Pontine hemorrhage following a recently implanted intrathecal drug delivery system

This report describes a pontine hemorrhage in a patient following implantation of an intrathecal drug delivery system.

A 70-year-old old female patient with metastatic breast carcinoma underwent placement of an implantable intrathecal drug delivery system. Before implant she was neurologically intact with only mild memory deficiencies attributed to narcotics and malignancy. No recent brain magnetic resonance imaging (MRI) was on record. On post-implant day 2 after the initiation of intrathecal hydromorphone 0.45 mg/day and bupivacaine 2.7 mg/day, she developed dizziness, lethargy, and mild gait instability. Despite decreasing drug dosages, these symptoms progressed over the ensuing days, and subsequently the patient developed upper extremity numbness and tinnitus. The device was turned off on post-implant day 9 with the patient showing no signs of improvement. She underwent computerized tomography scan of the head, which identified an acute pontine hemorrhage. A follow-up MRI scan confirmed the hemorrhage and revealed a previously undiagnosed underlying metastatic lesion with surrounding vasogenic edema. She was treated with supportive measures in hospice and expired 20 days after implantation.

This case emphasizes several important points. First, changes in neurologic and mental status after initiating intrathecal drug therapy may be related to new or pre-existing pathology and not due to intrathecal medications. Second, consideration should be given to central nervous system imaging before intrathecal pump insertion in patients with widely metastatic malignancies. Finally, cerebral spinal fluid hypotension from dural puncture may have contributed to the timing of the hemorrhage in this patient.