title: An unusual cause of overdose after baclofen pump implantation: case report.
abstract: OBJECTIVE
  Intrathecal baclofen delivery for the treatment of spasticity has been used for almost 20 years with a great deal of success. A wide variety of complications and pitfalls have been described. This report details a novel complication involving inadvertent and initially unrecognized canalization of the subdural space with the spinal catheter, which ultimately resulted in an overdose.
  
  
  METHODS
  An intrathecal pump system was implanted in a 15-year-old girl with spasticity. This initially resulted in a lack of therapeutic effect. The diagnostic workup ultimately led to contrast administration through the pump system, which precipitated a baclofen overdose when sequestered medication in the subdural compartment was released into the intrathecal space.
  
  
  METHODS
  The spinal catheter was subsequently revised, and the patient made a full recovery.
  
  
  CONCLUSIONS
  The possibility of a subdural catheter should be included in the differential diagnosis in patients who experience a lack of drug effect after pump implantation, despite increases in dosage. Close monitoring is required because of the risk of spontaneous or induced overdose, which may occur when a communication develops between the subdural and intrathecal compartments.
authors.affiliation: Division of Pediatric Neurosurgery, Children Hospital of Wisconsin/ Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. slew@neuroscience.mcw.edu
authors.forename: Sean M
authors.initials: SM
authors.lastname: Lew
authors.forename: Estee L
authors.initials: EL
authors.lastname: Psaty
authors.forename: Rick
authors.initials: R
authors.lastname: Abbott
mesh_terms: D000293:Adolescent; D001418:Baclofen / Q000008:administration & dosage / Q000009:adverse effects*; D002547:Cerebral Palsy / Q000150:complications / Q000188:drug therapy*; D003244:Consciousness Disorders / Q000139:chemically induced*; D003287:Contrast Media / Q000008:administration & dosage; D062787:Drug Overdose; D020821:Dystonic Disorders / Q000188:drug therapy / Q000209:etiology; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007022:Hypotension / Q000139:chemically induced*; D007040:Hypoventilation / Q000139:chemically induced* / Q000628:therapy; D015918:Infusion Pumps, Implantable / Q000009:adverse effects*; D007278:Injections, Spinal / Q000295:instrumentation; D007472:Iohexol / Q000008:administration & dosage; D009123:Muscle Hypotonia / Q000139:chemically induced; D009128:Muscle Spasticity / Q000188:drug therapy / Q000209:etiology; D010276:Parasympatholytics / Q000008:administration & dosage / Q000009:adverse effects*; D012121:Respiration, Artificial; D013355:Subdural Space
chemical_list: D003287:Contrast Media; D010276:Parasympatholytics; D007472:Iohexol; D001418:Baclofen