Localized neuropathic pain.

Localized neuropathic pain (LNP) is of peripheral origin and is characterized by circumscribed areas of pain with abnormal skin sensitivity or spontaneous symptoms that are characteristic of neuropathic pain, e.g., burning pain. It should be noted that LNP is confined to a specific area no larger than a letter size sheet of paper. LNP accounts for 60 % of neuropathic pain syndromes. There is no single etiology of LNP. The diagnostic approach is similar to that for other neuropathic pain conditions. General diagnostic tools are used to assess clinical features. So far, there are no specific guidelines for the management of LNP; for this reason, guidelines for general neuropathic pain are used. Topical treatments are included as part of second-line strategies in the Canadian Pain Society guidelines. Despite the lack of guidelines, 5 % lidocaine patches and 8 % capsaicin patches have been proven effective in LNP models.

El dolor neuropático localizado (DNL) es de origen periférico y se caracteriza por áreas circunscritas de dolor con sensibilidad anormal de la piel o síntomas espontáneos característicos de dolor neuropático, por ejemplo, dolor urente. Se debe resaltar que el DNL está confinado a un área específica no mayor a una hoja de papel tamaño carta. El DNL representa 60 % de las condiciones de dolor neuropático. No existe una única etiología. El abordaje diagnóstico es similar al de otros síndromes dolorosos neuropáticos. Se utilizan herramientas diagnósticas generales para evaluar las características clínicas. En la actualidad no existen guías específicas de manejo del DNL, por lo que se utilizan las guías para dolor neuropático en general. En las guías de la Sociedad Canadiense de Dolor se incluyen los tratamientos tópicos como parte de las estrategias de segunda línea. Pese a la falta de guías, los parches de lidocaína a 5 % y los parches de capsaicina a 8 % han demostrado ser efectivos en modelos de DNL.

Consenso multidisciplinario de diagnóstico y tratamiento del dolor neuropático periférico y localizado en México.

Neuropathic pain is an entity that causes patient disability and its diagnosis and treatment is a challenge for physicians. In a significant percentage of patients with neuropathic pain, it is restricted to one dermatome or to a particular region of the body; in this case, it is referred to as localized neuropathic pain. There are no Mexican clinical guidelines proposing recommendations for the diagnosis and treatment of localized neuropathic pain in our population. This article presents the recommendations of a multidisciplinary consensus of specialists from different areas involved in the diagnosis and treatment of this type of patients.

El dolor neuropático es una entidad que provoca discapacidad al paciente y su diagnóstico y tratamiento es un reto para los médicos. En un porcentaje importante de pacientes afectados, el dolor neuropático se presenta circunscrito a un dermatoma o a una región concreta del cuerpo, denominándose en ese caso dolor neuropático localizado. No existen guías clínicas mexicanas que postulen recomendaciones para el diagnóstico y tratamiento del dolor neuropático localizado en nuestra población. En este artículo se exponen las recomendaciones de un consenso multidisciplinario realizado con especialistas de distintas áreas implicadas en el diagnóstico y tratamiento de este tipo de pacientes.

Aplicaciones terapéuticas por acción de los cannabinoides.

The interest on cannabinoids became evident between the 1940 and 1950 decades. Although the active substance of the plant was not known, a series of compounds with cannabinomimetic activity were synthesized, which were investigated in animals and clinically. The most widely tested was Δ6a, 10a-THC hexyl. Δ6a, 10a-THC dimethylheptyl (DMHP) antiepileptic effects were studied in several children, with positive results being obtained in some cases. DMHP differs from sinhexyl in that its side chain is DMHP instead of n-hexyl. The first cannabinoid isolated from Cannabis sativa was cannabinol, although its structure was correctly characterized several years later. Cannabidiol was isolated some years later and was subsequently characterized by Mechoulam and Shvo. In 2013, the National Academy of Medicine and the Faculty of Medicine of the National Autonomous University of Mexico, through the Seminar of Studies on Entirety, decided to carry out a systematic review on a subject that is both complex and controversial: the relationship between marijuana and health. In recent years, studies have been conducted with cannabis in several diseases: controlled clinical trials on spasticity in multiple sclerosis and spinal cord injury, chronic, essentially neuropathic, pain, movement disorders (Gilles de Latourette, dystonia, levodopa dyskinesia), asthma and glaucoma, as well as non-controlled clinical trials on Alzheimer's disease, neuroprotection, intractable hiccups, epilepsy, alcohol and opioid dependence and inflammatory processes.

El interés por los cannabinoides se hizo evidente entre las décadas de 1940 y 1950. Aunque no se conocía el principio activo de la planta, se sintetizaron compuestos con actividad cannabinomimética, los cuales fueron investigados en animales y en la clínica. El más probado fue el ∆6a,10a-THC hexilo. Las acciones antiepilépticas del ∆6a,10a-THC dimetilheptil fueron estudiadas en varios niños; en algunos casos se obtuvieron resultados positivos. El ∆6a,10a-THC dimetilheptil se diferencia del sinhexil en que su cadena lateral es dimetilheptilo en vez de n-hexilo. El primer cannabinoide aislado de Cannabis sativa fue el cannabinol, si bien su estructura fue correctamente caracterizada varios años después. El cannabidiol fue aislado algunos años más tarde y caracterizado posteriormente por Mechoulam y Shvo. Durante 2013, la Academia Nacional de Medicina y la Facultad de Medicina de la Universidad Nacional Autónoma de México, a través del Seminario de Estudios sobre la Globalidad, decidieron realizar una revisión sistemática sobre un tema tan complejo como controvertido: la relación entre la marihuana y la salud. En los últimos años se han realizado estudios con cannabis en varias enfermedades: ensayos clínicos controlados sobre espasticidad en esclerosis múltiple y sobre lesiones medulares, dolor crónico fundamentalmente neuropático y trastornos del movimiento (Gilles de Latourette, distonía, discinesia por levodopa), asma y glaucoma, así como ensayos clínicos no controlados sobre Alzheimer, neuroprotección, hipo intratable, epilepsia, dependencia al alcohol y opioides y procesos inflamatorios.

Complex regional pain syndrome type i. An analysis of 7 cases in children.

INTRODUCTION: Complex regional pain syndrome (CRPS) is characterised by the presence of pain accompanied by sensory, autonomic and motor symptoms, usually preceded by a lesion or immobilisation. The clinical course is disproportionate to the initial injury in intensity and in duration. Its distribution is regional, predominantly in limbs. It is classified as type I and type II according to the absence or presence of nerve injury. CASES: We present the cases of seven children, 6 girls and 1 boy, aged 7 to 15 years. Three had a history of previous trauma. In 5 cases, the symptoms were located in the lower limbs. Time to diagnosis was between 4 and 90 days. Three patients had clinical features of anxiety and depression. Imaging and immunological studies were performed to rule out differential diagnoses in all the children. Interdisciplinary treatment was performed with physiotherapy, psychotherapy, and gabapentin or pregabalin. All patients had a good clinical outcome, with no relapses in the follow-up period (between 4 and 30 months). CONCLUSIONS: CRPS is frequently unrecognised in children, leading to family anxiety and unnecessary para-clinical costs. Paediatricians and paediatric neurologists should be aware of this syndrome in order to avoid delay in diagnosis, unnecessary studies, and multiple visits to specialists, with a view to providing effective treatment.

A pain in the pocket: Prevalence of pocket pain in patients with implantation of neuromodulation systems: A retrospective study.

INTRODUCTION: Implantable pulse generator (IPG) is a neurostimulation therapy mediated by electrodes and surgically implanted in a subcutaneous "pocket" used for the control of numerous pathologies. This study examines both the prevalence of pain associated with IPG implantation ("pain pocket syndrome") and its associated characteristics. MATERIALS AND METHODS: 56 patients with an IPG were included in the study. A health questionnaire was conducted to determine the presence of pain associated with the pocket and its neuropathic characteristics, as well as associated aesthetic concerns, location, situations that accentuate or alleviate pain, medications used for baseline and pocket pain control and other factors associated. RESULTS: Pain in the area of implantation of the IPG had a prevalence of 52.6% of patients (n = 27), in our sample, with a mean score on the visual analogic scale (VAS) of 4.9 points [3.9-5.8 points], with neuropathic characteristics in 53.3% (n = 16) of the patients with pain, with differences between the mean VAS score of the female (5.5 [4.3-5.8 points]) and males (3.5 points [2.1-4.9 points]) (p = 0.04). CONCLUSION: Pocket pain is a condition with a higher prevalence than described in previous studies, being of a higher intensity in females, involving a moderate pain in the area of implantation of the neuromodulating therapy. This pain has neuropathic characteristics and could require a repositioning intervention. Hence, more studies in this field should be carried to detect and prevent this syndrome.

[Thermal radiofrequency as an alternative in the treatment of persistent localized neuropathic pain due to entrapment of a collateral nerve of the hand]. / Radiofrecuencia térmica como alternativa en el tratamiento del dolor neuropático localizado persistente por atrapamiento de un nervio colateral de la mano.

Localized neuropathic pain (LNP) is a relatively common cause of musculoskeletal pain, which can be present in up to 60% of neuropathic pain conditions. Its appearance can be associated with numerous pathologies (herpes, diabetes, etc.). A less common cause would be the direct compression of a peripheral nerve branch. Its diagnosis is usually clinical since complementary tests such as neurophysiological tests do not provide definitive data. As therapeutic measures we have oral analgesics, anticonvulsants, analgesic skin patches and interventional actions, including radiofrequency (RF). Thermal RF consists in the transmission of an electric impulse through a needle reaching a controlled increase in temperature with which a nerve ablative injury is achieved. We present a clinical case where thermal RF of the collateral nerve of the hand is proposed as a therapeutic alternative, whose entrapment is the cause of pain, obtaining a satisfactory clinical improvement.

[Involuntary movements of the stump after transtibial amputation: Jumping stump syndrome]. / Movimientos involuntarios del muñón tras una amputación transtibial: síndrome del muñón saltarín.

45-year-old woman with history of hallux valgus surgery and torpid evolution, which led to transtibial amputation. Six months after surgery, she began to experience involuntary movements of the stump such as myoclonus, that were triggered by touch or hip extension, associating worsening of the previous stump and phantom limb pain. During the following year, concurring with change of prosthesis, symptoms progressively worsened, which limited walking. The therapeutic approach to pain and myoclonus was initially pharmacological, without response. Given the clinical and ultrasound suspicion of neuroma in the external popliteal sciatic nerve, it was infiltrated with corticosteroid and anesthetic, and the gastrocnemius with botulinum toxin type A, without success. Finally, the myoclonus disappeared, and the pain decreased after surgical remodeling of the stump and resection of the neuroma. This clinical picture is known as jumping stump syndrome and is a rare complication that must be considered after amputation.

Role of vortioxetine in the treatment of neuropathic pain.

Neuropathic pain is an important and disabling clinical problem, its management constitutes a challenge for healthcare professionals. Vortioxetine is a new antidepressant drug with multimodal action, which gives it a unique profile. Tricyclic antidepressants, in particular amitriptyline, and serotonin and norepinephrine reuptake inhibitors venlafaxine and duloxetine are first-line drugs in the treatment of neuropathic pain. The interaction between the pain and depression binomial is very frequent, being the most frequent psychological complication in patients with chronic pain. This comprehensive and descriptive review summarizes the most relevant pharmacological data on vortioxetine, as well as the specific literature on vortioxetine in neuropathic pain and chronic pain.

Long-lasting disabling photophobia after uneventful cataract surgery.

The case concerns a 54-year-old woman, with a history of fibromyalgia and normal preoperative ocular and systemic study, who presented with a long-lasting disabling photophobia, after sequential bilateral cataract surgery without complications. Photophobia was accompanied by good uncorrected VA, with no pain or subjective eye discomfort, without migraine or indicators of psychic conflict. It was refractory to any prescribed treatment of the ocular surface, finally responding to oral anticonvulsants (carbamazepine) that are frequently used in neuropathic pain. To the best of our knowledge this is the first reported case of a long-lasting disabling photophobia without pain and good VA after cataract surgery.

Effectiveness of monopolar dielectric transmission of pulsed electromagnetic fields for multiple sclerosis-related pain: a pilot study.

INTRODUCTION: Pain is highly prevalent in patients with multiple sclerosis (MS); it is chronic in 50% of cases and is classified as nociceptive, neuropathic, or mixed-type. Pain affects quality of life, sleep, and the activities of daily living. Electrotherapy is an interesting alternative or complementary treatment in the management of pain in MS, with new innovations constantly appearing. MATERIAL AND METHODS: This study evaluates the effectiveness of treatment with monopolar dielectric transmission of pulsed electromagnetic fields (PEMF) for pain associated with MS. We performed a randomised, placebo-controlled clinical trial including 24 patients, who were assessed with the Brief Pain Inventory, the Multiple Sclerosis International Quality of Life questionnaire, the Beck Depression Inventory, and the Modified Fatigue Impact Scale. RESULTS: Statistically significant improvements were observed in maximum and mean pain scores, as well as in the impact of pain on work, personal relationships, and sleep and rest. Not significant differences were found between the treatment and placebo groups. CONCLUSIONS: Treatment with PEMF may be effective in reducing pain in patients with MS, although further research is necessary to confirm its effectiveness over placebo and to differentiate which type of pain may be more susceptible to this treatment.

Role of vortioxetine in the treatment of neuropathic pain. / Papel de vortioxetina en el tratamiento del dolor neuropático.

Neuropathic pain is an important and disabling clinical problem, its management constitutes a challenge for healthcare professionals. Vortioxetine is a new antidepressant drug with multimodal action, which gives it a unique profile. Tricyclic antidepressants, in particular amitriptyline, and serotonin and norepinephrine reuptake inhibitors venlafaxine and duloxetine are first-line drugs in the treatment of neuropathic pain. The interaction between the pain and depression binomial is very frequent, being the most frequent psychological complication in patients with chronic pain. This comprehensive and descriptive review summarizes the most relevant pharmacological data on vortioxetine, as well as the specific literature on vortioxetine in neuropathic pain and chronic pain.

Foot drop after percutaneous treatment with radiopaque gelified ethanol (Discogel®).

Sciatica due to a lumbar disc herniation is a frequent symptom, between 13% and 40% of the general population will experience an episode of sciatica during their lives. Different techniques exist to treat this condition. Among them the percutaneous intradiscal Discogel®. In all the series of patients reviewed treated with Discogel®, so far, there is not any case reported with disc extrusion and significant neurological damage. We present a case of a foot drop, caused by a disc herniation after percutaneous treatment with Discogel®. We hypothesize that the pathogenic mechanism would be the increased intradiscal volume and pressure post-puncture and annulus fibrosus damage, which could produce the disc extrusion. The extrusion of Discogel® material is possible. To the best of our knowledge, this is the first reported case of this complication with this product.

The role of ultrasound guided serratus plane block on chronic neuropathic pain after breast surgery in cancer patient.

BACKGROUND: Breast cancer is the most commonly occurring cancer among women. Among its treatment sequelae is chronic neuropathic pain after breast surgery (CNPBS). Pain management is difficult and classicaly consists in a pharmacological approach, however recent studies have advocated the use of locoregional techniques as adjuvants. Serratus plane block (SPB) has recently emerged as a potential tool for the control of CNPBS. This study aims to evaluate the efficacy and potencial role of the ultrasound-guided SPB on CNPBS. METHODS: A retrospective analysis was performed on 30 patients with CNPBS refractory to drug therapy, who underwent SPB between 2017-2019. The following parameters were analyzed: basal pain, pain at 24 h, 1 week and at 1 month. The Mann-Whitney test was applied. Statistical significance was considered at the level of p < 0.05. All statistical analysis was performed with SPSS 20. RESULTS: 3 patients were excluded. At 24 h, we report pain improvement (at least 30% reduction on basal pain score) on 20 patients and after 1 week on 12. At 1 month after, 22 patients had improved, from these: 11 improved with no therapeutic adjustment; 11 patients improved with therapeutic adjustment (8 in gabapentinoid monotherapy, 3 with introduction of polytherapy). 5 patients didn't improve. CONCLUSION: Our study demonstrated SPB as a valid alternative for CNPBS management when pharmacologic therapy has been proven insufficient, with no side effects reported. Randomized studies are needed to assess the magnitude of SPB on CNPBS and to identify the patients who benefit the most from SPB.

The role of ultrasound guided serratus plane block on chronic neuropathic pain after breast surgery in cancer patient. / Papel del bloqueo ecoguiado del plano del músculo serrato en el dolor neuropático crónico tras una cirugía de mama en una paciente de cáncer.

BACKGROUND: Breast cancer is the most commonly occurring cancer among women. Among its treatment sequelae is chronic neuropathic pain after breast surgery (CNPBS). Pain management is difficult and classicaly consists in a pharmacological approach, however recent studies have advocated the use of locoregional techniques as adjuvants. Serratus plane block (SPB) has recently emerged as a potential tool for the control of CNPBS. This study aims to evaluate the efficacy and potencial role of the ultrasound-guided SPB on CNPBS. METHODS: A retrospective analysis was performed on 30 patients with CNPBS refractory to drug therapy, who underwent SPB between 2017-2019. The following parameters were analyzed: basal pain, pain at 24 hours, 1 week and at 1 month. The Mann-Whitney test was applied. Statistical significance was considered at the level of p < 0.05. All statistical analysis was performed with SPSS 20. RESULTS: 3 patients were excluded. At 24 hours, we report pain improvement (at least 30% reduction on basal pain score) on 20 patients and after 1 week on 12. At 1 month after, 22 patients had improved, from these: 11 improved with no therapeutic adjustment; 11 patients improved with therapeutic adjustment (8 in gabapentinoid monotherapy, 3 with introduction of polytherapy). 5 patients didn't improve. CONCLUSIóN: Our study demonstrated SPB as a valid alternative for CNPBS management when pharmacologic therapy has been proven insufficient, with no side effects reported. Randomized studies are needed to assess the magnitude of SPB on CNPBS and to identify the patients who benefit the most from SPB.

Quantitative Sensory Testing in pain assesment and treatment. Brief review and algorithmic management proposal. / Test sensitivos cuantitativos («Quantitative Sensory Testing¼) en el diagnóstico y tratamiento del dolor. Breve revisión y propuesta de protocolización de empleo.

Quantitative Sensory Testing (QST) is used to globally analyze the nociceptive system in order to obtain a more objective understanding of pain perception. In recent years, QST has become a common tool in many pain clinics and anesthesiology departments worldwide. In 2013, the Neuropathic Pain Special Interest Group of the IASP put forward the first recommendations for conducting QST in clinical practice and research. However, the wide variety of QST methodologies and standards in the literature make it difficult to generalize the used of this tool in clinical practice. In this study, we present the basic concepts of QST, the type of tests and devices used, how they are applied, and the role of QST in anesthesiology and pain management.

[Small fibre neuropathy: A review]. / Neuropatía de fibras pequeñas: una revisión.

Small fibre neuropathy is a disorder of the peripheral nervous system for which main clinical manifestation is chronic neuropathic pain, often accompanied by alterations of the autonomic nervous system. This disease affects the small diameter myelinated (Aδ) and non-myelinated nerve fibres (C). Its causes are primary or secondary, such as metabolism defects, infection, and autoimmune, neurological or toxic diseases, among others. Routine neurophysiological tests are usually negative. Diagnosis can be made with complementary tests which are difficult to access from Primary Health Care. These include microneurography, and the sensory stimulation test; but the most used technique is the skin biopsy. Treatment is directed at the causes and the neurological symptoms. Due to the variability of symptoms that can be presented, the importance of being aware of this condition is emphasised in order to reach a diagnosis and offer the appropriate treatment.

Neuropathic pain in Systemic Sclerosis patients: A cross-sectional study.

OBJECTIVES: To investigate if patients with Systemic Sclerosis (SSc) show a higher prevalence of neuropathic pain (NP) in comparison with controls. To study the relationship between clinical variables of the disease and NP among SSc patients. MATERIAL AND METHODS: 48 patients and 45 controls were included. Presence of NP was assessed applying the DN4 "Douleur Neuropathique en 4 Questions" questionnaire. Different clinical variables were also assessed in patients. Statistical analysis included parametric, nonparametric tests and multivariate logistic regression. RESULTS: NP was significantly higher in SSc patients (56.2% vs 13.3%, p<0.001). Mean Modified Rodnan Skin Score was independently associated with the presence of NP (p<0.05, OR 1.90). CONCLUSIONS: Peripheral nervous system involvement in SSc is not well studied and, as far as the authors are aware, this is the first study published evaluating NP in SSc patients and controls. These findings should raise the awareness of the clinician to recognize and address the presence of NP in these patients, especially in those with severe skin involvement.

Photophobia and neuropathic pain in Sudecks syndrome. / Fotofobia y dolor neuropático en el síndrome de Sudeck.

The case is presented of a 14 year-old patient diagnosed with Sudeck's syndrome secondary to uneventful foot trauma. The patient complained of decreased visual acuity along with photophobia and intense ocular pain not correlated with the exploratory findings. Sudeck's syndrome is an idiopathic neuropathic inflammatory disease characterised by disproportionate pain, unrelated to a previous traumatic event, which can evolve to severe and generalised pain. A new explanation has recently described this as "neuropathic eye pain" for those patients with severe eye pain that do not correlate with clinical signs. In the case presented here, the pain became widespread and led to photophobia and very intense ocular neuropathic pain. It is believed that this was the cause of the visual decrease presented by this patient. It is proposed that the Sudeck syndrome should become part of the differential diagnosis of neuropathic eye pain.

[Update in the pharmacological treatment of neuropathic pain]. / Actualización en el tratamiento farmacológico del dolor neuropático.

We provide an updated review of the pharmacological treatment of neuropathic pain, with emphasis on the latest evidence-based recommendations. Drugs proposed as first line include tricyclic antidepressants (particularly amitriptyline), serotonin-noradrenaline reuptake inhibitors (particularly duloxetine), pregabalin and gabapentin. Second-line treatments include 5% lidocaine medicated plasters and capsaicin 8% patches, only for peripheral neuropathic pain and tramadol; whereas potent opioids and botulinum toxin A (for peripheral neuropathic pain) are considered third-line treatments. Future perspectives include the development of new drugs and a more personalised therapeutic approach, which is made possible by recent progress in the assessment and understanding of neuropathic pain.

Emerging therapies in clinical development and new contributions for neuropathic pain. / Terapias emergentes en desarrollo clínico y nuevas aportaciones en dolor neuropático.

Neuropathic pain is very challenging to manage because of the heterogeneity of aetiologies, symptoms, and underlying mechanisms. Conventional oral therapies have been limited by negative factors such as systemic side effects, drug-drug interactions, slow onset of action, the need for titration, multiple daily dosing, as well as the potential risk of addiction, dependence, withdrawal symptoms and abuse. Therefore, new therapeutic perspectives are justified. New drugs that act on different therapeutic targets are currently in preclinical development or in their first phases of clinical development. In this review, focus will be directed specifically on new pharmacological treatments for neuropathic pain for which clinical data are already available, including older and known drugs with new data on their anti-neuropathic activity.