(168) The Risk of Substance Misuse with Intrathecal Pain Pumps: Two Case Reports

Abstract: Background. Targeted Drug Delivery (TDD) is the administration of medication via an intrathecal pump directly to the cerebrospinal fluid. More commonly known as a “pain pump” when used to treat pain, TDD administers medications for chronic pain (most commonly opioids) or spasticity (most commonly baclofen). (Napoli, 2021) While rates of misuse appear to be lower than with oral opioids, misuse and diversion remain a possibility.

Case Information. We present two cases of substance misuse of TDD in patients seen by our consultation-liaison psychiatry team. In the first case, a 48-year-old female with a history of chronic pancreatitis managed with TDD was suspected of surreptitious reservoir access. She first endorsed symptoms of withdrawal; three days after pump refill, she began to have symptoms of opioid intoxication. On interrogation, her pump was functioning appropriately but with an unexpectedly empty reservoir. In the second case, a 36-year-old healthcare worker with chronic pancreatitis was suspected of reservoir manipulation due to a non-healing puncture wound near the pump, skin infection near the pump, opioid withdrawal symptoms, and discrepancy in anticipated reservoir volume from actual volume.

Discussion. Though infrequently reported, TDD pump manipulation is a risk. Signs of manipulation include symptoms of intoxication or withdrawal, escalating medication dosing, puncture marks around the reservoir, and lower-than-expected reservoir volumes. (Williams, 2011) Additionally, higher than expected reservoir volumes can be seen when exogenous substances are injected into the pump. (Burton, 1998) It is worth noting that withdrawal from intrathecal opioids can present somewhat differently than from oral opioids, with diuresis, agitation, hyperalgesia, diarrhea, and yawning being more frequently reported. (Jackson, 2013) Additionally, psychosis has been reported, albeit rarely, with intrathecal morphine withdrawal. (Aiyer, 2017)

Conclusion. Psychiatrists frequently treat patients with chronic pain conditions and should be familiar with common pain management strategies, including TDD, and signs and symptoms of TDD misuse.

References.
1. Di Napoli R, Esposito G, Cascella M. Intrathecal Catheter. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2021.

2. Williams BS, Wong D, Amin S. Case scenario: self-extraction of intrathecal pump medication with a concomitant intrathecal granulomatous mass. Anesthesiology. 2011;114:424–30.

3. Burton AW, Conroy B, Garcia E, Solanki D, Williams CG. Illicit substance abuse via an implanted intrathecal pump. Anesthesiology. 1998;89:1264–67..

4. Jackson TP, Lonergan DF, Todd RD, Martin PR. Intentional intrathecal opioid detoxification in 3 patients: characterization of the intrathecal opioid withdrawal syndrome. Pain practice: the official journal of World Institute of Pain. 2013;13:297–309.

5. Aiyer R, Jain V, Bhatia A, Mekinulov B, Gungor S. Rare presentation of intrathecal morphine withdrawal psychosis. Pain management. 2017;7:171–73.

Objectives.
1. Understand the basics of how an intrathecal pump, or TDD, works
2. Recognize the risk of substance misuse with TDD
3. Recognize signs of pump manipulation and misuse