Systemic adverse events after botulinum neurotoxin A injections in children with cerebral palsy.

AIM: To identify factors that increase the likelihood of systemic adverse events after botulinum neurotoxin A (BoNT-A) injections in children with cerebral palsy (CP). METHOD: A prospective observational study of patients attending a BoNT-A clinic at a tertiary paediatric hospital (2010-2014). Occurrences of systemic adverse events, defined as lower respiratory tract illnesses, generalized weakness, dysphagia, and death were determined at follow-up. The relationship between systemic adverse events and eight preinjection variables (age, Gross Motor Function Classification System [GMFCS] level, history of dysphagia, gastrostomy, aspiration pneumonia, recent history of illness, BoNT-A dose, and type of sedation) were examined using univariable and multivariable logistic regression with generalized estimating equations methods. RESULTS: In total 591 children underwent 2219 injection episodes with follow-up in 2158 (97%) cases. Systemic adverse events were reported in 77 (3.6%) injection episodes. Univariable analysis suggested that GMFCS levels IV and V, a history of dysphagia, gastrostomy, aspiration pneumonia, and increasing BoNT-A dose increase the likelihood of systemic adverse events. In multivariable analysis, a history of dysphagia (odds ratio [OR] 3.42) and/or aspiration pneumonia (OR 2.31) remained associated with increased likelihood of systemic adverse events. INTERPRETATION: A history of dysphagia and/or aspiration pneumonia are the factors that most increase the likelihood of systemic adverse events after BoNT-A. WHAT THIS PAPER ADDS: Systemic adverse events occur in 3.6% of botulinum neurotoxin A (BoNT-A) injection episodes. Dysphagia and/or aspiration pneumonia are associated with increased likelihood of systemic adverse events. Multivariable models showed no evidence of association between Gross Motor Function Classification System and systemic adverse events. Multivariable models showed no evidence of association between BoNT-A dose and systemic adverse events.

Severity of cerebral palsy and likelihood of adverse events after botulinum toxin A injections.

AIM: To determine the incidence of common adverse events after botulinum toxin A (BoNT-A) injections in children with cerebral palsy (CP) and to identify whether the severity of CP influences the incidence of adverse events. METHOD: This was an observational study of patients attending a BoNT-A clinic at a tertiary paediatric hospital (2010-2014). Data examined included procedural adverse events at the time of injection and at follow-up. Systemic adverse events were defined as lower respiratory tract illnesses, generalized weakness, dysphagia, and death. Severity of CP was categorized by the Gross Motor Function Classification System (GMFCS). The relationships between GMFCS and adverse events were analysed using negative binomial regression models. RESULTS: In total, 591 children underwent 2219 injection episodes. Adverse events were reported during the procedure (130 [6%] injection episodes) and at follow-up (492 [22%] injection episodes). There were significantly increased rates of systemic adverse events in injection episodes involving children in GMFCS level IV (incidence rate ratio [IRR] 3.92 [95% confidence interval] 1.45-10.57]) and GMFCS level V (IRR 7.37 [95% confidence interval 2.90-18.73]; p<0.001). INTERPRETATION: Adverse events after BoNT-A injections are common but mostly mild and self-limiting. Children in GMFCS levels IV and V are at increased risk of systemic adverse events. The relationship between CP severity and BoNT-A adverse events is complex and further research is required to better understand this relationship. WHAT THIS PAPER ADDS: Adverse events reported at the time of botulinum toxin A injection occurred in 6% of injection episodes. Adverse events were reported at follow-up in 22% of injection episodes. Children in Gross Motor Function Classification System (GMFCS) levels IV and V have increased rates of systemic adverse events. Children in GMFCS levels IV and V report less local weakness and pain.