Why can't you achieve adequate regional anesthesia in the presence of infection?

Observed in this study were morphologic changes in inflamed nerves, along with biochemical changes, which appear to act concurrently to deactivate or prevent activation of the local anesthetic solution. Morphologic changes were observed along the nerve fiber distant from the inflammatory site. These neuro-degenerative changes were seen at the axon and myelin sheaths level. The biochemical data support the presence in the inflamed nerve of amino acids which may be the product of lysosomal rupture and proteolytic enzyme release. These inflammatory mediators may affect either the local anesthetic or the environment of the nerve fiber. The precise mechanism of action of these catalytic products cannot be determined from this study.