Facial weakness and Bell's palsy

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  • See also

    Stroke
    Acute otitis media
    Hypertension in children and adolescents

    Key Points

    1. Bell’s palsy is an idiopathic unilateral lower motor neuron facial nerve palsy
    2. Other causes of facial weakness should be excluded before making a diagnosis of Bell’s palsy
    3. Almost all children recover within 12 months without treatment, however some children may have a prolonged period of functional impairment, facial asymmetry and emotional distress

    Background

    • Facial nerve palsy in children may be idiopathic or caused by infection, inflammation, trauma, tumour or a vascular event
    • Bell’s palsy is an idiopathic lower motor neuron palsy of the facial nerve
    • It is important to rule out other causes before making a diagnosis of Bell’s palsy
    • Idiopathic or post-viral facial palsy is uncommon in children less than 2 years

    Assessment

    Assessment of Bell’s palsy is aimed at confirming the diagnosis and excluding other important causes of facial weakness

    History

    Features typical of Bell’s palsy

    • Onset: Bell’s palsy usually occurs very quickly (over hours or no more than 1-2 days)
    • Facial pain: usually mild pain in the face or behind the ear (common in Bell’s palsy)
    • Dry eyes and poor tear clearance from the eyes
    • Previous similar episodes

    Red flags for conditions other than Bell’s palsy

    • Other neurological features such as severe headache, blurred vision, double vision, weakness/numbness in arms or extremities, ataxia (consider Stroke)
    • Hyperacusis (increased sensitivity to sound) and altered taste (both uncommon in Bell’s palsy)
    • Preceding viral infections or trauma to the head or face
    • Severe pain (may indicate mastoiditis, VZV)

    Examination

    • Full neurological examination (cranial and peripheral) is essential
      • Bell’s palsy involves all facial nerve branches on the affected side. Ptosis and forehead muscle weakness must be present for a diagnosis of Bell’s palsy. These features are absent in upper motor neuron lesions
    • Eye examination (to look for corneal abrasions)
    • Skin lesions or vesicles on the face or in the ear canal (Ramsay Hunt Syndrome)
    • Signs of malignancy (pallor, hepatosplenomegaly, lymphadenopathy)
    • Signs of otitis media, mastoiditis or parotitis
    • Blood pressure and temperature (hypertension may rarely be associated with facial nerve palsy)

    Assessment of severity

    Severity can be measured using the House Brackmann grading scale (see Additional notes). This can be useful to monitor progress

    Management

    Facial weakness and Bell’s palsy - Diagram

    Investigations

    • The diagnosis of Bell’s palsy is made on clinical history and examination. Investigations are not usually required
    • FBE (to exclude haematological malignancy)
      • If features of an alternative cause of facial weakness, particularly malignancy
      • If commencing steroids
    • If features of an alternative cause of facial weakness, consider
      • Swab for HSV and VZV (if vesicles are present)
      • Neuroimaging (in consultation with neurology)

    Treatment

    • Almost all children recover within 12 months without treatment (most within 6 weeks of onset). However some children may have a prolonged period of functional impairment, facial asymmetry and emotional distress. Provide Bell's palsy parent handout

    Eye care

    • All children with an inability to close their eye should have eye care to prevent corneal abrasions (dry eye syndrome)
    • Lubricating (Hypromellose) ocular drops at least three times during the day
    • Pad eye shut after application of lubricating ocular ointment at night

    Steroids

    • The vast majority of children with Bell’s palsy recover without treatment. There is not enough evidence that early treatment with prednisolone improves complete recovery in children
    • In adults there is good evidence that steroids (1 mg/kg/day (max 50 mg) oral daily for 10 days) improve recovery, particularly within 72 hours of onset. The age of transition to adult evidence is unknown

    Antivirals

    • Acyclovir may be considered if vesicular rash present

    Consider consultation with local paediatric/specialist team when

    • Child is <2 years of age or atypical features on history or examination (consult Neurology)
    • Child with evidence of otitis media, mastoiditis or parotitis (consult ENT)

    Consider transfer when

    Children requiring care beyond the level of comfort of the local hospital

    For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services

    Consider discharge when

    • No signs of complications
    • Follow up with health professional (eg GP, paediatrician) within 1-2 weeks is arranged

    Parent information

    Bell's palsy

    Additional notes

    House Brackmann facial nerve grading scale

    Grade

    Description

    Gross function

    Resting appearance

    Dynamic appearance

    1

    Normal

    Normal

    Normal

    Normal

    2

    Mild dysfunction

    Slight weakness with effort, may have mild synkinesis*

    Normal

    Mild oral and forehead asymmetry, complete eye closure with minimal effort

    3

    Moderate dysfunction

    Obvious asymmetry with movement, noticeable synkinesis* or contracture

    Normal

    Mild oral asymmetry, complete eye closure with effort, slight forehead movement

    4

    Moderately severe dysfunction

    Obvious asymmetry, disfiguring asymmetry

    Normal

    Asymmetrical mouth, incomplete eye closure, no forehead movement

    5

    Severe dysfunction

    Barely perceptible movement

    Asymmetric

    Slight oral/nasal movement with effort, incomplete eye closure

    6

    Total paralysis

    None

    Asymmetric

    No movement

    *Synkinesis: voluntary muscle movement causing involuntary contraction of other muscles. Due to abnormal re-wiring of nerves with healing, develops over time

    Last updated February 2023

  • Reference List

    • Babl F, Herd D, Borland M, Kochar A, et al. Efficacy of Prednisolone for Bell’s Palsy in Children: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. Neurology 2022.
    • Gilden DH. Bell's Palsy. N Eng J Med. 2004. 351(13), p1323-31.
    • House JW, Brackmann DE. Facial nerve grading system. Otolaryngol Head Neck Surg. 1985. 93(2), p146-7.
    • Lee M, MacKay M, Blackbourn L, Babl FE. Emotional impact of Bell's palsy in children. J Paediatr Child Health. 2014. 50(3), p245-6.
    • Mackay MT, Chua ZK, Lee M, et al. Stroke and nonstroke brain attacks in children. Neurology. 2014. 82(16), p1434-40.
    • Peitersen E. Bell's palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Oto-Laryngologica. 2002. 122(7), p4-30.
    • Rowhani-Rahbar A, Baxter R, Rasgon B, et al. Epidemiologic and clinical features of Bell's palsy among children in Northern California. Neuroepidemiology. 2012.  38(4), p252-8.