Disclosures: Nathan W. Truex, MD: No financial relationships or conflicts of interest

Case Description: 2 patients, both with intrathecal baclofen pumps, presented to clinic for refills. Both were admitted to the hospital within hours after their refills with signs and symptoms of baclofen overdose including prolonged unresponsiveness, significant sedation, hypotension, respiratory depression, agonal breathing, and seizure like activity. During their admission, significant amounts of baclofen were aspirated from the peri-pump serous pocket. With supportive care, both patient made full recoveries.

Setting: Outpatient Clinics in a University Hospital

Patient: 44 year old Female with Cerebral Palsy, 59 year old Male with history of a Right MCA Stroke Assessment/

Results: The amount of baclofen aspirated from the pockets averaged 60mg. Systemically, this dosage would not be expected to cause such profound side effects. However, if confined to the intrathecal space (ITS), this dose could result in the life threatening effects seen. This is a rare, but significant, complication during refill. Around 7000 fills have been performed in this clinic in the past decade; these are the only 2 overdose cases that have been described as a result of pocket fills.

Discussion: Pocket fills are a known complication when performing baclofen pump refills. However, the literature typically describes symptoms of baclofen withdrawal, not overdose. Baclofen acts on the lower motor neurons as they exit the spinal cord, and does not cross the blood-brain barrier. Given the clinical presentations, the baclofen likely was concentrated in the ITS. The pocket fills presumably tracked along the catheters and into the ITS, delivering a large bolus of Baclofen, causing overdoses.

Conclusion: Pocket fills, while rare, do occur with pump refills. Until now, literature has described cases of withdrawal with pocket fills. However, overdose may occur if the baclofen in the pocket tracks along the catheter to the ITS. In the future, alternative approaches, such as ultrasound or fluoroscopic guided refills, may be necessary to avoid these cases.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/two-cases-of-intrathecal-baclofen-pump-pocket-fill-resulting-in-baclofen-overdose/