellent, and the risk of recurrence is only from 7% to 10%.22 Almost all patients demonstrate signs of recovery between 3 weeks and 3 months.23 The lack of any signs of recovery or progression of FNP should raise a suspicion of an underlying cause which should be thoroughly investigated including radiologically.

Surgical treatment: facial reanimation techniques, static or dynamic or both, may be employed for treatment of FNP that does not recover. The ideal time for the intervention is controversial.