A boy with sanfilippo syndrome with refractory hip pain requiring intra-thecal opoid infusion for control

Abstract

A 7-year-old male with known mucopolysaccharidosis IIIA (MPSIIIA) presented with hip pain. MRI identified bilateral avascular necrosis of the hips. Pain was initially managed successfully with intra-articular steroid injections and 1 to 3-monthly Pamidronate infusions for 4.5 years. At 11.8 years, the pain became resistant to ongoing Pamidronate infusions and multimodal analgesia. Oral medications trialed included paracetamol, NSAIDs (ibuprofen and meloxicam), long and short acting opioids (oxycodone/naloxone sustained release, morphine sulphate sustained release, methadone), gabapentin, antidepressants, clonidine, ketamine and baclofen. Parenteral analgesia trialed included fentanyl patches and subcutaneous ketamine infusions. At 12.8 years, a right-sided femoral head excision and valgus femoral osteotomy was performed, but severe pain persisted. Nurse/carer controlled analgesia of intravenous hydromorphone provided modest benefit. A tunneled femoral nerve catheter and continuous bupivacaine infusion was trialed for one week but was ineffective. At 13 years, a test dose of intrathecal bupivacaine and morphine provided temporary analgesia. At 13.2 years, an intrathecal Port-a-cath was implanted to provide a continuous infusion of morphine and bupivacaine. This allowed the child to remain pain free, except during a brief period due to inadvertent port decannulation. Due to skin integrity problems, the port was deneedled and pain had not returned for 12 weeks. Conclusion: Bone pain in MPSIIIA can be difficult to manage. When systemic multimodal analgesia and peripheral regional analgesia are ineffective and pain remains localized, continuous intrathecal analgesia can be considered. The intrathecal route avoided adverse effects seen with systemic opioids and was very effective in this case.L6298897462019-11-22 <br />