Postherpetic neuralgia: epidemiology, pathophysiology, and pain management pharmacology

Current status of immunisation for herpes zoster

Herpes zoster (HZ) is increasingly common in the aging and is experienced by approximately one in three people in their lifetime. It is also relatively common in immune-compromised people. Acute HZ causes severe pain, reduced quality of life and severe complications, including prolonged pain, or postherpetic neuralgia (PHN), and ocular zoster, which may rarely progress to blindness. In severely immune-compromised people disseminated zoster may affect the brain and liver. A second-generation vaccine, the Recombinant Zoster Vaccine, consisting of recombinant viral glycoprotein E and the Adjuvant System 01 (AS01B), now offers >90% efficacy against HZ and associated complications in immune-competent people. Efficacy persists above 80% for 11 years. In severely immune-compromised patients, the vaccine is safe with efficacy and/or immunogenicity of 68-87%. There is also excellent immunogenicity for those on JAK inhibitors and corticosteroid therapy. The vaccine offers a paradigm for successful and durable immunization in the aging and immune-compromised.

Relieving postherpetic neuralgia pain via gabapentin-loaded bigels as an auspicious topical drug delivery system

BACKGROUND

Over the past decades, a substantial portion of the population worldwide has been infected with varicella zoster and most cases developed shingles. Unfortunately, shingles is usually accompanied by postherpetic neuralgia, which may persist for months to years after the resolution of the viral infection.

OBJECTIVES

Gabapentin is an orally gamma-aminobutyric acid analogue approved by the Food and Drug Administration to manage shingles postherpetic neuralgia. However, gabapentin shows nonlinear pharmacokinetics, with variable absorption and bioavailability along with its short half-life and long side effects that may include dizziness and somnolence, which calls for an appropriate topical dosage form. Bigels are unique semisolid dosage forms with boosted penetrability and satisfactory hydrophilic texture.

METHODS

The current work pointed to formulating gabapentin-loaded bigels for the treatment of postherpetic neuralgia, where the analysis and optimization of design were performed via Design-Expert®.

RESULTS AND CONCLUSIONS

The selected bigel (F5), incorporating 400 mg Span 60, 1000 mg Tween 80, and 1000 mg Transcutol, displayed spherical nanosized particles with acceptable viscosity and spreadability. Subsequent topical application of the selected bigel on the skin of Wistar rats, F5, demonstrated a boosted accumulation of gabapentin in the skin similar to PLO gel but superior to the drug solution. Furthermore, a histopathological study demonstrated the biosafety of the selected bigel when applied topically. Accordingly, gabapentin-loaded bigel would be considered a potentially topical dosage form for the delivery of gabapentin for the management of postherpetic neuralgia.

Investigating the causal effect of various metabolites on postherpetic neuralgia: a Mendelian randomization study

Background

Common side effect of Herpes Zoster, postherpetic neuralgia (PHN), causes persistent pain that seriously affects quality of life. Lack of dependable biomarkers makes the clinical diagnosis and treatment of PHN difficult, so complicating the assessment of therapeutic efficacy. Blood metabolites are becoming more and more well known as significant disease markers. With an aim to find possible biomarkers for diagnosis and treatment, this work investigates the causal link between blood metabolites and PHN using Mendelian randomization.

Methods

This work evaluated causal relationships between PHN and 1,091 plasma metabolites using Mendelian randomization (MR). Complementing MR-Egger and weighted median approaches, the main causality analysis was done using inverse variance weighted (IVW) and Wald ratio (WR) approaches. Robustness was checked using sensitivity analyses including CAUSE, Cochran's Q tests, leave-one-out analysis, MR-PRESSO, and MR-Egger intercept analysis. Reverse MR analysis and linkage disequilibrium score regression (LDSC) was used to assess significant correlations as well. Two-step MR analysis was also used to look at the mediating function of positively correlated metabolites in the causal pathway.

Results

The results of this study indicated a significant association between N-acetyl-aspartyl-glutamate (NAAG) and PHN, with an odds ratio (OR) of 0.83 (95% CI: 0.76-0.91, p = 2.68E-05). Moreover, five potential associated metabolites were identified: Gamma-glutamylthreonine (OR = 1.60, 95% CI: 1.16-2.20, p = 0.004), 3-hydroxyphenylacetoylglutamine (OR = 1.43, 95% CI: 1.00-2.05, p = 0.048), Caprate (10:0) (OR = 1.86, 95% CI: 1.11-3.12, p = 0.018), X-12013 (OR = 1.64, 95% CI: 1.03-2.60, p = 0.035), and X-17328 (OR = 1.50, 95% CI: 1.04-2.18, p = 0.032). Additionally, NAAG likely acts as a complete mediator between FOLH1(CGPII) and postherpetic neuralgia in the causal pathway.

Conclusion

The results of this study indicated a significant association between N-acetyl-aspartyl-glutamate (NAAG) and PHN, with an odds ratio (OR) of 0.83 (95% CI: 0.76-0.91, p = 2.68E-05). Furthermore five possible related metabolites were found: Glutamylthreonine gamma-wise (OR = 1.60, 95% CI: 1.16-2.20, p = 0.004), 3-hydroxyphenylacetoylglutamine (OR = 1.43, 95% CI: 1.00-2.05, p = 0.048), Caprate (10:0) (OR = 1.86, 95% CI: 1.11-3.12, p = 0.018), X-12013 (OR = 1.64, 95% CI: 1.03-2.60, p = 0.035), and X-17328 (OR = 1.50, 95% CI: 1.04-2.18, p = 0.032). Furthermore, in the causal pathway NAAG most certainly serves as a complete mediator between FOLH1(CGPII) and postherpetic neuralgia.

Effect of topical application of amitriptyline and nortriptyline on irreversible pulpitis pain in teeth with failed pulpal anesthesia after a successful inferior alveolar nerve block: A randomized clinical trial

Background

No consensus has been reached on the effect of topical application of amitriptyline and nortriptyline on irreversible pulpitis pain in teeth with failed pulpal anesthesia after a successful inferior alveolar nerve (IAN) block. This study aimed to assess the effect of topical application of amitriptyline and nortriptyline on irreversible pulpitis pain in teeth with failed pulpal anesthesia after a successful IAN block.

Materials and Methods

This double-blind randomized controlled clinical trial was conducted on 45 patients with irreversible pulpitis. The patients were randomly assigned to three groups (n = 15) for topical application of 10 mg amitriptyline, 10 mg nortriptyline, and starch (placebo). An IAN block was primarily administered by injection of lidocaine with 1:80,000 epinephrine. Next, the abovementioned medications were topically applied in each group. The pain level of patients was quantified by the McGill Visual Analog Scale (VAS) and the Wong-Baker Faces Pain Rating Scale (FPRS) before the intervention, immediately after injection, and after topical application of materials and compared. Data were analyzed by SPSS version 21 using the Chi-square test, likelihood ratio, one-way ANOVA, repeated-measures ANOVA, and the Kruskal-Wallis test. P < 0.05 was considered statistically significant.

Results

All three interventions significantly decreased pain (P < 0.05). Although nortriptyline caused a greater pain relief, the difference among the three groups was not significant regarding the VAS or Wong-Baker FPRS scores (P > 0.05).

Conclusion

Although nortriptyline caused a greater reduction in irreversible pulpitis pain than amitriptyline, the difference between the two medications was not significant. Future studies without a placebo group are recommended.

Transcutaneous Electrical Nerve Stimulation for Prevention and Treatment of Post-Herpetic Neuralgia: A Narrative Review

The present investigation evaluated transcutaneous electrical nerve stimulation (TENS) for the non-pharmacological treatment of post-herpetic neuralgia (PHN). PHN is the most common complication of the Herpes Zoster virus, affecting one in every five patients with shingles, and presents as intense neuropathic pain that can persist for 90 days or longer after the initial onset of symptoms. Current pharmacological treatment options are mainly limited to symptom management, including oral medications such as tricyclic antidepressants and gabapentinoid preparations, as well as topical options such as lidocaine or capsaicin. TENS is a minimally invasive, non-pharmacological electrical nerve stimulation device currently approved for the treatment of neuropathic pain in adults, providing patients with an alternative or adjunct treatment option to medication with a reduced potential for unwanted side effects, drug-drug interactions or potentially life-threatening toxicity. Current indications for the use of TENS in the treatment of PHN are recommended only after therapeutic goals are attempted and unsuccessfully met by current mainstay medications. More research into the efficacy and safety of TENS for treating PHN should be conducted to clarify further its role as a mainstay treatment for this condition.

Possible Role of Platelet-Rich Plasma in the Treatment of Patients with Postherpetic Neuralgia: A Prospective, Single-Arm, Open-Label Clinical Study

Background

Currently, no treatment can fully and finally treat postherpetic neuralgia (PHN).

Aim and Objectives

This study aimed to evaluate the possible efficacy of autologous intralesional platelet-rich plasma (PRP) injection in treating patients with PHN.

Materials and Methods

A prospective, single-arm, open-label clinical study was conducted on 45 patients with PHN attending the Dermatology Outpatient Clinics of Sohag University Hospital, Egypt, between November 2019 and November 2021. Patients were subjected to full clinical general and dermatologic examinations. Patient's assessment included severity of pain through visual analogue scale (VAS), numerical rating scale (NRS), and verbal rating scale (VRS), in addition to Medical Outcomes Study 36 Item Short-Form (SF-36). Patients were treated by autologous PRP injection every 2 weeks for 2 months (4 sessions). Patients were evaluated before every session and 3- months after the last session.

Results

There was a significantly decreased VAS, NRS, VRS, and SF-36 questionnaire values in the last session and three months after the last session. There was a highly significant moderate correlation between both scales (VAS and VRS) and patient's age in years and who have aggravating factors. Likewise, there was a significant moderate positive correlation between scales (VAS and VRS) and the disease duration, medical co-morbidities, and associated myalgia.

Limitations

These findings require further confirmations on more inclusive large-sized multicenter, randomized, placebo-controlled, clinical trials with longer follow-up.

Conclusion

This clinical pilot study concluded that autologous intralesional PRP injection was an effective therapeutic option for patients with PHN.

Temporary Gasserian ganglion stimulation utilizing SNM electrode in subacute herpetic trigeminal neuralgia

Objective

Gasserian ganglion stimulation (GGS) is a neuromodulation technique that has been extensively applied in treating postherpetic trigeminal neuralgia. However, permanent implantation of GGS was preferred in most treatment approaches. Few studies have investigated temporary GGS for the treatment of acute/subacute herpetic trigeminal neuralgia. Moreover, previous research has reported lead dislocation when utilizing traditional electrodes, which was associated with poor pain relief. In GGS research, preventing the accidental displacement of lead following implantation has consistently been a primary objective.

Methods

We report a case of a 70-year-old woman with subacute herpetic trigeminal neuralgia who underwent temporary GGS for 14 days utilizing a sacral neuromodulation (SNM) quadripolar-tined lead. Computed tomography-guided percutaneous foramen ovale (FO) puncture and temporary SNM electrode implantation were performed during the surgery. A telephone interview was conducted to record a 12-month follow-up.

Results

At admission, zoster-related trigeminal pain severity was assessed to be 9/10 on the visual analog scale (VAS). After a 14-day GGS treatment, the pain assessed on the VAS score reduced to 1/10 at discharge but increased to 4/10 at the 12-month follow-up after surgery. Additionally, the anxiety level improved from 58 points to 35 points on the Self-Rating Anxiety Scale (SAS), and the depression level improved from 62 points to 40 points on the Self-Rating Depression Scale (SDS). The Physical Component Summary score of the 12-item Short-Form Health Survey (SF-12) increased from 33.9 to 47.0, and the Mental Component Summary (MCS) score of the SF-12 increased from 27.4 to 41.9.

Conclusion

Temporary GGS might be a potentially effective treatment for subacute herpetic trigeminal neuralgia, and an SNM electrode might be a good choice for reducing the risk of dislocation.

Herpes zoster in Belgium: a new solution to an old problem

Herpes zoster (HZ) is caused by reactivation of the varicella-zoster virus. The life-time risk of developing HZ is ~ 30%. Management of HZ can be challenging due to limited efficacy of oral antivirals on pain control, and neuropathic pain that may require aggressive management. Post-herpetic neuralgia (PHN) can cause substantial pain and occurs in up to one-quarter of patients with HZ. Up to 48,000 HZ cases are estimated to occur annually in Belgium, estimated to cost almost 7 million euros in treatment. The recombinant zoster vaccine (RZV, Shingrix, GSK) was approved in Europe in 2017. In 2022, the Belgian Superior Health Council recommended vaccination with RZV for immunocompetent adults aged ≥ 60 years, and immunocompromised patients aged ≥ 16 years, including those receiving immunosuppressive therapy, in particular Janus kinase inhibitors. RZV showed high age-independent efficacy in preventing HZ infection and in clinical trials that has since been confirmed in real-world effectiveness studies. In clinical trials, protection was sustained for at least 10 years after vaccination. As of 1 November 2023, RZV is reimbursed for three immunocompromised patient groups aged ≥ 18 years: malignancy treated in the past 5 years, HIV infection, and organ or haematological stem cell transplantation or are a transplant candidate. HZ is vaccine-preventable and RZV provides a highly effective tool for HZ prevention. While reimbursement for some at-risk groups is welcomed, reimbursement currently falls well short of Superior Health Council recommendations. Adult immunisation strategies should be promoted to achieve high vaccination coverage against HZ, contributing to healthy aging in Belgium.

Increased Risk of Herpes Zoster in Rheumatoid Arthritis Not Only Due to JAK Inhibitors-Study of 392 Patients from Single University Center

Background/Objectives: Patients with rheumatoid arthritis (RA) have an increased risk of infection. Their risk of presenting herpes zoster (HZ) is 1.5-2 times higher than immunocompetent individuals and disseminated presentation is more frequent. Our aim was to analyze the prevalence and general features of HZ in RA patients. Methods: This was a prospective study of 392 RA patients included in the vaccination program of our hospital between 2011 and 2016, and follow-up continued until December 2020. A diagnosis of HZ was made according to clinical manifestations: skin rash, blisters, paresthesia, and local pain in one or more dermatomes. Results: We studied 392 participants (309 women/83 men), mean age 59 ± 13 years. Every patient was followed-up over a mean period of 137 ± 110 months (range: 42 months-42 years). HZ infection was observed in 30 of 392 (25 women/5 men) patients, age (mean ± SD) 64.7 ± 11.8 years. Prevalence was 7.65% in this period and the incidence rate was 13.22/1000 patients/year. Three patients had facial involvement, one had optic involvement, and one patient presented disseminated HZ. Seven patients presented post herpetic neuralgia treated with gabapentinoids. The main features of RA of these 30 patients were: positive RF (n = 17; 56.6%), positive anti-CCP (n = 13; 43.3%), and erosive disease (n = 10; 33.3%). At HZ infection, the treatments were glucocorticoids (n = 19; 63.3%), conventional DMARDs (n = 15; 50%), biological DMARDs (n = 15; 50%), tofacitinib (n = 2; 6.6%), and upadacitinib (n = 1; 3.3%). Conclusions: HZ is a relatively frequent viral complication in RA patients. In our series, one patient presented disseminated HZ and nearly 25% of patients had post-herpetic neuralgia. Including a HZ vaccine in our vaccination program for RA patients may be beneficial.

PROCESS Trial: Effect of Duloxetine Premedication for Postherpetic Neuralgia Within 72 Hours of Herpes Zoster Reactivation-A Randomized Controlled Trial

BACKGROUND

Postherpetic neuralgia (PHN) is the most common chronic complication of herpes zoster (HZ) and results in severe refractory neuropathic pain. This study aimed at evaluating the efficacy of premedication with duloxetine in the prevention of PHN.

METHODS

The PROCESS trial is a multicenter, randomized, open-label, blinded-endpoint trial used a 1:1 duloxetine:control ratio. Adults 50 years or older with HZ who presented with vesicles within 72 hours were recruited. The primary outcome was the incidence of PHN at 12 weeks. PHN was defined as any pain intensity score other than 0 mm on the visual analog scale (VAS) at week 12 after the onset of the rash. The secondary outcomes were the number of participants with VAS >0 and VAS ≥3. The modified intention-to-treat (mITT) principle and per-protocol (PP) principle were used for the primary outcome analysis.

RESULTS

A total of 375 participants were randomly assigned to the duloxetine group and 375 were assigned to the control group. There was no significant difference in the incidence of PHN in the duloxetine group compared with the control group in the mITT analysis (86 [22.9%] of 375 vs 108 [28.8%] of 375; P = .067). PP analysis produced similar results. However, there were significant differences between the 2 groups in the number of participants with VAS >0 and VAS ≥3 (P < .05 for all comparisons).

CONCLUSIONS

Although absolute prevention of PHN does not occur, this trial found that premedication with duloxetine can reduce pain associated with HZ, and therefore can have clinically relevant benefits. Clinical Trials Registration. Clinicaltrials.gov, NCT04313335. Registered on 18 March 2020.

Trigeminal Postherpetic Neuralgia: From Pathophysiology to Treatment

PURPOSE OF REVIEW

Trigeminal postherpetic neuralgia (TG-PHN) is a neuropathic pain condition complicating herpes zoster (HZ) attributed to the trigeminal nerve. It poses significant challenges due to its persistent and debilitating nature. This review explores the clinical characteristics of TG-PHN, analyzes its pathophysiological underpinnings, and addresses existent and potential therapies.

RECENT FINDINGS

TG-PHN is one of the most common and complex PHN locations. It has distinguishing clinical and pathophysiological characteristics, starting with viral triggered injuries to the trigeminal ganglion (TG) and peripheral tissue and involving the ascending and descending brain modulation pathways. Current therapies include vaccines, oral and topical medications, and interventional approaches, like nerve blocks and neurostimulation. This review covers TG-PHN's clinical and physiological components, treatment options, and potential future targets for improved management. By exploring the complexities of this condition, we aim to contribute to developing more effective and targeted therapies for patients suffering from trigeminal PHN.

Management of Herpes Zoster Infection Using a Combination of Allopathic and Herbal Medication: A Case Report

Herpes zoster (HZ) also known as shingles is the reactivation of varicella-zoster virus (VZV) that causes chickenpox. It usually occurs in adults after remaining dormant in the dorsal root ganglia or ganglia of the cranial nerves for several years. It typically manifests as vesicle crops in a dermatomal or "zosteriform" pattern, which shows vesicle, ulcer, and scab distribution that is unilateral, clustered, and linear in a dermatome that is supplied by a single nerve. Patients usually experience prodromal symptoms of deep, severe aching or burning pain. Medicinal treatment frequently includes antiviral drugs to decrease the severity of the lesion and steroidal drugs to reduce symptoms of inflammation. It is also a known fact that steroid has several adverse effects on patients due to which therapeutic drugs with lesser side effects may be given to patients such as herbal medications. This case presentation reports a patient with HZ viral infection who was successfully treated with a meticulous combination of conventional allopathic drugs with ayurvedic medication with a significant positive response to the medication.

An Unusual Case of Denervation Changes of the Intercostal Muscles Associated with Intercostal Neuralgia in a Patient with Chest Pain

Musculoskeletal aetiologies account for most patients presenting with chest pain. Intercostal neuralgia is a lesser-known cause of musculoskeletal chest pain, which can present a diagnostic challenge with nonspecific imaging findings. We report a case of a 31-year-old male who presented with severe lower thoracic and chest wall pain following a suspected viral infection, where Magnetic Resonance Imaging (MRI) revealed characteristic features of denervation oedema within the affected intercostal muscles. This pattern of imaging findings in intercostal neuralgia is sparely described in the current literature. MRI along with history and examination was crucial in diagnosing the condition and excluding other potential causes of musculoskeletal chest wall pain on this occasion. The patient's symptoms were subsequently managed conservatively. The case highlights the importance of considering intercostal neuralgia as a potential cause of chest wall pain, particularly in the setting of post viral infection and absence of preceding mechanical musculoskeletal injury and explores an uncommon yet characteristic imaging finding which may be important in diagnosing the condition.

Efficacy and safety of bloodletting puncture and cupping in postherpetic neuralgia: A systematic review and meta‑analysis

The present study aimed to evaluate the efficacy and safety of bloodletting puncture and cupping (BLP-C) in postherpetic neuralgia (PHN) and to provide guidance for clinical treatment. Randomized controlled trials (RCTs) of BLP-C therapy in PHN were systematically searched in eight databases from inception to September 2022. Literature screening, data extraction and quality assessment were performed by two independent researchers. Dichotomous and continuous variables were pooled using the risk ratio (RR) and weighted mean difference (WMD), respectively. A total of 13 studies involving 1,129 patients with PHN (571 in the experimental group and 558 in the control group) were included in the present meta-analysis. Overall efficacy (RR=1.21, 95% CI: 1.15 to 1.28, P<0.00001), VAS score (WMD=-1.10, 95% CI: -1.31 to -0.90, P<0.00001) and PSQI score (WMD=-2.42, 95% CI: -2.87 to -1.96, P<0.0001) were significantly different between the BLP-C group and Western medicine group. Furthermore, subgroup analysis demonstrated that BLP-C alone or combined with other traditional Chinese medicines was more effective than Western medicine in PHN. A total of four RCTs mentioned adverse reactions, most of which were in the Western medicine group and were relieved after treatment discontinuation. In conclusion, BLP-C is superior to Western medicine in relieving pain and improving the sleep quality of patients with PHN with a lower incidence of adverse effects.

Diagnostic Methods and Management Strategies of Herpes Simplex and Herpes Zoster Infections

Herpesviruses are medium-sized double-stranded DNA viruses. Of more than 80 herpesviruses identified, only 9 human herpesviruses have been found to cause infection in humans. These include herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), human cyto-megalovirus (HCMV), Epstein-Barr virus (EBV), and human herpesvirus (HHV-6A, HHV-6B, HHV-7, HHV-8). HSV-1, HSV-2, and VZV can be problematic given their characteristic neurotropism which is the ability to invade via fusion of its plasma membrane and reside within neural tissue. HSV and VZV primarily infect mucocutaneous surfaces and remain latent in the dorsal root ganglia for a host's entire life. Reactivation causes either asymptomatic shedding of virus or clinical manifestation of vesicular lesions. The clinical presentation is influenced by the portal of entry, the immune status of the host, and whether the infection is primary or recurrent. Affecting 60% to 95% of adults, herpesvirus-associated infections include gingivostomatitis, orofacial and genital herpes,and primary varicella and herpes zoster. Symptomatology, treatment, and potential complications vary based on primary and recurrent infections as well as the patient's immune status.

Acupoint herbal patching for postherpetic neuralgia: A systematic review and meta-analysis

BACKGROUND

This study aimed to systematically evaluate the clinical effectiveness and safety of acupoint herbal patching in the treatment of postherpetic neuralgia.

METHODS

Eight databases including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wan-Fang Database, China Biomedical Literature Service System, and Chongqing VIP Chinese Science were searched. The search time was set to October 2023. Two researchers independently screened the literature according to the inclusion and exclusion criteria; extracted the basic information, acupoints, Chinese herbal medicine, pain score, sleep score, depression score, and other information of the subjects, and independently assessed the risk of bias by 2 researchers. Meta-analysis of the included studies was performed using the StataMP 16 software.

RESULTS

Fifteen studies with 1362 participants were included in this meta-analysis. Ashi is the acupoint frequency at the forefront, and Borneol is the Chinese herbal medicine frequency at the forefront. The acupoint herbal patching group showed significant improvements in visual analog score (SMD: -2.09; 95% Cl: -2.77, -1.42; P < .001), sleep score (SMD: -1.58; 95% Cl: -2.11, -1.05; P < .001), depression score (SMD: -1.61; 95% Cl: -2.22, -0.99; P < .001), Chinese medicine syndrome score (SMD: -2.32; 95% Cl: -2.84, -1.80; P = .06), dermatology life quality index (weighted mean differences: -4.11; 95% Cl: -4.58, -3.63; P = .98), and related laboratory indicators compared to the control group, and the total effective rate was significantly higher (relative risk: 1.20; 95% confidence interval: 1.15, 1.26; P = .99) than the control group. Two studies reported adverse reactions, but the 2 groups were not statistically significant.

CONCLUSIONS

Acupoint herbal patching intervention in postherpetic neuralgia is effective in improving the pain, sleep, anxiety, depression, quality of life of patients, and related laboratory indicators.

Effect of Korean Medicine Treatment on Patients with Postherpetic Neuralgia: A Retrospective Chart Review

Evidence regarding Korean medicine treatment (KMT) for neuropathic pain is lacking. We aimed to identify the effects of integrative KMT in patients with postherpetic neuralgia (PHN). We retrospectively analyzed the electronic medical records of patients with PHN who received KMT at Kyung Hee University Korean Medicine Hospital between August 2021 and July 2022. We evaluated the effects of KMT-comprising acupuncture, pharmacopuncture, herbal medicine, cupping, and moxibustion-on pain intensity using the numerical rating scale (NRS), Short-Form McGill Pain Questionnaire (SF-MPQ), Hospital Anxiety and Depression Scale-Anxiety (HADS-A), Hospital Anxiety and Depression Scale-Depression (HADS-D), Daily Sleep Interference Scale (DSIS), Fatigue Severity Scale (FSS), and EuroQol-5D. Among 53 patients with PHN, 13 were included. The NRS score for worst pain over 1 week decreased from 6.54 ± 0.64 at baseline to 3.85 ± 0.63 at 8 weeks (41% reduction, p < 0.01), while that for average pain over 1 week decreased from 4.93 ± 0.67 at baseline to 3.08 ± 0.46 at 8 weeks (37% reduction, p < 0.01). From baseline to 8 weeks, there were significant reductions in the SF-MPQ, HADS-A, FSS, and EuroQol-5D scores. No adverse events were reported after KMT. Therefore, KMT may be an effective treatment option for patients with PHN.

Medication Management of Neuropathic Pain Disorders

It is important for Oral and Maxillofacial Surgeons to be familiar with the various neuropathic facial pain disorders and their appropriate treatments. Neuropathic pain can be characterized by the nature of the pain experienced by patients; episodic or continuous. Episodic neuropathic pain disorders include trigeminal neuralgia and glossopharyngeal neuralgia. Continuous neuropathic pain disorders compromise of disorders such as idiopathic trigeminal neuralgia, postherpetic neuralgia, central post-stroke pain, and complex regional pain syndrome. Various forms of pharmacologic management exist for these neuropathic pain disorders.

Herpes Zoster after COVID-19 Infection or Vaccination: A Prospective Cohort Study in a Tertiary Dermatology Clinic

Background

Herpes zoster (HZ) has been observed to occur after COVID-19 infection and vaccination; however, knowledge regarding the demographic data, clinical presentations, and treatment outcomes of HZ is limited.

Objective

To compare the demographic data, clinical manifestations, treatments, and outcomes of patients with and without HZ within 14 days of COVID-19 infection or vaccination.

Methods

This prospective cohort study involving patients diagnosed with cutaneous HZ was conducted at a dermatology clinic from October 2021 to January 2023.

Results

Among a total of 232 patients with HZ, the median age was 62.0 years and 59.1% were female. HZ developed in 23 (9.9%) and four (1.7%) patients after COVID-19 vaccination and infection, respectively. The mean duration from vaccination and the median duration from infection to HZ onset were 5.7 and 8.5 days, respectively. The proportion of female patients was significantly higher in the group of patients with COVID-19 vaccination or infection than in those without such a history (P = 0.035). Patients who developed HZ following the recent COVID-19 infection had a median age of 42.5 years, which was lower than that of the other groups. Dissemination occurred in 8.7% of the patients after COVID-19 vaccination. HZ recurrence was reported in five cases, of which 80% had been vaccinated or infected with COVID-19 during the previous 21 days. All patients had similar durations of antiviral treatment, crust-off time, and duration of neuralgia.

Conclusions

HZ after COVID-19 vaccination is more frequently observed in females, while HZ after COVID-19 infection tends to occur in younger patients. Disseminated HZ is more common in patients recently vaccinated against COVID-19. COVID-19 vaccination or infection may trigger recurrent HZ infection.

Unveiling the Pain Relief Potential: Harnessing Analgesic Peptides from Animal Venoms

The concept of pain encompasses a complex interplay of sensory and emotional experiences associated with actual or potential tissue damage. Accurately describing and localizing pain, whether acute or chronic, mild or severe, poses a challenge due to its diverse manifestations. Understanding the underlying origins and mechanisms of these pain variations is crucial for effective management and pharmacological interventions. Derived from a wide spectrum of species, including snakes, arthropods, mollusks, and vertebrates, animal venoms have emerged as abundant repositories of potential biomolecules exhibiting analgesic properties across a broad spectrum of pain models. This review focuses on highlighting the most promising venom-derived toxins investigated as potential prototypes for analgesic drugs. The discussion further encompasses research prospects, challenges in advancing analgesics, and the practical application of venom-derived toxins. As the field continues its evolution, tapping into the latent potential of these natural bioactive compounds holds the key to pioneering approaches in pain management and treatment. Therefore, animal toxins present countless possibilities for treating pain caused by different diseases. The development of new analgesic drugs from toxins is one of the directions that therapy must follow, and it seems to be moving forward by recommending the composition of multimodal therapy to combat pain.

Comprehensive Comparison of Therapeutic Efficacy of Radiofrequency Thermocoagulation and Pulsed Radiofrequency in Treatment of Elderly Patients with Thoracic Postherpetic Neuralgia

BACKGROUND We comprehensively compared the therapeutic efficacy of radiofrequency thermocoagulation (RFT) and pulsed radiofrequency (PRF) in the treatment of elderly patients with thoracic postherpetic neuralgia (PHN). MATERIAL AND METHODS We divided 149 elderly patients with thoracic PHN into 2 groups - the RFT group (n=79) and the PRF group (n=70) - based on the radiofrequency mode administered. The Visual Analog Scale (VAS), Athens Insomnia Scale (AIS), Generalized Anxiety Disorder 7 items (GAD-7), and Patient Health Questionnaire 9 items (PHQ-9) were used to analyze the degree of pain, sleep quality, and psychological state of patients before and 1 week, 1 month, 3 months, 6 months, and 12 months after treatment. RESULTS VAS, AIS, GAD-7, and PHQ-9 scores were significantly decreased after RFT and PRF treatment (P<0.001). There was no significant difference in VAS scores between the 2 groups at 1 week and 1 month after treatment (P>0.05). Then, VAS scores in the RFT group were significantly lower than those in the PRF group at 3, 6, and 12 months after treatment (P<0.001). At 1 week after treatment, there were no significant differences in AIS, GAD-7, and PHQ-9 scores between the 2 groups (P>0.05). However, the RFT group had significantly lower AIS, GAD-7, and PHQ-9 scores than the PRF group at 1, 3, 6, and 12 months after treatment (P<0.05). CONCLUSIONS RFT and PRF both effectively reduced pain in the distribution area of thoracic spinal neuropathy and improved the sleep quality and psychological state of elderly patients with thoracic PHN, but RFT had a better long-term effect.

Burden of Herpes Zoster in Individuals with Immunocompromised Conditions and Autoimmune Diseases in the Republic of Korea: A Nationwide Population-Based Database Study

INTRODUCTION

To estimate herpes zoster (HZ) incidence rate (IR) and economic burden in individuals with immunocompromised conditions and autoimmune diseases (IC/AID) in the Republic of Korea (ROK).

METHODS

The nationwide Health Insurance Review and Assessment Service database was used to identify HZ cases from 2016 to 2020 in ROK. HZ and non-HZ IC/AID cases were matched 1:3 using age, sex, institution, Charlson comorbidity index, IC/AID, and index date. Annual HZ IRs/1000 persons and 1-year HZ-associated all-cause direct medical costs for IC/AID cases were calculated.

RESULTS

Among 65,976 individuals with IC/AID (mean age 57.14 years [standard deviation 14.1]; 64.94% female), annual HZ IR (95% confidence interval) fluctuated from 2016 to 2020, averaging 23.41/1000 persons (22.21-24.62) and was higher in women (26.85 [25.40-28.31]) than men (18.96 [18.03-19.89]). IRs were highest in individuals aged ≥ 50 years, and in those with transplants (including solid organ and hematopoietic stem cell transplants; 37.12 [35.45-38.79]) and hemato-oncology conditions (35.5 [31.6-39.3]). Mean 12-month all-cause direct medical costs were higher in individuals with IC/AID and HZ (4,759,671 Korean Republic won [KRW]; approximately 4046 United States dollar [USD; according to the 2020 conversion rate from UNCTAD; 1 KRW = 0.00085 USD]) than those without HZ (3,786,658 KRW; 3219 USD).

CONCLUSION

Individuals with IC/AID have a substantial disease and economic burden from HZ in ROK, highlighting the need for appropriate HZ prevention measures in the IC/AID population.

A bibliometric and visualization analysis of global research on postherpetic neuralgia from 2000 to 2022: A review

Postherpetic neuralgia (PHN) represents a notable clinical challenge as it is the most prevalent and severe complication of herpes zoster (HZ). The primary objective was to investigate the current research status and hotspots of PHN research during the period from 2000 to 2022. The literature pertaining to PHN was gathered through the utilization of the Web of Science Core Collection, spanning from January 2000 to December 2022. The software, CiteSpace version 6.2.R2, was employed to produce visual depictions of publications related to PHN across various dimensions such as year, country/region, institution, journal, author, keyword, and reference. This study involved a total of 3505 papers. The USA held a dominant position in the production of scholarly articles. Argentina exhibited the highest frequency of participation in international collaboration. Out of all the institutions, Pfizer exhibited the highest degree of productivity. Harvard University exhibited the highest frequency of participation in international collaboration. The Pain exhibited the most noteworthy productivity rate and citation count among all other journals. Ralf Baron was identified as the most productive author, whereas DWORKIN RH attained the highest citation count. Contemporary scholarly investigations are predominantly centered on identifying risk factors, devising preventative measures, and exploring novel and secure methods of pain management. The current investigation has revealed the focal areas and patterns of studies pertaining to PHN. Presently, the research in this field is focused on identifying the risk factors and preventive measures for PHN, alongside exploring novel and secure pain management strategies.

miRNAs: Targets to Investigate Herpesvirus Infection Associated with Neurological Disorders

Herpesvirus is associated with various neurological disorders and a specific diagnosis is associated with a better prognosis. MicroRNAs (miRNAs) are potential diagnostic and prognostic biomarkers of neurological diseases triggered by herpetic infection. In this review, we discuss miRNAs that have been associated with neurological disorders related to the action of herpesviruses. Human miRNAs and herpesvirus-encoded miRNAs were listed and discussed. This review article will be valuable in stimulating the search for new diagnostic and prognosis alternatives and understanding the role of these miRNAs in neurological diseases triggered by herpesviruses.

Exploring the prevalence, characteristics and nursing assessment of neuropathic pain

Neuropathic pain results from damage to the nerves. It affects many in the general population, but its prevalence is higher in certain groups, for example those who have undergone certain procedures or systemic anti-cancer therapy and people with conditions such as diabetes mellitus, viral infections or central nervous system disorders. Regardless of the cause, neuropathic pain can have significant adverse effects on people's quality of life, so nurses need to be able to conduct a holistic pain assessment that incorporates physical, emotional, social and spiritual aspects. This article explores the prevalence, characteristics and nursing assessment of neuropathic pain with the aim of improving nurses' awareness, practice and care of people affected by this type of pain.

Therapeutic Strategies for Postherpetic Neuralgia: Mechanisms, Treatments, and Perspectives

PURPOSE OF REVIEW

Postherpetic neuralgia is an annoying pain that mainly affects older people. In order to give patients more options, this review summarizes the pharmacological and interventional treatments for postherpetic neuralgia and updates the research on the efficacy, thereby providing doctors with more treatment options. The adverse effects and effective doses of its various treatments are also presented so that the therapy can be prescribed according to their concrete physical conditions. In a word, this review is dedicated to providing a comprehensive overview of the treatment options for postherpetic neuralgia and offering patients more choices.

RECENT FINDINGS

Combinational therapy is more excellent than monotherapy. The local anesthesia and gabapentin comprised outstanding compatibility. In addition, two therapeutic tools for PHN patients, especially for the intractable ones, electroacupuncture (EA), and osteopathic manipulative treatment (OMT), show their efficacy and become potential options to alleviate pain. In terms of treatment, guidelines recommend patients use tricyclic antidepressants (TCAs), gabapentin, pregabalin, and 5% lidocaine patches as the first-line medications, and gabapentin is investigated most, especially the gabapentin enacarbil (GEn). And drug efficacy can be limited by adverse effects and tolerated doses. Interventional treatments, with their invasiveness and operational difficulty, are usually considered for intractable patients. Combinational therapies may be used when a single therapy cannot achieve the desired effect. Therapies such as OMT and EA have also been proposed to palliate pain in some cases, and future directions of treatment may be investigated in Chinese medicine and acupuncture.

Peripheral Nerve Stimulation of the Lesser Occipital and Greater Auricular Nerve for Post Herpetic Neuralgia in a Case of Ramsay Hunt Syndrome: Case Report

Background

Post-herpetic neuralgia (PHN) is a painful condition that presents after herpes zoster reactivation in the peripheral and central nervous system. When medical treatment fails, options are limited, and patients may suffer with chronic pain indefinitely.

Case Presentation

We present the case of a gentleman with a 3-year history of PHN in the distribution of the right lesser occipital and greater auricular nerves that failed to respond to medical treatment. He underwent a trial of neuromodulation, and post-operative pain scores improved by 80%, and at 60 days post-operatively his average pain score was 0 out of 10.

Conclusions

PNS is an effective and safe option for the treatment of chronic pain, and we present a report of successful treatment of PHN in a particularly difficult anatomic distribution. PNS of the lesser occipital and greater auricular nerves is a novel treatment for PHN and shows promise as an effective, safe therapy when other treatment fails.

Investigational Drugs for the Treatment of Postherpetic Neuralgia: Systematic Review of Randomized Controlled Trials

The pharmacological treatment of postherpetic neuralgia (PHN) is unsatisfactory, and there is a clinical need for new approaches. Several drugs under advanced clinical development are addressed in this review. A systematic literature search was conducted in three electronic databases (Medline, Web of Science, Scopus) and in the ClinicalTrials.gov register from 1 January 2016 to 1 June 2023 to identify Phase II, III and IV clinical trials evaluating drugs for the treatment of PHN. A total of 18 clinical trials were selected evaluating 15 molecules with pharmacological actions on nine different molecular targets: Angiotensin Type 2 Receptor (AT2R) antagonism (olodanrigan), Voltage-Gated Calcium Channel (VGCC) α2δ subunit inhibition (crisugabalin, mirogabalin and pregabalin), Voltage-Gated Sodium Channel (VGSC) blockade (funapide and lidocaine), Cyclooxygenase-1 (COX-1) inhibition (TRK-700), Adaptor-Associated Kinase 1 (AAK1) inhibition (LX9211), Lanthionine Synthetase C-Like Protein (LANCL) activation (LAT8881), N-Methyl-D-Aspartate (NMDA) receptor antagonism (esketamine), mu opioid receptor agonism (tramadol, oxycodone and hydromorphone) and Nerve Growth Factor (NGF) inhibition (fulranumab). In brief, there are several drugs in advanced clinical development for treating PHN with some of them reporting promising results. AT2R antagonism, AAK1 inhibition, LANCL activation and NGF inhibition are considered first-in-class analgesics. Hopefully, these trials will result in a better clinical management of PHN.

Efficacy and Safety of SIKD1977 in Combination with Standard Treatment for Postherpetic Neuralgia: Study Protocol for a Double Blind, Placebo-Controlled, Randomized, Multicenter, Phase 2 Clinical Trial

Purpose

Postherpetic neuralgia (PHN) is the most common chronic complication of herpes zoster, associated with poor quality of life and increased patient and healthcare resource expenditure. This randomized controlled trial aims to evaluate the efficacy and safety of SIKD1977 (Sogeonjungtang) in combination with standard treatment and estimate an effective dose for treating PHN.

Patients and Methods

This is a protocol for a randomized, placebo-controlled, double-blind, multicenter trial. A total of 90 eligible participants with PHN will be recruited from three hospitals and randomly allocated to high-dose group, low-dose group, or placebo group in a 1:1:1 ratio. The trial will involve a 6-week oral administration of SIKD1977/placebo, and a 1-week follow-up period. The primary outcome will be the weekly average change in average daily pain score (ADPS) from baseline to the end of treatment. The secondary outcomes will include the weekly average changes in ADPS from baseline to week 2, 4, and 7, differences in Short-Form McGill Pain Questionnaire, Visual analogue scale, 5-level EuroQol-5 dimensions, Patient Global Impression of Change, and consumption of rescue drugs. All adverse events will be assessed during the trial.

Conclusion

This study will provide evidence for the efficacy and safety of SIKD1977, and an effective dose for PHN.

Trial Registration

This protocol has been registered in the Clinical Research Information Service with the identification code KCT0007939.

Analgesic Treatment Approach for Postherpetic Neuralgia: A Narrative Review

Post-herpetic neuralgia (PHN) is an entity derived from peripheral nerve damage that occurs during the reactivation of the Varicella Zoster Virus (VZV), which manifests itself through pain with neuropathic characteristics. This can prove to be very difficult to manage in the chronic stages of disease reappearance. There currently exists a multitude of treatment alternatives for PHN, however, prevention through the early initiation of antiviral regimens is vital. There are various pharmacological options available, but it is important to individualize each patient to maximize efficacy and minimize adverse effects. Interventional procedures have become a cornerstone in difficult-to-manage cases, and have shown promising outcomes when used in a multimodal approach by experienced specialists. It is necessary to make an objective diagnosis of PHN and start early treatment. Additionally there is current evidence that vouches for interventional therapies as well as individualization, with a clear establishment of therapeutic objectives according to the needs of each patient.

Efficacy of different acupuncture therapies on postherpetic neuralgia: A Bayesian network meta-analysis

Background

Postherpetic neuralgia (PHN) is a common, complex, and refractory type of neuropathic pain. Several systematic reviews support the efficacy of acupuncture and related treatments for PHN. Nevertheless, the efficacy of various acupuncture-related treatments for PHN remains debatable.

Objective

We aimed to assess the efficacy and safety of acupuncture-related treatments for PHN, identify the most effective acupuncture-related treatments, and expound on the current inadequacies and prospects in the applications of acupuncture-related therapies.

Methods

We searched PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, Google Scholar, four Chinese databases (China National Knowledge Infrastructure, China Biomedical, Chongqing VIP, and Wan Fang databases), clinical research registration platform (World Health Organization International Clinical Trial Registration platform, China Clinical Trial Registration Center) for relevant studies. We also examined previous meta-analyses; gray literature; and reference lists of the selected studies. We then evaluated the risk of bias in the included studies and performed a Bayesian multiple network meta-analysis.

Results

We included 29 randomized controlled trials comprising 1,973 patients, of which five studies showed a high risk of bias. The pairwise meta-analysis results revealed that the efficacy of all acupuncture-related treatments for pain relief related to PHN was significantly better than antiepileptics. The network meta-analysis results showed that pricking and cupping plus antiepileptics were the most effective treatment, followed by electroacupuncture (EA) plus antiepileptics for pain relief in patients with PHN. EA plus antiepileptics ranked the best regarding reduced Pittsburgh Sleep Quality Index (PSQI) and Self-Rating Depression Scale (SDS) scores in patients with PHN. No results were found regarding the total response rate or quality of life in this study. Acupuncture-related treatments showed a lower incidence of adverse events than that of antiepileptics.

Conclusion

Acupuncture-related therapies are potential treatment options for PHN and are safe. Pricking and cupping plus antiepileptics, are the most effective acupuncture-related techniques for pain relief, while EA plus antiepileptics is the best acupuncture-related technique for improving PHN-related insomnia and depression symptoms. However, owing to the limitations of this study, these conclusions should be cautiously interpreted, and future high-quality studies are needed.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021226422, identifier CRD42021226422.

The Effect of CT-Guided Pulsed Radiofrequency Combined with Ozone Injection on Zoster-Associated Pain: A Retrospective Study

Purpose

Globally, the incidence of herpes zoster (HZ) is increasing, and the resulting zoster-associated pain (ZAP) severely affects the quality of life of patients. Therefore, active treatment of ZAP and prevention of postherpetic neuralgia (PHN) are very important for patients in the early stage of the disease. This retrospective observational study aimed to evaluate the effect of CT-guided pulsed radiofrequency (PRF) combined with ozone injection on zoster-associated pain.

Patients and Methods

From 2018 to 2020, 84 patients with AHN (n=28), SHN (n=32), or PHN (n=24) underwent PRF combined with ozone injection treatment after pharmacologic and conservative therapies failed. The visual analogue scale (VAS), the Pittsburgh Sleep Quality Index (PSQI), and pregabalin consumption were recorded at baseline, post-PRF, and at 1, 3, 6, and 12 months after treatment. The number of remediations performed and adverse reactions were recorded, and treatment inefficiency was calculated using a VAS score greater than 3 as the criterion.

Results

The pooled results demonstrated statistically significant decreases in VAS scores, PSQI scores and consumption of pregabalin post-PRF and at 1, 3, 6, and 12 months follow-up (P<0.05). Compared with the PHN group, both the AHN and SHN groups showed clinical and statistical improvement in VAS scores and PSQI scores and in consumption of pregabalin (P< 0.05). At 1 year after the operation, the PHN group had a significantly greater number of remediation events and greater treatment inefficiency than the other two groups. No serious adverse events were observed during the procedure or during the follow-up period.

Conclusion

CT-guided PRF combined with ozone injection is safe and effective for individuals with ZAP, and its short-term and long-term effects are significant. In a sense, early PRF combined with ozone injection is more effective.

Pain Fluctuations of Women with Subacute Herpetic Neuralgia During Local Methylcobalamin in Combination with Lidocaine Treatment: A Single-Blinded Randomized Controlled Trial

Purpose

To evaluate the efficacy and pain fluctuations of methylcobalamin in combination with lidocaine local injection treatment for subacute herpetic neuralgia (SHN).

Methods

Seventy-nine women (60.4 ± 2.7 years) with thoracic SHN were enrolled and randomized to receive a combination of methylcobalamin and lidocaine local injection (MI, N=40), or a combination of lidocaine patch 5% and oral methylcobalamin (PO, N=39) for four weeks. Repeated-measures analyses of variance were used to evaluate the effect on pain levels. Generalized estimation equations were used to analyze the cause-effect relationship between pain fluctuations and influencing factors.

Results

At the treatment endpoint, the group, treatment time, and group interacted with treatment time effects of the pain scores and area were statistically significant (P<0.001), The pain scores were 2.9 ±0.9 (MI) and 4.3 ± 1.5 (PO). 80.00% (MI) or 28.21% (PO) of patients had pain scores ≤ 3, the odds ratio was 2.84 (95% CI: 1.68 to 4.79). The incidence of postherpetic neuralgia was 5.0% (2/40) at 3 months. Pain fluctuated repeatedly during treatment. The pain fluctuation increased from 8.75 log folds in the afternoon, to 79.85 log folds at night. With the ADLs level increasing from 1 to 3, the pain fluctuated from 4.28 to 17.70 log folds. Allodynia, itching, sleep quality, and ADLs were the significant influencing factors (P<0.05).

Conclusion

This study validated the efficacy of methylcobalamin combined with lidocaine for SHN, and confirmed that pain levels in patients with SHN had an obvious circadian rhythm. ADLs were an important cause of pain fluctuations.

The Effectiveness of Various Types of Electrical Stimulation of the Spinal Cord for Chronic Pain in Patients with Postherpetic Neuralgia: A Literature Review

Introduction

Postherpetic neuralgia (PHN) is a severe condition that remains a challenge to treat. Spinal cord stimulation (SCS) is used in cases of insufficient efficacy of conservative treatment. However, in contrast to many other neuropathic pain syndromes, there is a huge problem in reaching long-term stable pain relief in patients with PHN using conventional tonic SCS. The objective of this article was to present a review of the current management strategies of PHN, their efficacy, and safety.

Materials and Methods

We searched for articles containing the keywords "spinal cord stimulation AND postherpetic neuralgia," "high-frequency stimulation AND postherpetic neuralgia," "burst stimulation AND postherpetic neuralgia" and "dorsal root ganglion stimulation AND postherpetic neuralgia" in Pubmed, Web of Science, and Scopus databases. The search was limited to human studies published in the English language. There were no publication period limitations. Bibliographies and references of selected publications on neurostimulation for PHN were further manually screened. The full text of each article was studied once the abstract was analyzed by the searching reviewer and found appropriate. The initial search yielded 115 articles. Initial screening based on abstract and title allowed us to exclude 29 articles (letters, editorials, and conference abstracts). The full-text analysis allowed us to exclude another 74 articles (fundamental research articles, research utilizing animal subjects, and systemic and nonsystemic reviews) and results of PHN treatment presented with other conditions, leaving 12 articles for the final bibliography.

Results

12 articles reporting on the treatment of 134 patients with PHN were analyzed, with a disproportionally large amount of traditional SCS treatment than that to alternative SCS: DRGS (13 patients), burst SCS (1 patient), and high-frequency SCS (2 patients). Long-term pain relief was achieved in 91 patients (67.9%). The mean VAS score improvement was 61.4% with a mean follow-up time of 12.85 months. Although the number of patients in alternative SCS studies was very limited, almost all of them showed good responses to therapy with more than 50% VAS improvement and reduction of analgesic dosage. The article contains a review analysis of 12 articles concerning the current methods of treatment for postherpetic neuralgia including conservative treatment, spinal cord stimulation, and novel neuromodulation strategies. Available information on the pathophysiology of PHN and the effect or stimulation on its course, together with a number of technical nuances concerning various types of neurostimulation are also elucidated in this article. A number of alternative invasive treatments of PHN are also discussed.

Conclusions

Spinal cord stimulation is an established treatment option for patients with pharmacologically resistant PHN. High-frequency stimulation, burst stimulation, and dorsal root ganglion stimulation are promising options in the management of PHN due to the absence of paresthesias which can be painful for patients with PHN. But more research is still required to recommend the widespread use of these new methods.

Oral herbal medicine for treatment of postherpetic neuralgia: A protocol for systematic review and meta-analysis

BACKGROUND

Postherpetic neuralgia (PHN) is the most common complication of shingling. Herbal medicine for PHN is clinically used to improve chronic pain and other symptoms that reduce the quality of life (QoL), such as sleep disturbances and emotional problems. This study aims to describe methods for synthesizing evidence for the effectiveness and safety of herbal medicine for treating PHN.

METHODS

Randomized controlled trials using herbal medicine in patients with PHN will be included in this review. Electronic databases such as MEDLINE via PubMed, EMBASE, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, China National Knowledge Infrastructure, WanFang, KoreaMed, Research Information Service System, Korean Studies Information Service System, Database Periodical Information Academic, Oriental Medicine Advanced Searching Integrated System, and Korea Citation Index will be searched without language limitations from their inception to September 2022. Two authors will perform quality assessments independently using the Cochrane risk-of-bias tool. The primary outcome will be pain intensity, and the secondary outcomes will be global impression, anxiety, depression, sleep disturbance, QoL, and safety. All data from eligible studies will be synthesized for meta-analysis.

RESULTS

This study will be a systematic review and meta-analysis to evaluate the effectiveness and safety of oral herbal medicine for treatment of PHN.

CONCLUSION

This study will provide evidence for herbal medicine as a potential treatment for PHN which is advantageous not only for patients but also for researchers and policymakers.

Family Herpesviridae and neuroinfections: current status and research in progress

This article addresses the relationship between human herpesviruses (HHVs) and neuroinfections. Alphaherpesviruses, betaherpesviruses and gammaherpesviruses are neurotropic viruses that establish latency and exhibit reactivation capacity. Encephalitis and meningitis are common in cases of HHV. The condition promoted by HHV infection is a purported trigger for certain neurodegenerative diseases. Ongoing studies have identified an association between HSV-1 and the occurrence of Alzheimer's disease, multiple sclerosis and infections by HHV-6 and Epstein-Barr virus. In this review, we highlight the importance of research investigating the role of herpesviruses in the pathogenesis of diseases that affect the nervous system and describe other studies in progress.

Ultrasound-Guided Dry Needling for Trigger Point Inactivation in the Treatment of Postherpetic Neuralgia Mixed with Myofascial Pain Syndrome: A Prospective and Controlled Clinical Study

Objective

To evaluate the safety and effectiveness of ultrasound-guided dry needling for trigger point inactivation in the treatment of postherpetic neuralgia (PHN) mixed with myofascial pain syndrome (MPS).

Methods

A prospective and controlled clinical study was conducted. From January 2020 to December 2020, among the 100 patients who received PHN treatment in the pain department, 54 patients complicated with MPS were randomly divided into the dry needling group D (n = 28) and pharmacotherapeutic group P (n = 26). Visual analogue score (VAS) and McGill Pain Questionnaire (MPQ) were taken as primary indicators. Ultrasound-guided inactivation of myofascial trigger points (MTrPs) with dry needling and intradermal needling combined with press needling were applied on group D and pharmacotherapeutic only treatment on group P respectively. The VAS score <3 and/or the MPQ score <2 represents effective treatment. The VAS score >3 and/or the MPQ score >2 represents recurrent in follow-up study three months after the treatment.

Results

After four weeks treatment, the effective rate of one month later of the group D was 92.9% and the effective rate of group P was 38.5%, respectively. The recurrent rate of group D was 7.1% and 34.6% for group P, respectively, for follow-up three months later. The satisfactory rate of group D was higher than that of group P.

Conclusion

Ultrasound-guided dry needling and intradermal needling combined with press needling were more effective than only pharmacotherapeutic treatment for PHN mixed with MPS, with lower recurrent rate and higher patient's satisfactory rate.

Physiological changes from ageing regarding pain perception and its impact on pain management for older adults

Physiological changes that occur during ageing can affect the incidence, experience and treatment of pain in older adults. This article reviews these physiological changes and how they can affect the best approach to management.

Pulsed Radiofrequency Combined With Methylene Blue Paravertebral Nerve Block Effectively Treats Thoracic Postherpetic Neuralgia

Objective

To compare the effect, safety, and patient satisfaction of pulsed radiofrequency combined with methylene blue paravertebral nerve block and pulsed radiofrequency alone in the treatment of thoracic postherpetic neuralgia (PHN).

Methods

A total of seventy-two patients with PHN diagnosed in the Department of Pain Management of Shengjing Hospital at China Medical University, from September 2019 to April 2021, were enrolled in the study. Patients were randomly divided into two groups. Group A (n = 36) received pulsed radiofrequency treatment. Group B (n = 36) received pulsed radiofrequency + methylene blue paravertebral nerve block. Patients were followed-up at 1 day, 1 week, 1 month, 3 months, and 6 months after treatment. Observation at each follow-up included basic patient characteristics, Visual Analog Scale (VAS), Hospital Anxiety and Depression Scale (HAD), the Insomnia Severity Index (ISI), patient satisfaction, complications, and side effects.

Results

Compared with preoperative values, the VAS scores significantly decreased in both groups at each postoperative time point (1 day, 1 week, and 1, 3, and 6 months; all p < 0.05). Compared with group A, VAS scores in group B were significantly lower 1 week and 1 month after surgery (p < 0.05). Patients in group B had lower HAD scores than those in group A 1 week after surgery (p < 0.05). Patients in group B had lower ISI scores than those in group A 1 day, 1 week, and 1, 3, and 6 months after surgery (p < 0.05). The pregabalin dosage in group B was lower than that in group A at 1 and 6 months after surgery (p < 0.05). Patient satisfaction was higher in group B than in group A at 1 week and 6 months after surgery (p < 0.05). There were no serious complications or side effects in either group.

Conclusion

Pulsed radiofrequency combined with methylene blue paravertebral nerve block is superior to pulsed radiofrequency alone in the treatment of thoracic PHN, which can significantly relieve PHN and improve the condition of sleep and emotional disorders. Therefore, it is a safe and effective treatment method.

Corydalis decumbens Can Exert Analgesic Effects in a Mouse Neuropathic Pain Model by Modulating MAPK Signaling

Objectives

This study is aimed at investigating the analgesic effect of the administration of Corydalis decumbens (CD) in a mouse model of postherpetic neuralgia (PHN) and at elucidating its mechanism of analgesic action.

Methods

Adult Kunming (KM) mice were randomly divided into control, CD, and vehicle-treated groups. Neuropathic pain was induced with a single intraperitoneal injection of resiniferatoxin (RTX). Thermal hyperalgesia was assessed with a hot/cold plate test, and mechanical allodynia was evaluated using von Frey filaments. The activation states of astrocytes, microglia, and the mitogen-activated protein kinase (MAPK) pathway in the spinal cord were determined by immunofluorescence staining and Western blot analysis of Iba-1, GFAP, phospho-p38, and phospho-Jun N-terminal kinase (JNK).

Results

RTX diminished thermal sensitivity and gradually increased sensitivity to tactile stimulation. The expression of Iba-1, GFAP, phospho-p38 MAPK, and phospho-JNK was upregulated in the RTX-induced postherpetic neuralgia mouse model. Systemic treatment with CD significantly ameliorated thermal sensitivity and mechanical hyperalgesia and was accompanied by a reduction in the expression of Iba-1 and GFAP and reduced phosphorylation of p38 and JNK.

Conclusions

This study suggests that CD is effective at ameliorating mechanical hyperalgesia in PHN mice and that its mechanism of action may involve modulation of MAPK phosphorylation and glial cell activation. Thus, CD may be a promising alternative therapy for PHN.

Comparing the efficacy and safety of short-term spinal cord stimulation and pulsed radiofrequency for zoster-related pain: A systematic review and meta-analysis

BACKGROUND

Pulsed radiofrequency (PRF) is a commonly used method for the treatment of zoster-related pain in the clinic. However, PRF therapy has a high recurrence rate and many adverse reactions. Recent studies have shown that short-term spinal cord stimulation (stSCS) can effectively alleviate zoster-related pain. Due to the lack of evidence, it is unclear whether stSCS is superior to PRF in the efficacy of treating zoster-related pain.

OBJECTIVE

This study aimed to compare the efficacy and safety of stSCS and PRF for zoster-related pain.

METHODS

We searched seven electronic databases from the establishment of the database to January 2021. Related randomized controlled trials were included in this meta-analysis. After extracting the data and evaluating the methodological quality of the included trials, the outcome indicators were statistically analyzed by using RevManV.5.3.

RESULTS

This meta-analysis included 6 trials with a total of 509 patients. Compared with PRF group, stSCS group showed lower pain intensity (standardized mean difference=-0.83, 95%CI [-1.37, -0.30], P=.002), better sleep quality (mean difference=-1.43, 95%CI [-2.29, -0.57], P=.001), lower pain rating index scores, and less incidence of adverse events (RR=0.32, 95%CI [0.12, 0.83], P<.05). However, the efficacies of PRF and stSCS for treating postherpetic neuralgia were consistent in the response rate (RR= 1.10, 95% CI [0.82, 1.48], P=.51) and the complete remission rate (RR=1.05, 95% CI [0.66, 1.68], P=.84).

CONCLUSIONS

In this study, stSCS showed a better analgesic effect and higher safety than PRF. Our meta-analysis results suggested that stSCS may be a feasible and safe invasive treatment for zoster-related pain. However, high-quality, randomized controlled trials with large sample sizes are needed to further verify our conclusions.

Determining the Definitive Time Criterion for Postherpetic Neuralgia Using Infrared Thermographic Imaging

Introduction

The time criteria used in many studies of postherpetic neuralgia (PHN) are arbitrary and do not have supporting evidence. Therefore, this study sought to determine the definite time criterion for PHN by analyzing the skin temperature to estimate the time point when zoster-induced skin inflammatory reaction ends.

Methods

Infrared thermography was used to measure the difference in skin temperature between the affected and unaffected areas (ΔTemp) in the craniocervical and thoracic regions of patients with herpes zoster (HZ). Because the ΔTemp changes from a positive value to zero when the skin is no longer inflamed, a ΔTemp ≤ 0 was defined as the end of skin inflammation, and this time point was considered the starting point for PHN. This cutoff time point was estimated using receiver operating characteristic (ROC) curve analysis.

Results

A total of 503 patients were included in this study. The ROC curve analysis showed that the time point when the ΔTemp was ≤ 0 occurred at 12 weeks after HZ onset (95% confidence interval 11–15 weeks, area under the ROC curve 0.901). Using this time point as the time criterion of PHN, the sensitivity, specificity, and classification accuracy were 0.807, 0.905, and 0.871, respectively.

Conclusions

The transition of skin temperature from warm to cold occurs 12 weeks after HZ onset, which implies the end of local inflammation. Therefore, PHN associated with pathophysiologic change may be defined as 12 weeks after the skin rash. This finding provides a theoretical basis for the timing definition of PHN.

Post-Varicella Neurological Complications: A Preliminary Observation from a Tertiary Care Centre of Eastern India

Objectives:

The objective of this study is to analyse detailed clinical presentations, imaging findings, and outcome in a series of 17 cases (n = 17) with neurological complications following acute varicella infection.

Methods:

It is an observational study on the patients who presented to the neurology outpatient department of our institute with neurological abnormalities following acute varicella infection within the last 3 months.

Results:

Neuroimaging, either computed tomography or magnetic resonance imaging, cerebrospinal fluid analysis, electroencephalography and nerve conduction studies were performed in all the patients along with other specialized investigations as per clinical context. The age of presentation varied from childhood to middle age (median age was 23 years) and range of clinical spectrum was also wide. Peripheral nervous system involvement was more common in the form of Guillain–Barré syndrome (29.4%) and isolated lower motor neuron facial nerve palsy (23.5%) compared to central nervous system (CNS) involvement. CNS involvement was documented in the form of ataxia (11.76%), myelopathy (17.6%), stroke (5.88%) and encephalitis (5.88%).

Conclusion:

Chickenpox is a common viral disease and most patients recover without any complication. Although rare, neurological complications following acute varicella infection may have myriad presentations ranging from lower motor neuron facial palsy to life-threatening encephalitis. Compared to other studies, varicella encephalitis and ataxia were not so common in our study group. Response to therapy was uniformly good except in the patients presenting with ataxia. Response was particularly good to central and peripheral demyelinating disorders.

Efficacy of local anaesthetic and steroid combination in prevention of post-herpetic neuralgia: A meta-analysis

Objective

The objective was to provide synthesized evidence on the efficacy of local anaesthetics and steroid injections for prevention and management of PHN, compared to the standard treatment using anti-viral and analgesic medications. The primary outcomes of interest were incidence of PHN and duration of neuralgic pain.

Methods

Comprehensive searches were done systematically through PubMed, Scopus, Cochrane Central Register of Controlled Trials and Google scholar databases. Randomized controlled trials that compared the efficacy of local anaesthetics and steroid injections for preventing and managing PHN were included for this meta-analysis. A comprehensive search was done for papers published until 15th July 2021.

Results

A total of 10 RCTs were included in the meta-analysis. In the overall pooled analyses, compared to standard care/placebo, those receiving a combination of local anaesthetic and steroid injection had 55% lower risk of PHN at 3 months from onset of rash (RR 0.45; 95% CI, 0.29; 0.70). Out of the different modes of intervention delivery i.e., intravenous, subcutaneous and nerve block, maximum beneficial effect in reducing the incidence of PHN was noted in nerve block (RR 0.55; 95% CI, 0.34, 0.89).

Conclusions

The meta-analysis provides some evidence to support the use of combined local anaesthetic and steroids in reducing risk of post-herpetic neuralgia and duration of neuralgic pain in patients with herpes zoster rash.

Safety of Recombinant Zoster Vaccine in Rheumatology Patients

OBJECTIVES

Recombinant zoster vaccine (RZV) is Food and Drug Administration approved for the prevention of herpes zoster (shingles) in adults 50 years old and older. Immunocompromised subjects were excluded from the pivotal vaccine trials. We studied the safety of this vaccine in our university-affiliated rheumatology practice.

METHODS

This was a single-center, retrospective study focusing on subjects who received RZV during 2018. We collected the demographic data, any self-reported adverse events after vaccination, C-reactive protein, Routine Assessment of Patient Index Data 3 (RAPID3) scores for subjects with rheumatoid arthritis, and available RAPID3 scores for all study subjects before and after the vaccination.

RESULTS

Comparision of C-reactive protein (n = 40), RAPID3 scores for subjects with rheumatoid arthritis (n = 16), and available RAPID3 scores for all subjects (n = 21) using the paired t test, did not show significant differences before and after the administration of RZV. A total of 6.4% of patients reported adverse events after vaccination. The adverse events were mild and did not lead to hospitalization, end organ damage, or change in treatment plan.

CONCLUSIONS

The RZV was safe and well tolerated among our study population.

Acupuncture (superficial dry-needling) as a treatment for chronic postherpetic neuralgia - a randomized clinical trial

BACKGROUND

Postherpetic neuralgia is a painful condition where finding sufficient treatment poses a great challenge. Acupuncture is often used as an alternative treatment for these pains, yet no randomized trials, using a sham-placebo have been performed to confirm its effect. Our objective was to investigate the efficacy of acupuncture compared to sham-acupuncture when treating chronic postherpetic dermal pain.

METHODS

We performed a sham-controlled double-blinded randomized clinical trial (RCT) with two arms. The intervention group received superficial dry-needling, and the control group received sham acupuncture using blunted needles. Twenty-six patients received two treatments. They filled out questionnaires at baseline and 1 month after treatment: (1) average and maximum pain (Numeric Rating Scale), (2) neuropathic pain (Neuropathic Pain Scale Inventory) and (3) Quality of Life (QoL) (Short-form 36).

RESULTS

Thirteen patients were allocated to the intervention group and 15 to the control group. We did not detect any significant changes in levels of pain and neuropathic pain. One QoL parameter, regarding emotional problems, reached a level of statistical significance. The sham-blinding was successful. This is the first RCT on the effect of acupuncture (superficial dry-needling) on postherpetic neuralgia (PHN), using a sham procedure as control. We observed no significant changes or tendencies in the measured levels of pain. One QoL parameter had significant improvement in the intervention group compared to the control group.

CONCLUSION

In conclusion, acupuncture was not superior to treatment with sham acupuncture. Though individual patients may experience some pain relief from acupuncture, our results do not support the routine use of this type of acupuncture to treat PHN.

Clinical Characteristics, Treatment Effectiveness, and Predictors of Response to Pharmacotherapeutic Interventions Among Patients with Herpetic-Related Neuralgia: A Retrospective Analysis

BACKGROUND

The treatment for herpetic-related neuralgia focuses on symptom control by use of antiviral drugs, anticonvulsants, and tricyclic antidepressants. We aimed to explore the clinical characteristics associated with medication responsiveness, and to build a classifier for identification of patients who have risk of inadequate pain management.

METHODS

We recruited herpetic-related neuralgia patients during a 3-year period. Patients were stratified into a medication-resistant pain (MRP) group when the pain decrease in the visual analogue scale (VAS) is < 3 points, and otherwise a medication-sensitive pain (MSP) group. Multivariate logistic regression was performed to determine the factors associated with MRP. We fitted four machine learning (ML) models, namely logistic regression, random forest, supporting vector machines (SVM), and naïve Bayes with clinical characteristics gathered at admission to identify patients with MRP.

RESULTS

A total of 213 patients were recruited, and 132 (61.97%) patients were diagnosed with MRP. Subacute herpes zoster (HZ) (vs. acute, OR 8.95, 95% CI 3.15-29.48, p = 0.0001), severe lesion (vs. mild lesion, OR 3.84, 95% CI 1.44-10.81, p = 0.0084), depressed mood (unit increase OR 1.10, 95% CI 1.00-1.20, p = 0.0447), and hypertension (hypertension, vs. no hypertension, OR 0.36, 95% CI 0.14-0.87, p = 0.0266) were significantly associated with MRP. Among four ML models, SVM had the highest accuracy (0.917) and receiver operating characteristic-area under the curve (0.918) to discriminate MRP from MSP. Phase of disease is the most important feature when fitting ML models.

CONCLUSIONS

Clinical characteristics collected before treatment could be adopted to identify patients with MRP.

Oral Administration of East Asian Herbal Medicine for Peripheral Neuropathy: A Systematic Review and Meta-Analysis with Association Rule Analysis to Identify Core Herb Combinations

This review aimed to comprehensively assess the efficacy and safety of oral East Asian herbal medicine (EAHM) for overall peripheral neuropathy (PN). In addition, an Apriori algorithm-based association rule analysis was performed to identify the core herb combination, thereby further generating useful hypotheses for subsequent drug discovery. A total of 10 databases were searched electronically from inception to July 2021. Randomized clinical trials (RCTs) comparing EAHM with conventional analgesic medication or usual care for managing PN were included. The RCT quality was appraised using RoB 2.0, and the random effects model was used to calculate the effect sizes of the included RCTs. The overall quality of evidence was evaluated according to the Grading of Recommendations Assessment, Development, and Evaluation. By analyzing the constituent herb data, the potential association rules of core herb combinations were explored. A total of 67 RCTs involving 5753 patients were included in this systematic review. In a meta-analysis, EAHM monotherapy and combined EAHM and western medicine therapy demonstrated substantially improved sensory nerve conduction velocity, motor nerve conduction velocity, and response rate. Moreover, EAHM significantly improved the incidence rate, pain intensity, Toronto clinical scoring system, and Michigan diabetic neuropathy score. The evidence grade was moderate to low due to the substantial heterogeneity among the studies. Nine association rules were identified by performing the association rule analysis on the extraction data of 156 EAHM herbs. Therefore, the constituents of the herb combinations with consistent association rules were Astragali Radix, Cinnamomi Ramulus, and Spatholobi Calulis. This meta-analysis supports the hypothesis that EAHM monotherapy and combined therapy may be beneficial for PN patients, and follow-up research should be conducted to confirm the precise action target of the core herb.