Letters to the Editor

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1 April 2008 Dear Editor, RE: RESPONSE TO SCHEINBERG et al Thank you for the opportunity of responding to the letter by Adam Scheinberg et al. commenting on our case report: Botulinum Neurotoxin A: An Unusual Systemic Effect. Scheinberg et al. have provided timely reassurance by their careful audit of adverse events, suggesting that the incidence of adverse events in percentage terms is low and all adverse events recorded were self-limiting. However, their average dose was lower than that used in the patient reported by Howell and in addition, it is my understanding that they do not administer botulinum toxin A (BTX-A) under general anaesthetic but utilise a combination of other techniques principally nitrous oxide. The patient referred to in our case report unfortunately represented with an insufficiency fracture of his femur and required a general anaesthetic on several occasions to internally fix his fracture, to replace a fixation rod and then to remove the fixation rod after a fracture healing. He was noted to have significant respiratory distress after each general anaesthetic even though our anaesthetic team were aware of his particular problems. It may be the combination of a relatively high dose of BTX-A and general anaesthesia which puts vulnerable patients at particular risk. However, unfortunately, our case report may have been the ‘canary in the mineshaft’. Since we submitted this case report, 16 deaths related to the administration of various forms of BTX-A have been reported to the Federal Drug Administration in the United States. We understand that four of these deaths may have been in children with cerebral palsy. In addition, a child in Switzerland has died after multilevel injection of BTX for spasticity related to cerebral palsy. In the light of this recent information and in consideration of our patient's adverse event published in the Journal of Paediatrics and Child Health, we have undertaken the following steps: We have suspended injections of BTX-A in children at Gross Motor Function Classification System (GMFCS) level V. We have set a revised upper dose limit of 18 units/kg of the Botox preparation from Allergan. Those of us who use this most useful drug are having to come to terms with the possibility of severe adverse events and even deaths, in children with cerebral palsy. The careful audit of adverse events by Scheinberg et al. is somewhat reassuring. We agree entirely that a prospective study of large cohorts of children would be very timely. Yours sincerely