Bell's palsy syndrome: mimics and chameleons

Abstract

In this article we will explore the mimics and chameleons of Bell's palsy and in addition argue that we should use the term 'Bell's palsy syndrome' to help guide clinical reasoning when thinking about patients with facial weakness. The diagnosis of Bell's palsy can usually be made on clinical grounds without the need for further investigations. This is because the diagnosis is not one of exclusion (despite this being commonly how it is described), a lower motor neurone facial weakness where all alternative causes have been eliminated, but rather a positive recognition of a clinical syndrome, with a number of exclusions, which are described below. This perhaps would be more accurately referred to a 'Bell's palsy syndrome'. Treatment with corticosteroids improves outcome; adding an antiviral probably reduces the rates of long-term complications.

Lyme disease and Bell’s palsy: an epidemiological study of diagnosis and risk in England

“…Bell's palsy typically presents with an acute onset to a maximum within 72 hours. 11 About 50% of patients have a mild-tomoderate post-auricular pain (25% before the weakness, 50% contemporaneous with the weakness, and 25% after the weakness), with altered taste in 35%. 11 In 30% a dry eye is noticed, and in 20% a dry mouth, due to parasympathetic involvement.…”

“…11 About 50% of patients have a mild-tomoderate post-auricular pain (25% before the weakness, 50% contemporaneous with the weakness, and 25% after the weakness), with altered taste in 35%. 11 In 30% a dry eye is noticed, and in 20% a dry mouth, due to parasympathetic involvement. 11 Patients with Lyme disease with facial palsy may have noticed a tick bite -a hard-bodied tick attachment with or without engorgement is particularly relevant.…”

Therapie der idiopathischen Fazialisparese (Bell’s palsy)

“…B. Hypakusis, Tinnitus, sensible Ausfälle, Doppelbilder) ist allerdings eine dif-▶ Tab. 1 Differenzialdiagnose der peripheren Fazialisparese [4,22,23]. [36].…”

“…Die Zahl von 80 -90 % unauffälliger Liquorbefunde impliziert aber auch, dass bei 10 -20 % der Patientinnen und Patienten mit anfangs vermuteter idiopathischer Fazialisparese nach Liquordiagnostik doch noch eine symptomatische Fazialisparese zu konstatieren ist. Diese Einschätzung wird gestützt durch Therapiestudien, die 8 -11 % ihres Kollektivs mit vermuteter idiopathischer Fazialisparese aufgrund symptomatischer Ursachen aus der Studie ausschließen mussten [6,23,39]. In den Kliniken der Autoren wird daher im Allgemeinen bei der peripheren Fazialisparese eine Lumbalpunktion empfohlen, um höchstmögliche diagnostische Sicherheit zu erhalten.…”

Bell’s that did not ring true

“…This has a typical presentation of acute, unilateral lower motor neurone facial palsy, often associated with mild postauricular pain and sometimes with other features of facial nerve dysfunction, such as altered taste and hyperacusis, that should improve within 4 weeks. This has been termed ‘Bell’s palsy syndrome’ 2. Features outwith this typical presentation should raise concern and lead to consideration of ­alternative diagnoses.…”