Unilateral Horner's syndrome and brachial plexus anesthesia during lumbar epidural blockade.

Horner's syndrome is a rare side effect of epidural analgesia. In association with ipsilateral brachial plexus block, it has only been reported once before, in French. Unilateral blockade has also been reported, although its etiology is unclear and may be multifactorial. The patient described here experienced an asymmetrical epidural blockade with a unilateral Horner's syndrome and ipsilateral brachial plexus block.