Remote F-wave changes after local botulinum toxin application

Long-Distance Retrograde Effects of Botulinum Neurotoxin A

“…In clinical practice, doses of BoNT/A vary widely depending on type of the disease and size of the muscles to be treated. Doses of BoNT/A ranging from 2 to 22 ng are typically reported for the treatment of torticollis spasmodicus and head/ neck dystonia (Garner et al, 1993;Wohlfarth et al, 2001). Comparison of these doses with those used by us suggests that retrograde transport may be a common occurrence after intramuscular delivery of BoNT/A.…”

“…Several papers have described changes at the level of the CNS in man and animals treated intramuscularly with BoNT/A (Garner et al, 1993;Giladi, 1997;Moreno-Lopez et al, 1997a,b;Kanovsky et al, 1998;Wohlfarth et al, 2001;Abbruzzese and Berardelli, 2006;Kim et al, 2006). For example, delivery of BoNT/A into the lateral rectus muscle of cats dramatically reduces the firing rates of abducens motoneurons projecting to the injected muscle (Moreno-Lopez et al, 1997a,b).…”

“…For example, changes have been described at the level of spinal cord circuitry (Priori et al, 1995;Wohlfarth et al, 2001). An alteration of cortical excitability has also been reported in dystonic patients treated intramuscularly with BoNT/A (Kanovsky et al, 1998;Gilio et al, 2000).…”

Absorption and Transport of Botulinum Neurotoxins

“…Moreover, although BoNT remains relatively localized at the site of injection by binding to the local nerve endings, side effects of BoNT therapy have been observed due to toxin diffusion [26]. Most often, the undesired effects are related to local toxin diffusion to the adjacent muscles, but in rare cases, adverse effects occur in distant muscles or result in central effects or generalized intoxication [1,63,66,67,87,146,185]. Systemic spreading and autonomic side effects, including mouth dryness, blurred vision, swallowing difficulties and constipation, are more often observed with BoNT/B than BoNT/A [44].…”

Treatment of spasticity

“…As a consequence alphamotoneuron activity is reduced even in non-treated muscles. 10 There are hints that surgical interventions intended to improve the ability to walk and stand are made possible and facilitated by treatment with botulinum toxin. Results are best when botulinum toxin is combined with physiotherapy and oral antispastic medication.…”