8. Herpes zoster and post herpetic neuralgia.

INTRODUCTION: Patients suffering from postherpetic neuralgia (PHN) report unilateral chronic pain in one or more dermatomes after an acute herpes zoster (HZ) infection. The incidence of acute HZ ranges between three and five patients per 1000 person-years. In one out of four patients, acute HZ-related pain will transition into PHN. PHN can be very disabling for patients and reduce quality of life. Additionally, the treatment of PHN is characterized by high failure rates. The aim of this review is to give an update on the previous practical guideline published in 2011 and revised in 2015 (published in 2019) and to provide an overview of current interventional treatment options for HZ infection and PHN. METHODS: The literature on the diagnosis and treatment of HZ and PHN was systematically reviewed and summarized. RESULTS: The most important treatment for acute HZ-related pain is antiviral therapy within 72 h of symptom onset. Additional symptomatic treatment options are analgesic drugs according to the WHO pain ladder, tricyclic antidepressants (eg, nortriptyline), and antiepileptic drugs (eg, gabapentin). If pain is not sufficiently reduced, interventional treatment such as an epidural injection with local anesthetics and corticosteroids or pulsed radiofrequency of the dorsal root ganglion (DRG) are options. Treatment for PHN is preferably transdermal capsaicin, lidocaine, or oral drugs such as antidepressants or antiepileptics. CONCLUSIONS: Treatment of acute HZ-related pain especially PHN is challenging. Besides the conventional treatment for PHN, interventional management is considered a new treatment option. PRF of DRG seems to be the most promising interventional management.

Causal links between blood inflammation markers and postherpetic neuralgia risk: insights from a two-sample Mendelian randomization study.

Introduction: Previous studies have suggested an association between blood inflammation-related factors and postherpetic neuralgia. However, the causal relationship between blood inflammation-related factors and postherpetic neuralgia remains unclear. Methods: We employed a bidirectional Two-sample Mendelian randomization (MR) analysis to explore the causal relationship between blood inflammation-related factors and postherpetic neuralgia. The instrumental variables were obtained from a large Genome-wide association study (GWAS) meta-analysis dataset of European descent. The instrumental variables of the blood inflammation-related factors come from the database numbers GCST004420 to GCST004460 and GCST90029070. Postherpetic neuralgia has 195,191 samples with a total of 16,380,406 single nucleotide polymorphisms (SNPs). MR analyses were performed using inverse-variance weighted, MR-Egger, and weighted median methods. Results: The MR results revealed a significant causal effect of Macrophage Inflammatory Protein 1 Beta (MIP1ß) on reducing the risk of postherpetic neuralgia (95%CI = 0.492-0.991, p = 0.044). Additionally, higher levels of interleukin (IL)-10 (95%CI = 0.973-0.998, p = 0.019) and IL-12p70 (95%CI = 0.973-0.997, p = 0.013) were associated with a lower risk of postherpetic neuralgia. Other inflammatory markers showed no significant causal relationship with this condition. Conclusion: This study identifies MIP1ß, IL-10, and IL-12p70 as potential therapeutic targets for preventing or treating postherpetic neuralgia, underscoring the need for further research in this area.

Maxillary herpes zoster with nasociliary nerve involvement and Klebsiella superinfection: A rare occurrence.

Herpes zoster is an acute cutaneous viral disease resulting from reactivation of dormant varicella-zoster virus. The maxillary nerve is the least frequently affected branch of the trigeminal nerve. Rarely, cutaneous lesions can be secondarily infected with Klebsiella species. This report discusses a case of maxillary zoster with nasociliary nerve involvement and Klebsiella superinfection.

Peripheral Nerve Stimulation for Neuropathic Pain Management: A Narrative Review.

This narrative review examines the therapeutic efficacy of peripheral nerve stimulation (PNS) in the treatment of neuropathic pain (NP), a type of pain arising from lesions or diseases of the somatosensory system with a global prevalence ranging from 6.90% to 10.00%. Traditional pharmacological interventions often fall short for many persons, highlighting the need for alternative treatments such as PNS, which has demonstrated significant promise with minimal side effects. The review summarizes the effectiveness of PNS in various NP conditions, including trigeminal neuralgia and postherpetic neuralgia, and underscores the need for further research to refine treatment approaches. The mechanism of PNS is discussed, involving the activation of non-nociceptive Aß fibers and modulation of neurotransmitters, and offering pain relief through both peripheral and central pathways. Despite the proven efficacy of PNS, challenges remain, including the need for randomized controlled trials and the optimization of stimulation parameters. The review concludes that PNS is a promising treatment modality for NP, warranting additional high-quality trials to solidify its role in clinical practice.

Comparison of the efficacy of pulsed radiofrequency in treating acute herpetic neuralgia and postherpetic neuralgia in the thoracic segment.

Objectives: This study aimed to compare the efficacy of pulsed radiofrequency (PRF) to dorsal root ganglia (DRG) in treating acute herpetic neuralgia (AHN) and postherpetic neuralgia (PHN) in the thoracic segment. Methods: A total of 243 patients with thoracic herpes zoster-related pain (AHN or PHN) from January 2020 to September 2022 were retrospectively analyzed. They were divided into two groups based on the timing of PRF after herpes zoster onset: an acute herpetic neuralgia group (within 90 days) and a postherpetic neuralgia group (more than 90 days). All patients were treated with PRF at the thoracic DRG. The Visual Analog Scale (VAS), the Athens Insomnia Scale (AIS), the Generalized Anxiety Disorder-7 items (GAD-7), and the Patient Health Questionnaire-9 items (PHQ-9) scores were assessed before and at 1 week, 1 month, 3 months, 6 months, and 12 months after surgery, and the results were then compared between the two groups. Results: Postoperative scores of VAS, AIS, GAD-7, and PHQ-9 in both groups were significantly lower than preoperative scores (P < 0.001). From 1 month to 12 months after surgery, the AHN group showed significantly lower VAS, AIS, GAD-7, and PHQ-9 scores compared to the PHN group (P < 0.001). In the AHN group, there was a gradual improvement in these scores from 1 week to 12 months post-surgery. Conversely, the PHN group's scores began to worsen slowly from 1 week to 12 months post-surgery. Over time, the difference in scores between the two groups also increased gradually. Conclusion: PRF to the DRG is an effective treatment for patients with AHN or PHN who do not respond well to conventional treatments. For AHN patients, PRF to the DRG significantly enhances early pain control, improves sleep and psychological status, and may even prevent the development of PHN.

Patient Experience of Herpes Zoster Disease in Argentina: Validation of a Health-Related Quality of Life Conceptual Model.

OBJECTIVES: Herpes zoster (HZ) substantially affects patients' health-related quality of life (HRQoL), both in the acute phase and also in those developing postherpetic neuralgia (PHN). Building upon a previous qualitative concept elicitation study in Canada, we adopted a similar approach to further understand the patient experience of HZ/PHN in Argentina and impact on quality of life and qualitatively validate the previously published conceptual model for Argentina. METHODS: (1) Comprehensive literature review of HZ impact on HRQoL in Latin America. (2) Qualitative concept elicitation interviews with participants aged ≥50 years with acute HZ or PHN. Verbatim interview transcripts underwent thematic and content analysis related to symptoms and impacts. RESULTS: Studies from the literature (n = 6) identified 5 dimensions of HZ impact on HRQoL: pain management, disease management, family life, work, and emotional impact. A total of 10 participants were interviewed (5 acute HZ and 5 with PHN) with a mean age of 68.5 years (range 50-77 years) and 60% female. All participants reported rash and pain (some reporting a migratory element), fatigue (7 of 10), and itchiness (4 of 10). HRQoL domains most commonly affected were activities of daily living (9 of 10), emotional functioning (8 of 10), physical functioning (8 of 10), and sleep (7 of 10). Emergent themes on disease management included the need for greater public disease awareness/education, participants with PHN seeking alternative/traditional medical therapies. CONCLUSIONS: This study qualitatively validates the previously reported HRQoL conceptual framework. HZ symptoms, especially acute and chronic pain, substantially impair various aspects of HRQoL, prompting some participants to seek out alternative medical treatments.

Assessment of ultrasound-guided intercostal nerve block for acute herpes zoster and its' possible prophylaxis for postherpetic neuralgia: a retrospective and case-controlled trial.

Background: This study aimed to compare the intercostal nerve block (ICNB) and thoracic paravertebral block (TPVB) for acute herpes zoster-associated pain (ZAP) and possible prophylaxis for post-herpetic neuralgia (PHN). Methods: This study enrolled 128 patients with ZAP. Their records were stratified into standard antiviral treatment (AVT) plus US-guided TPVB (the TPVB group), AVT plus US-guided ICNB (the ICNB group) or AVT alone (the control group). Herpes zoster (HZ)-related burden of illness (HZ-BOI) within the post-procedural 30 days was defined as the primary endpoint, determined by a composite of pain severity and follow-up duration. Procedure time, rescue analgesic requirement, PHN incidence, health-related quality of life and side effects were also recorded. Results: Significantly lower HZ-BOI-AUC30 was reported in the TPVB and ICNB groups as compared to the control group, with a mean difference of 57.5 (P < 0.001) and 40.3 (P = 0.003), respectively. However, there was no difference between the TPVB and ICNB groups (P = 0.978). Both TPVB and ICNB reported significantly greater improvements in PHN incidence, EQ-5D-3L scores and rescue analgesic requirements during follow-up, as opposed to the control AVT. Shorter procedure time was observed in ICNB as compared to TPVB (16.47 ± 3.39 vs. 11.69 ± 2.58, P < 0.001). Conclusions: Both US-guided TPVBs and ICNBs were effective for ZAP, and accounted for possible prophylaxis for PHN, as compared to AVT alone. The ICNB approach could be recommended as an alternative to conventional TPVB with a better consumed procedure time and side effect profile.a.

Natural Language Processing Versus Diagnosis Code-Based Methods for Postherpetic Neuralgia Identification: Algorithm Development and Validation.

Background: Diagnosis codes and prescription data are used in algorithms to identify postherpetic neuralgia (PHN), a debilitating complication of herpes zoster (HZ). Because of the questionable accuracy of codes and prescription data, manual chart review is sometimes used to identify PHN in electronic health records (EHRs), which can be costly and time-consuming. Objective: This study aims to develop and validate a natural language processing (NLP) algorithm for automatically identifying PHN from unstructured EHR data and to compare its performance with that of code-based methods. Methods: This retrospective study used EHR data from Kaiser Permanente Southern California, a large integrated health care system that serves over 4.8 million members. The source population included members aged ≥50 years who received an incident HZ diagnosis and accompanying antiviral prescription between 2018 and 2020 and had ≥1 encounter within 90-180 days of the incident HZ diagnosis. The study team manually reviewed the EHR and identified PHN cases. For NLP development and validation, 500 and 800 random samples from the source population were selected, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), F-score, and Matthews correlation coefficient (MCC) of NLP and the code-based methods were evaluated using chart-reviewed results as the reference standard. Results: The NLP algorithm identified PHN cases with a 90.9% sensitivity, 98.5% specificity, 82% PPV, and 99.3% NPV. The composite scores of the NLP algorithm were 0.89 (F-score) and 0.85 (MCC). The prevalences of PHN in the validation data were 6.9% (reference standard), 7.6% (NLP), and 5.4%-13.1% (code-based). The code-based methods achieved a 52.7%-61.8% sensitivity, 89.8%-98.4% specificity, 27.6%-72.1% PPV, and 96.3%-97.1% NPV. The F-scores and MCCs ranged between 0.45 and 0.59 and between 0.32 and 0.61, respectively. Conclusions: The automated NLP-based approach identified PHN cases from the EHR with good accuracy. This method could be useful in population-based PHN research.

Altered Effective Connectivity of the Pain Matrix in Herpes Zoster and Postherpetic Neuralgia Patients: Granger Causality Analysis of Resting-State fMRI.

BACKGROUND: Shingles can cause long-term pain and negative emotions, along with changes in brain function. In this study, Granger Causality Analysis (GCA) was used to compare herpes zoster (HZ) and postherpetic neuralgia (PHN) differences in effective connections within the "pain matrix" between patients and healthy controls to further understand patterns of interaction between brain regions and explore the relationship between changes in effective connections and clinical features. METHODS: Resting-state functional magnetic resonance imaging (fMRI) scans were performed on 55 HZ; 55 PHN; and 50 age-, sex- matched healthy controls (HCs). The brain regions associated with the pain matrix are used as the seeds of effective connectivity. GCA was used to analyze effective connections in brain regions that differed significantly between groups. Then the correlation between GCA values and clinical indicators was studied. RESULTS: Compared with HC, GCA values between the thalamus and the amygdala, between the thalamus and the precentral gyrus, from the thalamus to the postcentral gyrus, and from the parahippocampal gyrus to the amygdala, anterior cingulate gyrus were significantly reduced in HZ patients. Compared with HC, GCA values between the insular and the postcentral gyrus, from the insular to the inferior parietal lobe, and from the postcentral gyrus to the amygdala were significantly reduced in PHN patients. Compared with HZ, GCA values between the inferior parietal lobe and the parahippocampal gyrus, between the inferior parietal lobe and the anterior cingulate gyrus, and from the anterior cingulate gyrus to the amygdala were significantly increased in PHN patients. The visual analogue scale (VAS) score of PHN patients was positively correlated with the GCA value from the central posterior lobe to the insula. CONCLUSIONS: PHN and HZ patients showed a broad reduction in effective connections, mainly reflected in abnormal pain pathway regulation, pain perception, negative emotion and memory production, providing new perspectives to understand the neuroimaging mechanisms of shingles.

[Pricking-cupping combined with auricular thumbtack needle for postherpetic neuralgia of qi stagnation and blood stasis on chest and waist: a randomized controlled trial].

OBJECTIVE: To observe the clinical effect of pricking-cupping combined with auricular thumbtack needle for postherpetic neuralgia (PHN) of qi stagnation and blood stasis on chest and waist. METHODS: A total of 98 patients with PHN of qi stagnation and blood stasis on chest and waist were randomized into an observation group (49 cases, 1 case was eliminated, 1 case dropped out) and a control group (49 cases, 1 case dropped out). In the observation group, treatment of pricking-cupping combined with auricular thumbtack needle was delivered, pricking and cupping were applied at Jiaji points (EX-B 2) at the related spinal segments corresponding to the pain sites and regional ashi points, once every other day, auricular thumbtack needle was applied at Xin (CO15), Shenmen (TF4), Neifenmi (CO18), Pizhixia (AT4), etc., once every 3 days. In the control group, pregabalin capsule was taken orally, 75 mg a time, twice a day. The treatment of 4 weeks was required in the two groups. Before and after treatment, the scores of TCM symptom, visual analogue scale (VAS), Pittsburgh sleep quality index (PSQI), self-rating depression scale (SDS) and self-rating anxiety scale (SAS) were observed, the serum levels of immunoglobulin G (IgG), interleukin-6 (IL-6), C-reactive protein (CRP) were detected, and the clinical efficacy and safety were evaluated in the two groups. RESULTS: After treatment, the item scores and total scores of TCM symptom, as well as the scores of VAS, PSQI, SDS and SAS were decreased compared with those before treatment (P<0.05); the item scores of pruritus degree, tactile sensitivity, skin numbness and total score of TCM symptom, as well as the scores of VAS, PSQI, SDS and SAS in the observation group were lower than those in the control group (P<0.05). After treatment, the serum levels of IgG were increased (P<0.05), while the serum levels of IL-6 and CRP were decreased (P<0.05) compared with those before treatment in the two groups; in the observation group, the serum level of IgG was higher (P<0.05), while the serum levels of IL-6 and CRP were lower (P<0.05) than those in the control group. The total effective rate was 95.7% (45/47) in the observation group, which was superior to 77.1% (37/48) in the control group (P<0.05). The incidence rate of adverse reaction was 6.4% (3/47) in the observation group, which was lower than 12.5% (6/48) in the control group (P<0.05). CONCLUSION: Pricking-cupping combined with auricular thumbtack needle can effectively relieve the clinical symptoms in patients with PHN of qi stagnation and blood stasis on chest and waist, reduce the pigmentation of herpes and improve itch or burning, numb sensations in the skin lesions, improve the sleep quality and relieve anxiety and depression.

Disrupted Balance of Short- and Long-Range Functional Connectivity Density in Patients with Herpes Zoster or Postherpetic Neuralgia: A Resting-State fMRI Study.

Purpose: This study aimed to explore the abnormal changes in short- and long-range functional connectivity density (FCD) in patients with herpes zoster (HZ) and postherpetic neuralgia (PHN). Patients and Methods: Twenty HZ patients, 22 PHN patients, and 19 well-matched healthy controls (HCs) underwent resting-state functional magnetic resonance imaging scans. We used FCD mapping, a data-driven graph theory method, to investigate local and global functional connectivity patterns. Both short- and long-range FCD were calculated and compared among the PHN, HZ, and HC groups. Then, the abnormal regions were used to calculate seed-based functional connectivity. Finally, correlation analyses were performed between the altered FCD values and clinical datas. Results: Compared with HCs, HZ patients showed significantly increased long-range FCD of the bilateral cerebellum, thalamus, parahippocampal gyrus, superior temporal gyrus and lingual gyrus. HZ patients also displayed significantly decreased short-range FCD of the bilateral posterior cingulate gyrus, median cingulate/paracingulate gyri, and left precuneus. Compared with HCs, PHN patients displayed significantly decreased long-range FCD of the bilateral superior frontal gyrus and decreased short-range FCD in the bilateral posterior cingulate gyrus, median cingulate/paracingulate gyri, and precuneus. However, there was no significant difference in either long-range or short-range FCD between the PHN and HZ patients. Long-range FCD deficit areas and the right insula showed altered functional connectivity in PHN patients. Furthermore, pain duration in patients with PHN was correlated with abnormal long-range FCD. Conclusion: Herpes zoster pain widely affects intra- and inter-regional functional connectivity, leading to disrupted short-range FCD and increased long-range FCD during different stages of the disease. Long-term chronic pain in PHN patients may impair the pain emotion regulation pathway. These findings could improve our understanding of the pathophysiological mechanisms of HZ and PHN and offer neuroimaging markers for HZ and PHN.

Exploring blood transcriptomic signatures in patients with herpes zoster and postherpetic neuralgia.

Postherpetic neuralgia (PHN) is a common, severe, and hard-to-treat chronic pain condition in clinics. Although PHN is developed from herpes zoster (HZ), the developing mechanism is unknown. A previous study investigated blood metabolomic and proteomic profiling in patients with PHN and HZ. The current study aims to explore the blood transcriptomic signature of PHN compared to HZ patients. Whole blood from eight PHN and 15 HZ patients was used for RNA-Seq analysis. There were 82 and 1,788 genes detected specifically in the PHN and HZ groups, respectively. PHN-specific genes are involved in viral infection, lipid and carbohydrate metabolism, and immune response. For genes coexpressed in PHN and HZ patients, there were 407 differential expression genes (DEGs), including 205 upregulated (UP DEGs) and 202 downregulated (DOWN DEGs) in PHN compared to HZ groups. DEGs are involved in viral infection, type I interferon (IFN), and hemoglobin and oxygen carrier activity. UP DEGs are associated with regulatory T cells (Tregs), activated NK cells, and neutrophils, while DOWN DEGs are associated with Tregs, resting NK cells, and monocytes. The results suggest that the metabolism of lipid, glycan, and nucleotides, type I IFN signaling, and altered neutrophil activation are associated with and might contribute to the development of PHN in HZ. It is also suggested that persistent or altered activation of nonspecific immunity may contribute to the development of PHN from HZ.

Efficacy of Botulinum Type A Injection for the Treatment of Postherpetic Neuralgia and Pruritus Persisting for More Than Four Years-A Case Report.

Background: Postherpetic neuralgia (PHN) and postherpetic pruritus (PHP) are common complications of shingles that affect patients' quality of life. PHN and PHP can be managed using various medications and interventional procedures; however, complications persisting for at least six months may hamper recovery. Subcutaneous injections of botulinum toxin type A (BTX-A) can control persistent PHN and PHP. Case presentation: A 71-year-old man presented at our hospital with itching and pain. He had been diagnosed with shingles in the ophthalmic branch of the trigeminal nerve one year previously. As the pain and itching persisted despite medication, a supraorbital nerve block, Gasserian ganglion block, epidural nerve block, and radiofrequency thermocoagulation were performed. A subcutaneous injection of BTX-A was administered into the ophthalmic area of the trigeminal nerve three years after the initial presentation. A decrease of >80% in pain and itching was reported after the injection; however, the left eyelid drooped and the eyeball shifted downward and outward immediately after the injection. No deterioration in vision or pupil dilation was observed, and almost complete resolution of these symptoms occurred spontaneously three months after the injection. Pain and itching continued to improve without further side-effects until six months after the injection. Conclusions: The subcutaneous injection of BTX-A may be an alternative treatment option for chronic and refractory neurological diseases such as PHN and PHP, which persist for four years and are resistant to conventional treatments. Nevertheless, care must be taken to minimize the risk of ptosis.

Identifying and Evaluating Biological Markers of Postherpetic Neuralgia: A Comprehensive Review.

Postherpetic neuralgia (PHN) manifests as persistent chronic pain that emerges after a herpes zoster outbreak and greatly diminishes quality of life. Unfortunately, its treatment efficacy has remained elusive, with many therapeutic efforts yielding less than satisfactory results. The research to discern risk factors predicting the onset, trajectory, and prognosis of PHN has been extensive. However, these risk factors often present as nonspecific and diverse, indicating the need for more reliable, measurable, and objective detection methods. The exploration of potential biological markers, including hematological indices, pathological insights, and supportive tests, is increasing. This review highlights potential biomarkers that are instrumental for the diagnosis, management, and prognosis of PHN while also delving deeper into its genesis. Drawing from prior research, aspects such as immune responsiveness, neuronal injury, genetic makeup, cellular metabolism, and pain signal modulation have emerged as prospective biomarkers. The immune spectrum spans various cell subtypes, with an emphasis on T cells, interferons, interleukins, and other related cytokines. Studies on nerve injury are directed toward pain-related proteins and the density and health of epidermal nerve fibers. On the genetic and metabolic fronts, the focus lies in the detection of predisposition genes, atypical protein manifestations, and energy-processing dynamics, with a keen interest in vitamin metabolism. Tools such as functional magnetic resonance imaging, electromyography, and infrared imaging have come to the forefront in the pain signaling domain. This review compiles the evidence, potential clinical implications, and challenges associated with these promising biomarkers, paving the way for innovative strategies for predicting, diagnosing, and addressing PHN.

Intravenous patient-controlled analgesia with esketamine improves early depressive symptoms in patients with postherpetic neuralgia: a single-center retrospective cohort study.

OBJECTIVE: Patients with Postherpetic Neuralgia (PHN) often exhibit depressive-like symptoms, significantly impacting their quality of life. Esketamine, known for its analgesic properties, has also been recognized for its rapid antidepressant effects. However, its efficacy in the treatment of PHN requires further exploration. This study aims to evaluate the impact of intravenous patient-controlled analgesia(PICA) with esketamine on depressive mood in PHN patients. METHODS: This retrospective study analyzed PHN patients hospitalized and treated at the affiliated hospital of Southwest Medical University from June 2021 to March 2023. Patients were divided into the esketamine group (E group) and the sufentanil group (S group) based on their treatment regimens. Primary outcomes included pain numerical rating scale(NRS), depression patient health questionaire-9(PHQ-9), and anxiety generalized anxiety disorder-7(GAD-7) scores measured before treatment, and at 3 days, 7 days, 1 month, 2 months, and 3 months post-treatment. RESULTS: A total of 83 patients were included in the analysis. Before treatment, there were no statistically significant differences in pain NRS, depression PHQ-9, and anxiety GAD-7 scores between the two groups (P > 0.05). Compared to before treatment, significant reductions in pain NRS scores were observed at all post-treatment time points in both groups (P < 0.05), with no differences between groups (P > 0.05). The E group exhibited significantly lower depression PHQ-9 scores than the S group at 3 days and 7 days post-treatment (P < 0.05), but no significant differences were observed at 1 month, 2 months, and 3 months (P > 0.05). Anxiety GAD-7 scores were significantly lower in the E group compared to the S group at 3 days, 7 days post-treatment (P < 0.05), with no statistical differences at 1 month, 2 months, and 3 months post-treatment (P > 0.05). CONCLUSION: Both PICA with esketamine and sufentanil alleviated pain equally in PHN patients. However, PICA with esketamine specifically improved early symptoms of anxiety and depression.

Peripheral and central pathogenesis of postherpetic neuralgia.

BACKGROUND: Postherpetic neuralgia (PHN) is a classic chronic condition with multiple signs of peripheral and central neuropathy. Unfortunately, the pathogenesis of PHN is not well defined, limiting clinical treatment and disease management. OBJECTIVE: To describe the peripheral and central pathological axes of PHN, including peripheral nerve injury, inflammation induction, central nervous system sensitization, and brain functional and structural network activity. METHODS: A bibliographic survey was carried out, selecting relevant articles that evaluated the characterization of the pathogenesis of PHN, including peripheral and central pathological axes. RESULTS: Currently, due to the complexity of the pathophysiological mechanisms of PHN and the incomplete understanding of the exact mechanism of neuralgia. CONCLUSION: It is essential to conduct in-depth research to clarify the origins of PHN pathogenesis and explore effective and comprehensive therapies for PHN.

Analysis of factors selectively related to herpes zoster involving peripheral sensory ganglia: Retrospective study.

Herpes zoster (HZ), resulting from the reactivation of the varicella-zoster virus, is a significant disease. This study aimed to explore the factors influencing sensory neuron involvement in HZ at different locations and its association with postherpetic neuralgia (PHN). A total of 3143 cases were retrieved from an electronic medical record system, including 2676 cases of HZ and 467 cases of PHN. Gender, age, site of onset, past surgical history, and comorbidities were analyzed using a multifactorial logistic regression model. The results revealed correlations between age, gender, comorbidities (diabetes, coronary heart disease, percutaneous coronary intervention [PCI]), and sensory neuron involvement in HZ. Specifically, older age, female gender, and comorbid conditions such as diabetes/coronary heart disease were associated with sacral dorsal root ganglion (DRG) involvement, while PCI history was associated with lumbar DRG involvement. Additionally, sensory neuron involvement at different locations by HZ was linked to PHN. Furthermore, independent risk factors for PHN included thoracic DRG involvement, older age, and comorbidities (diabetes, surgical history, malignancy). It is crucial to prevent damage to the DRG, especially in individuals with comorbidities, through activities avoidance and active treatment, to minimize the occurrence of PHN.

Therapeutic effect of computed tomography-guided dorsal root ganglion pulsed radiofrequency regulation combined with platelet-rich plasma injection on postherpetic neuralgia: A retrospective study.

INTRODUCTION: Postherpetic neuralgia (PHN) is one of the common refractory neuropathic pains. Oral drug treatment has great side effects and poor efficacy. To study the efficacy of computed tomography (CT)-guided pulsed radiofrequency (PRF) targeting dorsal root ganglion (DRG) and platelet-rich plasma (PRP), this retrospective observation was performed. MATERIAL AND METHODS: All patients with PHN were divided into the control group, PRF group, and PRF + PRP group based on their different treatment methods. The control group (45 cases) received drug treatment, the PRF group (45 cases) received CT-guided PRF treatment targeted to DRG, and the PRF + PRP group received PRF and PRP treatment. The changes of the numeric rating scale (NRS), Pittsburgh sleep quality index (PSQI) levels, and short form 36 health survey questionnaire (SF-36) before treatment and 7 days, 14 days, 30 days, and 90 days after treatment were compared among three groups. RESULTS: NRS and PSQI scores in the PRF + PRP group were lower than those in the PRF group and control group at 90 days after treatment ( p < 0.001). At 90 days after the operation, the scores of SF-36 in the PRF + PRP group were obviously elevated compared with the data of the control group and PRF group ( p < 0.001). CONCLUSIONS: The pain degree, quality of sleep of patients, and quality of life with PHN were significantly improved after PRF combined with PRP treatments.

Neuromodulation for postherpetic neuralgia: Preliminary experience in a single center.

BACKGROUND: Postherpetic neuralgia (PHN) after herpes zoster is a debilitating complication that severely affects the quality of life of patients. Neuromodulation such as spinal cord stimulation (SCS) and trigeminal semilunar ganglion stimulation (TSGS) have become effective methods for treating postherpetic neuralgia. METHODS: A retrospective analysis of clinical data from 30 patients with postherpetic neuralgia who underwent SCS or TSGS treatment from January 2022 to January 2024. Patients received conventional treatment before neuromodulation. Clinical data including patient age, gender, pain characteristics, treatment outcomes were collected. The efficacy was evaluated using the Visual Analog Scale (VAS) and the Modified Global Impression of Change scale. Optimal stimulation parameters were also analyzed. RESULTS: The results showed that postoperative pain was significantly reduced in both SCS and TSGS groups, with a higher satisfaction rate in the SCS group (89 % vs. 77 %). The optimal stimulation parameters for the two treatments were also different. Compared to SCS, TSGS required a higher frequency but lower pulse width and voltage. CONCLUSION: This study suggests that neuromodulation may be an effective treatment for PHN, but the subtle differences between SCS and TSGS support a more personalized treatment approach.

Genetics of causal relationships between circulating inflammatory proteins and postherpetic neuralgia: a bidirectional Mendelian randomization study.

Objective: According to data from several observational studies, there is a strong association between circulating inflammatory cytokines and postherpetic neuralgia (PHN), but it is not clear whether this association is causal or confounding; therefore, the main aim of the present study was to analyze whether circulating inflammatory proteins have a bidirectional relationship with PHN at the genetic inheritance level using a Mendelian randomization (MR) study. Methods: The Genome-Wide Association Study (GWAS) database was used for our analysis. We gathered data on inflammation-related genetic variation from three GWASs of human cytokines. These proteins included 91 circulating inflammatory proteins, tumor necrosis factor-alpha (TNF-α), macrophage inflammatory protein 1b (MIP-1b), and CXC chemokine 13 (CXCL13). The PHN dataset was obtained from the FinnGen biobank analysis round 5, and consisted of 1,413 cases and 275,212 controls. We conducted a two-sample bidirectional MR study using the TwoSampleMR and MRPRESSO R packages (version R.4.3.1). Our main analytical method was inverse variance weighting (IVW), and we performed sensitivity analyses to assess heterogeneity and pleiotropy, as well as the potential influence of individual SNPs, to validate our findings. Results: According to our forward analysis, five circulating inflammatory proteins were causally associated with the development of PHN: interleukin (IL)-18 was positively associated with PHN, and IL-13, fibroblast growth factor 19 (FGF-19), MIP-1b, and stem cell growth factor (SCF) showed reverse causality with PHN. Conversely, we found that PHN was closely associated with 12 inflammatory cytokines, but no significant correlation was found among the other inflammatory factors. Among them, only IL-18 had a bidirectional causal relationship with PHN. Conclusion: Our research advances the current understanding of the role of certain inflammatory biomarker pathways in the development of PHN. Additional verification is required to evaluate the viability of these proteins as targeted inflammatory factors for PHN-based treatments.