[Characteristics of pain in oncologic disease of the knee]. / Caracterización del dolor de la rodilla con patología oncológica.

BACKGROUND: 10% of > 55-year-old adults suffer some kind of non-neoplastic knee pain and 75% of the musculoskeletal neoplastic disease develops in the knee. OBJECTIVE: to identify clinical characteristics of knee pain in neoplastic knee pathology. METHODS: after appropriate authorization of the Local Committee of Investigation and under informed consent, we made a crosssectional and a risk analysis study. We included 160 patients who were seeking medical help due to knee pain. They answered a standardized questionnaire relating to the characteristics of their pain symptomatology. Data were integrated into two groups with knee pain; a) neoplasic (cases, n = 65), b) non-neoplasic (controls, n = 95) and analyzed (SPSS v.15™). We used homogeneity tests between groups (p > 0.05); inferential analysis (Student t test, χ(2)) and risk assessment (OR), p ≤ 0.05, (CI 95%), Statistical power was > 0.80. RESULTS: female gender predominated (55%); age was 40.3 ± 19.6 years. The most prevalent diagnoses were knee osteoarthritis 37% for non-neoplasic group; giant cell tumor 10% for benign neoplasic group and osteosarcoma 6.1% for neoplasic malignant group. Knee pain lasting < 4 months (OR 7.6; CI 95% 3.48-16.5) and severe intensity (OR 5.7; CI 95% 2.82-11.64), constant pain (OR 2.9; CI 95% 1.37-6.36), rapidly progressive fluctuation (OR 31; CI 95% 7.01-137) and nocturnal predominance (OR 7.72; CI 95% 3.2-18.5) were characteristics of neoplasic knee pain. CONCLUSIONS: the neoplasic knee pain was characterized for a rapid onset, severe and constant pain, progressive, fluctuation and predominantly by night-time.

[Pain characteristics in HIV/AIDS patients]. / Características del dolor en el enfermo con VIH/sida.

BACKGROUND: Human immunodeficiency virus infection (HIV), affects 0.6 % of world population and 0.3 % of the adult population in Mexico. Pain, in this group, is frequently not identified by the health care team, is poorly defined, and undertreated. Our objective was to evaluate the prevalence of pain and its characteristics in Mexican HIV patients. METHODS: HIV diagnosed patients were included. Social and demographic information about pain characteristics, response to analgesic treatment and the presence of comorbidities were analyzed. The illness status was identified and CD4 cell count was documented. RESULTS: Pain was identified in 11 of 55 cases. Mean time of pain onset was 26 months (SD 28.6). Mean pain intensity by visual analogue scale was 7 (SD 2.3), and by verbal analogue scale proportions were reported as follows: 18 % mild, 36.5 % moderate, and 45 % severe pain. CONCLUSIONS: We observed that pain appeared in 20 % of subjects. CD4 count was observed to be related to pain decrease. Type of study and sample size does not permit a definite interpretation of the results; therefore a generation of prospective studies with larger samples is needed.

Absence of histological changes after the administration of a continuous intrathecal clonidine in Wistar rats.

BACKGROUND: The administration of epidural and spinal clonidine has demonstrated an antinociceptive effect in animals and humans. For that reason, its spinal administration has been proposed as an adjuvant in chronic pain management. However, there is limited information about its possible neurotoxic effect after its continuous neuraxial administration. METHOD: Twelve male Wistar rats were randomly divided into two groups. Using an osmotic mini-pump a continuous infusion of intrathecal clonidine, (21.4 micrograms/day, Group A) or saline solution (Group B), was administered for 14 consecutive days. For evaluating the neurological damage a neuropathological analysis of the spinal cord was performed by light microscopy. RESULTS: Neurohistopathologic examination of the spinal cord specimens failed to show evidence of neurotoxic damage in either group. CONCLUSIONS: These findings showed that continuous intrathecal administration of clonidine did not produce evidence of histological neurotoxicity; therefore it is possible that continuous administration of intrathecal clonidine might be a safe option for treatment of chronic intractable pain; however, further investigations are necessary for evaluating diverse doses and periods of time, and to define its possible behavioral effects.

Effect of acute gouty arthritis on sleep patterns: a preclinical study.

BACKGROUND: It has been demonstrated that the interrelation between pain and sleep produces changes in sleep patterns and pain perception. Although some evidences suggest that sleep and pain may interact in a complex way, polysomnographic studies in animals with acute nociception are limited in number. AIMS: This study was carried out in order to evaluate the effect of intra-articular knee injection of uric acid on sleep-wake patterns. METHODS: Surgical electrode implantation was performed in seven anesthetized Wistar rats to carry out 10 h polysomnographic recordings. Acute nociception was induced by the intra-articular administration of 30% uric acid crystals into the knee joint of the right hind limb. Two recordings before and after intra-articular drug administration were obtained. Sleep-wake parameters were classified as (i) wakefulness (W), (ii) slow wave sleep (SWS), and (iii) rapid eye movement (REM) sleep. Frequency and duration from each parameter were evaluated under the two above-mentioned conditions. RESULTS: Intra-articular administration of uric acid induced: (i) an increased duration of wakefulness (p=0.014), (ii) a decrement in the duration (p=0.001) and number of events (p=0.027) in REM sleep, and (iii) a decrement in the total sleep time (p=0.001). SWS did not present statistical differences between groups. CONCLUSIONS: These data suggest that a nociceptive stimulus, induced by the intra-articular administration of uric acid, alters the sleep-wake equilibrium with REM sleep being particularly altered. However, further research concerning pain-sleep interaction is needed.

Evaluación del consumo de medicina herbal en el enfermo con dolor: Un estudio piloto / Evaluation of the consumption of herbal medicine in the patient with pain: A pilot study

Antecedentes: En México, se estima que cerca del 80% de la población utiliza la medicina herbal para el alivio de sus enfermedades. En personas que padecen una afección crónica e incurable se ha documentado el uso de esta forma de medicina; dado a que el dolor es un padecimiento que cumple con estas características, es posible que en estos sujetos se identifique esta tendencia. Son escasos los reportes acerca de esta conducta en la población masculina. Por tal motivo, el objetivo del presente estudio, es el de evaluar dichas tendencias en hombres con dolor. Material y métodos: Se realizó un estudio piloto, descriptivo y transversal a 35 sujetos. El instrumento de evaluación se aplicó mediante entrevista directa; recabando información acerca de sus características demográficas (grupo de edad, estado civil y años de estudio), frecuencia de consumo de medicina herbal (en algún momento de la vida, durante el último mes o semana), y el tipo de medicina herbal utilizada. Resultados: 25 fueron completadas «ad integrum¼ y susceptibles de análisis; observando que 96% de los sujetos, han consumido medicina herbal en algún momento de su vida. En los consumidores de medicina herbal se obtuvieron 25 compuestos diferentes; identificando a la manzanilla como el más frecuente (14%). Conclusiones: Estos datos sugieren que el consumo de medicina herbal es una práctica común y que se emplean una amplia gama de compuestos; así mismo, se requieren otros estudios con un número mayor de sujetos para evaluar cabalmente el empleo de la MAC en diversos grupos poblacionales.

[Clinical pattern of patients cared for at pain clinic by first time]. / Característkicas de los enfermos que acuden a clínicas del dolor por primera vez.

BACKGROUND: Epidemiological studies about frequency and prevalence of chronic pain in Mexico are scarce. However, it has been documented that chronic pain is a frequent complain in general population and mainly in older adults. It influences physical patient capacity and it impacts social health services with its expensive cost. Our objective was to identify the clinical pattern of patients attending at a Pain Clinic by first time. METHODS: We conducted a descriptive-retrospective study, in a five years period, with patients attending a Pain Clinic by first time. We collected demographic data and information about the cause of pain (malignant vs. non-malignant etiology), its intensity by visual analogue scale (VAS), and type (somatic, visceral, neuropathic and mixed). RESULTS: 1453 clinical records were analyzed. Women were more affected; the average age was 59 +/- 16 years; non-malignant pain and neuropathic pain were more frequent; the intensity average was 6 +/- 2, and it increases with age. CONCLUSIONS: It is necessary to generate epidemiological studies to fundament health policies regarding the management of these patients.

[Anxiety and depression in patients with chronic pain: neuropathic and nociceptive]. / Ansiedad y depresión por dolor crónico neuropático y nociceptivo.

OBJECTIVE: To describe and compare anxiety and depression symptoms between two group patients with neuropathic and nociceptive pain those arrive for first time to a clinic of pain. METHODS: Non-experimental, exploratory and descriptive design. Seventy-eight patients that arrive the first time to a clinic of pain were evaluated; those patients were divided in two groups: neuropathic pain with 44 patients and nociceptive pain with 34 patients. To evaluate anxiety and depression we use the Anxiety and Depression Scale (HAD), this scale is adapted and validated in Mexico. RESULTS: From the 78 patients in the study, the 76.9% were female and 23.1% were male. The age average was (56.9 +/- 16.8 year-old for neuropathic pain and 63.1 +/- 17.2 year-old for nociceptive pain). The reliability of the scale HAD was evaluated by the Chronbach's alpha analysis with an r = 0.826. There was no significance difference in anxiety and depression between types of pain, but after analyzing all of the patients we found that anxiety was more frequent than depression p < 0.0001. CONCLUSIONS: Independently of the algological diagnosis, patients presented almost the same affective symptoms.

[Burden, anxiety and depression in patient's caregivers with chronic pain and in palliative care]. / Sobrecarga, ansiedad y depresión en cuidadores primarios de pacientes con dolor crónico y terminales.

BACKGROUND: In Mexico there are few studies about the psychological characteristics of the person that voluntary and in a complete sense assumes the role of responsible of a patient. The purpose of this study was to assess and compare the levels of burden, anxiety and depression of 56 caregivers of patients with chronic pain with the ones of 35 caregivers of terminally ill patients. METHODS: The study was conduced at the Chronic Pain and Palliative Medicine Department of the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán". We used the Spanish version of the Burden Interview and the Informal Primary Caregiver Health Survey. RESULTS: Both groups went over the cut off point of the Burden Scale even though no significative differences between groups were found nor in burden or in anxiety. The caregivers of terminal patients had more depression symptoms and a greater perception of the impact of the care activity in their mood. Positive correlations between burden and depression, depression and anxiety and burden and anxiety were found. CONCLUSIONS: All caregivers reported multiple depression symptoms--greater if they cared terminally ill patients--so, it may suggest that the patient's illness directly influences the depression symptoms of their caregivers. This study can help to develop intervention programs directed to help this population that is the principal support of the patient's treatment.

[Anti-hyperalgesic effect of one combination of morphine and gabapentin in neuropathic pain induced by chronic constriction injury in rat]. / Efecto anti-hiperalgésico de una combinación de morfina y gabapentina en dolor neuropático inducido por constricción crónica en rata.

BACKGROUND: Neuropathic pain is associated with disease or injury to the peripheral or central nervous system, which is considered particularly difficult to treat due to its diverse etiology and underlying physiopathological mechanisms. Recent experimental and clinical data support the potential of pharmacotherapy using a combination of drugs for neuropathic pain. METHODS: In order to assess a possible synergistic anti-hyperalgesic interaction, the anti-hyperalgesic effects of morphine and gabapentin, single-dose administered either separately or in combination, were determined using the von Frey test in a rat model of neuropathic pain (Bennett model). RESULTS: Time course analysis showed that morphine (3.2 mg/kg s.c.) and gabapentin (17.8 mg/kg s.c.) individually reached their maximum effect at 60 min after treatment, producing an anti-hyperalgesic effect of 51.7+/-10.5% and 55.0+/-11.7%, respectively, whereas the combination morphine + gabapentin (3.2+17.8 mg/kg s.c.) produced an almost total anti-hyperalgesic effect at 30 min (96.7+/-2.1%) and at 60 min showed 100% anti-hyperalgesia. This anti-hyperalgesic effect remained during 180 min of observation. Analysis of global effects as area under the curve of time course showed that the nature of the anti-hyperalgesic interaction of the analyzed dose had an additive effect. There was no significant difference observed in the theoretical sum of anti-hyperalgesic effect produced by each drug alone (225.4+/-29.1 area units, au) compared with the corresponding effects produced by the combination of drugs (263.33+/-3.3 au). CONCLUSIONS: These findings are useful in determining the type of interaction that these drugs produce using this combination ratio in neuropathic pain.

[Antinociceptive effects of the combination metamizol + morphine in rats with intense pain (arthritic gout-type pain produced with AU)]. / Efectos antinociceptivos de la combinación metamizol+morfina en ratas con dolor intenso (artritis de tipo "gota" producida por ácido úrico).

BACKGROUND: The antinociceptive effects of metamizol and morphine administered either separately or in combination were determined in the "Pain-Induced Functional Impairment Model in the Rat" (PIFIR antinociceptive model). METHODS: Intense nociception (or intense pain) was induced by the intra-articular injection of uric acid (50%) in the right hind limb inducing its dysfunction. Animals then received analgesic agents, and the recovery of functionality over time was assessed as an expression of antinociception. RESULTS: Metamizol (177.8 mg/kg s.c.) or morphine (3.2 mg/kg s.c.) separately resulted in a lower antinociceptive effect (22.1+/-5.4 area units [au] and 31.8+/-9.4 au, respectively). Moreover, the combination of metamizol (177.8 mg/kg) with morphine (3.2 mg/kg) resulted in a potentiation (293.7+/-16.6 au). The antinociceptive effect observed using the combination was significantly greater than expected on the basis of addition of the individual effects. The percent change in antinociceptive effects, using the combination, was 444.9%. CONCLUSIONS: This represents the first study to show that metamizol + morphine can produce potentiation of their antinociceptive effects in intense pain.

[Practice guidelines for pain management in Mexico]. / Parámetros de práctica para el manejo del dolor en México.

BACKGROUND: It has been documented that pain, in its diverse modalities, is the most common cause of medical attention in Mexico. Due to the increased frequency, pain management has been under consideration in health programs. On the other hand, inadequate pain management can cause severe physical, psychoaffective, and socioeconomic repercussions for patients, families, and public health services. Despite this panorama, there has been no agreement to establish better diagnostic and therapeutic methods. METHODS: Three consensus groups were reunited in different times; those were integrated by medical experts from private and public institutions and form diverse states of the Mexican Republic. To assure the development of these practice guidelines, these experts had experience in the assessment and treatment of painful conditions. Following the methodology used for other consensus groups, diverse meetings were held to review medical evidence about the assessment and treatment of acute, perioperative and cancer pain. RESULTS: A series of recommendations were obtained and classified according to their methodological strength. CONCLUSIONS: As a result of these meetings, a series of recommendations based on the medical evidence were obtained. These recommendations are outlined in three practice guidelines that are intended to allow Mexican practitioners to provide optimal management for painful conditions.

[Importance of the obstructive sleep apnea disorder for perioperative medicine]. / El síndrome de apnea obstructiva de sueño y su importancia en la medicina perioperatoria.

Obstructive sleep apnea (OSA) is a common sleep-related disorder among the general population. This disorder occurs in all sleep stages, although is more intense during the REM sleep (rapid eye movement). In this stage appears generalized muscle atony, which includes the hypopharyngeal muscles; this causes narrowing of the upper airway lumen, difficult inside/outside air movement and mechanical obstruction. OSA is considered a risk for: a) difficult airway intubation/ventilation; b) increase of cardiovascular morbidity; c) development of hypoxia and hypercarbia during spontaneous or assisted ventilation techniques. For these reasons, it is possible to assume that OSA may increase the perioperative risk and should be timely and properly ascertained. The main objective of this paper is to review the effect of OSA in patients undergoing anesthetic and surgical procedures, whether it increases the perioperative risk, and the advantages of its timely identification and assessment when carrying out the pre-anesthetic evaluation.

[High tibial dome osteotomy complications in genu varum patients]. / Complicaciones en pacientes con osteotomía tibial proximal alta en domo por genu varo.

OBJECTIVE: To identify if pre-surgical risk factors or the surgical technique were associated with the complications of the osteotomy in genu varus patients. METHODOLOGY: A case-control study was conducted in patients that underwent Maquet proximal tibial osteotomy for treatment of genu varus between January and December 2003. The risk factors were the following: age 50 or more years old, comorbidity such as type 2 diabetes, hypertension, rheumatoid arthritis, overweight and obesity (BMI > or = 25 and > or = 30), duration of ischemia longer than 60 min and local pain. Cases were those who developed one or more complications. Descriptive and inferential statistical analyses were performed. RESULTS: One hundred and thirty-four patients were included, among which 53% had complications. None of the risk factors were statistically significant (p > 0.05). CONCLUSIONS: None of pre-surgical risk factors were associated with the complications of osteotomy; therefore, these could be attributable to the surgical technique. It is necessary to outweigh the temporary benefits of the tibial osteotomy versus the increase in the risk of complications when performing total knee arthroplasty.

Parámetros de práctica para el manejo del dolor en cáncer: Grupo de Consenso para el Manejo del Dolor en Cáncer / Practice guidelines for cancer pain management: Task Force for Cancer Pain Management

El dolor por cáncer es un problema frecuente en nuestro medio, se presenta en 80 a 90 % de los pacientes y en aproximadamente 90 % de ellos se resuelve con medidas relativamente sencillas. No obstante, aproximadamente 40 % de los pacientes se encuentra insatisfecho con el médico o la enfermera respecto al manejo de su dolor. Por tal motivo, se convocó a un grupo de consenso con la finalidad de generar parámetros de práctica clínica fundamentados en la evidencia publicada y en la opinión de los expertos. Este grupo estuvo integrado por 31 médicos líderes de opinión es este campo, quienes con base en 599 documentos emitieron esta serie de recomendaciones, identificadas cada una según su nivel de evidencia.

Cancer pain is a frequent medical problem in our society. This syndrome affects from 80 to 90% of cancer patients and can be solved with relatively simple measures in 90% of the cases. Approximately 40% of cancer patients reported to be unsatisfied with the physician or nurse about their pain management. For these reasons, we gathered a task force in order to generate practice guidelines based on medical evidence and on the opinion of experts in this area. These guidelines were generated by a task force of 31 physicians who were leaders in this field and based on 599 papers selected by a previous literature search. This group evaluated the results of this search in three work sessions, during which a level of evidence was assigned to each recommendation.

[Algological treatment of trigeminal neuralgia. Experience of 15 years]. / Tratamiento algológico de neuralgia del trigémino. Experiencia de 15 años.

BACKGROUND: We present the experience in the treatment of trigeminal neuralgia (TN) during 15 years in one institute, evaluating epidemiological variables and clinical presentation, and comparing the results obtained with different treatments available. METHODS: A retrospective, descriptive study was carried out by reviewing cases diagnosed by the Neurology Service, such as TN, and treated by the Pain Medicine and Palliative Care Unit of the Insituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubíran," from January 1, 1998 to December 31, 2003. Age, sex, type of neuralgia, anatomical site affected and intensity of pain were evaluated by means of the Analogue Visual Scale (AVS). The following treatments were evaluated (pharmacologic, surgical, and blockade of Gasser ganglion). Descriptive statistics, linear regression and bivariate correlation were used (statistical package SPSS). RESULTS: Fifty two cases were studied with a female predominance (2:1). Average age was 60 years. Clinical presentation most frequently was typical neuralgia (51.9%), right predominance (59.6%) and affected branch V2 (50%). In 88%, pharmacological treatment was used. The reduction of pain was 74% in all cases, with r-.765 for the pharmacological treatment, r-.715 in the blockade of the Gasser ganglion, and r-.901 for surgical treatment (p < 0.01). CONCLUSIONS: In the experience of the INCMNSZ, treatment of choice in most cases of TN is pharmacological, with surgical treatment useful in cases where vascular alterations were identified.

[Practice guidelines for neuropathic pain management]. / Parámetros de práctica para el manejo del dolor neuropático.

UNLABELLED: Neuropathic pain (NP) is a heterogeneous entity with wide diversity of symptoms. Despite the controversies regarding its definition and classification, which difficult its epidemiology, it has been estimated that 4 million people, in USA develop NP. OBJECTIVE: A task force was created to generate a series of recommendations which facilitate the decision making and therapeutic approach of this kind of pain. METHOD: A search of medical literature was made in different electronic data bases (MEDLINE, EMBASE, COCHRANE); after this search we conducted three work-sessions and evaluated the evidence regarding the diagnosis and treatment of pain in painful diabetic poli-neuropathy, post-herpetic neuralgia, and trigeminal neuralgia were evaluated. RESULTS: We found 329 documents for further analysis, and with the aid of the literature results we generate this practice guidelines.

Parámetros de práctica para el manejo del dolor neuropático / Practice guidelines for neuropathic pain management

Neuropathic pain (NP) is a heterogeneous entity with wide diversity of symptoms. Despite the controversies regarding its definition and classification, which difficult its epidemiology, it has been estimated that 4 million people, in USA develop NP. Objective. A task force was created to generate a series of recommendations which facilitate the decision making and therapeutic approach of this kind of pain. Method. A search of medical literature was made in different electronic data bases (MEDLINE, EMBASE, COCHRANE); after this search we conducted three work-sessions and evaluated the evidence regarding the diagnosis and treatment of pain in painful diabetic polineuropathy, post-herpetic neuralgia, and trigeminal neuralgia were evaluated. Results. We found 329 documents for further analysis, and with the aid of the literature results we generate this practice guidelines.

El dolor neuropático (DN) es una entidad heterogénea con una sintomatología diversa. Las controversias existentes respecto a su definición y clasificación dificultan conocer su epidemiología, a pesar de esto se ha estimado que cerca de cuatro millones de personas en Estados Unidos son portadoras de este problema médico. Objetivo. Se conformó un grupo de consenso con la finalidad de crear recomendaciones médicas que faciliten la toma de decisiones y el abordaje terapéutico del mismo. Método. Se realizó una búsqueda en la literatura en diferentes bases de datos electrónicas (MEDLINE, EMBASE, COCHRANE). Se efectuaron tres sesiones de trabajo en las cuales se evaluaron las evidencias médicas científicas sobre el diagnóstico y tratamiento de la polineuropatía diabética dolorosa, la neuralgia postherpética y neuralgia trigeminal. Resultados. Se encontraron 329 documentos para su análisis, con base en este sustento bibliográfico se delinearon estos parámetros de práctica.

[Practice guidelines for cancer pain management. Task Force for Cancer Pain Management]. / Parámetros de práctica para el manejo del dolor en cáncer. Grupo de Consenso para el Manejo del Dolor en Cáncer.

Cancer pain is a frequent medical problem in our society. This syndrome affects from 80 to 90% of cancer patients and can be solved with relatively simple measures in 90% of the cases. Approximately 40% of cancer patients reported to be unsatisfied with the physician or nurse about their pain management. For these reasons, we gathered a task force in order to generate practice guidelines based on medical evidence and on the opinion of experts in this area. These guidelines were generated by a task force of 31 physicians who were leaders in this field and based on 599 papers selected by a previous literature search. This group evaluated the results of this search in three work sessions, during which a level of evidence was assigned to each recommendation.

[Practice guidelines for the management of acute pain]. / Parámetros de práctica para el manejo del dolor agudo.

Acute pain is a frequent entity in the hospital setting and the complexity of its management results in the necessity for practice guidelines to assist health care personnel in decision making for treatment of pain. In Mexico, as in other countries, different task forces have provided recommendations in order to achieve this goal. The present report presents the results obtained by a multidisciplinary group who explored the actual state of acute pain in the country using a questionnaire. Meanwhile, they also analyzed the scientific evidence contained in the literature. The results of these efforts are contained in the practice guidelines proposed by this task force.