Prolonged duration of anesthesia in a patient with multiple sclerosis following paravertebral block

To explore the possibility that the prolonged duration of anesthesia following paravertebral block was related to the presence of multiple sclerosis in a patient undergoing elective inguinal hernia repair.

A healthy 33-yr-old female presented for elective inguinal hernia repair. The procedure was performed under general anesthesia and a paravertebral block was performed at the end of the procedure for postoperative pain relief, whilst the patient was still anesthetized. Upon recovering from general anesthesia it was noted that the patient had a flaccid paralysis of both lower extremities. She was also very nauseated and required antiemetics and vasopressors for hypotension. A differential diagnosis of subarachnoid, subdural or epidural spread was considered. The presence of an epidural hematoma was also considered. The block regressed very slowly with full return of function in 12.5 hr. The duration of action of the block was far longer than one would expect following spinal, epidural or subdural spread of a local anesthetic. Urinary catheterization was performed electively to prevent urinary retention. The patient was discharged home late that evening. Prior to discharge she volunteered that she was being investigated for multiple sclerosis. One month later the diagnosis of multiple sclerosis was confirmed.

In conclusion the extended duration of central neural blockade following paravertebral block, may have been related to an abnormal uptake of local anesthetics into the spinal cord in the presence of demyelination.