|This 62 year-old woman who recovers from a right
Ramsey-Hunt's syndrome complained of the above appearance.
a. What is the diagnosis?
Aberrant facial nerve regeneration resulting in synkinesis.
Involuntary synkinesis between the orbicularis oculi and orbicularis
oris muscle can be an unwanted side effect in patients who recovers from
facial nerve palsy. It results from an aberrant connection of the motor
fibres originally innervating orbicularis oris to the orbicularis oculi,
causing lid closure whenever the patients smile, talking or eating. If
severe, this can lead to social embarrassment and functional visual loss.
b. What other condition may be present?
Aberrant regeneration may involve the lacrimal gland causing
crocodile tear. In this condition, the parasympathetic fibres which normally
innervate the salivary gland are misdirected to the lacrimal gland. As
a result, there is excessive tear secretion when the patient eats.
c. How would you treat the condition?
Before the discovery of botulinum toxin, several methods have
been tried with variable results and these include orbicularis myectomy,
blepharoplasty and fascial slings.
The use of botulinum toxin as chemical neurectomy offers an effective
though not a curative treatment. The toxin is injected subcutaneously in
the pretarsal areas in both the upper and lower lids as in blepharospasm.
This has the effect of paralysing the orbicularis and therefore reduces
the synkinesis. The exact dose required differs for different patients
but the dose given is generally half of that for blepharospasm.
Repeated injection is required when the effect wanes. The treatment
takes a few days to work and usually lasts between two to three months.