HISTOLOGIC EFFECT OF DOXYCYCLINE SCLEROTHERAPY ON RAT FEMORAL NERVE

Background: This study stems from an encounter with a phrenic nerve pa ralysis in a patient following doxycycline sclerotherapy for treatment of chylous fistula. The purpose of this study is to identify possible histologic evidence of doxycycline-induced nerve injury. Methods: The femoral nerves of CD rats were used as the in vivo animal model. The nerves were exposed to varying concentrations doxycycline and normal s aline was the control. The nerves were studied at several time interva ls using two different staining techniques. Results: The results sugge st that topical doxycycline induces tissue reactions which are differe nt from normal saline. These reactions include stimulation of a local giant cell inflammatory reaction and disruption of the myelin sheath. Conclusions: Despite the fact that this study does not give physiologi c evidence of neurotoxicity, the histologic results suggest that topic al doxycycline may cause nerve damage directly or indirectly. We concl ude that doxycycline should not be used for sclerotherapy where unprot ected nerves are exposed to the agent until further physiologic tests are performed to prove its safety.