Botulinum toxin for the treatment of lower limb cramp pain in patients with Amyotrophic Lateral Sclerosis

Background: Muscle cramps and pain associated with them can be seen in patients with amyotrophic lateral sclerosis (ALS) and are known to reduce the quality of life. Pharmacological treatment may not benefit all patients in treating these cramps. We assess the efficacy of Onabotulinum toxin A (BTX-A) in the treatment of lower limb cramps in patients with ALS. Methods: This retrospective chart review included a total of ten patients with ALS who suffered from pain due to lower limb cramps and were managed with BTX-A. Data including patient demographics, visual analog pain scale at different intervals during follow up, ALS functional rating scale and site of onset of ALS symptoms were documented. The pain score at baseline (before administration), at 3 months follow up and at 6 months follow up were compared using Wilcoxon test to assess BTX-A’s efficacy. Results: A significant improvement in average pain score due to cramps from baseline to the 6-month interval with a change of 3.1±0.7 (p<0.05,95%CI) was seen on the pain scale. No adverse events were noted during administration or post injections. Conclusion: Local BTX-A administration is an efficacious and safe procedure for improving pain associated with cramps in patients with ALS.