Botulinum toxin type A (BoNT-A) appears to effectively alleviate dystonia in patients with Wilson disease (WD), according to a recently published study in Toxicon

Dystonia is 1 of the most common neurological symptoms associated with WD. The sustained, intermittent muscle contractions can seriously impact the quality of life of patients, even leading to full immobilization in some cases. Currently, symptomatic treatment for dystonia in the context of WD is the same as for dystonia caused by other etiologies, Zeyu Cao, of the Anhui University of Chinese Medicine in China, and colleagues noted.

BoNT-A injections have proved to be an effective therapeutic approach for dystonia in general. Nonetheless, there are few studies regarding its effectiveness in patients with WD, the study authors added.

Therefore, the authors aimed to assess the efficacy of BoNT-A through a prospective, single-blind study including 4 patients with lower limb dystonia due to WD with poor response to conventional cooper drive. 

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Patients were evaluated at baseline and 2 weeks after treatment initiation. Clinical examination was performed using clinical assessment tools such as the modified Ashworth scale (MAS), the Activities of Daily Living Scale (ADL), and the Burke Fahn Marsden Scale (BFM). Surface electromyography (EMG) and gait analysis were performed as well. 

After 2 weeks of treatment, all of the participants improved their initial scores in the clinical assessment tools used in the study. Changes were particularly important in the MAS, BFM, and ADL scales.

Although EMGs performed 2 weeks after beginning treatment reported significant improvement regarding muscle tone, there was no significant improvement in muscle fatigue. The authors noted that the high variability of muscle activity and tissue thickness in the participants could cause instability in the studied EMG parameters.

Instrument gait analysis revealed a significant increase in the velocity of the patients, suggesting a restored walking function.

“Our findings showed that BoNT-A injection therapy effectively alleviates the dystonia symptoms in the lower limbs of WD patients,” the authors concluded.

Reference

Cao Z, Rao R, Wu T, et al. Botulinum toxin type A treatment of four cases of Wilson disease with lower limb dystonia: a prospective study. Toxicon. Published online November 4, 2022. doi:10.1016/j.toxicon.2022.106959