Marin-Amat Syndrome
A Jogiya and C Sandy1
Department Of Ophthalmology, The Royal London Hospital, Whitechapel, London
and 1Department Of Ophthalmology, North Hampshire Hospital,
Aldermaston Road, Basingstoke
Correspondence to: Dr Aryan Jogiya, Department Of
Ophthalmology, The Royal London HospitalWhitechapelLondon E11BBEmail: aryanjogiya@aol.com
Accepted for publication: 1st March 2003
Involuntary lid closure on jaw movement with Marin-Amat syndrome.
1) Patient
was asked to repeatedly open and close her mouth.
2) Patient was asked to repeatedly draw in her lips.
3) Patient was asked to
repeatedly simulate the action of chewing.
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Background
Synkinesis is the presence of unintentional muscle activation in one area when intentionally performing movement in another area. Marin-Amat syndrome is a synkinesis which develops following facial nerve palsy and manifests as involuntary lid closure on jaw opening. The most commonly held theory is that it arises as a result of aberrant regeneration of the facial nerve.1,2,3,4 We present a case of facial synkinesis in a patient recovering from Bell’s palsy. This manifests with involuntary narrowing of the ipsilateral palpebral fissure on volitional jaw movements.
Case Report
The patient presented 8 months following a left sided Bell’s palsy from which she had mostly recovered. Her initial presenting symptoms were those of blurred vision, and watering. She had a past history of sarcoidosis, migraine, ureteric calculus, thyrotoxicosis with thyroid eye disease treated with radioiodine rendering her hypothyroid. She was on thyroxine and had no known drug allergies.
Examination revealed left hemi-facial spasm and mild left facial palsy. She was reviewed 4 months later and she had noticed that the spasm worsened on opening her mouth or chewing. There was lid closure on opening her mouth or when she simulated chewing. She was offered Botulinum Toxintreatment5 for the spasm but declined in favour of more conservative measures.6 She underwent facial physiotherapy and at the last review her facial nerve function had improved but the involuntary lid closure was unchanged.
Discussion
The facial nucleus is somatotopically organized and this organization is continued from the facial nucleus through the facial nerve itself, and distally to the muscles. After facial nerve lesion, and regeneration, the topography of the facial nucleus is disturbed; and this has been illustrated in animal models. This proposed reorganization at the nuclear level would be accompanied by new synapses and, therefore result in the altered motor control that might be causal or at least contributory towards synkinesis.9
Several authorities have also suggested that synkinesis could also be a result of an increase in collateral branching. Other factors that proposed as contributing towards synkinesis are hyperexcitability of the facial nucleus following paresis and regeneration of the facial nerve. Ephaptic transmission is another mechanism implicated in synkinesis where neuroelectrical transmission can occur in the absence of anatomic coupling.7,8,9
Although this condition has also been described by some as the inverse Marcus-Gunn phenomenon we agree with other authorities that the term inverse Marcus-Gunn phenomenon be reserved for a congenital lesion whose pathogenesis is quite different.2 It has been suggested that the inverse Marcus-Gunn phenomenon is related to Wartenberg’s hypothesis of ‘release-phenomenon’ where a primitive reflex association between the deep and superficial facial muscles is re-established through failure of inhibition.12
References