Subpial vacuolar myelopathy after intrathecal ketamine: report of a case.

Previous studies of intrathecal ketamine use in humans have documented the clinical effects of its administration without reference to local central nervous system (CNS) toxicity (Reich and Silvay, 1989). Although several post-mortem studies in small groups of rabbits, monkeys, and baboons have largely shown no significant CNS damage after intrathecal ketamine use, a study in rats reported vacuolation of dorsal root ganglia (Ahuja, 1983). We report post-mortem CNS histopathological changes of subpial spinal cord vacuolation in a terminally ill cancer patient who received continuous infusion intrathecal ketamine at a rate of 5 mg/day for a duration of 3 weeks.