Evidence-based guideline: Treatment of painful diabetic neuropathy: report of the American Academy of Neurology, the American Association of Neuromuscular and Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation

Distinguish different sensorimotor performance of the hand between the individuals with diabetes mellitus and chronic kidney disease through deep learning models

Diabetes mellitus and chronic kidney disease represent escalating global epidemics with comorbidities akin to neuropathies, resulting in various neuromuscular symptoms that impede daily performance. Interestingly, previous studies indicated differing sensorimotor functions within these conditions. If assessing sensorimotor features can effectively distinguish between diabetes mellitus and chronic kidney disease, it could serve as a valuable and non-invasive indicator for early detection, swift screening, and ongoing monitoring, aiding in the differentiation between these diseases. This study classified diverse diagnoses based on motor performance using a novel pinch-holding-up-activity test and machine learning models based on deep learning. Dataset from 271 participants, encompassing 3263 hand samples across three cohorts (healthy adults, diabetes mellitus, and chronic kidney disease), formed the basis of analysis. Leveraging convolutional neural networks, three deep learning models were employed to classify healthy adults, diabetes mellitus, and chronic kidney disease based on pinch-holding-up-activity data. Notably, the testing set displayed accuracies of 95.3% and 89.8% for the intra- and inter-participant comparisons, respectively. The weighted F1 scores for these conditions reached 0.897 and 0.953, respectively. The study findings underscore the adeptness of the dilation convolutional neural networks model in distinguishing sensorimotor performance among individuals with diabetes mellitus, chronic kidney disease, and healthy adults. These outcomes suggest discernible differences in sensorimotor performance across the diabetes mellitus, chronic kidney disease, and healthy cohorts, pointing towards the potential of rapid screening based on these parameters as an innovative clinical approach.

Dorsal Root Ganglion Stimulation in Chronic Painful Polyneuropathy: A Potential Modulator for Small Nerve Fiber Regeneration

OBJECTIVES

Neuromodulatory treatments like spinal cord stimulation and dorsal root ganglion stimulation (DRGS) have emerged as effective treatments to relieve pain in painful polyneuropathy. Animal studies have demonstrated that neurostimulation can enhance nerve regeneration. This study aimed to investigate if DRGS may impact intraepidermal nerve fiber regeneration and sensory nerve function.

MATERIALS AND METHODS

Nine patients with chronic, intractable painful polyneuropathy were recruited. Intraepidermal nerve fiber density (IENFD) quantification in 3 mm punch skin biopsy was performed 1 month before DRGS (placed at the level of the L5 and S1 dorsal root ganglion) and after 12- and 24-month follow-up. Quantitative sensory testing, nerve conduction studies, and a clinical scale score were also performed at the same time points.

RESULTS

In 7 of 9 patients, DRGS was successful (defined as a reduction of ≥ 50% in daytime and/or night-time pain intensity), allowing a definitive implantable pulse generator implantation. The median baseline IENFD among these 7 patients was 1.6 fibers/mm (first and third quartile: 1.2; 4.3) and increased to 2.6 fibers/mm (2.5; 2.9) and 1.9 fibers/mm (1.6; 2.4) at 1- and 2-years follow-up, respectively. These changes were not statistically significant (p = 1.000 and 0.375). Sensory nerve tests did not show substantial changes.

CONCLUSIONS

Although not significant, the results of this study showed that in most of the patients with implants, there was a slight increase of the IENFD at the 1- and 2-year follow-up. Larger-scale clinical trials are warranted to explore the possible role of DRGS in reversing the progressive neurodegeneration over time.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT02435004; Swiss National Clinical Trials Portal: SNCTP000001376.

Issues and challenges in diabetic neuropathy management: A narrative review

Diabetic neuropathy (DN) is a devastating disorder with an increasing prevalence globally. This epidemic can pose a critical burden on individuals and com-munities, subsequently affecting the productivity and economic output of a country. With more people living a sedentary lifestyle, the incidence of DN is escalating worldwide. Many researchers have relentlessly worked on ways to combat this devastating disease. Their efforts have given rise to a number of commercially available therapies that can alleviate the symptoms of DN. Unfortunately, most of these therapies are only partially effective. Worse still, some are associated with unfavorable side effects. This narrative review aims to highlight current issues and challenges in the management of DN, especially from the perspective of molecular mechanisms that lead to its progression, with the hope of providing future direction in the management of DN. To improve the approaches to diabetic management, the suggested resolutions in the literature are also discussed in this review. This review will provide an in-depth understanding of the causative mechanisms of DN, apart from the insights to improve the quality and strategic approaches to DN management.

Evaluation of a polymer-coated nanoparticle cream formulation of resiniferatoxin for the treatment of painful diabetic peripheral neuropathy

ABSTRACT

Painful diabetic peripheral neuropathy (PDPN) is one of the major complications of diabetes. Currently, centrally acting drugs and topical analgesics are used for treating PDPN. These drugs have adverse effects; some are ineffective, and treatment with opioids is associated with use dependence and addiction. Recent research indicates that transient receptor potential vanilloid 1 (TRPV1) expressed in the peripheral sensory nerve terminals is an emerging target to treat pain associated with PDPN. Block of TRPV1 ion channel with specific antagonists, although effective as an analgesic, induced hyperthermia in clinical trials. However, TRPV1 agonists are useful to treat pain by virtue of their ability to cause Ca 2+ influx and subsequently leading to nerve terminal desensitization. Here, we report the effectiveness of an ultrapotent TRPV1 agonist, resiniferatoxin (RTX) nanoparticle, in a topical formulation (RTX-cream; RESINIZIN) that alleviates pain associated with DPN in animal models of diabetes. Resiniferatoxin causes nerve terminal depolarization block in the short term, which prevents pain during application and leading to nerve terminal desensitization/depletion in the long term resulting in long-lasting pain relief. Application of RTX cream to the hind limbs suppresses thermal hyperalgesia in streptozotocin-induced diabetic rats and mini pigs without any adverse effects as compared with capsaicin at therapeutic doses, which induces intense pain during application. Resiniferatoxin cream also decreases the expression of TRPV1 in the peripheral nerve endings and suppresses TRPV1-mediated calcitonin gene-related peptide release in the skin samples of diabetic rats and mini pigs. Our preclinical data confirm that RTX topical formulation is an effective treatment option for PDPN.

Stem Cell Therapy in Diabetic Polyneuropathy: Recent Advancements and Future Directions

Diabetic polyneuropathy (DPN) is the most frequent, although neglected, complication of long-term diabetes. Nearly 30% of hospitalized and 20% of community-dwelling patients with diabetes suffer from DPN; the incidence rate is approximately 2% annually. To date, there has been no curable therapy for DPN. Under these circumstances, cell therapy may be a vital candidate for the treatment of DPN. The epidemiology, classification, and treatment options for DPN are disclosed in the current review. Cell-based therapies using bone marrow-derived cells, embryonic stem cells, pluripotent stem cells, endothelial progenitor cells, mesenchymal stem cells, or dental pulp stem cells are our primary concern, which may be a useful treatment option to ease or to stop the progression of DPN. The importance of cryotherapies for treating DPN has been observed in several studies. These findings may help for the future researchers to establish more focused, accurate, effective, alternative, and safe therapy to reduce DPN. Cell-based therapy might be a permanent solution in the treatment and management of diabetes-induced neuropathy.

Efficacy of perineural hypertonic saline injection versus acupoints of foot in the management of diabetic neuropathy: a multicenter, double-blinded randomized controlled trial

Aim: Painful diabetic polyneuropathy is one of the most common disabling problems worldwide. We aimed to determine if a perineural injection of hypertonic saline compared with foot acupoints decreased the neuropathic pain score in patients with diabetes. Patients & methods/materials: Patients were assigned to receive either perineural or acupoints injection of hypertonic saline 5% in their feet for three weekly sessions. Douleur Neuropathique 4 (DN4) questionnaire for neuropathic pain was assessed. Results: Both groups observed a significant reduction of the DN4 score throughout 8 weeks of follow-up. Conclusion: Both perineural and acupoints hypertonic saline injections of the foot could improve neuropathic pain in patients with diabetes.

Alpha-Lipoic Acid and Glucose Metabolism: A Comprehensive Update on Biochemical and Therapeutic Features

Alpha-lipoic acid (ALA) is a natural compound with antioxidant and pro-oxidant properties which has effects on the regulation of insulin sensitivity and insulin secretion. ALA is widely prescribed in patients with diabetic polyneuropathy due to its positive effects on nerve conduction and alleviation of symptoms. It is, moreover, also prescribed in other insulin resistance conditions such as metabolic syndrome (SM), polycystic ovary syndrome (PCOS) and obesity. However, several cases of Insulin Autoimmune Syndrome (IAS) have been reported in subjects taking ALA. The aim of the present review is to describe the main chemical and biological functions of ALA in glucose metabolism, focusing on its antioxidant activity, its role in modulating insulin sensitivity and secretion and in symptomatic peripheral diabetic polyneuropathy. We also provide a potential explanation for increased risk for the development of IAS.

An overview of painful diabetic peripheral neuropathy: Diagnosis and treatment advancements

Diabetes mellitus remains a public health problem, affecting 422 million people worldwide. Currently, there is no consensus around treating painful diabetic peripheral neuropathy in a step-wise manner. Among the non-pharmacological interventions, neuromodulation has become a promising alternative. Over the past decade, significant clinical trials have paved the way for prompt inclusion of high-frequency spinal cord stimulation within the painful diabetic peripheral neuropathy treatment algorithm. This article aims to provide an updated evidence-based approach for the management of painful diabetic peripheral neuropathy.

A prospective long-term follow-up of dorsal root ganglion stimulation for the management of chronic intractable pain

ABSTRACT

Initial clinical studies have shown that the stimulation of the dorsal root ganglion (DRG) can significantly reduce chronic intractable pain. However, clinical data on long-term results and complications of these systems are limited. The aim of this prospective study is to report on a single center long-term follow-up of DRG stimulation for intractable chronic pain. Participants were implanted with DRG stimulation devices between 2013 and 2015 with an observation period of 24 months. Patients were contacted again in 2020 for a final follow-up (ie, between 5 and 7 years postimplantation). Forty-two participants were recruited, of whom 32 received the fully implantable pulse generator (IPG). At the final follow-up, 50% (16/32) of participants were still using DRG stimulation. Two participants still had the original IPG and 14 had received a replacement IPG. Pain scores were significantly reduced at 24 months, mean difference 1.7 (95% confidence interval: 0.2-3.3, P = 0.03), and at the last follow-up, mean difference 2.1 (95% confidence interval: 0.3-4, P = 0.03). Significant improvements were observed for health-related quality of life. The findings were generally robust to imputation methods of missing data. Implantable pulse generators of 8 patients were explanted because of dissatisfaction with pain relief. In conclusion, DRG stimulation can provide effective pain relief and improved quality of life in patients suffering with neuropathic pain, although this study had a revision rate of 42% within the first 24 months, and 56% of IPGs that were replaced because of battery depletion had a shorter than expected battery life.

Nonopioid drug combinations for cancer pain: a systematic review

Supplemental Digital Content is Available in the Text.

This review is an evaluation of the efficacy and safety of nonopioid drug combinations for cancer pain. Little evidence exists to support the use of any given agent/combination.

Pain is highly prevalent in patients with cancer—nearly 40% report moderate-severe pain, which is commonly treated with opioids. Increasing cancer survivorship, opioid epidemics in some regions of the world, and limited opioid access in other regions have focused attention on nonopioid treatments. Given the limitations of monotherapy, combining nonopioids—such as antiepileptics and antidepressants—have shown promise in noncancer pain. This review seeks to evaluate efficacy of nonopioid combinations for cancer-related pain. Systematic searches of PubMed, EMBASE, and Cochrane CENTRAL were conducted for double-blind, randomized, controlled trials comparing a nonopioid combination with at least one of its components and/or placebo. This search yielded 4 randomized controlled trials, published between 1998 and 2019 involving studies of (1) imipramine + diclofenac; (2) mitoxantrone + prednisone + clodronate; (3) pentoxifylline + tocopherol + clodronate; and (4) duloxetine + pregabalin + opioid. In the first 3 of these trials, trends favouring combination efficacy failed to reach statistical significance. However, in the fourth trial, duloxetine + pregabalin + opioid was superior to pregabalin + opioid. This review illustrates recognition for the need to evaluate nonopioid drug combinations in cancer pain, although few trials have been published to date. Given the growing practice of prescribing more than 1 nonopioid for cancer pain and the need to expand the evidence base for rational combination therapy, more high-quality trials in this area are needed.

Hidden pharmacological activities of valproic acid: A new insight

Valproic acid (VPA) is an approved drug for managing epileptic seizures, bipolar disorders, and migraine. VPA has been shown to elevate the level of gamma-aminobutyric acid (GABA) in the brain through competitive inhibition of GABA transaminase, thus promoting the availability of synaptic GABA and facilitating GABA-mediated responses. VPA, which is a small chain of fatty acids, prevents histone deacetylases (HDACs). HDACs play a crucial role in chromatin remodeling and gene expression through posttranslational changes of chromatin-associated histones. Recent studies reported a possible effect of VPA against particular types of cancers. This effect was partially attributed to its role in regulating epigenetic modifications through the inhibition of HDACs, which affect the expression of genes associated with cell cycle control, cellular differentiation, and apoptosis. In this review, we summarize the current information on the actions of VPA in diseases such as diabetes mellitus, kidney disorders, neurodegenerative diseases, muscular dystrophy, and cardiovascular disorders.

Novel Mechanism for Memantine in Attenuating Diabetic Neuropathic Pain in Mice via Downregulating the Spinal HMGB1/TRL4/NF-kB Inflammatory Axis

Diabetic neuropathic pain (DNP) is a common diabetic complication that currently lacks an efficient therapy. The aim of the current work was to uncover the anti-allodynic and neuroprotective effects of memantine in a model of mouse diabetic neuropathy and its ameliorative effect on the high-mobility group box-1 (HMGB1)/toll-like receptor 4 (TLR4)/nuclear factor-k B (NF-kB) inflammatory axis. Diabetes was prompted by an alloxan injection (180 mg/kg) to albino mice. On the ninth week after diabetes induction, DNP was confirmed. Diabetic mice were randomly allocated to two groups (six mice each); a diabetes mellitus (DM) group and DM+memantine group (10 mg/kg, daily) for five weeks. DNP-related behaviors were assessed in terms of thermal hyperalgesia and mechanical allodynia by hot-plate and von Frey filaments. Enzyme-linked immunosorbent assay (ELISA) kits were used to measure the spinal glutamate, interleukin-1 beta (IL-1β), and tumor necrosis factor-α (TNF-α). The spinal levels of N-methyl-D-aspartate type 1 receptor (NMDAR1), HMGB1, TLR4, and phosphorylated NF-kB were assessed using Western blotting. Histopathological investigation of the spinal cord and sciatic nerves, together with the spinal cord ultrastructure, was employed for assessment of the neuroprotective effect. Memantine alleviated pain indicators in diabetic mice and suppressed excessive NMDAR1 activation, glutamate, and pro-inflammatory cytokine release in the spinal cord. The current study validated the ability of memantine to combat the HMGB1/TLR4/NF-kB axis and modulate overactive glutamate spinal transmission, corroborating memantine as an appealing therapeutic target in DNP.

Status of Analgesic Drugs and Quality of Life Results for Diabetic Peripheral Neuropathy in China

OBJECTIVE

The purpose of this study is to describe the current clinical situation of patients with painful diabetic peripheral neuropathy (DPN) and related anxiety, depression, and the quality of life of patients in mainland China, and to report the current status of the use of analgesics.

METHODS

Between June 15, 2021, and October 15, 2021, a total of 401 participants participated in the study. Recruitment was carried out using a multi-level sampling method. Participants' demographics, medical history, analgesic use, Michigan Symptom Score (MNSI), Numerical Rating Scale (NRS) pain score, Patient Health Questionnaire 9 (PHQ-9) score, Generalized Anxiety Disorder 7 (GAD) -7) Score, quality of life score (SF-12) and diabetes treatment status were collected.

RESULTS

Among the participants, there were 236 male patients and female patients. Participants were 322 patients over 40 years old. Regarding the use of analgesics: 132 patients reported using analgesics, 221 patients reported not using analgesics, and 48 patients reported having used analgesics. The results of the scale showed that the scores of NRS, GAD-7, PHQ-9 and SF-12 were 5.12 ± 2.15, 6.33 ± 3.67, 8.46 ± 4.07 and 47.84 ± 19.92 for patients who used analgesics, Compared with patients who did not use analgesics (NRS: 1.99 ± 1.7, GAD-7: 1.81 ± 2.81, PHQ-9: 3.13 ± 4.10, SF-12: 78.34 ± 21.66) there are significant differences (p< 0.001). In addition, patients' NRS scores are also closely related to GAD-7, PHQ-9 and SF-12 scores.

CONCLUSION

The severity of symptoms, mental status and quality of life of patients who used analgesics were more severe than those of patients who did not use analgesics. Pregabalin is still the preferred analgesic for patients with painful DPN, and the use of opioids in my country is extremely low, which is consistent with current international guidelines. Age, diabetic duration, DPN duration, PHQ-9 score, GAD-7 score and SF-12 scores are closely related to NRS pain scores. In addition, there are still a considerable number of patients who have not used analgesics due to financial burdens and other reasons, suggesting that China still has insufficient pain management in DPN patients.

Dorsal Root Ganglion Stimulation for the Management of Intractable Painful Polyneuropathy: A Prospective Pilot Study

OBJECTIVES

Dorsal root ganglion stimulation (DRGS) is a promising neurostimulation modality in the treatment of painful polyneuropathy. The aim of this prospective pilot study was to investigate the effect of DRGS on pain intensity in patients with intractable painful polyneuropathy.

MATERIALS AND METHODS

Nine patients with chronic, intractable painful polyneuropathy in the lower limbs were recruited. In each subject, between two and four DRGS leads were placed at the level of the L5 and S1 dorsal root ganglion. If trial stimulation was successful, a definitive implantable pulse generator (IPG) was implanted. Pain intensity was scored using an 11-point numeric rating scale (NRS) and reported as median and interquartile range (IQR), and compared to baseline values using the Wilcoxon signed-rank test. Additionally, patients' global impression of change (PGIC), pain extent, presence of neuropathic pain, physical functioning, quality of life, and mood were assessed.

RESULTS

Eight out of nine patients had a successful trial phase, of which seven received an IPG. Daytime pain decreased from a median (IQR) NRS score of 7.0 (5.9-8.3) to 2.0 (1.0-3.5) and 3.0 (1.6-4.9) in the first week and at six months after implantation, respectively. Similar effects were observed for night time and peak pain scores.

CONCLUSIONS

The results of this study suggest that DRGS significantly reduces both pain intensity and PGIC in patients with intractable painful polyneuropathy in the lower extremities. Large-scale clinical trials are needed to prove the efficacy of DRGS in intractable painful polyneuropathy.

The Effect of Intradermal Botulinum Toxin a injections on painful diabetic polyneuropathy

BACKGROUND AND AIMS

Botulinum toxin type A (BTX-A) have been recently administered to improve Diabetic neuropathies; however, the efficacy of this treatment for relieving pain in painful diabetic polyneuropathy (DPN) has not been studied yet. Herein, we investigated the efficacy of botulinum toxin A (BTX-A) on DPN.

METHODS

This prospective, randomized, double-blind, controlled trial was performed in Imam Hossein Medical Center, pain clinic (Tehran, Iran). Diabetic patients (141 cases), between 40 and 70 years old with polyneuropathy in lower limbs were randomly assigned to one of these three groups: 1. Group D1 received 150 units of BTX-A in one foot and normal saline 0.9% in the other foot, 2. Group D2 received BTX-A 150 units in both feet, 3. Group N received normal saline 0.9% in both feet. All injections were performed intradermally using insulin syringes in 20 different points of foot. Visual analogue scale (VAS) and neuropathy pain scale (NPS) were used to compare the groups.

RESULTS

The improvement of VAS, pain intensity, sharp and hot sensation, sensitive and unpleasant sensation, deep and surface sensation was significant when comparing BTX-A and placebo groups. However, dull and cold sensations improvement (p = 0.114, and p = 0.653; respectively) did not show a significant difference between BTX-A injection and placebo groups. Furthermore, the percentage of changes after treatment indicated that sharp pain was improved more than other complaints (80%, 81%, and 37% for D1, D2, and N groups; respectively).

CONCLUSION

Intradermal administration of BTX-A was effective in improving VAS and all of the items of NPS in patients with diabetic polyneuropathy, except for dull and cold sensation.

Postoperative penile prosthesis pain: is it worse in diabetic patients?

Inflatable penile prosthesis (IPP) surgery is an effective, safe and satisfactory treatment option for medication-refractory erectile dysfunction. Postoperative complications include infection, mechanical failure, erosion, and pain. Current literature suggests the need for a better approach to postoperative pain management after IPP surgery. Clinical studies have demonstrated that postoperative pain is different in diabetic patients. We sought to determine if there is a difference in pain after IPP placement in diabetics. This is a single-institution retrospective review. The main outcome measure was the number of 30-day postoperative visits for pain. The secondary outcome included differences in how pain was managed. The top HbA1c quartile was compared with the other HbA1c quartiles. Diabetes was present in 92 (54.4%) patients and 96% of these had HbA1c > 8. Significant postoperative pain was more common in patients with HbA1c > 8 (41% vs 13%, p = 0.047) and resulted in more unplanned visits (27% vs 11%, p = 0.042). Patients with HbA1c > 8 with significant postoperative pain were more likely to be managed with opioids and gabapentin (30% vs 14%, p = 0.05). There were no statistical differences in age between diabetics and non-diabetics (mean 59 vs 61, p = 0.193). Hispanic and African-American patients represented 87% of the poorly controlled diabetics compared with only 13% of white patients (p < 0.001). Poorly controlled diabetics had more medical comorbidities (p < 0.001). On logistic regression, a HbA1c > 8 was predictive of an unplanned visit for pain with an OR of 2.83 (p = 0.04). Significant pain after IPP surgery was higher in diabetics with HbA1c > 8, which resulted in more unplanned 30-day postoperative visits. Patients with significant postoperative pain were managed with a combination of opioids and gabapentin. Future studies are required to optimize pain management in diabetics following IPP placement.

Transcranial Magnetic Stimulation for Pain, Headache, and Comorbid Depression: INS-NANS Expert Consensus Panel Review and Recommendation

BACKGROUND

While transcranial magnetic stimulation (TMS) has been studied for the treatment of psychiatric disorders, emerging evidence supports its use for pain and headache by stimulating either motor cortex (M1) or dorsolateral prefrontal cortex (DLPFC). However, its clinical implementation is hindered due to a lack of consensus in the quality of clinical evidence and treatment recommendation/guideline(s). Thus, working collaboratively, this multinational multidisciplinary expert panel aims to: 1) assess and rate the existing outcome evidence of TMS in various pain/headache conditions; 2) provide TMS treatment recommendation/guidelines for the evaluated conditions and comorbid depression; and 3) assess the cost-effectiveness and technical issues relevant to the long-term clinical implementation of TMS for pain and headache.

METHODS

Seven task groups were formed under the guidance of a 5-member steering committee with four task groups assessing the utilization of TMS in the treatment of Neuropathic Pain (NP), Acute Pain, Primary Headache Disorders, and Posttraumatic Brain Injury related Headaches (PTBI-HA), and remaining three assessing the treatment for both pain and comorbid depression, and the cost-effectiveness and technological issues relevant to the treatment.

RESULTS

The panel rated the overall level of evidence and recommendability for clinical implementation of TMS as: 1) high and extremely/strongly for both NP and PTBI-HA respectively; 2) moderate for postoperative pain and migraine prevention, and recommendable for migraine prevention. While the use of TMS for treating both pain and depression in one setting is clinically and financially sound, more studies are required to fully assess the long-term benefit of the treatment for the two highly comorbid conditions, especially with neuronavigation.

CONCLUSIONS

After extensive literature review, the panel provided recommendations and treatment guidelines for TMS in managing neuropathic pain and headaches. In addition, the panel also recommended more outcome and cost-effectiveness studies to assess the feasibility of the long-term clinical implementation of the treatment.

Hereditary Transthyretin Amyloidosis: Clinical Presentation and Management Updates

Hereditary transthyretin amyloidosis, once a rare progressive neuropathy and/or cardiomyopathy, is now recognized with increasing worldwide frequency, various phenotypes, and over 130 gene mutations identified to date. This inherited disorder develops as a result of mutated transthyretin amyloid aggregation and systematic deposition throughout the body. With increasing knowledge about the pathophysiology of this disease, new disease-modifying therapies are being developed. In addition to slowing progression, these new agents were found to improve quality of life and reduce the severity of neuropathic symptoms. Two new gene-modifying therapies recently received Food and Drug Administration approval following the positive results from phase III trials. These include an antisense oligonucleotide, inotersen, and small interfering RNA, patisiran, which were reported to reduce the production of transthyretin and had promising safety profiles. Additional novel therapies are being explored with hopes to prolong survival. Therefore, early diagnosis of this treatable disorder has become increasingly important in clinical practice.

The Relationship Between Evaluation Methods for Chemotherapy-Induced Peripheral Neuropathy

Numbness and pain are currently evaluated using subjective methods such as the visual analogue scale (VAS). PainVision (PV) is an analytical instrument that was designed to quantitatively assess sense perception and nociception in patients. Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most important adverse events that renders prolonged chemotherapy difficult. To assess the features of CIPN, we aimed to compare PV methods with existing methods. A total of 73 patients received oxaliplatin for metastatic colorectal cancer. Registered patients included 37 men and 36 women in the range of 37 to 89 years (median 70). CIPN was evaluated a total of 483 times (median per patient six times). Our study examined the correlation between evaluation methods of CIPN using VAS and PV, respectively. The average VAS (hand), VAS (foot) and PV scores of CIPN were 18.4 (range: 0–100), 23.8 (range: 0–100), and 24.7 (range: 0–496), respectively. VAS (hand), VAS (foot), and FACT/GOG-NTX (NTX2, NTX4 and NTX8) were significantly correlated with PV. PV showed no correlation with a Disk-Criminator or the monofilament test used as a quantitative evaluation. The evaluation of CIPN is complex, and further improvement is required for evaluation with PV.

Randomized controlled trial of a clinical decision support system for painful polyneuropathy

INTRODUCTION

Despite the existence of guidelines, painful neuropathy is often inappropriately treated. We sought to determine the effectiveness of a clinical decision support system on guideline-recommended medication use.

METHODS

We randomized neurology providers, stratified by subspecialty, to a best practice alert (BPA) linked to a Smartset or a BPA alone when seeing patients with neuropathy. The primary outcome was the proportion of patients with uncontrolled nerve pain prescribed a guideline-recommended medication. Generalized estimating equations were used to assess effectiveness.

RESULTS

Seventy-five neurology providers (intervention 38, control 37) treated 2697 patients with neuropathy (intervention 1026, control 671). Providers did not acknowledge the BPA in 1928 (71.5%) visits. Only four of eight intervention arm neurologists who treated patients with uncontrolled nerve pain opened the Smartset. The intervention was not associated with guideline-recommended medication use (odds ratio 0.52, 0.18-1.48; intervention 52%, control 54.8%).

DISCUSSION

Our intervention did not improve prescribing practices for painful neuropathy. Physicians typically ignored the BPAs/Smartset; therefore, future studies should mandate their use or employ alternate strategies.

Epidemiology of Peripheral Neuropathy and Lower Extremity Disease in Diabetes

PURPOSE OF REVIEW

Diabetic peripheral neuropathy eventually affects nearly 50% of adults with diabetes during their lifetime and is associated with substantial morbidity including pain, foot ulcers, and lower limb amputation. This review summarizes the epidemiology, risk factors, and management of diabetic peripheral neuropathy and related lower extremity complications.

RECENT FINDINGS

The prevalence of peripheral neuropathy is estimated to be between 6 and 51% among adults with diabetes depending on age, duration of diabetes, glucose control, and type 1 versus type 2 diabetes. The clinical manifestations are variable, ranging from asymptomatic to painful neuropathic symptoms. Because of the risk of foot ulcer (25%) and amputation associated with diabetic peripheral neuropathy, aggressive screening and treatment in the form of glycemic control, regular foot exams, and pain management are important. There is an emerging focus on lifestyle interventions including weight loss and physical activity as well. The American Diabetes Association has issued multiple recommendation statements pertaining to diabetic neuropathies and the care of the diabetic foot. Given that approximately 50% of adults with diabetes will be affected by peripheral neuropathy in their lifetime, more diligent screening and management are important to reduce the complications and health care burden associated with the disease.

Infiltration of Blood-Derived Macrophages Contributes to the Development of Diabetic Neuropathy

Background and Objective

Diabetic neuropathic pain (DNP) is a common complication associated with diabetes. Currently, its underlying pathomechanism remains unknown. Studies have revealed that the recruitment of blood monocyte-derived macrophages (MDMs) to the spinal cord plays a pivotal role in different models of central nervous system injury. Therefore, the present study aimed at exploring the infiltration and function of MDMs in DNP using a mice model.

Methods

Diabetes was induced using streptozotocin in male A/J mice. Mechanical withdrawal thresholds were measured weekly to characterize neuropathy phenotype. Quantitative analysis of CD11b was performed and visualized by immunofluorescence. Spinal cord cells were isolated from myelin and debris by Percoll gradient. Flow cytometry was used to label CD11b and CD45 antibodies to differentiate MDMs (CD45^highCD11b⁺) from resident microglia (CD45^lowCD11b⁺). Mice were injected with clodronate liposomes to investigate the role of MDMs in DNP. The successful depletion of monocytes was determined by flow cytometry.

Results

The DNP mice model was successfully established. Compared with nondiabetic mice, diabetic mice displayed a markedly higher level of CD11b immunofluorescence in the spinal cord. The number of CD11b-positive microglia/macrophages gradually increased over the 28 days of testing after STZ injection, and a significant increase was observed on Day 14 (P < 0.01) and 28 (P < 0.01). Further analysis by flow cytometry showed that the infiltration of peripheral macrophages began to increase in 2 weeks (P < 0.001) and reached a maximum at 4 weeks (P < 0.001) post-STZ injection compared to the control. The depletion of MDMs by clodronate liposomes alleviated diabetes-induced tactile allodynia (P < 0.05) and reduced the infiltration of MDMs (P < 0.001) as well as the expression of IL-1β and TNF-α in the spinal cord (P < 0.05).

Conclusions

The infiltration of blood MDMs in the spinal cord may promote the development of painful neuropathy in diabetes.

Topical treatments for diabetic neuropathic pain

Diabetic neuropathic pain (DNP) has a huge impact on quality of life and can be difficult to treat. Oral treatment is the most frequently used method for DNP, but its use is often limited by systemic side effects. Topical use of drugs as an alternative option for DNP treatment is currently gaining interest. In the present review, a summary is provided of the available agents for topical use in patients with DNP, including lidocaine plasters or patches, capsaicin cream, gel or patches, amitriptyline cream, clonidine gel, ketamine cream, extracts from medicinal plants including nutmeg extracts and Citrullus colocynthis extract oil, and certain compounded topical analgesics. Furthermore, the potential efficacy of these treatments is addressed according to the available clinical research literature. It has been indicated that these topical drugs have the potential to be valuable additional options for the management of DNP, with adequate safety and continuous long-term treatment efficacy. Compounded topical agents are also effective and safe for patients with DNP and could be another area worthy of further investigation based on the strategy of using low-dose, complementary therapies for DNP. The findings indicate that developing topical drugs acting on different targets in the process of DNP is a valuable area of future research.

Lack of a Clinically Significant Pharmacokinetic Interaction Between Pregabalin and Thioctic Acid in Healthy Volunteers

PURPOSE

Pregabalin and thioctic acid are likely to be used concomitantly for the treatment of painful diabetic neuropathy. In this study, the pharmacokinetic interaction between pregabalin and thioctic acid was investigated at steady state.

METHODS

A randomized, open-label, 6-sequence, 3-period, 3-treatment crossover study was conducted in 42 healthy male volunteers. The volunteers randomly received pregabalin 300 mg BID for 6 times, thioctic acid 600 mg once daily for 3 times, or the combination of pregabalin and thioctic acid. Serial blood samples were collected up to 24 hours after the last dosing in each period. Pharmacokinetic parameters were calculated by using noncompartmental analysis methods.

FINDINGS

The mean concentration-time curves were similar between each drug alone and in combination with the other drug. The 90% CIs of the geometric mean ratios with and without the co-administered drug for C_max at steady state and AUC during the dosing interval were well within the conventional bioequivalence range of 0.8 to 1.25, except for C_max at steady state for thioctic acid, which barely exceeded only the lower bound (0.78-1.15). Co-administered pregabalin and thioctic acid was well tolerated.

IMPLICATIONS

Repeatedly administered pregabalin and thioctic acid do not interact pharmacokinetically. This study suggests that the combination of pregabalin and thioctic acid can safely be administered concomitantly without dose adjustment. ClinicalTrials.gov identifier: NCT01808300.

Neural Mobilization Attenuates Mechanical Allodynia and Decreases Proinflammatory Cytokine Concentrations in Rats With Painful Diabetic Neuropathy

BACKGROUND

Painful diabetic neuropathy (PDN) is a common complication in patients with diabetes. It is related to ischemic nerve damage and the increase in the levels of proinflammatory mediators, such as tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). Neural mobilization may have the potential to alleviate PDN, but it has not yet been tested. Also, the physiological mechanism of neural mobilization is unclear.

OBJECTIVE

The objective of this study was to investigate treatment effect and physiological mechanism of neural mobilization.

DESIGN

This was an experimental study using rats with streptozocin (or streptozotocin)-induced type 1 diabetes.

METHODS

Three groups were used in the study, the control group (vehicle), the diabetes group (PDN group), and the neural mobilization treatment group (PDN-NM group) (n = 6). Rats in the vehicle group were healthy rats. Rats in the PDN and PDN-NM groups were rats with diabetes. Rats in the PDN-NM group received treatment in the right sciatic nerve, whereas rats in the PDN group did not. Mechanical pain sensitivity and the levels of IL-1β and TNF-α in the sciatic nerve branches and trunk, the L4 to L6 dorsal horn ganglion, and the spinal cord dorsal horn were measured.

RESULTS

Techanical allodynia was alleviated after treatment, but the effect was limited to the treatment side. The concentrations of proinflammatory cytokines were decreased in the nerves that received treatment compared with those on the other side, indicating that neural mobilization may reduce mechanical sensitivity by decreasing the concentrations of local sensitizing agents.

LIMITATIONS

A limitation of this study was that no direct measurement of nerve blood flow was done.

CONCLUSIONS

The results of this study showed that neural mobilization effectively alleviated mechanical allodynia in rats with PDN. The side that received treatment had lower concentrations of TNF-α and IL-1β in the sciatic nerve branches and sciatic nerve trunk; this result may have been related to the alleviation of mechanical allodynia.

Effects of acetyl-L-carnitine and methylcobalamin for diabetic peripheral neuropathy: A multicenter, randomized, double-blind, controlled trial

AIMS/INTRODUCTION

To assess the efficacy and safety of acetyl-L-carnitine (ALC) on diabetic peripheral neuropathy compared with methylcobalamin (MC).

MATERIALS AND METHODS

This was a multicenter, randomized, parallel-group, double-blind, double-dummy, positive-controlled, non-inferior phase II clinical trial. Diabetic patients with abnormal nerve conduction test results were randomized in a 1:1 ratio to receive oral ALC 500 mg t.i.d. or MC 0.5 mg t.i.d. for 24 weeks. The neuropathy symptom score, neuropathy disability score and neurophysiological parameters were measured during follow up.

RESULTS

A total of 232 patients were randomized (ALC n = 117, MC n = 115), 88% of which completed the trial. At week 24, patients from both groups had significant reductions in both neuropathy symptom score and neuropathy disability score with no significant difference between two groups (neuropathy symptom score reduction: ALC vs MC 2.35 ± 2.23, P < 0.0001 vs 2.11 ± 2.48, P < 0.0001, intergroup P = 0.38; neuropathy disability score reduction ALC vs MC 1.66 ± 1.90, P < 0.0001 vs 1.35 ± 1.65, P < 0.0001, intergroup P = 0.23). Neurophysiological parameters were also improved in both groups. No significant difference was found between groups in the development of adverse events.

CONCLUSIONS

ALC is as effective as MC in improving clinical symptoms and neurophysiological parameters for patients with diabetic peripheral neuropathy over a 24-week period with good tolerance.

Small fiber neuropathy: Getting bigger!

Etiological and clinical heterogeneity of small fiber neuropathy (SFN) precludes a unifying approach and necessitates reliance on recognizable clinical syndromes. Symptoms of SFN arise from dysfunction in nociception, temperature, and autonomic modalities. This review focuses on SFN involving nociception and temperature, examining epidemiology, etiology, clinical presentation, diagnosis, pathophysiology, and management. Prevalence of SFN is 52.95 per 100,000 population, and diabetes and idiopathic are the most common etiologies. Dysesthesia, allodynia, pain, burning, and coldness sensations frequently present in a length-dependent pattern. Additional autonomic features in gastrointestinal, urinary, or cardiovascular systems are frequent but poorly objectified. SFN is diagnosed by intraepidermal nerve fiber density and quantitative sensory and autonomic tests in combination with normal nerve conduction. Pathophysiological understanding centers on sodium channel dysfunction, and genetic forms are beginning to be understood. Treatment is directed at the underlying etiology supported by symptomatic treatment using antidepressants and anticonvulsants. Little is known about long-term outcomes, and systematic cohort studies are needed.

Current Ideas on the Treatment Of Diabetic Neuropathies

Diabetic neuropathies are common and their prevalence is rising with the growth in the global prevalence of type 2 diabetes. Several patterns of neuropathy have now been described, with diabetic sensorimotor polyneuropathy (DPN) being the most common. Autonomic neuropathy, entrapment neuropathies including carpal tunnel syndrome and ulnar neuropathy at the elbow pose additional burdens. DPN can be detected in over half of all diabetic subjects and approximately 20% of all patients with DPN also experience neuropathic pain, a complication with major impacts on quality of life. Currently, the only available treatments for DPN are optimal glucose control and pain management, whereas interventions, beyond optimizing hyperglycemic control, to address the underlying polyneuropathy are not available. Here we review current treatment options and new literature relating to DPN, with an emphasis on novel and emerging treatments.

Subjective and objective assessment of oxaliplatin-induced peripheral neuropathy

Numbness and pain are currently evaluated using subjective methods such as the visual analog scale (VAS). However, because assessment of pain can vary greatly depending on the mood and physical state of the patient at the time of assessment, it is best to evaluate pain objectively. pain vision PS-2100 (PV) is an analytical instrument that was designed to quantitatively and objectively assess sense perception and nociception in patients. The present study examined the correlation of subjective and objective assessment of oxaliplatin-induced peripheral neuropathy (PN) using VAS and PV, respectively. The mean VAS and PV scores of PN were 20.5 (range 0-100) and 27.9 (range 0-416), respectively. The partial correlation coefficient was 0.274 (p = 0.0003). No strong correlation was observed between the results and a weak correlation was observed between VAS and PV.

Patient reported outcomes for diabetic peripheral neuropathy

OBJECTIVE

Multiple patient-reported outcomes (PROs) have been used to assess symptoms among patients with Diabetic Peripheral Neuropathy (DPN). However, there is little consistent application of measures in clinical or research settings. Our goal was to identify and compare patient reported outcome measures (PROs) specifically evaluated in neuropathy populations.

METHODS

Literature search, summary, and qualitative comparison of PROs validated in neuropathy populations.

RESULTS

We identified 12 studies of PROs evaluated in neuropathy populations that included DPN patients. Two assessed sleep quality, 5 assessed painful symptoms, and 5 assessed quality of life. The number of items per measure ranged from one to 97, and the number of domains ranged from one to 18. All had adequate internal consistency (Chronbach's Alpha>0.70). There was mild to moderate standardization of domains across measures and only a few instruments used common comparators. The spectrum of DPN symptoms addressed included: sensory symptoms, autonomic symptoms, and function, beliefs, role participation, sleep quality, and perceptions of illness.

CONCLUSIONS

There remains a need for a gold standard for DPN symptom assessment. Few existing instruments are adequately validated and the domains assessed are inconsistent. Current instrument selection should depend on the clinical and social context of the assessment.

Valproate modulates glucose metabolism in patients with epilepsy after first exposure

Valproate (VPA) treatment has been reported to be associated with weight gain and metabolic changes, such as hyperinsulinemia. The question of whether hyperinsulinemia and other metabolic changes are consequences of increased weight, or are instead direct results of VPA treatment, remains a matter of debate. The aim of the current study was to explore the influence of VPA treatment on glucose and insulin levels during the oral glucose tolerance test (OGTT) directly following the first intravenous (IV) administration. Sixteen patients (18-46 years old) with newly diagnosed epilepsy underwent an OGTT with 75 g glucose prior to the start of VPA treatment, as well as directly following the first IV VPA administration. We observed that plasma glucose levels during the 120 min of OGTT session following infusion of VPA were significantly lower than those measured during OGTT without VPA treatment (mean ± standard deviation [SD] 4.28 ± 0.94 mmol/l vs. 4.75 ± 1.09 mmol/l respectively, p = 0.038). However, blood concentrations of insulin and C-peptide did not differ significantly between the two measurements. This is the first study to show a potential acute glucose-lowering effect of VPA during OGTT in patients with newly diagnosed epilepsy.

Amitriptyline for neuropathic pain in adults

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 12, 2012. That review considered both fibromyalgia and neuropathic pain, but the effects of amitriptyline for fibromyalgia are now dealt with in a separate review.Amitriptyline is a tricyclic antidepressant that is widely used to treat chronic neuropathic pain (pain due to nerve damage). It is recommended as a first line treatment in many guidelines. Neuropathic pain can be treated with antidepressant drugs in doses below those at which the drugs act as antidepressants.

OBJECTIVES

To assess the analgesic efficacy of amitriptyline for relief of chronic neuropathic pain, and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and EMBASE to March 2015, together with two clinical trial registries, and the reference lists of retrieved papers, previous systematic reviews, and other reviews; we also used our own hand searched database for older studies.

SELECTION CRITERIA

We included randomised, double-blind studies of at least four weeks' duration comparing amitriptyline with placebo or another active treatment in chronic neuropathic pain conditions.

DATA COLLECTION AND ANALYSIS

We performed analysis using three tiers of evidence. First tier evidence derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for dropouts; at least 200 participants in the comparison, 8 to 12 weeks' duration, parallel design), second tier from data that failed to meet one or more of these criteria and were considered at some risk of bias but with adequate numbers in the comparison, and third tier from data involving small numbers of participants that were considered very likely to be biased or used outcomes of limited clinical utility, or both.

MAIN RESULTS

We included 15 studies from the earlier review and two new studies (17 studies, 1342 participants) in seven neuropathic pain conditions. Eight cross-over studies with 302 participants had a median of 36 participants, and nine parallel group studies with 1040 participants had a median of 84 participants. Study quality was modest, though most studies were at high risk of bias due to small size.There was no first-tier or second-tier evidence for amitriptyline in treating any neuropathic pain condition. Only third-tier evidence was available. For only two of seven studies reporting useful efficacy data was amitriptyline significantly better than placebo (very low quality evidence).More participants experienced at least one adverse event; 55% of participants taking amitriptyline and 36% taking placebo. The risk ratio (RR) was 1.5 (95% confidence interval (CI) 1.3 to 1.8) and the number needed to treat for an additional harmful outcome was 5.2 (3.6 to 9.1) (low quality evidence). Serious adverse events were rare. Adverse event and all-cause withdrawals were not different, but were rarely reported (very low quality evidence).

AUTHORS' CONCLUSIONS

Amitriptyline has been a first-line treatment for neuropathic pain for many years. The fact that there is no supportive unbiased evidence for a beneficial effect is disappointing, but has to be balanced against decades of successful treatment in many people with neuropathic pain. There is no good evidence of a lack of effect; rather our concern should be of overestimation of treatment effect. Amitriptyline should continue to be used as part of the treatment of neuropathic pain, but only a minority of people will achieve satisfactory pain relief. Limited information suggests that failure with one antidepressant does not mean failure with all.

HIV neuropathy

PURPOSE OF REVIEW

To present an overview of HIV-associated distal symmetric polyneuropathy (HIV-DSP) and other HIV-related peripheral neuropathies in the post-highly active retroviral therapy era.

RECENT FINDINGS

HIV-DSP has become the most common neurologic complication of HIV largely due to the prolonged survival of HIV-positive patients with the advent of highly active retroviral therapy. HIV-DSP can be attributed to the disease itself or to secondary effects of certain HAART agents, and often the two disease entities cannot be distinguished. HIV-DSP can lead to significant morbidity and interfere with daily activities. Diagnosis can be obtained from a detailed history and neurologic exam revealing absent ankle jerks and abnormal, vibratory perception or decreased pinprick or temperature. Supporting studies include nerve conduction studies and skin biopsy. Although there are no United States Food and Drug Administration-approved treatments for HIV-DSP, clinicians often use off-label medications, including antidepressants, anticonvulsants, topical agents and other analgesics.

SUMMARY

The prevalence of those affected by HIV-DSP will continue to grow with the aging population of HIV-infected individuals. Compared to the diabetic neuropathy drug trials, trials in both symptomatic and disease-modifying agents for HIV-DSP have had little success. Other forms of HIV-related peripheral neuropathies are discussed briefly, and include acute and chronic inflammatory demyelinating polyneuropathy, autonomic neuropathy, polyradiculopathy, mononeuropathies, mononeuritis multiplex, cranial neuropathies, and amyotrophic lateral sclerosis-like motor neuropathy.

Review of antidepressants in the treatment of neuropathic pain

Introduction

Neuropathy is a pathological pain disorder characterized by burning, stabbing, and cramping sensations. There are multiple etiologies for this pain such as diabetes, vascular disorders, and chemotherapy treatment. Neurotransmitters, such as norepinephrine and serotonin, are thought to play a part in the modulation of this pain. The objective of this review is to summarize the current literature to support the efficacy and impact of adverse events of the various classes of antidepressants utilized in the treatment of neuropathic pain.

Methods

A Medline/Pubmed search was conducted to identify randomized clinical trials within the last 12 years examining the efficacy and safety of antidepressants for the treatment of neuropathy. Systematic reviews and meta-analyses were also included.

Results

Antidepressants are commonly used in the treatment of neuropathy, with meta-analyses supporting the use of tricyclic antidepressants and selective norepinephrine serotonin reuptake inhibitors. Trials indicate that venlafaxine, duloxetine, and tricyclic antidepressants (TCAs) have comparable efficacy, but TCAs have a higher incidence of adverse effects. Other antidepressants, such as citalopram, paroxetine, and bupropion have limited evidence supporting their use in neuropathy.

Discussion

Based on the evidence reviewed, venlafaxine and duloxetine should be used as first-line agents. TCAs should be used as second-line agents, due to higher incidence of adverse effects. Other treatment options include citalopram, paroxetine, and bupropion, but data supporting their efficacy is limited.

Pharmacological management of chronic neuropathic pain: revised consensus statement from the Canadian Pain Society

BACKGROUND

Neuropathic pain (NeP), redefined as pain caused by a lesion or a disease of the somatosensory system, is a disabling condition that affects approximately two million Canadians.

OBJECTIVE

To review the randomized controlled trials (RCTs) and systematic reviews related to the pharmacological management of NeP to develop a revised evidence-based consensus statement on its management.

METHODS

RCTs, systematic reviews and existing guidelines on the pharmacological management of NeP were evaluated at a consensus meeting in May 2012 and updated until September 2013. Medications were recommended in the consensus statement if their analgesic efficacy was supported by at least one methodologically sound RCT (class I or class II) showing significant benefit relative to placebo or another relevant control group. Recommendations for treatment were based on the degree of evidence of analgesic efficacy, safety and ease of use.

RESULTS

Analgesic agents recommended for first-line treatments are gabapentinoids (gabapentin and pregabalin), tricyclic antidepressants and serotonin noradrenaline reuptake inhibitors. Tramadol and controlled-release opioid analgesics are recommended as second-line treatments for moderate to severe pain. Cannabinoids are now recommended as third-line treatments. Recommended fourth-line treatments include methadone, anticonvulsants with lesser evidence of efficacy (eg, lamotrigine, lacosamide), tapentadol and botulinum toxin. There is support for some analgesic combinations in selected NeP conditions.

CONCLUSIONS

These guidelines provide an updated, stepwise approach to the pharmacological management of NeP. Treatment should be individualized for each patient based on efficacy, side-effect profile and drug accessibility, including cost. Additional studies are required to examine head-to-head comparisons among analgesics, combinations of analgesics, long-term outcomes and treatment of pediatric, geriatric and central NeP.

Clinical value of tapentadol extended-release in painful diabetic peripheral neuropathy

Painful diabetic peripheral neuropathy is difficult to treat, partially because the underlying mechanism of pain is not fully understood. Various treatment guidelines recommend first-line agents, such as α2-δ ligands, serotonin-norepinephrine reuptake inhibitors, and tricyclic antidepressants but combination therapy of alternative agents including opiates is often warranted. Tapentadol extended-release has a novel dual mechanism of action; it is both a mu-opioid receptor agonist and a norephinephrine reuptake inhibitor. It has been in the spotlight since it was FDA-approved specifically for the treatment of painful diabetic peripheral neuropathy in 2012. Previous reviews of tapentadol have focused on chronic pain. The purpose of this review article is to assess the efficacy and safety of tapentadol extended-release in adult populations with painful diabetic peripheral neuropathy and provide guidance for formulary decisions.

An epidemiological study to assess the prevalence of diabetic peripheral neuropathic pain among adults with diabetes attending private and institutional outpatient clinics in South Africa

OBJECTIVE

To determine the prevalence of diabetic peripheral neuropathic pain (DPNP) among South African adults with type 1 or type 2 diabetes.

METHODS

This cross-sectional study recruited patients with diabetes from 50 institutional/private clinics. DPNP was diagnosed using Douleur Neuropathique 4 (DN4) questionnaire (score ≥4). Health-related quality-of-life (HRQoL) and sleep were assessed with EQ-5D and Daily Sleep Interference Scale (DSIS), respectively.

RESULTS

Prevalence of DPNP was 30.3% (n = 1046). Risk of DPNP was significantly increased in people aged 50-64 years (odds ratio [OR] 1.71, 95% confidence intervals [CI] 1.21, 2.41), with diabetes for ≥10 years (OR 1.55, 95% CI 1.15, 2.08), female patients (OR 1.58, 95% CI 1.18, 2.12), and black patients (OR 1.71, 95% CI 1.19, 2.46). Mean ± SD EQ-5D and DSIS scores were 0.84 ± 0.16 and 0.83 ± 1.90, respectively, in participants without DPNP versus 0.64 ± 0.25 and 3.62 ± 2.96, respectively, in those with DPNP.

CONCLUSIONS

DPNP is widely prevalent in South Africa. Despite its negative impact on HRQoL and sleep, DPNP is inadequately treated. DN4 is an easy-to-use, validated questionnaire that can be used widely as a DPNP screening tool in clinical practice.

Depression and chronic kidney disease: A review for clinicians

OBJECTIVE

To review the recent academic literature surrounding the prevalence, aetiopathology, associations and management of depression in chronic kidney disease (CKD), in order to provide a practical and up-to-date resource for clinicians.

METHODS

We conducted electronic searches of the following databases: MEDLINE, EMBASE and PsycINFO. The main search terms were: depression, mood disorders, depressive disorder, mental illness, in combination with kidney disease, renal insufficiency, dialysis, kidney failure. Separate searches were conducted regarding antidepressant use in CKD.

RESULTS

A number of recent, large and well-conducted studies have confirmed markedly raised rates of depression amongst those with CKD, with meta-analysis suggesting the prevalence of interview-defined depression to be approximately 20%. The interactions between depression and CKD are complex, bidirectional and multifactorial. Depression in CKD has been shown to be associated with multiple poor outcomes, including increased mortality and hospitalisation rates, as well as poorer treatment compliance and quality of life. Clinical evaluation of depression in patients with CKD can be challenging; however, once a diagnosis is made, a range of treatment modalities can be considered.

CONCLUSIONS

Depression is common in CKD and is associated with a significant risk of adverse outcomes. Given the importance of this issue, there is now an urgent need for well-conducted randomised trials of interventions for depression in CKD in order to provide information on the safety and efficacy of treatments.

Conditioned pain modulation: a predictor for development and treatment of neuropathic pain

Psychophysical evaluation of endogenous pain inhibition via conditioned pain modulation (CPM) represents a new generation of laboratory tests for pain assessment. In this review we discuss recent findings on CPM in neuropathic pain and refer to psychophysical, neurophysiological, and methodological aspects of its clinical implications. Typically, chronic neuropathic pain patients express less efficient CPM, to the extent that incidence of acquiring neuropathic pain (e.g. post-surgery) and its intensity can be predicted by a pre-surgery CPM assessment. Moreover, pre-treatment CPM evaluation may assist in the correct choice of serotonin-noradrenalin reuptake inhibitor analgesic agents for individual patients. Evaluation of pain modulation capabilities can serve as a step forward in individualizing pain medicine.

Effect of pain in pediatric inherited neuropathies

OBJECTIVE

Assess the prevalence and impact of pain in children with Charcot-Marie-Tooth (CMT) disease.

METHODS

In this prospective cross-sectional study on children with CMT disease seen at study sites of the Inherited Neuropathy Consortium, we collected standardized assessments of pain (Wong-Baker FACES Pain Rating Scale) from 176 patients (140 children aged 8-18 years, and 36 children aged 2-7 years through parent proxies), along with standardized clinical assessments and quality-of-life (QOL) outcomes. We then developed a series of multivariate regression models to determine whether standardized measures of neuropathy severity, functional impact, or structural changes to the feet explained the observed pain scores.

RESULTS

The mean score on the Wong-Baker FACES Pain Rating Scale was 2 (range 0-5). Increased pain strongly correlated with worse QOL scores but not with more severe neuropathy. Independent determinants of increased pain in children with CMT disease included measures of ankle inflexibility.

CONCLUSION

Pain is present in children with CMT disease and negatively affects QOL. Pain scores do not positively correlate with neuropathy severity but do correlate in limited univariate analyses with measures of ankle inflexibility. Further studies to elucidate the mechanisms of pain may help identify treatments that can reduce pain and improve QOL in patients with CMT disease.

Systematic review and meta-analysis of pharmacological therapies for painful diabetic peripheral neuropathy

BACKGROUND

Painful diabetic peripheral neuropathy (pDPN) is prevalent among persons with diabetes and increases over time. Published guidelines recommend a number of medications to treat this condition providing clinicians with a variety of treatment options. This study provides a comprehensive systematic review and meta-analysis of published pharmacologic therapies for pDPN.

METHODS

The published literature was systematically searched to identify randomized, controlled trials of all available pharmacologic treatments for pDPN (recommended or nonrecommended) reporting predefined efficacy and safety outcomes. Bayesian fixed-effect mixed treatment comparison methods were used to assess relative therapeutic efficacy and harms.

RESULTS

Data from 58 studies including 29 interventions and 11,883 patients were analyzed. Pain reduction over that of placebo on the 11-point numeric rating scale ranged from -3.29 for sodium valproate (95% credible interval [CrI] = [-4.21, -2.36]) to 1.67 for Sativex (-0.47, 0.60). Estimates for most treatments were clustered between 0 and -1.5 and were associated with more study data and smaller CrIs. Pregabalin (≥ 300 mg/day) was the most effective on the 100-point visual analog scale (-21.88; [-27.06, -16.68]); topiramate was the least (-3.09; [-3.99, -2.18]). Relative risks (RRs) of 30% pain reduction ranged from 0.78 (Sativex) to 1.84 (lidocaine 5% plaster). Analysis of the RR ratio of these 2 treatments reveals marginal significance for Sativex (3.27; [1.07, 9.81]), indicating the best treatment is only slightly better than the worst. Relative risks of 50% pain reduction ranged from 0.98 (0.56, 1.52) (amitriptyline) to 2.25 (1.51, 3.00) (alpha-lipoic acid). RR ratio for these treatments was not statistically different (3.39; [0.88, 3.34]). Fluoxetine had the lowest risk of adverse events (0.94; [0.62, 1.23]); oxycodone had the highest (1.55; [1.45, 1.64]). Discontinuation RRs were clustered around 0.8 to 1.5, with those on the extreme having greater uncertainty.

CONCLUSIONS

Selecting an appropriate pDPN therapy is key given the large number of available treatments. Comparative results revealed relative equivalence among many of the studied interventions having the largest overall sample sizes and highlight the importance of standardization of methods to effectively assess pain.