Botulinum toxin for the treatment of acute-onset concomitant esotropia in Chiari I malformation

The latter may result in temporary correction of the strabismus, as the strabismus can recur and resolves only following decompression. 3 Botulinum toxin (BT) has been reported as successful in one case where the ET did not resolve following neurosurgery. 4 Despite BT being a common treatment for acute acquired concomitant ET, 5 no previous case has been reported in which BT was used prior to neurosurgical decompression for Chiari I malformation. MRI scan revealed Chiari I malformation with tonsillar descent to about 12 mm below the foramen magnum, with loss of cerebrospinal fluid (CSF) spaces indicating impaction of neural tissue (fig 1).