Painful tic convulsif and Botulinum toxin

Background: Painful tic convulsif is a rare disorder that associates trigeminal neuralgia (TN) and ipsilateral hemifacial spasm (HFS). These two disorders are the most common examples of hyperactive cranial rhizopathy and are frequently caused by vascular compression of these cranial nerves at the nerve root entry and exit zone in the brain stem, which leads to paroxysmal ephaptic transmission.

Methods: We report the cases of four patients with combined TN and HFS out of a total of 247 patients with HFS who were treated with botulinum toxin. One patient had TN that was contralateral to the HFS, while the other three were ipsilateral, and one of these had bilateral HFS. In all four cases both the HFS and the TN improved with botulinum toxin treatment.

Conclusions: These four patients with TN and HFS suggest a common aetiology for the two disorders, due either to central neuronal hyperactivity or to vascular compression of several cranial nerves. The beneficial effect of botulinum toxin in both disorders supports the idea of this toxin having a central mechanism of action that acts by controlling neuronal hyperactivity in the brain stem, as well as its peripheral action.