Baclofen Overdose After Pump Replacement Due to a Seroma at the Baclofen Pump Site: A Case Report

Case Diagnosis: Baclofen pump overdose after pump replacement with catheter thinning and a seroma at the pump site

Case Description or Program Description: A 26-year-old male with spastic triplegic cerebral palsy and an intrathecal baclofen pump was admitted to the hospital for planned pump replacement due to nearing the end of battery life. Intraoperatively, there was noted to be thinning of the catheter at the connector junction and fluid in the pocket. Approximately 12 hours after surgery, the patient had bradycardia, somnolence, and hypotonia consistent with baclofen overdose. He was admitted to the intensive care unit for monitoring. His baclofen dose was decreased slowly over hours to days. He demonstrated medical stability with good spasticity control at a dose 60% of his original dose.

Setting: Tertiary care pediatric hospital

Assessment/Results: Despite receiving the same dose of baclofen administered after the pump was replaced, the patient experienced an overdose. With the implantation of this patient’s new pump, it is suspected that the patient was not intrathecally receiving as much baclofen as the old pump was dispensing due to the catheter leaking baclofen into a seroma at the abdominal pump site.

Discussion (relevance): This case demonstrates a rare occurrence of catheter thinning and an abdominal seroma contributing to impaired baclofen delivery. Since the pump was originally implanted, the patient had a trend of about one 10% baclofen dose increase per year. However, in the year leading up to his replacement, he was noted to have increased spasticity and required three dose increases over a 5-month period. Pump delivery system dysfunction should be considered for patients who require escalating baclofen dosing, and further investigation with imaging and catheter studies may be utilized to prevent erroneous dosing following pump replacement.

Conclusions: Baclofen overdose can be life threatening and this case highlights the rare phenomenon of catheter thinning with seroma formation contributing to impaired baclofen delivery.