prognosis

Last reviewed 01/2018

  • almost 75% of patients recovering normal mimetical function and just over a tenth having minor sequelae
  • about one sixth of patients are left with either moderate to severe weakness, hemifacial spasm, contracture or synkinesis
  • patients with a partial palsy fair better
    • 94% making a full recovery
    • in partial palsy, outcome is worse when herpes zoster virus infection is involved
  • in patients who recover without treatment
    • in the majority, major improvement occurs within three weeks
    • if recovery does not occur within this time
      • recovery is then unlikely to be seen until four to six months - this is when nerve regrowth and reinnervation have occurred
  • it is clear by six months who will have moderate to severe sequelae
    • indicators of poor prognosis in Bell's palsy include:
      • a complete facial palsy
      • no recovery by three weeks
      • if there are associated conditions
        • hypertension, diabetes, pregnancy
      • if the patient is aged over 60 years
      • if there is severe pain associated with the facial palsy
      • Ramsay Hunt syndrome (herpes zoster virus)
      • if electrophysiological testing shows severe degeneration of the facial nerve
  • in facial palsies caused by herpes simplex virus or herpes zoster virus there remains a strong correlation between the peak severity of the palsy and the outcome
  • there is currently no reliable investigation or test at presentation that can indicate who will make a full recovery
  • 80% of patients with Bell's palsy have a conduction block in the facial canal which is probably caused by segmental demyelination
    • in this group, recovery occurs within about 4 weeks

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