Herpetic Pain Research Articles

Radiofrequency regulation of the sphenopalatine ganglion in managing herpes zoster ophthalmicus neuralgia: A case series.

Trigeminal herpes zoster, which comprises 10% to 20% of cases of herpes zoster, often leads to severe pain in the ophthalmic branches. Current treatments, including drug therapy and minimally invasive interventions, have limitations; accordingly, there is a need to explore alternative approaches. This study aimed to evaluate the efficacy and safety of computerized tomography (CT)-guided pulsed radiofrequency of the sphenopalatine ganglion in patients with intractable trigeminal herpetic pain. Three patients with intractable trigeminal ophthalmic zoster neuralgia were studied. All patients complained of bursts of headache, which occurred at least 10 times a day, usually in the periorbital and frontal regions. Conventional treatments, including oral medications and radiofrequency therapy targeting the trigeminal-semilunar ganglion and supraorbital nerve, could not sufficiently provide relief. Two patients were diagnosed with herpes zoster in the ocular branch of the trigeminal nerve with conjunctivitis, while one patient was diagnosed with postherpetic neuralgia in the ocular branch of the trigeminal nerve. This study employed a novel approach that involved CT-guided radiofrequency regulation of the pterygopalatine fossa sphenopalatine ganglion. In all three patients, pain relief was achieved within 1 to 3 days after treatment. During the follow-up, one patient had pain recurrence; however, its severity was ≈ 40% lower than the pretreatment pain severity. The second patient had sustained and effective pain relief. However, the pain of the third patient worsened again after 2 months. The average follow-up duration was 3 months. None of the enrolled patients showed treatment-related adverse reactions or complications. Our findings indicated that CT-guided radiofrequency regulation of the pterygopalatine fossa sphenopalatine ganglion was a safe and effective intervention for pain in patients with trigeminal ophthalmic zoster neuralgia, suggesting that it may be a therapeutic option if other treatments fail.

Devising of Lazūq (A Conventional Unani Dosage Form) with reference to Transdermal Patch; Then and Now: A Critical Review

Objective: The endeavor is made to criticize the classical indications, preparations and application of Lazūq even after passing many centuries since its inception. Background: According to classical Unani literature, Lazūq is primarily formulated for headache, migraine, toothache, cervical pain, dropping of uvula and different types of pain like sciatica, backache, myalgia and some orthopedic conditions. Its approach is still conventional that encompasses thick sticky stuff of drug/s which is pasted over a cloth or thick paper, consequently, maximum ratio of medicinal properties remains insignificant owed to stratum corneum (layer of skin that functions as a barrier). Devising and method of drug delivery in classical form of Lazūq makes it inconvenient to the patient, thus, it drops patient’s compliance and anticipated efficacy. In this day and age, Unani practitioners do not prescribe it very often because of its devising and limited indications documented in classical literature. Hence, it’s now becoming out of practice. Whereas, modern medicine is practicing its novel approach epitomized as Transdermal patch for several bodily conditions like Acute post-operative pain, Alzheimer disease, Angina pectoris, Anti-emetic patch, Atrial fibrillation, Attention deficit hyperactivity disorder, Dementia, Depression, Dysmenorrhea, Hypertension, Local dermal analgesia, Menopausal symptoms, Motion sickness, Osteoporosis, Overactive bladder, Parkinson’s disease, Post herpetic neuralgia pain, Smoking cessation, Tic disorder, Tourette syndrome and to prevent pregnancy. In transdermal patch, drug is used in micro/nano form with chemically produced permeation enhancers (CPEs) and other smart physio-chemical techniques that makes it very easy to apply, imparts maximum active pharmaceutical ingredients with controlled release of drug. Methodology: Ancient classical Unani formulations of Lazūq was appraised and then its course with respect to today’s newer formulations as transdermal patch was reviewed to look for its progress and application in novel dosage form with the advantage of innovations in pharmaceutical and allied sciences. Conclusion: Classical Unani formulations of Lazūq must be reviewed, transformed, evaluated, coped and applied as per the standard operating procedures (SOPs) of transdermal drug delivery system. Future Prospects: New formulations of Lazūq should be designed and appraised from the medicinal treasure of Unani system of medicine for different therapeutic conditions.

Erector spinae plane block (ESPB) for intractable, non-surgical abdominal pain: a scoping review.

Abdominal pain is one of the most common presenting chief complaints in the emergency department (ED). Erector spinae plane block (ESPB) is an ultrasound-guided nerve block with proven effectiveness in treating visceral and somatic abdominal pain. Despite the increasing popularity of ESPB, its role in the management of non-surgical abdominal pain has not yet been characterized. Our scoping review aims to review the current literature on the safety and efficacy of ESPB in the management of patients experiencing intractable, non-surgical abdominal pain. We searched PubMed and Scopus to evaluate the existing literature on ESPB for non-surgical abdominal pain. Reviewers screened 30 titles and abstracts that met the predefined inclusion and exclusion criteria. Following initial screening, 24 articles underwent full-text review. Two reviewers also screened references included in each study. A total of 14 journal articles were reviewed, including 12 case-based studies, one systematic review, and one narrative review of ESPB in the treatment of non-surgical abdominal pain. All cases described the successful use of ESPB in treating abdominal pain refractory to oral or intravenous analgesic medications, and each case reported no complications. This scoping review provides support for ESPB in the management of intractable, non-surgical abdominal pain. ESPB demonstrates efficacy in alleviating various conditions such as functional abdominal pain, renal colic, pancreatitis, herpetic pain, and cancer-related pain. Theoretical risks such as pneumothorax, bleeding, and infection are possible, although the studies reviewed did not report such complications.

Efficacy and Safety of Electroacupuncture for Pain Control in Herpes Zoster: A Systematic Review and Meta-Analysis

Introduction Herpes zoster is caused by the reactivation of the latent varicella-zoster virus, which leads to acute pain that may disturb routine activities and affect patients' quality of life. Electroacupuncture (EA) has been commonly used for treating herpetic pain in clinical treatment. However, no relevant studies have been performed to evaluate the efficacy and safety of EA for acute control in herpetic neuralgia patients. The purpose of the current study was to conduct a systematic review and meta-analysis to address the deficiencies of the current research. Methods Three English (PubMed, Cochrane Library, and Web of Science) and four Chinese (China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature database (CBM), Wan-fang database, and the Chinese Scientific Journals Full-text Database (VIP)) were comprehensively searched from inception to 31 December 2021. Two independent reviewers evaluated the retrieved data based on the eligibility criteria in advance. In addition, the Cochrane Risk of Bias Tool was used to assess the methodological quality of the included studies. Outcome indexes in this study included the visual analog scale, the time to cessation of pustules, the time to scabs, the time to rash healing, adverse reactions, and the incidence of postherpetic neuralgia. Sensitivity and subgroup analyses were also performed to evaluate the intervention effect specifically. In addition, publication bias was analyzed. Results Six randomized controlled trials (167 participants in the experimental groups and 174 participants in the control groups) were identified as reporting the application of EA for acute herpes zoster pain and were included in this study. The results from our meta-analysis revealed that EA was superior to control treatment according to visual analog scale, the time of rash healing, and the incidence of postherpetic neuralgia. However, in terms of the time to cessation of pustules, scabs, and adverse reactions, the results showed that EA compared with the control group showed no significant difference. In addition, subgroup analyses indicated that 2/100 Hz-EA has more significant effects on herpetic pain. Sensitivity analyses revealed that the results of EA for acute pain control and the rash healing time in herpetic neuralgia patients were stable. However, a publication bias was observed. Conclusion Our meta-analysis results showed that EA could offer certain advantages in treating acute pain in herpetic neuralgia patients. However, small sample sizes, heterogeneity in study design, and variable methodological quality weaken these inferences. In addition, weak evidence was found for the safety of EA.

Effect of Repeated Paravertebral Injections with Local Anesthetics and Steroids on Prevention of Post-herpetic Neuralgia

Background The usefulness of early sympathetic blockade in the prevention of postherpetic neuralgia (PHN) has been reported. However, the optimal duration and frequency of paravertebral blocks that prevent or maximally reduce the incidence of PHN need to be clarified. Objectives To assess the impact of weekly separated 2 versus 3 paravertebral injections using local anesthetic and steroids, early in the course of acute thoracic herpes zoster, on the incidence of postherpetic neuralgia. Study design Randomized single-blind study. Setting University hospitals. Methods Eighty patients suffering from acute thoracic herpes zoster eruption were randomly allocated into 2 groups. Group I received paravertebral block using 25 mg bupivacaine plus 8 mg dexamethasone in a total volume of 10 mL twice one week apart. Group II received paravertebral block using 25 mg bupivacaine plus 8 mg dexamethasone in a total volume of 10 mL 3 times one week apart. All patients received daily 300 mg pregabalin in divided doses (150 mg/12 hours). Pain scores were evaluated during each visit. Once the patient reported mild pain, the trial for reducing the pregabalin dose was done. Acetaminophen was available as a rescue analgesia. At each assessment visit, the total analgesic consumption was recorded. The times of the complete resolution of the pain and the skin eruption were recorded. The incidence of PHN after 3, 6, and 12 months was also reported. Results Pre-eruptive pain severity and duration were comparable between both groups. There was no statistically significant difference between both groups with respect to the day of the block, the total duration of pain until the first block, and eruptive and herpetic pain duration parameters. The severity of skin lesions was comparable among both groups. Four patients (10.5%) had PHN in group I versus 3 patients (8.1%) in group II after 3 months of follow-up. Meanwhile, these numbers were 3 patients (7.9%) and 2 patients (5.4%) at 6 and 12 months in both groups, respectively. Compared with basal parameters, effective pain control was noticed in both groups with no significant difference between groups. Limitations Small size, lack of complete blindness, and the use of fluoroscopy in block performance in the era of performing this block under ultrasound. Conclusions Repeated paravertebral blocks using local anesthetic and steroids weekly over 2 or 3 weeks in the management of acute thoracic herpes zoster can provide safe and effective pain relief and minimize the incidence of PHN. However, no added benefit was detected from repeated blocks more than twice.

γ-Aminobutyric Acid and Derivatives Reduce the Incidence of Acute Pain after Herpes Zoster - A Systematic Review and Meta-analysis.

Herpes zoster (HZ) causes considerable pain and distress, and γ-Aminobutyric acid (GABA) and its derivatives are assumed to control this, but the available data are inconsistent. This meta-analysis and systematic review aimed to assess the effectiveness of GABA derivatives in the prevention of acute herpetic pain. The meta-analysis was conducted following the PRISMA guidelines using PICO format, registered in PROSPERO number CRD42018095758. PubMed, Web of Science, Ovid, Scopus, and EMBASE databases were searched. Records were included if they were randomized controlled trials of patients undergoing HZ infection, investigating the effect of GABA derivatives versus placebo in the treatment of HZ pain. Eligible trials were evaluated for the risk of bias. Then data were extracted and analysed. The number of patients with observed presence of pain after treatment was used to calculate odds ratio in a random effect model with the DerSimonian-Laird estimator. The I2 statistic was analysed for heterogeneity. The potential risk of bias was measured using Egger’s regression test. The meta-analysis included three randomized controlled trials with a total of 297 patients. The incidence of acute HZ pain events for GABA group was significantly lower compared to placebo group,18/148 vs 44/149, respectively (OR = 0.36; 95% CI = 0.14 to 0.93; Z = 2.11; P = 0.035), Egger’s test yielded P = 0.308. In conclusion, the present meta-analysis demonstrates that GABA derivatives reduce the incidence of acute herpetic pain. However, additional, well-designed randomized clinical trials are needed to determine their dose- and time-dependency regarding this symptom.

Inhibitory effect of amenamevir on acute herpetic pain and postherpetic neuralgia in mice infected with herpes simplex virus-1

BackgroundAmenamevir (AMNV) is a helicase-primase inhibitor with antiviral activity against herpesviruses [herpes simplex viruses (HSV)-1 and -2, and varicella-zoster virus], which are associated with the development of acute herpetic pain (AHP) and postherpetic neuralgia. However, the inhibitory effects of helicase-primase inhibitors on AHP and postherpetic neuralgia remain incompletely understood. ObjectiveIn this study, we investigated the effects of AMNV on AHP and postherpetic pain (PHP) in HSV-1-infected mice accompanied by zosteriform-like skin lesions. MethodsHSV-1 was percutaneously infected on the femoral region of mice. AMNV was orally administered twice a day for 5 days. Pain-related response in the hind paw was evaluated using a paintbrush. The infiltration of inflammatory cells in dorsal root ganglion (DRG) and spinal cord (SC) was evaluated by hematoxylin and eosin staining. The viral load in DRG and the expression of pain-related genes in SC were measured by real-time PCR. ResultsPain response was begun to be observed from day 3 post-infection (pi) in HSV-1-infected mice. AMNV administered repeatedly from day 3 pi or day 4 pi, but not day 5 pi, showed an inhibitory effect on the development of AHP and the transition to PHP. Repeated AMNV administration inhibited inflammatory cell infiltration and increases in the viral load and the expression of pain-related genes (ATF-3, TNF-α, COX-2). ConclusionThese results demonstrate that AMNV potently suppresses the development of AHP and the transition to PHP as a consequence of decreased viral load in DRG and reduced expression of pain-related genes in SC.

Delayed Initiation of Supplemental Pain Management is Associated with Postherpetic Neuralgia: A Retrospective Study

Background: Acute pain is a risk factor for developing postherpetic neuralgia (PHN), the most common complication of herpes zoster (HZ). Supplemental analgesics are frequently used in the treatment of acute herpetic pain. However, there are insufficient data regarding when to begin supplemental analgesics, and it is unknown whether the delayed use of supplemental analgesics increases the risk of PHN in high-risk patients. Objectives: This study aimed to evaluate the association between initial time of supplemental pain management and the risk of PHN in high-risk patients. Study Design: Retrospective study. Setting: The Department of Anesthesiology and Pain Medicine, Second Affiliated Hospital, Zhejiang University School of Medicine. Methods: We performed a retrospective study between May 13, 2017 and August 8, 2018 in our clinic. Multivariable logistic regression analysis was conducted to examine the independent factors associated with PHN. Supplemental pain management was defined as any use of opioids, tricyclic antidepressants, or nerve blocks. A subgroup analysis was conducted in patients who received supplemental pain management within the first 30 days of onset. According to the initial time of supplemental pain management, patients were divided into 2 groups: the early treatment group (≤ 14 days), and the late treatment group (> 14 days). The clinical outcomes in these 2 groups was compared for propensity score (PS) matching. Results: A total of 134 patients with HZ aged 50 years or older with moderate to severe pain were enrolled in this study. The delayed initiation of supplemental pain management (> 14 days) (odds ratio, 4.11; 95% confidence interval, 1.69-9.92; P = 0.002) and severity of rash (odds ratio, 2.93; 95% confidence interval, 1.22-7.01; P = 0.016) were independent factors associated with PHN. In the subgroup analysis, after PS matching, there were no significant differences in the baseline clinical parameters between the early and late treatment groups. The incidence of PHN was significantly lower in the early treatment group than the late treatment group (36. 4% vs. 72.7%; P = 0.015). Reduction in pain was also greater in the early treatment group. Limitations: The findings identified in the present study are specific to the patients who were relatively older and with moderate to severe pain. It is impossible to determine from our study whether younger individuals and individuals with mild acute pain will benefit from early supplemental treatments. Furthermore, because of the retrospective nature of the study, there may be some confounders that could not be controlled. Further prospective studies with larger sample sizes and longer follow-up periods are needed. Conclusions: The early use of supplemental pain management may decrease the risk of PHN. It might therefore be beneficial to consider administering supplemental pain management earlier in older patients with moderate to severe acute herpetic pain. Key words: Herpes zoster, postherpetic neuralgia, analgesia, opioid, nerve block, tricyclic antidepressant

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

BackgroundHerpes 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.MethodsThe 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.ResultsAll 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.ConclusionOur 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.

Roles of α-Adrenoceptors and Sympathetic Nerve in Acute Herpetic Pain Induced by Herpes Simplex Virus Inoculation in Mice

Percutaneous inoculation with herpes simplex virus type-1 brings about herpes zoster-like skin lesions, tactile allodynia, and mechanical hyperalgesia in mice. This study was conducted to determine whether the sympathetic nervous system and α-adrenoceptors would be involved in these pain-related responses and whether the α2-adrenoceptor agonist clonidine would suppress these responses. The adrenergic neuron blocker guanethidine and the non-selective α-adrenoceptor antagonist phentolamine did not affect the pain-related responses, although these agents suppressed the pain-related responses induced by partial ligation of the sciatic nerve. The pain-related responses induced by herpetic inoculation was suppressed by intraperitoneal and intrathecal injections, but not by intraplantar and intracerebroventricular injections, of clonidine. The suppressive effect of an intraperitoneal injection of clonidine (0.1 mg/kg) was antagonized by intrathecal injections of phentolamine and the α2-adrenoceptor antagonist yohimbine, but not the a1-adrenoceptor antagonist prazosin. The results suggest that sympathetic nerves and α-adrenoceptors are not involved in the pain-related responses induced by herpetic infection. Clonidine suppresses the responses probably through the action on α2-adrenoceptors in the dorsal horn.

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

BackgroundPostherpetic 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.ObjectiveTo 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.MethodsThis 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.ResultsSeventy-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.ConclusionAddition 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 registrationISRCTN Registry identifier: ISRCTN79871784

Relief of Acute Herpetic Pain by Intravenous Vitamin C: The Dosage May Make a Difference: Authors' Reply.

Relief of Acute Herpetic Pain by Intravenous Vitamin C: The Dosage May Make a Difference: Authors' Reply.

Relief of Acute Herpetic Pain by Intravenous Vitamin C: The Dosage May Make a Difference.

Relief of Acute Herpetic Pain by Intravenous Vitamin C: The Dosage May Make a Difference.

Neuroimmune-Glia Interactions in the Sensory Ganglia Account for the Development of Acute Herpetic Neuralgia.

Herpetic neuralgia is the most important symptom of herpes zoster disease, which is caused by Varicella zoster Nevertheless, the pathophysiological mechanisms involved in herpetic neuralgia are not totally elucidated. Here, we examined the neuroimmune interactions at the sensory ganglia that account for the genesis of herpetic neuralgia using a murine model of Herpes Simplex Virus Type-1 (HSV-1) infection. The cutaneous HSV-1 infection of mice results in the development of a zosteriform-like skin lesion followed by a time-dependent increase in pain-like responses (mechanical allodynia). Leukocytes composed mainly of macrophages and neutrophils infiltrate infected DRGs and account for the development of herpetic neuralgia. Infiltrating leukocytes are responsible for driving the production of TNF, which in turn mediates the development of herpetic neuralgia through downregulation of the inwardly rectifying K+ channel Kir4.1 in satellite glial cells. These results revealed that neuroimmune-glia interactions at the sensory ganglia play a critical role in the genesis of herpetic neuralgia. In conclusion, the present study elucidates novel mechanisms involved in the genesis of acute herpetic pain and open new avenues for its control.SIGNIFICANCE STATEMENT Acute herpetic neuralgia is the most important symptom of herpes zoster disease and it is very difficult to treat. Using a model of peripheral infection of mice with HSV-1, we have characterized for the first time the neuroimmune-glia interactions in the sensory ganglia that account for the development of acute herpetic neuralgia. Among these mechanisms, leukocytes composed mainly of macrophages and neutrophils infiltrate infected sensory ganglia and are responsible for driving the production of TNF. TNF, via TNFR1, mediates herpetic neuralgia development through downregulation of the inwardly rectifying K+ channel Kir4.1 in satellite glial cells. This study elucidates novel mechanisms involved in the genesis of acute herpetic neuralgia and open new avenues for its control.

A novel P2X4 receptor-selective antagonist produces anti-allodynic effect in a mouse model of herpetic pain

Accumulating evidence indicates that purinergic P2X4 receptors (P2X4R: cation channels activated by extracellular ATP) expressed in spinal microglia are crucial for pathological chronic pain caused by nerve damage, suggesting a potential target for drug discovery. We identified NP-1815-PX (5-[3-(5-thioxo-4H-[1,2,4]oxadiazol-3-yl)phenyl]-1H-naphtho[1, 2-b][1,4]diazepine-2,4(3H,5H)-dione) as a novel antagonist selective for P2X4R with high potency and selectivity compared with other P2XR subtypes. In in vivo assay for acute and chronic pain, intrathecal administration of NP-1815-PX produced an anti-allodynic effect in mice with traumatic nerve damage without affecting acute nociceptive pain and motor function (although its oral administration did not produce the effect). Furthermore, in a mouse model of herpetic pain, P2X4R upregulation in the spinal cord exclusively occurred in microglia, and intrathecal NP-1815-PX suppressed induction of mechanical allodynia. This model also showed K+/Cl− cotransporter 2 (KCC2) downregulation, which is implicated in dorsal horn neuron hyperexcitability; this downregulation was restored by intrathecal treatment with NP-1815-PX or by interfering with brain-derived neurotrophic factor (BDNF) signaling, a P2X4R-activated microglial factor implicated in KCC2 downregulation. Taken together, the newly developed P2X4R antagonist NP-1815-PX produces anti-allodynic effects in chronic pain models without altering acute pain sensitivity, suggesting that microglial P2X4R could be an attractive target for treating chronic pain.

Herpetic pain with complex regional pain syndrome-like symptoms that recovered with limited-duration spinal cord stimulation combined with physical therapy

Herpetic pain with complex regional pain syndrome-like symptoms that recovered with limited-duration spinal cord stimulation combined with physical therapy

Evaluation of the efficacy of different regimens in decreasing the incidence of postherpetic neuralgia

Introduction Herpes zoster (HZ) is a transient disease caused by reactivation of the varicella-zoster virus that remains dormant within the dorsal root ganglia after varicella. Major complications, such as PHN, often defined as pain that persists for 3 months or more, may occur after the onset of the HZ rash. Our aim is to compare between two regimens in relieving HZ pain and their effects in preventing progression to PHN. Patients and methods This study was carried out on 80 outpatients of both sexes who had acute herpetic pain. Group D, which included 40 patients, received acyclovir (800 mg/day), pregabalin (600 mg/day), and fentanyl transdermal patch (75 μg/each 3 days). Group E included 40 patients who received acyclovir (800 mg/day), pregabalin (600 mg/day), and an epidural injection of bupivacaine with 80 mg methylprednisolone twice weekly over 14 days. Results In terms of pain assessment, in group D, there was a significant analgesic effect up to the sixth month compared with the first day. However, an insignificant analgesic effect was observed on the fourth and seventh days, with significant changes afterwards up to the sixth month in group E. The incidence of PHN was observed in 40 and 20% of all patients, whereas the incidence of allodynia was observed in 57.5 and 22.5% of patients in groups D and E, respectively. The incidence of herpetic pain in children reaches 2.5%, but usually does not progress to PHN. Conclusion Acyclovir together with a pregabalin anticonvulsant results in significant pain relief, although it does not reduce the incidence of PHN. However, use of epidural methylprednisolone leads to a lower analgesic effect in addition to less significant effect in decreasing the incidence of PHN.

A Study of Intravenous Administration of Vitamin C in the Treatment of Acute Herpetic Pain and Postherpetic Neuralgia.

BackgroundAlthough there are several available management strategies for treatment of both acute pain of herpes zoster (HZ) and postherpetic neuralgia (PHN), it is difficult to treat them adequately.ObjectiveThe aim of this study was to evaluate the efficacy of intravenously administrated vitamin C on acute pain and its preventive effects on PHN in patients with HZ.MethodsBetween September 2011 and May 2013 eighty-seven patients who were admitted for HZ were assessed according to age, sex, underlying diseases, duration of pain and skin lesion, dermatomal distribution, and PHN. It was a randomized controlled study, in which 87 patients were randomly allocated into the ascorbic acid group and control group. Each patient received normal saline infusion with or without 5 g of ascorbic acid on days 1, 3, and 5 then answered questionnaires that included side effects and pain severity using visual analogue scale on days 1, 2, 3, 4, and 5. After discharge, the severity of pain was obtained at out-patient clinic or by telephone on weeks 2, 4, 8, and 16.ResultsThere was no differences in severity of pain on patients' age, sex, underlying diseases, duration of pain and skin lesion and dermatomal distribution between two groups (p>0.05). Since 8th week, pain score in ascorbic acid treatment group was significantly lower than control group (p <0.05). The incidence of PHN was significantly lower in the treatment group compared to control group (p=0.014). The changes of overall pain score was significantly different between the two groups (p<0.05).ConclusionIntravenously administered ascorbic acid did not relieve acute HZ pain; but is effective for reducing the incidence of PHN.

Plerixafor may treat intractable post-herpetic neuralgia

Varicella-zoster virus (VZV) causes varicella (chicken pox) and establishes latency in ganglia. A reactivation of latent VZV leads to herpes zoster (shingles). Herpes zoster often causes herpetic pain that can last for months or years after the rash has healed. Prolonged herpetic pain is defined as post-herpetic neuralgia (PHN). There is an unmet need to explore novel therapeutic approaches for intractable PHN. Postmortem studies have shown that VZV induces neuro-inflammation and damage to the ganglia and spinal cord. These pathological changes may be critical factors resulting in PHN. Accumulated evidence suggests that stem cells may alleviate neuropathic pain in animal models through immunomodulatory actions and neuronal repair. Unfortunately, exogenous stem cell transplantation has limited clinical use due to safety concerns, immune rejection, and complications. Pharmacological mobilization of endogenous bone marrow stem cells may overcome these obstacles. Plerixafor is a SDF-1/CXCR4 axis blocker which can stimulate the release of stem cells from the bone marrow into blood circulation. We propose a hypothesis that endogenous stem cells mobilized by plerixafor may relieve the symptoms of PHN. If so, it may represent a novel approach for the treatment of intractable PHN.

Spinal Cord Stimulation Failures in Refractory Chronic Pain

Background: Spinal cord stimulation (SCS) is a well-established modality for the treatment of refractory chronic pain and may utilize percutaneous or paddle leads. Methods: The study is conducted at the Unit of Functional Neurosurgery of University “Magna Graecia” of Catanzaro. We perform a retrospective review of our prospective database of 523 SCS patients undergoing surgery for routine indications between January 1993 and December 2013 to evaluate failures rates during trial period and during chronic stimulation. Results: SCS trial was less effective for patients with differentiation neuropathic pain and post herpetic pain. Patients with allodynic dominant pain can feel unpleasant or painful parenthesis during trial stimulation. SCS trial has presented a very low hardware-associated complication rate (lead migration 1.3%) and absence of biological complications. During chronic SCS 29% of cases had equipment failures. In particular mechanical failures occurred in 18% of cases with 8.5% of lead displacements or migrations and 9.5% of lead breakages; biological failures occurred in 11% of cases with 6% of skin erosions and 5% of infections. Conclusion: SCS is a minimally invasive procedure effective in managing medically intractable pain of various origins. Despite advances in the design and production of SCS systems, these devices remain prone to failure from various causes. A careful analysis of mechanical complications coupled to a clinical strategy to minimize the tensile loads on the components of the system should lead to an improvement of the performance of the SCS implanted system and the effectiveness of the stimulation and the long-term reduction in the rate of complications that currently it remains quite significant.