A systematic review and meta-analysis of risk factors for postherpetic neuralgia

Short-Term Peripheral Nerve Stimulation Relieve Pain for Elder Herpes Zoster Ophthalmicus Patients: A Retrospective Study

OBJECTIVE

Ophthalmic postherpetic neuralgia (PHN) is the final stage of herpes zoster (HZ) ophthalmicus and a severe refractory neuropathic pain, thus there is no curative treatment that could alleviate pain and reduce the incidence of ophthalmic PHN now. The purpose of this study is to evaluate therapeutic efficacy of short-term peripheral nerve stimulation (PNS) for elder patients with HZ ophthalmicus.

MATERIALS AND METHODS

We performed a retrospective study from March 2015 to August 2019 in our pain department. All the HZ ophthalmicus patients underwent supraorbital nerve short-term PNS were included. The patients' data, including numeric rating scale (NRS), 36-Item short form health survey (SF-36), and analgesic consumptions, were retrospectively analyzed. Severe side effects also were recorded.

RESULTS

A total of 68 patients were enrolled in this study. The NRS scores were significantly decreased at different time points after short-term PNS compared to baseline (p < 0.001). The SF-36 scores, including general health, social function, emotional role, mental health, bodily pain, physical functioning, physical role, and vitality, were significantly improved at different time points after treatment (p < 0.001). The average dosages of tramadol and pregabalin administered (mg/d) were both significantly reduced compared to baseline (p < 0.001). There was no bleeding, infection, pain increase, and other side effects after treatment.

CONCLUSIONS

Short-term PNS is an effective and safe therapeutic alternative for elder patients with HZ ophthalmicus and could reduce the incidence of ophthalmic PHN.

Sources of Individual Differences in Pain

Pain is an immense clinical and societal challenge, and the key to understanding and treating it is variability. Robust interindividual differences are consistently observed in pain sensitivity, susceptibility to developing painful disorders, and response to analgesic manipulations. This review examines the causes of this variability, including both organismic and environmental sources. Chronic pain development is a textbook example of a gene-environment interaction, requiring both chance initiating events (e.g., trauma, infection) and more immutable risk factors. The focus is on genetic factors, since twin studies have determined that a plurality of the variance likely derives from inherited genetic variants, but sex, age, ethnicity, personality variables, and environmental factors are also considered.

Community and topic modeling for infectious disease clinical trial recommendation

Clinical trials are crucial for the advancement of treatment and knowledge within the medical community. Although the ClinicalTrials.gov initiative has resulted in a rich source of information for clinical trial research, only a handful of analytic studies have been carried out to understand this valuable data source. Analysis of this database provides insight for emerging trends of clinical research. In this study, we propose to use network analysis to understand infectious disease clinical trial research. Our goal is to understand two important issues related to the clinical trials: (1) the concentrations and characteristics of infectious disease clinical trial research, and (2) recommendation of clinical trials to a sponsor (or an investigator). The first issue helps summarize clinical trial research related to a particular disease(s), and the second issue helps match clinical trial sponsors and investigators for information recommendation. By using 4228 clinical trials as the test bed, our study investigates 4864 sponsors and 1879 research areas characterized by Medical Subject Heading (MeSH) keywords. We use a network to characterize infectious disease clinical trials, and design a new community-topic-based link prediction approach to predict sponsors’ interests. Our design relies on network modeling of both clinical trial sponsors and keywords. For sponsors, we extract communities with each community consisting of sponsors with coherent interests. For keywords, we extract topics with each topic containing semantic consistent keywords. The communities and topics are combined for accurate clinical trial recommendation. This transformative study concludes that using network analysis can tremendously help the understanding of clinical trial research for effective summarization, characterization, and prediction.

Varicella-zoster virus early infection but not complete replication is required for the induction of chronic hypersensitivity in rat models of postherpetic neuralgia

Herpes zoster, the result of varicella-zoster virus (VZV) reactivation, is frequently complicated by difficult-to-treat chronic pain states termed postherpetic neuralgia (PHN). While there are no animal models of VZV-induced pain following viral reactivation, subcutaneous VZV inoculation of the rat causes long-term nocifensive behaviors indicative of mechanical and thermal hypersensitivity. Previous studies using UV-inactivated VZV in the rat model suggest viral gene expression is required for the development of pain behaviors. However, it remains unclear if complete infection processes are needed for VZV to induce hypersensitivity in this host. To further assess how gene expression and replication contribute, we developed and characterized three replication-conditional VZV using a protein degron system to achieve drug-dependent stability of essential viral proteins. Each virus was then assessed for induction of hypersensitivity in rats under replication permissive and nonpermissive conditions. VZV with a degron fused to ORF9p, a late structural protein that is required for virion assembly, induced nocifensive behaviors under both replication permissive and nonpermissive conditions, indicating that complete VZV replication is dispensable for the induction of hypersensitivity. This conclusion was confirmed by showing that a genetic deletion recombinant VZV lacking DNA packaging protein ORF54p still induced prolonged hypersensitivities in the rat. In contrast, VZV with a degron fused to the essential IE4 or IE63 proteins, which are involved in early gene regulation of expression, induced nocifensive behaviors only under replication permissive conditions, indicating importance of early gene expression events for induction of hypersensitivity. These data establish that while early viral gene expression is required for the development of nocifensive behaviors in the rat, complete replication is dispensable. We postulate this model reflects events leading to clinical PHN, in which a population of ganglionic neurons become abortively infected with VZV during reactivation and survive, but host signaling becomes altered in order to transmit ongoing pain.

Efficacy and safety of pulsed radiofrequency modulation of thoracic dorsal root ganglion or intercostal nerve on postherpetic neuralgia in aged patients: a retrospective study

BACKGROUND

Postherpetic neuralgia (PHN) is common in elderly patients and can be alleviated by pulsed radiofrequency (PRF). However, PRF treatments display different efficacy on different nerves. The purpose of this study was to evaluate the efficacy and safety of ultrasound-guided PRF modulation on thoracic dorsal root ganglion (DRG) or intercostal nerve (ICN) for PHN in aged patients and to provide a theoretical basis for clinical treatment.

METHODS

We classified aged patients into two groups, DRG group and ICN group, based on the needle tip position. Visual analogue scale (VAS) and concise health status questionnaire (Short-form 36 health/survey questionnaire, SF-36) were used to evaluate the pain intensity and the life quality of the patients before and 2, 4 and 12 weeks after the PRF treatments. We also recorded the adverse reactions during the treatments.

RESULTS

After the PRF treatment, the scores of VAS and SF-36 (assessing general health perception, social function, emotional role, mental health, and pain) improved significantly in both groups (P < 0.05). The mean VAS score in the DRG group was significantly lower than that in the ICN group 2 weeks after treatment, and remained for 12 weeks. The SF-36 scores in the DRG group were significantly higher than those in the ICN group (P < 0.05). We found a similar incidence of adverse reactions between the two groups (P > 0.05).

CONCLUSIONS

PRF therapy is safe and effective for elderly patients with postherpetic neuralgia. However, PRF treatment in dorsal root ganglion is superior to that in intercostal nerve with improving VAS and SF-36 scores to a greater extent in older patients.

TRIAL REGISTRATION

ChiCTR2100044176 .

Pulsed Radiofrequency of the Trigeminal Ganglion for Treating Postherpetic Neuralgia of the Ophthalmic Branch

Postherpetic neuralgia (PHN) is a painful, long-lasting condition as a consequence of nerve damage resulting from a herpes zoster infection. Although there are many different treatments available to reduce pain duration and severity, PHN is often refractory to them and no single therapy shows an effective cure for all cases of PHN, especially for those involving the ophthalmic branch of the trigeminal nerve. Pulsed radiofrequency (PRF) is a minimally invasive procedure for pain treatment that has been practiced over the past decade. However, its clinical efficacy and safety for treating PHN involving the ophthalmic branch of the trigeminal nerve have not been evaluated. Objective. This study aimed to evaluate the efficacy and safety of PRF for treating PHN involving the ophthalmic branch of the trigeminal ganglion. Study Design. An observational study. Setting. All patients received PRF of the ophthalmic branch of the trigeminal nerve, pain intensity was assessed by a visual analogue scale (VAS), and complications before and after PRF stimulation were noted. Methods. Thirty-two patients with PHN of the ophthalmic branch were treated by PRF of the ophthalmic branch with controlled temperature at 42°C for 8 min. Pain relief, corneal reflex, sleep quality, and satisfaction were assessed for all patients. Results. Thirty out of 32 patients (93.75%) reported significant pain reduction after PRF treatment. Twenty-eight of them (87.5%) were satisfied with their sleep and obtained a pain score lower than 3 following the procedure. Only two patients had a recurrence of the severe burning pain and returned to the hospital for other medical therapies 2 weeks after the PRF procedure. No patient lost the corneal reflex. Limitations. This study is an observational study and a nonprospective trial with a short-term follow-up period. Conclusion. PRF of the trigeminal ganglion of the ophthalmic branch can significantly reduce pain sensation and improve sleep quality and satisfaction for PHN of the ophthalmic branch.

Effectiveness of acupuncture therapy for postherpetic neuralgia: an umbrella review protocol

INTRODUCTION

Several systematic reviews and meta-analysis indicate that acupuncture and related therapies may be a valuable adjunctive technique to pharmacological interventions for pain management of postherpetic neuralgia (PHN). However, the robustness of the results of these studies has not been evaluated. The aim of this proposed umbrella review is to provide more reliable evidence of the effectiveness of acupuncture therapy for PHN based on medical references for healthcare decision makers.

METHODS AND ANALYSIS

PubMed, EMBASE, The Cochrane Library, Web of Science, Chinese BioMedical Literature Database, VIP Database for Chinese Technical Periodicals, China National Knowledge Infrastructure and Wan fang Database will be used to retrieve reviews. The time of publication will be limited from inception to March 2021. Two reviewers will screen all retrieved articles independently to identify their eligibility and extract the data. The quality will be assessed independently by two trained reviewers using Assessment of Multiple Systematic Reviews-2 for methodological quality, Risk of Bias in Systematic Review for level of bias, Preferred Reporting Items for Systematic Reviews and Meta-Analysis for reporting quality and Grading of Recommendations Assessment, Development and Evaluation for the quality of evidence. Any disagreements will be settled by discussion or the involvement of a third reviewer.

ETHICS AND DISSEMINATION

The protocol of this review does not require ethical approval because the research will be based on publicly available data. The findings will be disseminated through publication in peer-reviewed international journals or presentation in academic conference.

PROSPERO REGISTRATION NUMBER

CRD42020173341.

REPORTING CHECKLIST

PRISMA-P, 2015.

Herpes Zoster Risk in Immunocompromised Adults in the United States: A Systematic Review

BACKGROUND

The primary reported risk factors for herpes zoster (HZ) include increasing age and immunodeficiency, yet estimates of HZ risk by immunocompromising condition have not been well characterized. We undertook a systematic literature review to estimate the HZ risk in immunocompromised patients.

METHODS

We systematically reviewed studies that examined the risk of HZ and associated complications in adult patients with hematopoietic cell transplants (HCT), cancer, human immunodeficiency virus (HIV), and solid organ transplant (SOT). We identified studies in PubMed, Embase, Medline, Cochrane, Scopus, and clinicaltrials.gov that presented original data from the United States and were published after 1992. We assessed the risk of bias with Cochrane or Grading of Recommendations Assessment, Development, and Evaluation methods.

RESULTS

We identified and screened 3765 records and synthesized 34 studies with low or moderate risks of bias. Most studies that were included (32/34) reported at least 1 estimate of the HZ cumulative incidence (range, 0-41%). There were 12 studies that reported HZ incidences that varied widely within and between immunocompromised populations. Incidence estimates ranged from 9 to 92 HZ cases/1000 patient-years and were highest in HCT, followed by hematologic malignancies, SOT, and solid tumor malignancies, and were lowest in people living with HIV. Among 17 HCT studies, the absence of or use of antiviral prophylaxis at <1 year post-transplant was associated with a higher HZ incidence.

CONCLUSIONS

HZ was common among all immunocompromised populations studied, exceeding the expected HZ incidence among immunocompetent adults aged ≥60 years. Better evidence of the incidence of HZ complications and their severity in immunocompromised populations is needed to inform economic and HZ vaccine policies.

Expanding frontiers in telehealth: Video assisted at-home application of capsaicin 8% patch

In recent years, the delivery of health services has undergone a major paradigm shift towards expanded outpatient services and widespread use of telemedicine. Post-herpetic neuralgia (PHN) is a treatment recalcitrant neuropathic pain condition referring to pain persisting more than three months from the initial onset of an acute herpes zoster. QUTENZA® (capsaicin 8% patch) is a single 1-hr localized treatment for PHN and can provide several months of pain relief per application. However, patient access to capsaicin 8% patch is limited due to sensitive handling protocols that require the patch application to occur under physicians or healthcare professionals under the close supervision of a physician. Herein, we describe a successful treatment of PHN at-home, using capsaicin 8% patch, performed under full supervision and instruction from a physician using video telehealth services. SIGNIFICANCE: This is a case report of the successful treatment of post-herpetic neuralgia at-home using Capsaicin 8% patch. The procedure was performed under full supervision and instruction from a physician using video telehealth services. Not only did the patient tolerate the procedure and have significant efficacy, she voiced preference to repeat treatment in this manner versus going back to the office.

Efficacy of Acupuncture for Herpes Zoster: A Systematic Review and Meta-Analysis

INTRODUCTION

This study aimed to assess the efficacy of acupuncture in patients with herpes zoster (HZ) based on current randomized clinical trials (RCTs).

METHODS

Five databases were screened for RCTs published until August 2019. Studies that assessed the efficacy of acupuncture when used as an independent intervention for HZ were included. The outcomes of interest were pain intensity, as assessed using the visual analog scale (VAS), incrustation time, decrustation time, and incidence of post-herpetic neuralgia (PHN).

RESULTS

In total, 21 RCTs were included in this research. Compared with antiviral therapy, acupuncture was associated with a reduction in VAS score by 16.13, incrustation time by 1.86 days, decrustation time by 2.19 days, and incidence of PHN by 83%. According to a meta-regression analysis, the main sources of heterogeneity were sample size and duration of treatment. There was no publication bias except on decrustation time. A sensitivity analysis showed that the outcomes were relatively stable and reliable.

CONCLUSION

Acupuncture may be effective for patients with HZ. Nevertheless, this finding should be validated by conducting high-quality trials with a larger sample size.

Pain Manifestations of COVID-19 and Their Association With Mortality: A Multicenter Prospective Observational Study

OBJECTIVES

To determine the prevalence and breakdown of pain symptoms among patients with coronavirus disease 2019 (COVID-19) infection admitted for nonpain symptoms and the association between the presence of pain and intensive care unit (ICU) admission and death.

PATIENTS AND METHODS

In this multicenter prospective study, data on the intensity and type of pain were collected on 169 patients with active severe acute respiratory syndrome coronavirus 2 infection at 2 teaching hospitals in the United States and Korea and on 8 patients with acute pain at another large teaching hospital between February 1, 2020, and June 15, 2020.

RESULTS

Sixty-five of 169 patients (38.5%) reported an active pain condition. Among the 73 patients with pain, the most common pain symptoms were headache (n=22; 30.1%), chest pain (n=17; 23.3%), spinal pain (n=18; 24.7%), myalgia (n=13; 17.8%), abdominal or pelvic pain (n=13; 17.8%), arthralgia (n=11; 15.1%), and generalized pain (n=9; 12.3%). Those reporting headache as their main symptom were less likely to require ICU admission (P=.003). Acetaminophen or nonsteroidal anti-inflammatory drugs were prescribed to 80.8% (n=59), opioids to 17.8% (n=13), adjuvants to 8.2% (n=6), and ketamine to 5.5% (n=4) of patients with pain. When age 65 years and older and sex were controlled for in multivariable analysis, the absence of pain was associated with ICU admission (odds ratio, 2.92; 95% CI, 1.42 to 6.28; P=.004) and death (odds ratio, 3.49; 95% CI, 1.40 to 9.76; P=.01).

CONCLUSION

Acute pain is common during active COVID-19 infection with the most common manifestations being headache, chest pain and spine pain. Individuals without pain were more likely to require intensive care and expire than those with pain. Reasons why pain may be associated with reduced mortality include that an intense systemic stimulus (eg, respiratory distress) might distract pain perception or that the catecholamine surge associated with severe respiratory distress might attenuate nociceptive signaling.

Burst Stimulation of the Thoracic Spinal Cord near a Cardiac Pacemaker in an Elderly Patient with Postherpetic Neuralgia: A Case Report

New developments in spinal cord stimulation (SCS) have improved the treatment of patients with chronic pain. Although the overall safety of modern SCS has been established, there are no published reports regarding safety considerations when implanting a burst-mode spinal cord stimulator in patients with permanent cardiac pacemakers (PCPs). An 80-year-old man with a complete atrioventricular block implanted with a PCP was considered as a candidate for burst-mode SCS due to well-established postherpetic neuralgia (>180 days after rash). Cardiac monitoring during the burst-mode spinal cord stimulator trial and insertion did not indicate any interference. After the insertion of the burst-mode spinal cord stimulator, the patient showed functional improvement and significant pain relief. The safety of traditional tonic-mode SCS in patients with PCP has been previously reported. This is the first case report describing the safe and effective use of burst-mode SCS in a patient with PCP.

Facial pain beyond trigeminal neuralgia

PURPOSE OF REVIEW

Trigeminal neuralgia is a well-known facial pain syndrome with several treatment options. In contrast, non-neuralgiform idiopathic facial pain syndromes are relatively rare, reflected by the fact that, until 2020, no internationally accepted diagnostic classification existed. Like trigeminal neuralgia, these non-dental facial pain syndromes need to be managed by neurologists and pain specialists, but the lack of pathophysiological understanding has resulted in an underrepresented and undertreated patient group.

RECENT FINDINGS

This work provides a brief overview of the most common primary facial pain syndromes, namely, the facial attack-like facial pain, which corresponds to attack-like headache, the persistent idiopathic facial pain (formerly 'atypical facial pain'), and trigeminal neuropathy. What these disorders have in common is that they should all be treated conservatively.

SUMMARY

On the basis of pragmatic classifications, permanent and attack-like primary facial pain can be relatively easily differentiated from one another. The introduction of the new International Classification of Orofacial Pain offers the opportunity to better coordinate and concentrate scientific efforts, so that in the future the therapy strategies that are still inadequate, can be optimized.

Application of Nalbuphine in Trigeminal Ganglion Pulse Radiofrequency Surgery in Patients with Postherpetic Neuralgia

This study aimed to explore the application value of nalbuphine in pulsed radiofrequency operation of trigeminal ganglion in patients with postherpetic neuralgia (PHN). Thirty patients with PHN were randomly divided into the nalbuphine (Nalbu) group and ketorolac tromethamine (KT) group and received CT-guided pulsed radiofrequency surgery on trigeminal ganglion. The numeric rating scale (NRS) scores of patients were recorded at preoperative, intraoperative, and postoperative time points, before going to bed, and the next morning after the operation. In addition, the number of breakthrough pain before operation and within 24 hours after operation, the incidence of nausea and vomiting within 24 hours after surgery, and the patient's sleep quality before and on the day after surgery were evaluated. The outcome data demonstrated that patients treated with nalbuphine had lower NRS scores after the pulse radiofrequency operation during and after the pulse radiofrequency operation compared to those with KT. In addition, nalbuphine effectively decreased the number of breakthrough pain, reduced the occurrence of nausea and vomiting after surgery, and improved the sleep quality. In conclusion, intramuscular injection of nalbuphine 30 min before trigeminal ganglion pulse radiofrequency surgery can be conducive to pain relief and improve the postoperative comfort of patients, providing an effective alternative for the alleviation of PHN in clinic.

A systematic literature review to assess the burden of herpes zoster disease in China

INTRODUCTION

Herpes zoster (HZ) or shingles occurs as a result of reactivation after a primary infection with varicella zoster virus (chickenpox). The burden of HZ in older adults in China is not well understood. We conducted a systematic literature review to understand the burden of disease related to HZ, its complications, and associated costs in China.

AREAS COVERED

Using publications retrieved from Chinese and English literature databases, we described incidence and prevalence of HZ, occurrence of HZ-related complications, and costs associated with HZ in mainland China, Taiwan, and Hong Kong.

EXPERT OPINION

The data, although limited, indicate that the burden of disease due to HZ is substantial in China, with incidence rates that are comparable to the rest of the world. Recently, an adjuvanted recombinant HZ vaccine was approved for use in China. Disease prevention is likely to reduce the burden of disease, with potentially significant economic benefits. However, understanding the public health impact of vaccination in China will require extensive baseline information about incidence, complication rates, and associated costs. This review gives an overview of available research, but also reveals existing gaps. Well-designed observational studies are needed to quantify the total burden of disease and potential impact of prevention through vaccination.

[Pain prevention in the primary care setting : Facts for resident physicians]

Based on health insurance data, approximately 37.4 million patients (46%) in Germany are diagnosed with "pain". The prevalence of patients with debilitating chronic pain is around 7.3%. From the health care perspective, and given the high socioeconomic relevance of chronic pain, effective preventive measures represent useful therapeutic approaches. In the context of pain medicine, primary prevention aims to avoid acute pain. Secondary prevention is targeted at preventing acute pain from turning into chronic pain. Tertiary prevention comprises measures to diminish pain-associated disability and impairment to everyday life. Finally, quaternary prevention focuses on avoiding medically non-indicated or unhelpful medical interventions. In addition to general approaches of pain prevention, such as detecting and treating of chronification factors (yellow, black and blue flags), the present article also describes educational and disease-specific approaches in musculoskeletal and neuropathic pain syndromes as well as headaches.

Potential for increased prevalence of neuropathic pain after the COVID-19 pandemic

Although coronavirus disease 2019 (COVID-19) most commonly manifests with acute respiratory symptoms, one very common symptom of COVID-19 is pain. As COVID-19 often causes peripheral or central neurological complications, it is anticipated that a number of the chronic pain complications of COVID-19 will be neuropathic. This review first examines the most common viral infections responsible for neurological complications including neuropathic pain. These encompass herpes zoster, HIV, poliovirus, enteroviruses, and several tropical viruses. Neurological complications of COVID-19 including in particular Guillain-Barré syndrome, myelitis, and stroke are reviewed with regards to their potential risk of chronic neuropathic pain. Prospective longitudinal cohorts of patients should be implemented to evaluate the exact risk of neuropathic pain after COVID-19.

Intravenous Administration of Vitamin C in the Treatment of Herpes Zoster-Associated Pain: Two Case Reports and Literature Review

Background

Herpes zoster (HZ) is an acute inflammatory neurocutaneous disease caused by the reactivation of varicella-zoster virus. It is estimated that the incidence of postherpetic neuralgia following HZ is 10–20%. The leading risk factors of the prognosis are aging and immunity dysfunction. Vitamin C plays a pivoted role in enhancing white blood cell function. Epidemiological evidence and clinical studies have indicated an association between pain and suboptimal vitamin C status. At present, vitamin C has been used as an additional option in the treatment of HZ-associated pain. Despite the current controversy, case reports and randomized controlled studies have indicated that both acute- and postherpetic neuralgia can be dramatically alleviated following intravenous vitamin C infusions. Case Presentation. Two patients (male aged 72 and female 78 years) with HZ did not respond well to antiviral therapy and analgesics. Skin lesions in the right groin and front thigh healed after early antiviral therapy, but the outbreak of pain persisted in the male patient. The female patient presented to our clinic with clusters of rashes in the right forehead with severe edema of her right upper eyelid. Because nerve blockade could not be conducted for both patients, intravenous infusion of vitamin C was applied and resulted in an immediate remission of the breakthrough pain in the male patient and cutaneous lesions in the female patient.

Conclusions

The use of vitamin C appears to be an emerging treatment alternative for attenuating HZ and PHN pain. Hence, we recommend the addition of concomitant use of intravenously administered vitamin C into therapeutic strategies in the treatment of HZ-associated pain, especially for therapy-resistant cases. Furthermore, animal studies are required to determine analgesic mechanisms of vitamin C, and more randomized clinical trials are essential to further determine the optimal dose and timing of administration of vitamin C.

Effect of duloxetine premedication for postherpetic neuralgia within 72 h of herpes zoster reactivation [PROCESS]: a study protocol for a randomized controlled trial

Background

Postherpetic neuralgia (PHN) is the most common complication attributed to herpes zoster, which involves the reactivation of residual varicella zoster virus. It has been reported previously that pre-emptive amitriptyline following acute herpes zoster has shown latent positive effects in the prevention of PHN. In this study, by interfering with the same targets, norepinephrine and serotonin, we aim to evaluate whether pre-emptive duloxetine may proactively prevent PHN development.

Methods

This is a nationwide multicentric, randomized, open-label, blinded-endpoint study that will recruit 750 participants from 18 primary centres in China. Patients aged more than 50 years who are diagnosed with uncomplicated HZ, present with vesicles within 72 h of their emergence, and have an average pain score of at least 40/100 mm on a visual analogue scale (VAS, 0 mm = no pain, 100 mm = worst possible pain, at opposite ends of a 100-mm line) will be recruited for this study. Participants will be randomized into a duloxetine arm and a control arm. Participants allocated to the duloxetine arm will be given antivirals, analgesics and duloxetine, while those allocated to the control arm will receive antivirals and analgesics but no duloxetine. The primary outcome of this study is preventive efficacy against PHN, which will be evaluated based on a 100 mm VAS. Any pain scores other than 0 mm on the VAS 12 weeks after HZ onset will be defined as PHN. The secondary outcomes will consist of the average weekly VAS score, the average weekly consumption of each analgesic, weekly feature of the pain, patients’ quality of life based on the 12-item Short-Form Health Survey, Patient Global Impression of Change Scale, sleep quality as evaluated by the Pittsburgh Sleep Quality Index and adverse events during the study period.

Discussion

This study will investigate a prophylactic approach for reducing the prevalence of postherpetic neuralgia with duloxetine and will add significant new knowledge on the preventive effects of duloxetine on PHN.

Trial registration

Clinicaltrials.gov NCT04313335. Registered on 18 March 2020.

Efficacy of continuous epidural infusion with epidural electric stimulation compared to that of conventional continuous epidural infusion for acute herpes zoster management: a retrospective study

Background

Continuous epidural infusions are commonly used in clinical settings to reduce the likelihood of transition to postherpetic neuralgia via pain control. The purpose of this study was to compare the efficacy of conventional continuous epidural infusion to that of continuous epidural infusion in which the catheter is guided by electric stimulation to areas with neurological damage for the treatment of zoster-related pain and prevention of postherpetic neuralgia.

Methods

We analyzed the medical records of 114 patients in this study. The patients were divided into two groups: contrast (conventional continuous epidural infusion) and stimulation (continuous epidural infusion with epidural electric stimulation). In the contrast group, the position of the epidural catheter was confirmed using contrast medium alone, whereas in the stimulation group, the site of herpes zoster infection was identified through electric stimulation using a guidewire in the catheter. Clinical efficacy was assessed using a numerical rating scale (pain score) up to 6 months after the procedures. We compared the percentage of patients who showed complete remission (pain score less than 2 and no further medication) in each group. We also investigated whether the patients required additional interventional treatment due to insufficient pain control during the 6-month follow-up period after each procedure.

Results

After adjusting for confounding variables, the pain score was significantly lower in the stimulation group than in the contrast group for 6 months after the procedure. After adjustment, the odds of complete remission were 1.9-times higher in the stimulation group than in the contrast group (95% confidence interval [CI]: 0.81–4.44, P = 0.14). Patients in the contrast group were significantly more likely to require other interventions within 6 months of the procedure than patients in the stimulation group (odds ratio: 3.62, 95% CI: 1.17–11.19, P = 0.03).

Conclusion

Epidural drug administration to specific spinal segments using electric stimulation catheters may be more helpful than conventional continuous epidural infusion for improving pain and preventing postherpetic neuralgia in the acute phase of herpes zoster.

Herpes zoster risk and burden of disease in immunocompromised populations: a population-based study using health system integrated databases, 2009-2014

Background

Estimate the incidence of herpes zoster (HZ), its complications and healthcare utilization rates in adults (≥ 18-years-old) with a wide range of immunocompromised (IC) conditions compared to IC-free cohort.

Method

A population-based retrospective study using the Valencia healthcare Integrated Databases (VID) (2009–2014). HZ and IC were defined using ICD-9 codes in primary care (PC) and hospitalization registers. Incidence rates (IR), risk of HZ, HZ-recurrence, HZ-complications and healthcare utilization rates were estimated in the IC-cohort compared to IC-free.

Results

The study population consisted of 4,382,590 subjects, of which 578,873 were IC (13%). IR (in 1000 persons-year) of HZ overall, in IC and in IC-free cohort was 5.02, 9.15 and 4.65, respectively. IR of HZ increased with age in both cohorts and it was higher for all IC conditions studied, reaching up to twelvefold in subjects with stem cell transplantation. IC subjects had 51% higher risk of developing HZ, 25% higher HZ-recurrence and the risk of HZ-complications was 2.37 times higher than in IC-free. HZ-related healthcare utilization was higher in the IC-cohort than in IC-free (number of hospitalizations 2.93 times greater, hospital stays 12% longer, 66% more HZ-specialist visits, 2% more PC visits, sick leaves 18% longer and 20% higher antiviral dispensation).

Conclusions

Patients suffering from all the IC conditions studied are at higher risk of developing HZ, HZ-recurrence and post-herpetic complications, which implies a substantial morbidity and a high consumption of resources. These results should be considered for vaccine policy implementation.

Pathogenic mechanisms of lipid mediator lysophosphatidic acid in chronic pain

A number of membrane lipid-derived mediators play pivotal roles in the initiation, maintenance, and regulation of various types of acute and chronic pain. Acute pain, comprising nociceptive and inflammatory pain warns us about the presence of damage or harmful stimuli. However, it can be efficiently reversed by opioid analgesics and anti-inflammatory drugs. Prostaglandin E₂ and I₂, the representative lipid mediators, are well-known causes of acute pain. However, some lipid mediators such as lipoxins, resolvins or endocannabinoids suppress acute pain. Various types of peripheral and central neuropathic pain (NeuP) as well as fibromyalgia (FM) are representatives of chronic pain and refractory owing to abnormal pain processing distinct from acute pain. Accumulating evidence demonstrated that lipid mediators represented by lysophosphatidic acid (LPA) are involved in the initiation and maintenance of both NeuP and FM in experimental animal models. The LPAR₁-mediated peripheral mechanisms including dorsal root demyelination, Ca_vα2δ1 expression in dorsal root ganglion, and LPAR₃-mediated amplification of central LPA production via glial cells are involved in the series of molecular mechanisms underlying NeuP. This review also discusses the involvement of lipid mediators in emerging research directives, including itch-sensing, sexual dimorphism, and the peripheral immune system.

Acupuncture therapy for treating postherpetic neuralgia: A protocol for an overview of systematic reviews and meta-analysis

BACKGROUND

Postherpetic neuralgia (PHN) is the most common complication and sequela of herpes zoster (HZ) that greatly affects the life and emotional experience of patients. Acupuncture therapy has been confirmed as an effective and safe treatment for PHN. Several systematic reviews (SRs) and meta-analysis (MAs) have reported the evidence of acupuncture therapy for treating PHN. However, the evidence has not been systematically synthesized. This overview aims to synthesize and assess the reliability of evidence generated from these SRs and MAs of acupuncture therapy for PHN.

METHODS

We will conduct a systematic search of the China Biology Medicine (CBM), VIP database, Wangfang database, China National Knowledge Infrastructure (CNKI), Pubmed, Cochrane Library, Excerpt Medical Database (Embase), and Web of Science to identify eligible SRs and MAs, from their inception to October 31, 2020. We will use Assessment of Multiple Systematic Reviews-2 (AMSTAR2) for methodological quality assessment, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for report quality assessment, Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) for the quality of evidence assessment, and ROBIS for the bias assessment. Our reviewers will conduct systematic reviews, qualification evaluation, data extraction, methodological quality, and evidence quality screening in pairs. The outcomes include pain intensity, Quality of life (QoL), Hamilton Anxiety Scale (HAMA), Global impression, and adverse events. All the extracted data will be provided in tabular form to summarize characteristics of each review. The evidence will be a narrative synthesis of the type and content of the intervention and the results reported.

RESULTS

The results of this study will be published in a peer-reviewed journal.

CONCLUSIONS

This overview will provide comprehensive evidence of acupuncture therapy for patients with PHN.

ETHICS AND DISSEMINATION

This review will not involve private information of participants, so the ethical approval will not be required. The results will be disseminated in a peer-reviewed journal or conference presentation. Important protocol modifications will be updated on PROSPERO.

PROSPERO REGISTRATION NUMBER

CRD42020178738.

Transition from acute to chronic pain: where cells, systems and society meet

Current treatments for chronic pain are often ineffective. At the same as searching for novel therapeutics, there is growing interest in preventing acute pain becoming chronic. While the field is still in its infancy, its knowledge base is increasingly expanding. Certainly, biomedical factors, for example, the type of tissue damage, are important but they are often not modifiable. Psychosocial risk factors (e.g., thoughts and beliefs about pain, mood, social support, workplace problems) are modifiable. There is an increasing body of research that cognitive behavioral therapy can prevent transition. Internet-based delivery of cognitive behavioral therapy improves access. Clinicians need to be aware that they may inadvertently promote pain chronification in their patients by what they say and do.

Study on the related factors of post-herpetic neuralgia in hospitalized patients with herpes zoster in Sichuan Hospital of Traditional Chinese Medicine based on big data analysis

Although various factors were reported to be related to post-herpetic neuralgia (PHN), studies based on adequate and comprehensive data were absent. Data was extracted from cases of hospitalized patients with herpes zoster in dermatology department, Sichuan hospital of traditional Chinese medicine range from December, 2011 to February, 2018, and then cleaned to build prediction model with TREENET algorithms. Following evaluated the prediction model by ROC and confusion matrix, variables importance ranking and variables dependency analysis were performed, resulting in the importance ranking of factors for PHN and the dependency between factors and PHN. Based on strict inclusion and exclusion criteria, 1303 (571 PHN and 732 normal controls) cases and 2958 indicators were selected. Model evaluation showed high ROC value (training sample = 0.985, test samples = 0.752) and high accuracy value (70.27%), which indicated that the model was predictive. After variables importance ranking and variables dependency analysis, 62 variables in the model were associated with the occurrence of PHN. Our study identified 62 variables related to PHN and revealed that various variables were the important risk factors for PHN, including age, MCHC, sodium and UA.

Predicting Postherpetic Neuralgia in Patients with Herpes Zoster by Machine Learning: A Retrospective Study

Introduction

Postherpetic neuralgia (PHN) is a neuropathic pain secondary to shingles. Studies have shown that early pain intervention can reduce the incidence or intensity of PHN. The aim of this study was to predict whether a patient with acute herpetic neuralgia will develop PHN and to help clinicians make better decisions.

Method

Five hundred two patients with shingles were reviewed and classified according to whether they had PHN. The risk factors associated with PHN were determined by univariate analysis. Logistic regression and random forest algorithms were used to do machine learning, and then the prediction accuracies of the two algorithms were compared, choosing the superior one to predict the next 60 new cases.

Results

Age, NRS score, rash site, Charlson comorbidity index (CCI) score, antiviral therapy and immunosuppression were found related to the occurrence of PHN. The NRS score was the most closely related factor with an importance of 0.31. As for accuracy, the random forest was 96.24%, better than that of logistic regression in which the accuracy was 92.83%. Then, the random forest model was used to predict 60 newly diagnosed patients with herpes zoster, and the accuracy rate was 88.33% with a 95% confidence interval (CI) of 77.43–95.18%.

Conclusions

This study provides an idea and a method in which, by analyzing the data of previous cases, we can develop a predictive model to predict whether patients with shingles will develop PHN.

Disrupted default mode network dynamics in recuperative patients of herpes zoster pain

Introduction

Previous studies of herpes zoster (HZ) have focused on acute patient manifestations and the most common sequela, postherpetic neuralgia (PHN), both serving to disrupt brain dynamics. Although the majority of such patients gradually recover, without lingering severe pain, little is known about life situations of those who recuperate or the brain dynamics. Our goal was to determine whether default mode network (DMN) dynamics of the recuperative population normalize to the level of healthy individuals.

Methods

For this purpose, we conducted resting‐state functional magnetic resonance imaging (fMRI) studies in 30 patients recuperating from HZ (RHZ group) and 30 healthy controls (HC group). Independent component analysis (ICA) was initially undertaken in both groups to extract DMN components. DMN spatial maps and within‐DMN functional connectivity were then compared by group and then correlated with clinical variables.

Results

Relative to controls, DMN spatial maps of recuperating patients showed higher connectivity in middle frontal gyrus (MFG), right/left medial temporal regions of cortex (RMTC/LMTC), right parietal lobe, and parahippocampal gyrus. The RHZ (vs HC) group also demonstrated significant augmentation of within‐DMN connectivity, including that of LMTC‐MFG and LMTC‐posterior cingulate cortex (PCC). Furthermore, the intensity of LMTC‐MFG connectivity correlated significantly with scoring of pain‐induced emotions and life quality.

Conclusion

Findings of this preliminary study indicate that a disrupted dissociative pattern of DMN persists in patients recuperating from HZ, relative to healthy controls. We have thus provisionally established the brain mechanisms accounting for major outcomes of HZ, offering heuristic cues for future research on HZ transition states.

Efficacy and safety of the extracorporeal shockwave therapy in patients with postherpetic neuralgia: study protocol of a randomized controlled trial

Background

Postherpetic neuralgia (PHN) is one of the most common types of chronic neuropathic pain, which seriously affects quality of the life because of pain severity and poor response to the currently available treatments. The main strategies for PHN management are medication and invasive interventional therapies; however, these approaches have many adverse effects, so it is important to find another effective and safe treatment for PHN.

Methods

A single-center, single-blind randomized clinical trial will evaluate 98 study participants randomized in a 1:1 ratio into control and experimental groups. The control group will receive conventional treatment including medication therapy and invasive interventional therapy. The experimental group will receive extracorporeal shockwave therapy (ESWT) in addition to conventional therapy. The primary outcome is pain intensity assessed on a visual analogue scale (VAS); the secondary outcomes are the following: quality of life assessed by the 36-Item Short-Form Health Survey (SF-36), psychological state for anxiety and depression measured by the Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS), and sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI). Assessors blinded to the randomization will collect data during the intervention period at baseline and weeks 1, 4, and 12. The plasma levels of tumor necrosis factor-α and interleukin-6 will be assessed before and after ESWT to explore the biochemical mechanisms of ESWT in the treatment of PHN.

Discussion

This randomized controlled trial will evaluate the effectiveness and safety of ESWT in patients with PHN and thus will provide clinical evidence for its use in the management of PHN and explore the potential biochemical mechanisms of this treatment.

Trial registration

www.ChiCTR.org.cn, identifier: ChiCTR1900025828. Registered on 10 September 2019

Neuropathic Pain: From Mechanisms to Treatment

Neuropathic pain caused by a lesion or disease of the somatosensory nervous system is a common chronic pain condition with major impact on quality of life. Examples include trigeminal neuralgia, painful polyneuropathy, postherpetic neuralgia, and central poststroke pain. Most patients complain of an ongoing or intermittent spontaneous pain of, for example, burning, pricking, squeezing quality, which may be accompanied by evoked pain, particular to light touch and cold. Ectopic activity in, for example, nerve-end neuroma, compressed nerves or nerve roots, dorsal root ganglia, and the thalamus may in different conditions underlie the spontaneous pain. Evoked pain may spread to neighboring areas, and the underlying pathophysiology involves peripheral and central sensitization. Maladaptive structural changes and a number of cell-cell interactions and molecular signaling underlie the sensitization of nociceptive pathways. These include alteration in ion channels, activation of immune cells, glial-derived mediators, and epigenetic regulation. The major classes of therapeutics include drugs acting on α₂δ subunits of calcium channels, sodium channels, and descending modulatory inhibitory pathways.

Clinical Efficacy of Ultrasound-Mediated Transdermal Lidocaine and Capsaicin Delivery for the Treatment of Allodynia Caused by Herpes Zoster

OBJECTIVE

To investigate the efficacy of ultrasound-mediated drug delivery for allodynia caused by herpes zoster.

DESIGN

Unblinded randomized controlled study with two treatment groups and an additional control group.

SUBJECTS

Patients hospitalized with allodynia caused by herpes zoster were enrolled.

METHODS

Patients were randomly assigned to three groups: ultrasound-mediated transdermal drug delivery (group U), lidocaine intradermal injection (group I), or control group (group C). The primary outcome was pain intensity associated with allodynia, assessed with the visual analog scale (VAS) while brushing the skin with clothing after treatment stimulated allodynia. The secondary outcomes included an emotional functioning score (ES), average gabapentin consumption, and incidence of adverse events of each group.

RESULTS

Sixty patients were enrolled in the study, but two of them failed to complete the treatment process. Therefore, 58 patients were included in the final analysis. All groups had lower VAS and ES scores after treatment compared with baseline. The VAS scores in groups U and I decreased significantly more than in group C (P < 0.05). Mean VAS scores in group U on days 1, 2, and 3 were lower than in group C (P < 0.01). ES was significantly lower in group U compared with groups I and C after treatment (P < 0.001). Average gabapentin consumption and incidence of adverse events in group C were higher than in the other two groups.

CONCLUSIONS

In this study of treatment of allodynia caused by herpetic zoster, ultrasound-mediated lidocaine and capsaicin delivery provided better pain relief and improved emotional functioning compared with intradermal blockade with local anesthetics.

Comparison of ropivacaine with ropivacaine and fentanyl in continuous epidural analgesia for postherpetic neuralgia: A STROBE-compliant retrospective study

Continuous epidural analgesia (CEA) using local anesthetics is frequently used to control herpes zoster pain and prevent postherpetic neuralgia (PHN). However, few studies have been conducted to determine the efficacy of epidural drugs administered as CEA to manage PHN. This retrospective study was designed to evaluate the effectiveness of CEA with ropivacaine alone or with ropivacaine and fentanyl for controlling pain caused by PHN.We reviewed the medical records of 71 patients. We studied 2 groups: epidural ropivacaine (ER; CEA with ropivacaine alone; n = 44) and epidural ropivacaine and fentanyl (Epidural ropivacaine and fentanyl (ERF); CEA with ropivacaine and fentanyl; n = 27). To evaluate pain, a numeric rating scale (NRS) was evaluated at 6 time points: immediately before the procedure (baseline NRS score); 1 hour after the procedure; 14 days after the procedure; and 1, 3, and 6 months after the procedure. Complication rates were recorded during CEA. We also investigated whether additional invasive procedures were needed due to insufficient pain control during the 6-month follow-up period.After adjusting for confounding variables, there were no significant differences in the NRS scores between the 2 groups at any time point. The adjusted odds ratio for additional invasive procedures within 6 months after CEA was 1.03-times higher in the ERF group than in the ER group, but this difference was not statistically significant (95% confidence interval: 0.33-3.23, P = .96). Rates of complication (dysuria, vomiting, nausea, itching sensation, and hypotension) during CEA were higher in the ERF group than in the ER group. However, the differences were not statistically significant.There was no difference in the management of pain in patients with PHN between the groups. Epidural administration of fentanyl with ropivacaine did not improve pain management when compared to ropivacaine alone. Although not statistically significant, the incidence of complications during CEA was higher in the opioid combination group.

Postherpetic Neuralgia: Current Evidence on the Topical Film-Forming Spray with Bupivacaine Hydrochloride and a Review of Available Treatment Strategies

PURPOSE OF REVIEW

This is a comprehensive review of the literature about the use of bupivacaine hydrochloride for the treatment of post-herpetic neuralgia (PHN). It briefly reviews the background, biology, diagnosis and conventional treatment for PHN, and then introduces and compares the recent evidence for the use of topical bupivacaine.

RECENT FINDINGS

PHN is defined by pain lasting 90 days or more after the initial presentation of herpes zoster ("Shingles", HZ) rash and is the most common complication of this disease. A product of re-activation of the Varicella-Zoster virus (VZV), HZ is diagnosed more than 1 million times annually in the United States. Approximately 20% of patients with HZ will experience PHN and will continue to suffer intermittent neuropathic symptoms, including itching and pain, that is sharp, stabbing, throbbing or burning, with the pain localized to the site of their original rash. This long-lasting pain compares with the severity of long-standing rheumatics and osteo-arthritis and is accompanied by severe allodynia causing significant suffering, and a financial burden that is manifested in both healthcare costs and loss of quality-adjusted life years. Prevention of PHN may be achieved with the Zoster vaccine, although there is still a large segment of unvaccinated population. Moreover, the Zoster vaccine is not always effective for prevention. Current treatment includes medical (systemic tricyclic antidepressants, anticonvulsants and opioids, topical lidocaine and capsaicin) and interventional (subcutaneous Botox injections, nerve blocks and nerve stimulation) therapies. These therapies are not always effective, and each carries their own profile of side effects and risks. Moreover, up to 50% of patients with PHN are refractory to management. Recent evidence is emerging to support the use of topical local anesthetics for the treatment of PHN. Two small studies recently found topical lidocaine spray to be effective in treating paroxysmal pain attacks associated with PHN. Bupivacaine is a longer-lasting local anesthetic, and a film-forming formulation allows easy and durable application to the affected skin. Recent studies show that topical film-forming bupivacaine is safe and as effective as lidocaine for the treatment of PHN. PHN is an important though common complication of HZ and can cause long-lasting pain and disability. Current treatment for PNH is limited by efficacy and safety profiles of individual therapies. Recent evidence points to topical local anesthetics as an effective and safe alternative to conventional therapy. Film-forming bupivacaine may offer a durable and safe option for this otherwise difficult to treat syndrome.

Challenges of neuropathic pain: focus on diabetic neuropathy

Neuropathic pain is a frequent condition caused by a lesion or disease of the central or peripheral somatosensory nervous system. A frequent cause of peripheral neuropathic pain is diabetic neuropathy. Its complex pathophysiology is not yet fully elucidated, which contributes to underassessment and undertreatment. A mechanism-based treatment of painful diabetic neuropathy is challenging but phenotype-based stratification might be a way to develop individualized therapeutic concepts. Our goal is to review current knowledge of the pathophysiology of peripheral neuropathic pain, particularly painful diabetic neuropathy. We discuss state-of-the-art clinical assessment, validity of diagnostic and screening tools, and recommendations for the management of diabetic neuropathic pain including approaches towards personalized pain management. We also propose a research agenda for translational research including patient stratification for clinical trials and improved preclinical models in relation to current knowledge of underlying mechanisms.

[S2k guideline for the diagnosis and therapy of zoster and post-zoster neuralgia]

Diese Leitlinie richtet sich an Dermatologen, Ophthalmologen, HNO-Ärzte, Pädiater, Neurologen, Virologen sowie Infektiologen, Anästhesisten und Allgemeinmediziner in Klinik und Praxis und dient zur Information für andere medizinische Fachrichtungen, die an der Behandlung des Zoster beteiligt sind. Darüber hinaus soll die Leitlinie Kostenträgern und politischen Entscheidungsträgern zur Orientierung dienen. Die Leitlinie wurde im formellen Konsensusverfahren (S2k) von Dermatologen, Virologen/Infektiologen, Ophthalmologen, HNO-Ärzten, Neurologen, Pädiatern und Anästhesisten/Schmerzmedizinern erstellt.

Die Leitlinie stellt einen Überblick über die klinische und molekulare Diagnostik sowie den Antigennachweis, die Antikörperkultur und Viruskultur dar. Diagnostisch besondere Situationen und komplizierte Verläufe der Erkrankung finden ebenfalls Berücksichtigung. Die antivirale Therapie des Zoster und der Postzosterneuralgie wird im Allgemeinen und für besondere Situationen dargelegt. Detaillierte Angaben zur Schmerzbehandlung finden Erwähnung und sind in einer Übersicht dargestellt. Ebenso werden die lokaltherapeutischen Maßnahmen thematisiert.

Pain Neurology

Pain is often the initial complaint for which patients seek medical care, presenting both a diagnostic and therapeutic challenge to the primary care provider. The appreciation of pain is not merely the result of abnormal sensory stimulation causing an unpleasant sensation but rather a combination of the recognition of the somatic discomfort in association with an emotional response to that discomfort. The perception of pain and the extent of distress and disability can vary depending on previous experience, cultural background, situational factors, and comorbid psychiatric disease. Though acute pain is usually the result of tissue damage, this is not always the case, as evidenced by primary headache disorders. Chronic pain may be the result of an injury, irreversible underlying disease, or clinical conditions such as fibromyalgia for which the mechanism remains unclear. Treatment of the underlying cause will usually effect a resolution or improvement in the pain, but when the discomfort persists, a consultation with a neurologist or pain management specialist should be considered.

Botulinum toxin A treatment for post-herpetic neuralgia: A systematic review and meta-analysis

The present meta-analysis study aimed to investigate the safety and efficacy of local administration of botulinum toxin (BTX-A) vs. lidocaine in the treatment of post-herpetic neuralgia. A systematic search of the Cochrane Library, PubMed, Embase, Chinese National Knowledge Infrastructure, Wanfang, Chongqing VIP Information Co. and Chinese Biomedical Literature Database was performed to identify randomized controlled trials (RCTs) comparing BTX-A and lidocaine in the treatment of post-herpetic neuralgia. The primary outcomes were Visual Analogue Scale (VAS) pain scores at 1, 2 and 3 months after treatment and the effective rate. Secondary outcomes were scores on the McGill pain questionnaire and adverse event rate. A total of 7 RCTs comprising 752 patients were included. The VAS pain score was significantly lower at 1 month [mean difference (MD)=-2.31; 95% CI: -3.06, -1.56; P<0.00001)], 2 months (MD=-2.18; 95% CI: -2.24, -2.11; P<0.00001) and 3 months (MD=-1.93; 95% CI: -3.05, -0.82; P=0.0007) after treatment, the effective rate was significantly higher (odds ratio=2.9; 95% CI: 1.71, 4.13; P<0.0001) and scores on the McGill pain questionnaire were significantly lower (MD=-10.93; 95% CI: -21.02, -0.83; Z=2.12; P=0.03) in patients who received BTX-A for post-herpetic neuralgia compared to those who received lidocaine. There was no difference in the adverse event rate between treatments. In conclusion, BTX-A has potential as a safe and effective treatment option for post-herpetic neuralgia. Further large and well-designed RCTs are required to confirm this conclusion.

Comparison of the Analgesic Effect of Ropivacaine with Fentanyl and Ropivacaine Alone in Continuous Epidural Infusion for Acute Herpes Zoster Management: A Retrospective Study

Background and Objectives: Currently, few studies have reported the effects of opioids during continuous epidural infusion (CEI) to control pain owing to herpes zoster (HZ). This study aimed to retrospectively compare the effectiveness of epidural opioids in the treatment of acute HZ pain. Materials and Methods: We reviewed medical records of 105 patients who were divided into two groups: R group (CEI with ropivacaine) and RF group (CEI with ropivacaine and fentanyl). Clinical efficacy was evaluated using the numeric rating scale (NRS) score for 6 months after the procedures. We compared the percentage of patients with complete remission in each group. We investigated the complication rates during CEI. Results: No significant differences in the NRS scores were observed between the two groups in the 6-month period. The adjusted odds ratio (OR) for patients included in the complete remission was 0.6 times lower in the RF group than in the R group (95% confidence interval: 0.22–1.71, p = 0.35). The OR for complications during CEI was higher in the RF group than in the R group. However, the difference was not statistically significant. Conclusions: No difference was observed in the management of HZ pain and the prevention of postherpetic neuralgia between the two groups. The incidence of complications tended to be higher in the RF group than in the R group.

Diabetes as a risk factor for herpes zoster in adults: A synthetic literature review

AIM

The objective of this review was to evaluate the role of diabetes as a risk factor for herpes zoster (HZ) and to discuss implications of prevention by vaccination with available HZ vaccines.

METHODS

We reviewed studies that investigated the incidence rates of HZ in patients with diabetes. Papers in English or French published between January 2000 and December 2018 have been selected from PubMed and Google Scholarship by using appropriate key words.

RESULTS

The risk of HZ was significantly higher in patients with diabetes as compared to controls in 11 studies out of 16, although the magnitude of risk associated to diabetes varied across studies from 1.06 to 2.38 (p < 0.05). The incidence of HZ in patients with diabetes increased with age and was higher in women than in men. The incidence of the most common complication of HZ, i.e. post-herpetic neuralgia was also higher in patients with diabetes.

CONCLUSIONS

The presence of HZ adds supplementary complications to the pre-existing comorbidity in patients with diabetes. Investigating the impact of preventive measure by HZ vaccination is therefore of paramount importance in patients with diabetes.

Ischemia-modified albumin (IMA) and dynamic thiol-disulfide homeostasis in patients with postherpetic neuralgia

Background

Ischemia-modified albumin (IMA) is an isotype of albumin that increases under oxidative stress, and plasma thiols are main defense mechanisms against oxidative stress. The objective of this study was to investigate thiol-disulfide homeostasis and serum IMA levels in postherpetic neuralgia (PHN) patients.

Methods

A total of 29 PHN patients and 30 healthy controls were included in the study. Serum total and native thiol concentrations and serum disulfide concentration were measured using the method described by Erel and Neselioglu. The albumin cobalt binding test was used to measure serum IMA levels.

Results

Serum IMA levels were 1.21 ± 0.58 AU and 0.75 ± 0.09 AU in the PHN and control groups, respectively (p < 0.001). Serum total thiol concentrations were found to be 421.62 ± 90.28 μmol/L and 598.36 ± 73.63 μmol/L in the PHN and control groups, respectively (p < 0.001). Serum native thiol concentrations were found to be 365.75 ± 92.07 μmol/L and 531.90 ± 72.9 μmol/L in the PHN and control groups, respectively (p < 0.001). Serum disulfide concentrations were found to be 33.23 ± 5.33 μmol/L and 27.93 ± 7.81 μmol/L in the PHN and control groups, respectively (p = 0.003). The native thiol/total thiol ratio was significantly lower, and the disulfide/total thiol and disulfide/native thiol ratios were significantly higher in the PHN group compared to the controls.

Conclusions

IMA levels are high and dynamic thiol/disulfide homeostasis is disrupted in PHN patients.

Ultrasound-guided Erector Spinae Plane Block for the Management of Herpes Zoster Pain: Observational Study

Background

Herpes zoster is caused by the reactivation of latent varicella-zoster virus, which promotes acute and chronic pain that may interfere with daily activities and reduce the quality of life. Ultrasound-guided erector spinae plane (ESP) blocks are used for a wide variety of indications in the management of acute, chronic, and postoperative pain. Our aim was to evaluate the efficacy of ultrasound-guided erector spinae plane blocks for the management of pain in herpes zoster.

Methods

The medical records of 34 patients with acute or chronic pain during herpes zoster between May 2017 and June 2018 were investigated at two pain clinic centers. The patients received ultrasound-guided erector spinae plane block: We performed a single injection for the patients having acute pain and a continuous block for the patients having chronic pain. Patient characteristics, block characteristics (needle insertion level, catheter, or single insertion), the volume of given local anesthetics, the intensity of pain before and after the block procedure using a numerical rating score (NRS) between 0 and 10, and the duration of analgesia were evaluated.

Results

All patients reported a remarkable and rapid resolution of pain immediately after the block procedure. Median (min-max) NRS score before the block procedure was 9 (4-10). The median (min-max) NRS score was 1.5 (0-7) after the block procedure. The difference was found to be statistically significant (p<0.0001). NRS score after the third month was 1 (0-3); the difference is statistically significant (p=0.002). The median value of analgesia time (min-max) was 18 (3-24) hours.

Conclusion

Our preliminary experience demonstrated that an ESP block provided sufficient analgesia in acute herpetic pain. A combination of ESP block, pregabalin, and tramadol was also effective within the three-months-period after the block performance.

Association of rs3783641 single-nucleotide polymorphism in GTP cyclohydrolase 1 gene with post-herpetic neuralgia

Post-herpetic neuralgia (PHN) is a well-established clinical problem with potential severe personal and socioeconomic implications. GTP cyclohydrolase 1 (GCH1) gene, which encodes the rate-limiting enzyme in tetrahydrobiopterin synthesis, has been strongly implicated to be associated with neuropathic pain in previous animal and human studies. The rs3783641 (T > A) single-nucleotide polymorphism (SNP) in the GCH1 gene is functional. Here we examine the association between rs3783641 and PHN. A total of 292 subjects including 103 PHN patients, 87 herpes zoster (HZ) patients and 102 healthy controls were enrolled in this study. The rs3783641 polymorphisms were detected via the high-resolution melting curve (HRM) method. There were statistical differences between PHN group and the other two groups in genotype distribution (P = 0.029 and 0.017, respectively) and allele frequency (P = 0.032 and 0.005, respectively) of rs3783641. The proportion of subjects with AA genotype in the PHN group was significantly lower compared to HZ group and control group (P = 0.026 and 0.016, respectively). The frequency of A allele was lower in the PHN group than in control group (P = 0.005), and the frequency of T allele in the PHN group was higher than in HZ group and control group (P = 0.001 and 0.003, respectively). The results of this study suggest that the rs3783641 SNP in the GCH1 gene is associated with PHN, and the AA genotype showed a protective effect in PHN.

Is acupuncture an effective postherpetic neuralgia treatment? A systematic review and meta-analysis

Background

Postherpetic neuralgia (PHN) refers to pain which remains after the healing of rashes from herpes zoster. Previous literatures have shown that acupuncture has potential benefits for PHN, but evidence remains lacking. Thus, we have performed a systematic review and meta-analysis to identify the effectiveness of acupuncture in the treatment of PHN.

Methods

Six databases were searched for randomized controlled trials (RCTs) to assess the effects of acupuncture on PHN. After selecting the studies, extracting the data, and assessing study quality, meta-analysis was performed on several of the studies with RevMan 5.3. The GRADE (Grading of Recommendations Assessment Development and Evaluation) system was used to assess the overall quality of the evidence.

Results

Acupuncture helps relieve pain intensity (standardized mean difference [SMD]: -1.78, 95% confidence interval [CI]: -2.36 to -1.21). For other intervention types, electroacupuncture (SMD: -1.28, 95% CI: -2.51 to -0.05), fire needle (SMD: -2.23, 95% CI: -2.62 to -1.84), bloodletting and cupping (SMD: -2.46, 95% CI: -2.95 to -1.97) have better effects on pain intensity relief. To date, no study has reported on the onset of pain relief time. The Hamilton Anxiety Scale score (SMD: -18.94, 95% CI: -37.37 to -0.52) was lower for the acupuncture group than for the control group. It was also found that acupuncture can improve quality of life (QOL) (SMD: 3.78, 95% CI: 2.50 to 5.06). The quality of evidence for acupuncture for PHN pain intensity was moderate according to the GRADE system.

Conclusion

Acupuncture may reduce pain intensity, relieve anxiety and improve quality of life in patients with PHN. Further randomized trials with larger sample sizes and of higher methodological quality are needed to confirm these results.

The efficacy of selective nerve root block for the long-term outcome of postherpetic neuralgia

Background

Several nerve blocks can reduce the incidence of postherpetic neuralgia (PHN) as well as relieve acute zoster-related pain, but the long-term outcome of PHN has not been clearly determined. This study investigated the efficacy of selective nerve root block (SNRB) for herpes zoster (HZ) on the long-term outcome of PHN.

Methods

We prospectively conducted an interview of patients who had undergone an SNRB for HZ from January 2006 to December 2016 to evaluate their long-term PHN status. The relationship between the time from HZ onset to the first SNRB and the long-term outcome of PHN was investigated.

Results

The data of 67 patients were collected. The patients were allocated to acute (SNRB ≤ 14 days, n = 16) or subacute (SNRB > 14 days, n = 51) groups. The proportions of cured patients were 62.5% and 25.5% in the acute and subacute groups (P = 0.007), respectively. In logistic regression, an SNRB >14 days was the significant predictor of PHN (adjusted odd ratio, 3.89; 95% confidence interval, 1.02-14.93; P = 0.047). Kaplan-Meier analysis revealed that time from the SNRB to the cure of PHN was significantly shorter in the acute group (2.4 ± 0.7 yr) than in the subacute group (5.0 ± 0.4 yr; P = 0.003).

Conclusions

An early SNRB during the acute stage of HZ (within 14 days) appears to decrease the incidence and shorten the duration of PHN, with a median of 5.0 years of follow-up.

Analysis of the Risk Factors for Postherpetic Neuralgia

Background: Postherpetic neuralgia is the most common complication of herpes zoster, affecting 30% of patients. It seriously affects the quality of life of patients and the curative effect of treatment is limited. So far, researchers do not fully understand the risk factors for postherpetic neuralgia and more research is needed. Objective: The aim of this paper was to investigate the risk factors for postherpetic neuralgia and provide reference for clinical diagnosis and treatment. Methods: A total of 202 inpatients with herpes zoster in the General Hospital of Tianjin Medical University were recruited as study subjects. According to the occurrence of postherpetic neuralgia, the patients were divided into the postherpetic neuralgia group and the nonpostherpetic neuralgia group. Data on age, gender, initial symptoms, clinical classification, involved nerves, pain grading, antiviral therapy, glucocorticoid use, and other clinical data of patients in the two groups were collected and statistically analyzed. Univariate and multivariate analysis methods were used to analyze the differences between the two groups and determine the influencing factors of postherpetic neuralgia. Results: The univariate statistical analysis of the factors influencing postherpetic neuralgia showed that the contribution of gender, initial symptoms, general clinical classification, use of glucocorticoid, and the interval from onset to antiviral therapy were not statistically significant, while the differences in age, specific clinical classification, involved nerves, severity of pain during the acute stage, and body side of skin lesion distribution were statistically significant. Multivariate logistic regression analysis showed that gender, use of glucocorticoid, interval from onset to antiviral therapy, involved nerves, and specific clinical classification showed no statistical significance. However, there were significant differences in age, body side of skin lesion distribution, general clinical classification, and degree of pain during the acute stage of the disease. Conclusion: Pain during the acute stage of herpes zoster, age greater than 70 years, and serious type of skin lesion are risk factors for postherpetic neuralgia (p < 0.05, OR >1).

Efficacy of gabapentin for the prevention of postherpetic neuralgia in patients with acute herpes zoster: A double blind, randomized controlled trial

BACKGROUND

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ). Previous trials have reported that gabapentin can relieve chronic neuropathic pain, but its effect on prevention of PHN is unclear.

OBJECTIVE

To assess the efficacy of a 5-week course of gabapentin on acute herpetic pain and on the prevention of PHN at 12 weeks in patients with acute HZ.

METHODS

This was a randomized, double blind, placebo-controlled trial conducted in 17 primary care health centers in Mallorca, Spain. All patients were older than 50 years, presented with HZ within 72 h of rash onset, and had moderate-severe pain (≥4 on a 10-point visual analogue scale [VAS]). Ninety-eight patients were randomized to receive gabapentin or placebo. All patients received valaciclovir for 7 days and analgesia if needed. The treatment period was 5 weeks, followed by 7 weeks of follow-up. Gabapentin was initiated at 300 mg/day and gradually titrated to a maximum of 1800 mg/day. The main outcome measure was pain at 12 weeks.

RESULTS

Seventy-five patients completed the study, 33 in the gabapentin group and 42 in the control group. A total of 18.2% of patients in the gabapentin group and 9.5% in the control group reported pain at 12 weeks (p = 0.144). Four patients in the gabapentin group (12.1%), but no patients in the placebo group, reported pain of 4 or more on a 10-point VAS. Patients taking gabapentin reported worse health-related quality of life and poorer sleep quality. Three patients discontinued the trial due to adverse effects from gabapentin.

CONCLUSION

Addition of gabapentin to the usual treatment of HZ within 72 h of rash onset provided no significant relief from acute herpetic pain or prevention of PHN.

TRIAL REGISTRATION

ISRCTN Registry identifier: ISRCTN79871784.

Systematic review and meta-analysis of genetic risk factors for neuropathic pain

Neuropathic pain (NP) is an increasingly common chronic pain state and a major health burden, affecting approximately 7% to 10% of the general population. Emerging evidence suggests that genetic factors could partially explain individual susceptibility to NP and the estimated heritability in twins is 37%. The aim of this study was to systematically review and summarize the studies in humans that have investigated the influence of genetic factors associated with NP. We conducted a comprehensive literature search and performed meta-analyses of all the potential genetic variants associated with NP. We reviewed 29 full-text articles and identified 28 genes that were significantly associated with NP, mainly involved in neurotransmission, immune response, and metabolism. Genetic variants in HLA genes, COMT, OPRM1, TNFA, IL6, and GCH1, were found to have an association with NP in more than one study. In the meta-analysis, polymorphisms in HLA-DRB1*13 (odds ratio [OR], 2.96; confidence interval [CI], 1.93-4.56), HLA-DRB1*04 (OR, 1.40; CI, 1.02-1.93), HLA-DQB1*03 (OR, 2.86; CI, 1.57-5.21), HLA-A*33 (OR, 2.32; CI, 1.42-3.80), and HLA-B*44 (OR, 3.17; CI, 2.22-4.55) were associated with significantly increased risk of developing NP, whereas HLA-A*02 (OR, 0.64; CI, 0.47-0.87) conferred reduced risk and neither rs1799971 in OPRM1 (OR, 0.55; CI, 0.27-1.11) nor rs4680 in COMT (OR, 0.95; CI, 0.81-1.13) were significantly associated with NP. These findings demonstrate an important and specific contribution of genetic factors to the risk of developing NP. However, large-scale replication studies are required to validate these candidate genes. Our review also highlights the need for genome-wide association studies with consistent case definition to elucidate the genetic architecture underpinning NP.

The effects of repetitive transcranial magnetic stimulation on the whole-brain functional network of postherpetic neuralgia patients

The effects of repetitive transcranial magnetic stimulation (rTMS), the clinical treatment for postherpetic neuralgia (PHN), on whole-brain functional network of PHN patients is not fully understood.To explore the effects of rTMS on the whole-brain functional network of PHN patients.10 PHN patients (male/female: 5/5 Age: 63-79 years old) who received rTMS treatment were recruited in this study. High-resolution T1-weighted and functional Magnetic Resonance Imaging (fMRI) were acquired before and after 10 consecutive rTMS sessions. The whole-brain functional connectivity networks were constructed by Pearson correlation. Global and node-level network parameters, which can reflect the topological organization of the brain network, were calculated to investigate the characteristics of whole-brain functional networks. Non-parametric paired signed rank tests were performed for the above network parameters with sex and age as covariates. P < .05 (with FDR correction for multi-comparison analysis) indicated a statistically significant difference. Correlation analysis was performed between the network parameters and clinical variables.The rTMS showed significant increase in characteristic path length and decrease of clustering coefficient, global, and local efficiency derived from the networks at some specific network sparsity, but it showed no significant difference for small-worldness. rTMS treatment showed significant differences in the brain regions related to sensory-motor, emotion, cognition, affection, and memory, as observed by changes in node degree, node betweenness, and node efficiency. Besides, node-level network parameters in some brain areas showed significant correlations with clinical variables including visual analog scales (VAS) and pain duration.rTMS has significant effects on the whole-brain functional network of PHN patients with a potential for suppression of sensory-motor function and improvement of emotion, cognition, affection, and memory functions.

Patient report of herpes zoster pain: Incremental benefits of zoster vaccine live

INTRODUCTION

Pain following herpes zoster (HZ) can persist for months and negatively impact quality of life. To evaluate the effect of zoster vaccine live (ZVL) on progression of pain following HZ, we conducted a prospective cohort study of HZ cases at Kaiser Permanente Southern California.

METHODS

ZVL vaccinated and unvaccinated members aged ≥60 years with laboratory-confirmed HZ from January 18, 2012 to February 26, 2015 were followed up within 5 days of HZ diagnosis, and at 30, 60, and 90 days after diagnosis. Pain was assessed with the Zoster Brief Pain Inventory (ZBPI) on a 0-10 scale, using cut-points of ≥3, ≥5, and ≥7, with postherpetic neuralgia (PHN) defined as pain ≥3 at 90 days. Log binomial regression was used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (CIs) associated with pain, comparing vaccinated versus unvaccinated HZ patients.

RESULTS

We interviewed 509 vaccinated and 509 unvaccinated HZ patients. ZVL was associated with significantly lower risks of HZ-related pain at all time-points. The risk of PHN in vaccinated and unvaccinated patients, respectively, was 9.2% and 15.4% (aRR = 0.594, 95% CI: 0.413, 0.854); 2.0% and 4.8% of these patients reported pain ≥7 (aRR = 0.332, 95% CI: 0.153, 0.721). Irrespective of vaccination, the risk of PHN was lower in adults aged <70 years versus those ≥70 years and was similar or lower in females versus males.

CONCLUSION

We used laboratory confirmation of HZ cases and patient survey to show that aside from preventing HZ, ZVL reduced HZ-related pain and prevented PHN among vaccine recipients who experienced HZ. Observational studies will be needed to evaluate long-term effectiveness of the new recombinant zoster vaccine and its benefits in protecting patients against PHN.