1279. Proximal Block for Post Herpetic Neuralgia – a simple solution

Authors: Manish Joseph Mathew; Anudath Brahmadathan; B Rajendran (P O Nemmara Palakkad Kerala, India)

Introduction: Post herpetic neuralgia(PHN) is a distressing complication following a herpes zoster infection with an incidence of 5-30%. It is more common in females, immunocompromised and elderly people. For years, PHN is treated with anticonvulsants, tricyclic antidepressants and opioids. Topical lidocaine and capsaicin were newer additions in the armamentarium. But many patients continue to have excruciating pain even with maximum tolerable doses of medications and ultimately require surgical interventions which includes nerve blocks, botulinum injection and neuromodulation therapy. Herpes zoster commonly involves the trunk and face with lesser involvement of extremities in disseminated cases. Isolated involvement of thigh is rare and also difficult to treat surgically. Here we describe a case of drug resistant PHN involving only the thigh which was treated with proximal block. Methods: We report a case of a 58 year old truck driver, who developed PHN one month after herpes zoster infection involving only the medial aspect of right thigh. He presented to our neurology department with excruciating pain with hyperalgesia and allodynia involving the medial and anteromedial part of thigh. He was initially treated with oral medications. But his pain became resistant to all medications, disturbing his sleep and disrupting his work. He was referred to us with a visual analog score(VAS) 10/10 and underwent local subdermal and subcutaneous bupivacaine injections into the lesions and in a half ring pattern proximal to the involved area targetting the anterior and medial femoral cutaneous nerves. Results: Patient had immediate pain relief with VAS of 1/10 with minimal numbness in the lower medial thigh which lasted two days. At 3 months follow up, patient continued to be pain free and was able to resume his occupation. Conclusion: Proximal block is a cost effective and a gratifying treatment option for drug resistant post herpetic neuralgia involving the peripheral nerves.