Clinical Observation Of Botulinum Toxin Type A In The Treatment Of Postherpetic Neuralgia

Objectives:Postherpetic neuralgia(PHN)is a pain of variable duration and painful nature occurring in the primary lesion area after Herpes zoster(HZ)rash resolves.The incidence of postherpetic neuralgia is positively associated with age and primarily affects adults 50 years and older.It’s an age-dependent disease.As a result of long-term suffering from pain,patients are often accompanied by anxiety and depression,severe pain can lead to sleep disorders,neurasthenia,and even serious interference with patients’ daily life,so that the patient’s social ability weakened or lost,reduce their quality of life to varying degrees.So far,there has been no unified understanding of the specific mechanism of PHN pathogenesis,which has been a huge problem puzzling the medical community.As the pathogenesis of PHN has not been clarified,the existing therapeutic techniques cannot cure PHN,but can only temporarily relieve the pain symptoms of patients and improve their sleep and quality of life.In recent years,the application of Botulinum toxin type A(BTX-A)in PHN patients has been reported in some literatures at home and abroad.Therefore,the purpose of this study was to investigate the clinical efficacy and safety of BTX-A in the treatment of PHN,and to provide a reference scheme for the clinical treatment of PHN.Methods:Fifteen patients with PHN who attended the outpatient clinic of the Department of Neurology at the Second Hospital of Jilin University between January 2021 and January2023 and agreed to be treated with BTX-A were selected by strictly following the inclusion and exclusion criteria.All patients signed informed consent,and relevant data were collected and recorded before treatment.Basic data include age,gender,previous medical history and personal history of the patient.Details include the duration of PHN,occurrence of pain(including nature,frequency,duration,location and extent of pain)and the duration of sleep.Meanwhile,the Short-form of Mc Gill pain questionnaire(SF-MPQ)and Insomnia Severity Index(ISI)scores were also improved.A solution of BTX-A was prepared according to relevant references,and the patient was then injected subcutaneously into the area of pain.Follow-up visits were conducted at the 2 weeks,1 month and 3 months after treatment,and the above indicators were recorded and compared with the improvement of the indicators before and after treatment.As pain is the main manifestation of PHN,patients’ accompanying symptoms such as sleep disorders,anxiety and depression will be improved with pain relief.Therefore,we quantified patients’ pain and sleep conditions,but took pain as the main criterion when evaluating the efficacy.The clinical efficacy of BTX-A was evaluated according to the SF-MPQ score before and after treatment.At the same time,its safety was evaluated according to the occurrence of adverse reactions.Statistical software SPSS27.0 was used to analyze the data.Before and after treatment,paired T-test or Wilcoxon signed rank sum test were used for comparison.Significant difference was indicated when P < 0.05,and P < 0.01 indicated statistically significant difference.Results:Most patients experienced gradual relief of pain about 1 to 2 weeks after BTX-A injection,and the effect lasts for at least 3 months.Some of the nature of the pain was completely relieved after treatment,while the severity of other pain that was not completely relieved was reduced.During the follow-up period,patients experienced a decrease in the frequency and duration of pain episodes,a prolongation of sleep time,and different degrees of decrease in SF-MPQ,and ISI scores.The difference of each index before and after treatment was statistical significance(P < 0.05)or statistically significant(P <0.01).According to the SF-MPQ score,2 cases(13.33%)were ineffective,10 cases(66.67%)were improved,and 3 cases(20%)were effective.One month after treatment,there were 1ineffective case and 8 improved cases turned to effective cases.Three months after treatment,1 improved case turned into effective case,3 effective cases turned into obvious case,among which 1 invalid case(6.67%),1 improved case(6.67%),10 effective cases(66.67%),3obvious cases(20%),and the total effective rate was 93.33%.With regard to adverse drug reactions,none of the patients reported any other adverse reactions except local skin erythema.Conclusion:1.BTX-A local injection was effective in the treatment of PHN,and could significantly reduce the frequency,duration and severity of pain attacks;2.Local injection of BTX-A can significantly prolong the sleep duration and improve the sleep quality of PHN patients;3.BTX-A is relatively safe in the treatment of PHN and has no obvious toxic and side effects.