title: Long-term clinical outcome after botulinum toxin injection in children with nonrelaxing internal anal sphincter.
abstract: OBJECTIVE
  Children with surgically repaired Hirschsprung's disease (HD) and those with internal anal sphincter (IAS) achalasia may develop obstructive gastrointestinal symptoms and/or enterocolitis due to a functional obstruction caused by an inability of the IAS to relax. Anal sphincter Clostridium botulinum toxin (BoTox) injections may provide a reversible therapy. However, there is limited information regarding the long-term outcomes of children receiving this therapy. The primary aim of this study was to determine the long-term clinical outcomes of BoTox therapy in children with a nonrelaxing IAS. The secondary aim of this study was to determine prognostic factors predicting a favorable outcome following BoTox IAS injection.
  
  
  METHODS
  We conducted a retrospective review of children with nonrelaxing IAS who received anal sphincter BoTox at a tertiary medical center. Children were classified into one of four long-term clinical outcome groups (excellent, good, fair, poor).
  
  
  RESULTS
  A total of 73 children (30 HD, 43 IAS achalasia) received anal sphincter BoTox injections and had a mean follow-up of 32.1+/-2.9 (s.e.) months. A mean of 2.7+/-0.2 injections were given to each child, with 56 (76.7%) children receiving multiple injections. An initial clinical improvement was seen in 65 of 73 (89%) children after the first injection. A total of 39 (53.4%) children had an excellent or good long-term outcome that was maintained for a mean of 17.1+/-3.1 months from the time of the last BoTox injection. Hospitalization rates significantly decreased in those previously hospitalized before initial BoTox injection. Seven (9.5%) patients developed transient fecal incontinence, and one (1.3%) developed significant pain after an injection. Factors predicting a favorable long-term clinical outcome were initial short-term improvement after the first BoTox injection and having IAS achalasia rather than HD.
  
  
  CONCLUSIONS
  Anal sphincter BoTox may be an effective and safe long-term therapy for children with nonrelaxing IAS.
authors.affiliation: Center for Motility and Functional Gastrointestinal Disorders, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
authors.forename: Bruno P
authors.initials: BP
authors.lastname: Chumpitazi
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fishman
authors.forename: Samuel
authors.initials: S
authors.lastname: Nurko
mesh_terms: D000293:Adolescent; D001003:Anal Canal / Q000187:drug effects / Q000503:physiopathology*; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D003672:Defecation / Q000187:drug effects / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007273:Injections, Intramuscular; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000503:physiopathology; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D012002:Rectal Diseases / Q000188:drug therapy* / Q000503:physiopathology; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A