Contralateral weakness following botulinum toxin for post-stroke spasticity
Muscle & Nerve, 06/29/2012
Clinical Article
Thomas AM et al. - Isolated weakness of the contralateral limb following BoNT injection for post-stroke spasticity suggests diffusion of toxin through tissue planes from proximal upper extremity muscles, across the midline, to contralateral muscles. High doses of botulinum toxin, high dilution volumes, and injection of proximal upper extremity muscles appear be risk factors for this adverse effect.
Methods- Both patients received high doses of BoNT with large dilution volumes and injection of proximal upper extremity muscles, and developed weakness of the contralateral upper limb.
- Both patients underwent electrodiagnostic testing of the affected limb.
- Repetitive nerve stimulation of the axillary and spinal accessory nerves revealed decrements of 23% and 16% respectively.
- EMG revealed abnormal spontaneous activity and small polyphasic motor unit potentials with reduced recruitment.
- These findings indicated blockade of the neuromuscular junction.
- Both patients improved.
