Nerve block for management of early and postherpetic neuralgia in patients with herpes zoster

Abstract

Objective To assess the application of nerve block in management of early and post-herpetic neuralgia (PHN) in patients with herpes zoster. Methods Seventy three patients with herpes zoster were enrolled, the course of disease was within 15 d and the numeric rating scale (NRS) scores were ≥6. The course of disease was ≤7 d in 37 patients (group Ⅰ), the course was >7 d and <15 d in 36 patients (groupⅡ). After the conventional therapy, all the patients were treated with nerve block.The cervical, thoracic, lumbar paravertebral nerve blocks were performed by injecting 5 ml lidocaine in the concentrations of 0.40%, 0.40%, 0.80% respectively, with 0.25 mg vitamin B12 and 0.5 mg dexamethasone.For the nerve plexus and nerve branch blockages, the concentration of lidocaine was 1.00%, with 0.50 mg vitamin B12 and 2.0 mg dexamethasone, the dosage varied depending on the infection sites.Furthermore, 40 ml lidocaine with a concentration of 0.25% was used for the local infiltration.The NRS scores were documented before and after the treatment, and the differences in cure rate, effective rate and frequency of treatment were compared between groupⅠand groupⅡ. Results The scores of NRS decreased significantly in two groups after the treatment of nerve block, at d3 after the treatment, the score of NRS in group Ⅰwas reduced from 7.37±1.43 to 0.92±0.40(t=27.30, P<0.01), and the score of NRS in group Ⅱ was reduced from 7.16±1.41 to 0.75±0.39(t=29.62, P<0.01). There were no significant differences in cure rate, effective rate and frequency of treatment between two groups.The NRS scores of all patients were <3 one month after treatment. Conclusion Nerve block has a satisfactory efficacy in treatment of acute herpes zoster, it can also effectively prevent the occurrence of postherpetic neuralgia. Key words: Herpes zoster; Neuralgia, postherpetic; Nerve block; Time management