Bell’s palsy

General paediatrics, Neurology

bells palsyDiverse causes, some of which are extremely serious (mostly infiltrative):

  • Zoster sine herpete ie zoster reactivation without vesicles – probably responsible for a third of otherwise unexplained facial palsies
  • EBV- the most commonly found cause (20%)
  • Ramsay Hunt – look out for soft palate, tongue as well as external auditory meatus lesions
  • Mycoplasma
  • Cat scratch disease, HIV, Lyme disease (erythema chronicum migrans, travel history)
  • Acute otitis media (historically the most common cause!  Reactivation of virus?  Toxin induced demyelination?  But beware mastoiditis!)
  • Trauma
  • Malignancy – leukaemia, cerebellar astrocytoma, rhabdomyosarcoma
  • Histiocytosis
  • Haemophilia
  • Hypertension!

Bell’s Palsy is what you would call it if idiopathic, but perhaps you just haven’t looked hard enough? Often otalgia, facial or retroauricular pain. Typically mild except in Zoster, where it is severe. Pain may precede palsy.

Warning signs (for a serious underlying cause) are:

  • otitis media (in case direct inflammation, ie osteomyelitis),
  • hearing loss,
  • lymphadenopathy, tonsillar enlargement (parotid tumour),
  • mastoid enlargement,
  • frontal sparing, motor function of tongue/fingers (adjacent cortical representation) (UMN lesion)
  • or duration longer than 1 month.

Assess using House-Brackmann scale:

House Brackman criteria

Management

Do hearing test, blood pressure, check frontal sparing/tongue/finger function. FBC if any suspicion of leukaemia. Check blink reflex (prognostic).

Treatment

Apply lubricating drops hourly during day, and an ointment overnight. Patching seems to be frowned upon now.

Treat underlying cause!

For Bell’s, still controversial.  Cochrane review (2016) found that steroids reduce chance of permanent facial weakness (NNT=10), involuntary movements (motor synkinesis) and crocodile tears.  Adding antivirals may improve rate of recovery but low quality evidence – certainly less good than steroids, in fact not much different from placebo when used alone! Even without treatment most make a full recovery within 9 months. (Dundee study in adults, NEJM 2007; 357:1598 PMID 17942873)(Adour, Ann Otol Rhino 1996)(Hato Otol Neurotol 2003, PMID 14600480)

Only 2 studies in children from what I can see.

IV aciclovir in Ramsay Hunt since poor prognosis. Valciclovir would in theory be better, 96% recovery in Hato study (5 day course with steroids cf steroids alone) but unblinded (Otol Neurotol 2007;28:408-13)

Some evidence for methylcobalamin and hyperbaric oxygen.

Recovery usually within 3 weeks, else nerve regeneration takes 4-6 months. Beyond 6 months improvement is unlikely. For long term palsy, feedback training, surgical techniques may result in functional as well as cosmetic improvements. Synkinesis and facial spasm are complications, treat with botulinum. (BMJ 329:553)