Referral pathways for chronic pain patients from Canadian emergency departments: emergency physicians' practices, perspectives, and recommendations.

BACKGROUND: Patients with chronic pain account for 12-20% of total emergency department (ED) and was the primary presenting concern among 37% of patients who visited the ED > 12 times per year. Despite this, emergency physicians receive little focused training managing these patients, and there is a paucity of effective referral pathways from EDs, despite strong evidence that chronic pain is best treated longitudinally in multidisciplinary clinics. This study sought to explore the practices, perspectives, and recommendations of current Canadians emergency physicians in better serving the chronic pain patient (CPP) population in the ED. METHODS: An electronic cross-sectional survey was administered to members of the Canadian Association of Emergency Physicians (CAEP), consisting of 16 multiple choice and numerical response questions. Responses were summarized descriptively as percentages and as the median and inter-quartile range (IQR) for quantitative variables. RESULTS: The study was completed by 169/1635 respondents for a response rate of 10%. The most common presentations respondents saw were neuropathic pain and centrally mediated disorders (23% each) and low back pain (19%). 86% of respondents felt that chronic pain patients did not get appropriate referrals from the ED, and 70% of respondents were unaware of where they could even refer chronic pain patients from the ED. 96% of respondents felt that their ED did not have an effective referral pathway for chronic pain patients. Rapid access clinics for common conditions, reduced pain clinic wait times, and clear ED referral pathways were the commonest recommendations by respondents. CONCLUSION: There is a clear need to increase the accessibility to outpatient pain medicine clinics for chronic pain patients presenting to the ED. ED and pain medicine providers must collaborate to establish mutually beneficial referral pathways from EDs, and to advocate for increased funding for rapid access outpatient pain clinics.

RéSUMé: CONTEXTE: Les patients souffrant de douleur chronique représentent de 12 à 20% de l'ensemble du service d'urgence (SU) et constituaient la principale préoccupation chez 37% des patients qui ont visité le SU > 12 fois par année. Malgré cela, les urgentologues reçoivent peu de formation ciblée sur la gestion de ces patients, et il y a peu de voies d'aiguillage efficaces de la part des urgences, malgré de solides preuves que la douleur chronique est mieux traitée longitudinalement dans les cliniques multidisciplinaires. Cette étude visait à explorer les pratiques, les perspectives et les recommandations des médecins d'urgence canadiens actuels pour mieux servir la population de patients souffrant de douleur chronique (RPC) à l'urgence. MéTHODES: Un sondage transversal électronique a été administré aux membres de l'Association canadienne des médecins d'urgence (ACMU), comprenant seize questions à choix multiples et réponses numériques. Les réponses ont été résumées de façon descriptive sous forme de pourcentages et de fourchette médiane et inter quartile (IQR) pour les variables quantitatives. RéSULTATS: : L'étude a été complétée par 169/1635 répondants pour un taux de réponse de 10%. Les présentations les plus courantes que les répondants ont vues étaient des douleurs neuropathiques et des troubles médiés centraux (23% chacun) et des douleurs lombaires (19%). 86% des répondants estimaient que les patients souffrant de douleur chronique n'obtenaient pas de références appropriées de la part de l'urgence, et 70% des répondants ne savaient même pas où ils pouvaient référer les patients souffrant de douleur chronique de l'urgence. 96% des répondants estimaient que leur DE n'avait pas de voie d'aiguillage efficace pour les patients souffrant de douleur chronique. Les cliniques d'accès rapide pour les affections courantes, la réduction des temps d'attente dans les cliniques de traitement de la douleur et des voies d'aiguillage claires vers le service d'urgence étaient les recommandations les plus courantes des répondants. CONCLUSION: Il est clairement nécessaire d'accroître l'accessibilité aux cliniques de traitement de la douleur ambulatoire pour les patients souffrant de douleur chronique qui se présentent à l'urgence. Les fournisseurs de soins de l'urgence et de médicaments contre la douleur doivent collaborer pour établir des voies d'aiguillage mutuellement avantageuses à partir des urgences. et plaider en faveur d'un financement accru pour des cliniques de traitement de la douleur en consultation externe à accès rapide.

Drosophila Nociceptive Sensitization Requires BMP Signaling via the Canonical SMAD Pathway.

Nociceptive sensitization is a common feature in chronic pain, but its basic cellular mechanisms are only partially understood. The present study used the Drosophila melanogaster model system and a candidate gene approach to identify novel components required for modulation of an injury-induced nociceptive sensitization pathway presumably downstream of Hedgehog. This study demonstrates that RNAi silencing of a member of the Bone Morphogenetic Protein (BMP) signaling pathway, Decapentaplegic (Dpp), specifically in the Class IV multidendritic nociceptive neuron, significantly attenuated ultraviolet injury-induced sensitization. Furthermore, overexpression of Dpp in Class IV neurons was sufficient to induce thermal hypersensitivity in the absence of injury. The requirement of various BMP receptors and members of the SMAD signal transduction pathway in nociceptive sensitization was also demonstrated. The effects of BMP signaling were shown to be largely specific to the sensitization pathway and not associated with changes in nociception in the absence of injury or with changes in dendritic morphology. Thus, the results demonstrate that Dpp and its pathway play a crucial and novel role in nociceptive sensitization. Because the BMP family is so strongly conserved between vertebrates and invertebrates, it seems likely that the components analyzed in this study represent potential therapeutic targets for the treatment of chronic pain in humans.SIGNIFICANCE STATEMENT This report provides a genetic analysis of primary nociceptive neuron mechanisms that promote sensitization in response to injury. Drosophila melanogaster larvae whose primary nociceptive neurons were reduced in levels of specific components of the BMP signaling pathway, were injured and then tested for nocifensive responses to a normally subnoxious stimulus. Results suggest that nociceptive neurons use the BMP2/4 ligand, along with identified receptors and intracellular transducers to transition to a sensitized state. These findings are consistent with the observation that BMP receptor hyperactivation correlates with bone abnormalities and pain sensitization in fibrodysplasia ossificans progressiva (Kitterman et al., 2012). Because nociceptive sensitization is associated with chronic pain, these findings indicate that human BMP pathway components may represent targets for novel pain-relieving drugs.

Steroid Receptor Isoform Expression in Drosophila Nociceptor Neurons Is Required for Normal Dendritic Arbor and Sensitivity.

Steroid hormones organize many aspects of development, including that of the nervous system. Steroids also play neuromodulatory and other activational roles, including regulation of sensitivity to painful stimuli in mammals. In Drosophila, ecdysteroids are the only steroid hormones, and therefore the fly represents a simplified model system in which to explore mechanisms of steroid neuromodulation of nociception. In this report, we present evidence that ecdysteroids, acting through two isoforms of their nuclear ecdysone receptor (EcR), modulate sensitivity to noxious thermal and mechanical stimuli in the fly larva. We show that EcRA and EcRB1 are expressed by third instar larvae in the primary nociceptor neurons, known as the class IV multidendritic neurons. Suppression of EcRA by RNA interference in these cells leads to hyposensitivity to noxious stimulation. Suppression of EcRB1 leads to reduction of dendritic branching and length of nociceptor neurons. We show that specific isoforms of the ecdysone receptor play critical cell autonomous roles in modulating the sensitivity of nociceptor neurons and may indicate human orthologs that represent targets for novel analgesic drugs.

Measurement of larval activity in the Drosophila activity monitor.

Drosophila larvae are used in many behavioral studies, yet a simple device for measuring basic parameters of larval activity has not been available. This protocol repurposes an instrument often used to measure adult activity, the TriKinetics Drosophila activity monitor (MB5 Multi-Beam Activity Monitor) to study larval activity. The instrument can monitor the movements of animals in 16 individual 8 cm glass assay tubes, using 17 infrared detection beams per tube. Logging software automatically saves data to a computer, recording parameters such as number of moves, times sensors were triggered, and animals' positions within the tubes. The data can then be analyzed to represent overall locomotion and/or position preference as well as other measurements. All data are easily accessible and compatible with basic graphing and data manipulation software. This protocol will discuss how to use the apparatus, how to operate the software and how to run a larval activity assay from start to finish.