Spinal Cord Stimulation as a Novel Approach to the Treatment of Refractory Neuropathic Mediastinal Pain

Spinal cord stimulation (SCS) offers new hope for patients with neuropathic pain. SCS "neuromodulates" the transmission and response to "painful" stimuli. The efficacy of SCS has been established in the treatment of a variety of neuropathic pain conditions and more recently in refractory angina pectoris, peripheral vascular disease, and failed back surgery syndrome. Recent publications suggest that visceral pain could be successfully treated with SCS. We report the first successful use of a spinal cord stimulator in the treatment of refractory neuropathic mediastinal, esophageal, and anterior neck pain following esophagogastrectomy.     

Neuropathic Pain Syndrome

Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. This article provides information to patients regarding the treatment of neuropathic pain syndrome. It narrates how a doctor might explain neuropathic pain to a patient and particularly discusses the use of anticonvulsants.     

Pharmacotherapy for Neuropathic Pain

Abstract:   Refractory neuropathic pain can be devastating to a patient's quality of life. Ideally, the primary goal of therapy would be to prevent the pain, yet even the most appropriate treatment strategy may be only able to reduce the pain to a more tolerable level. Pharmacotherapy is currently the mainstay of treatment in patients with neuropathic pain, although at present the drugs are used on a mainly "off-label" basis. A wide variety of agents are used, especially antidepressants (ie, tricyclic antidepressants, selective serotonin-reuptake inhibitors) and anticonvulsants, but also opioids and tramadol, topical agents (eg, lidocaine), systemic local anesthetics, and anti-inflammatories. Even so, effective pain relief is achieved in less than half of patients with chronic neuropathic pain. In refractory patients, combination therapy using two agents with synergistic mechanisms of action may offer greater pain relief without compromising the side-effect profile of each agent.     

Topical Capsaicin in Severe Neuropathic Pain

ABSTRACT

A case of severe neuropathic pain in a middle-aged Swiss patient that did not respond well to several routine approaches is described. A topical 8% capsaicin patch was effective. The use, limitations, efficacy, and mechanism of action for this pharmacotherapy are discussed. Perspectives on this case are provided by consultants from the United Kingdom and Sweden are provided.

This feature is adapted from paineurope 2011; Issue 4, ©Haymarket Medical Publications Ltd., and is presented with permission. paineurope is provided as a service to pain management by Mundipharma International, Ltd., and is distributed free of charge to health care professionals in Europe. Archival issues can be accessed via the Web site: http://www.paineurope.com, at which European health professionals can register online to receive copies of the quarterly publication.     

Treatment of Neuropathic Orbital Pain with Gabapentin

We report and discuss a case of severe neuropathic orbital pain refractory to standard analgesics that responded well to treatment with the anticonvulsant gabapentin. Gabapentin may be a useful adjuvant analgesic in the treatment of neuropathic pain.     

Neuropathic Pain: Mechanisms and Treatment Options

Abstract : Neuropathic pain results from damage to the nervous system. The diseases responsible for neuropathic pain are diverse but they may have in common pathophysiological mechanisms. This review will focus on these mechanisms both in the peripheral as well as within the central nervous system. In addition, there will be discussion on the various treatment choices including both pharamcological and interventional options.     

Intrathecal Ziconotide for Neuropathic Pain: A Review

Neuropathic pain is a considerable burden that affects activities of daily living. The management of neuropathic pain can be challenging because of multiple etiologies and complex manifestations. Ziconotide is a nonopioid intrathecal (IT) analgesic option for patients with neuropathic pain refractory to conventional treatments. The objective of this article is to review the published literature on ziconotide for the treatment of neuropathic pain. Relevant publications were identified through searches of all years of 6 databases, which included PubMed, EMBASE, and CINAHL. Search terms used were ziconotide, SNX‐111, MVIIA, Prialt, and neuropathic pain. Publications were included if ziconotide was intrathecally administered (either alone or in combination with other IT agents) to treat neuropathic pain of any etiology and if pain assessment was an outcome measure. Data extracted included study design, IT drug doses, pain outcome measures, and adverse events (AEs). Twenty‐eight articles met the inclusion criteria: 5 were preclinical studies and 23 were clinical studies. In the preclinical studies, ziconotide demonstrated antiallodynic effects on neuropathic pain. Data from double‐blind, placebo‐controlled (DBPC) trials indicated that patients with neuropathic pain reported a mean percent improvement in pain score with ziconotide monotherapy that ranged from 15.7% to 31.6%. A low starting dose and slow titration of ziconotide resulted in an improved safety profile in the aforementioned trials. Common AEs associated with ziconotide include nausea and/or vomiting, dizziness, confusion, urinary retention, and somnolence. Evidence from DBPC trials, open‐label studies, case series, and case studies suggests that ziconotide, as either monotherapy or in combination with other IT drugs, is a potential therapeutic option for patients with refractory neuropathic pain. Additional studies are needed to establish the long‐term efficacy and safety of ziconotide for neuropathic pain.     

Cancer Pain With a Neuropathic Component: A Cross-sectional Study of Its Clinical Characteristics,Associated Psychological Distress,Treatments, and Predictors at Referral to a Cancer Pain Clinic

Context

In patients with cancer pain, identifying a neuropathic pain component (NPC) may inform the selection of subsequent therapeutic interventions.

星形胶质细胞与神经病理性疼痛

星形胶质细胞是中枢神经系统分布最广、数量最多的细胞群体,有着复杂的信号转导系统,通过释放许多神经递质、神经营养因子和细胞因子参与疼痛信号的转导与调控。另外,星形胶质细胞还参与外周和中枢水平神经病理性疼痛的形成和发展。本文主要就星形胶质细胞起源、分类、功能、激活,参与疼痛调节机制,以及与神经病理性疼痛关系等进行文献综述。     

NO Pain: Potential Roles of Nitric Oxide in Neuropathic Pain

Abstract: The disabling human syndrome of “neuropathic pain” is an intractable complication of peripheral nerve injury or degeneration. A complex interaction between injured peripheral axons, sensory neurons and central nervous system signaling is thought to account for it. In this brief review, we present evidence that the free radical signaling molecule, nitric oxide (NO) may act at several levels of the nervous system during the development of experimental neuropathic pain. For example, NO may directly influence injured axons in the periphery, may indirectly influence pain by its role in the process of Wallerian degeneration, and may signal in the dorsal horn of the spinal cord. While it is premature to argue for therapeutic approaches that alter NO actions, it may be an important player in the cascade of events that generate neuropathic pain.     

Validation of the Dutch Version of the DN4 Diagnostic Questionnaire for Neuropathic Pain

Difficulties in diagnosing neuropathic pain in routine clinical practice support the need for validated and easy‐to‐use diagnostic tools. The DN4 neuropathic pain diagnostic questionnaire aims to discriminate neuropathic pain from nociceptive pain, but needs clinical validation. A total of 269 patients with chronic pain in three pain clinics were included in the study of which 248 had analyzable data. The mean duration of pain was 4.9 years. The most frequent etiologies were posttraumatic (36%), (pseudo) radicular (14%), and mechanical back pain (12%). The mean intensity of pain at visit was 5.6 on a 0–10 scale. Hundred and ninety‐six of 248 patients had an identical pain diagnosis from both physicians: 85 had neuropathic pain, 57 had nociceptive pain, and 54 had mixed pain. Among patients with identical diagnoses of neuropathic or nociceptive pain, using a receiver operating characteristic curve analysis, the area under the curve (AUC) was 0.81 for the DN4 7‐item and 0.82 for the 10‐item version. A cutoff point of 5/10 for the full questionnaire resulted in a sensitivity of 75% and a specificity of 79%, while a cutoff point of 4/7 for the partial questionnaire resulted in a sensitivity of 74% and a specificity of 79%. The items “brushing,” “painful cold,” and “numbness” were most discriminating. The DN4 is an easy‐to‐use screening tool that is reliable for discriminating between neuropathic and nociceptive pain conditions in daily practice. Item‐specific scores provide important information in addition to the total score.     

AAPT Diagnostic Criteria for Peripheral Neuropathic Pain: Focal and Segmental Disorders

Peripheral neuropathic pain is among the most prevalent types of neuropathic pain. No comprehensive peripheral neuropathic pain classification system that incorporates contemporary clinical, diagnostic, biological, and psychological information exists. To address this need, this article covers the taxonomy for 4 focal or segmental peripheral neuropathic pain disorders, as part of the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership and the American Pain Society (APS) collaborative to develop a standardized, evidence-based taxonomy initiative: the ACTTION-APS Pain Taxonomy (AAPT). The disorders—postherpetic neuralgia, persistent posttraumatic neuropathic pain, complex regional pain disorder, and trigeminal neuralgia—were selected because of their clinical and clinical research relevance. The multidimensional features of the taxonomy are suitable for clinical trials and can also facilitate hypothesis-driven case-control and cohort epidemiologic studies.

Symptomatic Hyponatremia in Patients on Oxcarbazepine Therapy for the Treatment of Neuropathic Pain

Oxcarbazepine is an FDA approved anticonvulsant medication that has also been used clinically as a treatment for chronic neuropathic pain. Hyponatremia is occasionally seen with the older anticonvulsant carbamazepine, and oxcarbazepine is a derivative of that older drug. Two cases of hyponatremia associated with oxcarbazepine are reported and suggestions for monitoring for and managing this effect are provided.     

Neuropathic Pain and Pharmacological Treatment

Neuropathic pain is a serious chronic condition strongly affecting quality of life, which can be relieved but cannot be cured. Apart from symptomatic management, treatment should focus on the underlying disorder. The estimated prevalence is at least 1% to 5% of the general population. Neuropathic pain is characterized both by spontaneous and evoked pain. A diagnosis of neuropathic pain can usually be established based solely on history and neurological examination. Ancillary investigations may include EMG and computerized tomography/magnetic resonance imaging scans, depending on the localization of the suspected lesion. A limited number of agents, primarily directed at symptom control, are currently approved for use in neuropathic pain. A mechanism‐based approach to pharmacological intervention supports the use of polypharmacy in neuropathic pain.     

Lidocaine 5% Medicated Plaster for Spinal Neuropathic Pain

Spinal cord injuries frequently determine central pain symptoms that are difficult to control. The authors present the case of a 67-year-old suffering from a pleural mesothelioma. During the disease course, he developed a paraplegia syndrome from mesothelioma compression of the spinal cord at T4–T5 level. Following spinal decompression surgery, the patient presented an intense at-level, superficial neuropathic pain syndrome with allodynia and hyperalgesia. After systemic pharmacological therapies had failed, treatment with lidocaine 5% plaster was initiated. The superficial neuropathic symptoms almost completely disappeared within a few days. The lidocaine topical treatment was continued for months with durable analgesic effect.     

The Role of Pacemaker Currents in Neuropathic Pain

Abstract:   Hyperpolarization-activated cation nonselective cyclic nucleotide-gated (HCN) channels mediate pacemaker currents that control basic rhythmic processes including heartbeat. Alterations in HCN channel expression or function have been described in both epilepsy and cardiac arrhythmias. Recent evidence suggests that pacemaker currents may also play an important role in ectopic neuronal activity that manifests as neuropathic pain. Pacemaker currents are subject to endogenous regulation by cyclic nucleotides, pH and perhaps phosphorylation. In addition, a number of neuromodulators with known roles in pain affect current density and kinetics. The pharmacology of a number of drugs that are commonly used to treat neuropathic pain includes effects on pacemaker currents. Altered pacemaker currents in injured tissues may be an important mechanism underlying neuropathic pain, and drugs that modulate these currents may offer new therapeutic options.     

Electroencephalographic Predictors of Neuropathic Pain in Subacute Spinal Cord Injury

It is widely believed that cortical changes are a consequence of longstanding neuropathic pain (NP). In this article, we demonstrate that NP in individuals with subacute spinal cord injury (SCI) has characteristic electroencephalography markers (EEG) that precede the onset of pain. EEG was recorded in a relaxed state and during motor imagination tasks in 10 able-bodied participants and 31 patients with subacute SCI (11 with NP, 10 without NP, and 10 who had pain develop within 6 months of EEG recording). All 20 patients with SCI initially without NP were tested for mechanically induced allodynia, but only 1 patient, who later had pain develop, reported an unpleasant sensation. The EEG reactivity to eye opening was reduced in the alpha band and absent in the theta and beta bands in the patients who later developed pain and was reduced in those who already had pain. Alpha band power was reduced at BA7 in both the relaxed state and during motor imagination in patients who either had or later developed pain compared with those without pain. All SCI groups had reduced dominant alpha frequency and beta band power at BA7. EEG reactivity to eye opening and reduced spontaneous and induced alpha activity over the parietal cortex were predictors of future NP, as well as markers of existing NP.Clinical Trial Registration Number: NCT02178917

Patient-Tailored Combinations of Systemic and Topical Preparations for Localized Peripheral Neuropathic Pain: A Two-Case Report

This report describes two patients with peripheral neuropathic pain (PNP): a 43-year-old man with upper leg PNP and a 75-year-old woman with post herpetic neuralgia of the perineum and vagina. Pain was inadequately managed in both patients for a long time. A patient-tailored approach, including a combination of systemic and topical compounds, required multiple adjustments for each patient before finally achieving adequate pain control. The first patient achieved pain control with a combination of systemically-administered drugs: dipyrone (1 g 3 times a day), pregabalin (300 mg twice a day), duloxetine (60 mg once daily in the morning), and dextromethorphan (60 mg 3 times/day), plus topical compounds (10% ketamine, 5% lidocaine, and 10% ketoprofen) in penetrating enhancing gel, and sublingual ketamine (10 mg) for breakthrough pain. The second patient achieved optimal pain control with dipyrone (500 mg three times per day), pregabalin (150 mg twice a day), dextromethorphan (60 mg three times per day), plus topical compounds (10% ketamine, 0.3% clonidine, 5% diclofenac) in a penetrating enhancing gel. Notably, the individualized approach described herein was made possible through collaboration between a public health pain specialist and a private sector compounding pharmacist, highlighting the importance of such infrequent but, highly desirable collaborations.