Presented at the 2013 AAPM Annual Meeting « Back

Intermediate Doses of Hydromorphone Intrathecal Pump Leading to Myoclonus

Kevin Kohan, DO, kevinkohan@gmail.com¹, Michael Danko, MD², (1) University Of Cincinnati, West Chester, Ohio, (2) University of Cincinnati, Cincinnati, Ohio

Case: 56 year old male with a history of chronic low back pain presented to the hospital with one week duration of tremors and confusion. The patient was being treated with intrathecal (ITP) morphine pump, which had recently been revised to hydromorphone ITP due to severe urticaria. His family indicated that he was found in bed with intermittent tremors of the upper and lower extremities over the past week, with increased shortness of breath. On physical examination, he was noted to be saturating 94% on 5 liters of oxygen and required several verbal cues to continue the interview. His strength in the upper and lower extremities was 4/5 decreased due to poor effort. He was hyper-reflexic at 3/4. Results: Neurology admitted the patient and ruled out the patient for seizure and stroke. Pain service was consulted to evaluate the patient. After further questioning, it was discovered that the patient was receiving increasing doses of the hydromorphone. His dose was recently increased from 1.5 mg/day to 3.0 mg/day. Although 20 milligram/ milliliter concentration was used to refill the reservoir, this was not programmed in the Synchromed II Scanner. Therefore, the patient was receiving 6mg/day of hydromorphone. The dosage was corrected, and the patient’s symptoms improved over a 48-hour period. Discussion: Myoclonus is a rare side effect of increasing intrathecal opioid medications that has been reported more commonly with morphine ITP. Conclusion: Pain physicians should be aware of myoclonus as a side effect of increased dosages of intrathecal opioid medications. References: 1) De Conno F, Caraceni A, Martini C Hyperalgesia and Myoclonus with high dosages of intrathecal morphine. Pain. 1991 Dec;47(3):337-9. 2) Glavina MJ, Robertshaw R. Myoclonic spasms following intrathecal morphine. Anaesthesia. 1988 May;43(5):389-90. 3) Smith HS, Deer TR, Staats PS. Intrathecal Drug Delivery. Pain Physician. 2008 Mar;11(2 Suppl):S89-S104.

Funding: None