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Dystrophy: oculopharyngeal muscular
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(Barbeau disease)
Rare condition, Most common in Quebec (Saguenay-Lac-Saint-Jean) and in some families in Uruguay and in the Buckhara Jews. Autosomal dominant transmission. Amplification of a repeat of the GCN trinucleotide in the PABPN1 gene on 14q11-2 coding for a protein the function as well as the localization of which in the muscle cell are unknown. Normal individuals have 10 repetitions; the autosomal recessive form causes the presence of 11 repetitions and the autosomal dominant form has at least 12 repetitions.
Late (> 50 years, usually) and progressive onset of:
- ptosis: classic attitude: head in extension and contracted frontal muscle ("aiming into the air") to compensate for the ptosis
- dysphagia: pseudohypersalivation, chronic microaspirations
Later, proximal upper and lower limb weakness. No cardiac involvement. An involvement of the anal and bladder sphincters is possible but late.
Histology : electron microscopy shows striking abnormalities of muscle cell mitochondria. They appear to have laminated crystalline inclusions within the cristae. Some mitochondria are large with expanded area between the cristae.
Treatment: blepharoplasty, myotomy of the cricopharyngeal muscle (endoscopic or via cervicotomy).
Anesthetic implications:
Frequent pulmonary aspiration. No increased sensitivity to non-depolarising muscle relaxants. No risk of malignant hyperthermia. Avoid succinylcholine (risk of hyperkaliemia ?). The use of isoflurane has been reported without inducing rhabdomyolysis.
References :
Updated: December 2022