Adverse effects following botulinum toxin A injections in children with cerebral palsy

The study aimed to analyze the adverse events associated with botulinum toxin A (BoNT-A) injections in children with cerebral palsy (CP). The literature search was completed using the Medline, PubMed, Google Scholar, Scopus, and Cochrane Library databases from the earliest date possible up to December 2021. Search terms included 'botulinum toxin', 'cerebral palsy', 'spasticity', 'adverse effects', 'side effects', 'undesirable effects', 'complications', 'lower limb', 'upper limb', and 'children' including combinations of index and free-text terms. Fifty-five studies were included in the study. Data on 6333 pediatric patients and more than 14 080 BoNT-A injections were collected. Respiratory symptoms and respiratory tract infections were the most frequently registered adverse events (AEs). Other common AEs included procedural/focal AEs, flu-like symptoms, and asthenia. Sentinel events including four cases of death were reported. AEs were more frequent and severe in high-dose patients; however, the capacity of BoNT-A to spread systemically remains unclear. Since severe adverse events are not common, further research is needed to collect more definitive clinical and homogeneous data to support the findings of the present research and clarify the safety profile of BoNT-A, especially regarding the incidence of respiratory issues and complications in GMFCS IV or V patients.