Post-stroke pain case study: clinical characteristics, therapeutic options and long-term follow-up

Multiscale effects of excitatory-inhibitory homeostasis in lesioned cortical networks: A computational study

Stroke-related disruptions in functional connectivity (FC) often spread beyond lesioned areas and, given the localized nature of lesions, it is unclear how the recovery of FC is orchestrated on a global scale. Since recovery is accompanied by long-term changes in excitability, we propose excitatory-inhibitory (E-I) homeostasis as a driving mechanism. We present a large-scale model of the neocortex, with synaptic scaling of local inhibition, showing how E-I homeostasis can drive the post-lesion restoration of FC and linking it to changes in excitability. We show that functional networks could reorganize to recover disrupted modularity and small-worldness, but not network dynamics, suggesting the need to consider forms of plasticity beyond synaptic scaling of inhibition. On average, we observed widespread increases in excitability, with the emergence of complex lesion-dependent patterns related to biomarkers of relevant side effects of stroke, such as epilepsy, depression and chronic pain. In summary, our results show that the effects of E-I homeostasis extend beyond local E-I balance, driving the restoration of global properties of FC, and relating to post-stroke symptomatology. Therefore, we suggest the framework of E-I homeostasis as a relevant theoretical foundation for the study of stroke recovery and for understanding the emergence of meaningful features of FC from local dynamics.

Modulation of melatonin to the thalamic lesion-induced pain and comorbid sleep disturbance in the animal model of the central post-stroke hemorrhage

The devastating chronic central post stroke pain is associated with variety of comorbidities. Disrupted sleep is a severe comorbidity, causing an increase in the suicide rate, due to CPSP’s pain symptom. Melatonin is a well-known jet-lag compound, which helps in entrainment of sleep cycle. Accordingly, whether melatonin as a therapeutic measurement for the regulation of sleep disturbance related to central post stroke pain remains unclear. Exogenous melatonin administration entrained the disrupted 24 h circadian cycle, more effectively after 2 and 3 week of administration. The effect of melatonin was persisted on 4th week too, when melatonin administration was discontinued. Also, melatonin ameliorated the pain due to distorted sleep-activity behavior after melatonin administration for 3 weeks. The low levels of melatonin in blood plasma due to CPSP were restored after 3 weeks of melatonin administration. After 30 mg/kg melatonin administrations for 3 weeks, all the disrupted resting and activity behaviors were reduced during light and dark periods. The results suggested that melatonin significantly ameliorated CPSP’s pain symptoms and comorbid sleep disturbance showing in activity behavior.

Non-crisis related pain occurs in adult patients with sickle cell disease despite chronic red blood cell exchange transfusion therapy

BACKGROUND

Chronic red blood cell transfusions reduce acute care utilization for sickle cell disease (SCD) pain. However, little is known about whether chronic transfusions treat or prevent the development of non-crisis pain. We investigated patient-report of pain in adults with SCD receiving chronic exchange transfusions (CET) compared to adults not on CET with similar disease characteristics.

STUDY METHOD AND DESIGN

Eleven participants receiving chronic exchange transfusion (CET) for at least one year were compared to 33 participants not receiving CET. Participants completed validated patient-reported outcomes regarding pain impact and quality of life at regularly scheduled visits or before CET. One year of health care utilization and opioid prescriptions were examined.

RESULTS

After 1:1 propensity matching was performed for age, genotype, WBC and neutrophil counts, patients on CET had lower Pain Impact scores (-5.1, p = 0.03) and higher Neuropathic (7.4, p < 0.001) and Nociceptive Pain Quality (3.7, p < 0.001) scores, all indicating worse pain. However, CET was associated with a reduction in annual all cause admissions (-3.1, p < 0.001), length of stay (-2.1 days, p < 0.001) and ED visits (-2.7, p < 0.001). CET was not associated with differences in opioids dispensed.

CONCLUSIONS

After adjusting for disease characteristics, CET was associated with worse pain impact and neuropathic and nociceptive pain quality, lower health care utilization and with similar levels of opioids dispensed. This data suggest that CET may reduce hospitalizations for acute pain but may not adequately treat nociceptive or neuropathic pain in SCD.

ROBOCOP (ROBOtic Care of Poststroke Pain): Study Protocol for a Randomized Trial to Assess Robot-Assisted Functional and Motor Recovery and Impact on Poststroke Pain Development

Background

Stroke is one of the most frequent causes of death and disability worldwide. It is accompanied by the impaired motor function of the upper extremities in over 69% of patients up to hemiplegia in the following 5 years in 56% of cases. This condition often is characterized by chronic poststroke pain, difficult to manage, further worsening quality of life. Poststroke pain occurs within 3–6 months. Robot-assisted neurorehabilitation using the Automatic Recovery Arm Motility Integrated System (ARAMIS) has proven efficacy in motor function recovery exploiting the movements and the strength of the unaffected arm. The rationale of the ROBOCOP (ROBOtic Care of Poststroke pain) randomized trial is the assessment of the impact of robot-assisted functional and motor recovery on the prevention of poststroke pain.

Methods

A total of 118 patients with hemiplegic arms due to stroke will be enrolled and randomly allocated with a 1:1 ratio to ARAMIS or conventional neurorehabilitation group. After a baseline screening at hospital discharge, ARAMIS or conventional rehabilitation will be performed for 8 weeks. The primary endpoint is the prevention of the development of poststroke pain and the secondary endpoints are prevention of spasticity and efficacy in clinical motor rehabilitation. The primary outcome measures consist in the visual analog scale and the doleur neuropatique 4 and the secondary outcome measures include: the Modified Ashworth Scale, the Resistance to Passive movement Scale; the Upper Extremity Subscale of the Fugl–Meyer Motor Assessment; the Action Research Arm Test; the Barthel Index for activities of daily living; and the magnetic resonance imaging (MRI) recovery-related parameters. After baseline, both primary and secondary outcome measures will be performed in the following time points: 1 month after stroke (t₁, half of the rehabilitation); 2 months after stroke (t₂, after rehabilitation); and 3 months (t₃) and 6 months (t₄) after stroke, critical for poststroke pain development.

Discussion

This is the first clinical trial investigating the efficacy of robot-assisted neurorehabilitation using ARAMIS on poststroke pain prevention. This study could remarkably improve the quality of life of stroke survivors.

Tricyclic antidepressants and selective serotonin reuptake inhibitors but not anticonvulsants ameliorate pain, anxiety, and depression symptoms in an animal model of central post-stroke pain

Background

Central post-stroke pain (CPSP) is a type of neuropathic pain caused by dysfunction in the spinothalamocortical pathway. However, no animal studies have examined comorbid anxiety and depression symptoms. Whether the typical pharmacological treatments for CPSP, which include antidepressants, selective serotonin reuptake inhibitors (SSRIs), and anticonvulsants, can treat comorbid anxiety and depression symptoms in addition to pain remains unclear? The present study ablated the ventrobasal complex of the thalamus (VBC) to cause various CPSP symptoms. The effects of the tricyclic antidepressants amitriptyline and imipramine, the SSRI fluoxetine, and the anticonvulsant carbamazepine on pain, anxiety, and depression were examined.

Results

The results showed that VBC lesions induced sensitivity to thermal pain, measured using a hot water bath; mechanical pain, assessed by von Frey test; anxiety behavior, determined by the open-field test, elevated plus-maze test, and zero-maze test; and depression behavior, assessed by the forced swim test. No effect on motor activity in the open-field test was observed. Amitriptyline reduced thermal and mechanical pain sensitivity and anxiety but not depression. Imipramine suppressed thermal and mechanical pain sensitivity, anxiety, and depression. Fluoxetine blocked mechanical but not thermal pain sensitivity, anxiety, and depression. However, carbamazepine did not affect pain, anxiety, or depression.

Conclusion

In summary, antidepressants and SSRIs but not anticonvulsants can effectively ameliorate pain and comorbid anxiety and depression in CPSP. The present findings, including discrepancies in the effects observed following treatment with anticonvulsants, antidepressants, and SSRIs in this CPSP animal model, can be applied in the clinical setting to guide the pharmacological treatment of CPSP symptoms.

Long-term analgesic effects of peripheral nerve block in patients with central post-stroke pain: A retrospective series

BACKGROUND

Central post-stroke pain (CPSP) has a detrimental effect on the quality of life of post-stroke patients. However, no definitive and effective method has been established yet for the treatment of CPSP.

OBJECTIVE

We aimed to examine the applicability of single-injection peripheral nerve blocks (PNBs) for the treatment of CPSP.

SUBJECTS

In this retrospective study, we included 22 patients (mean age = 56.3 years; 13 men and 9 women) diagnosed with CPSP who visited an outpatient rehabilitation clinic in Seoul National University Bundang Hospital between December 2018 and April 2020.

METHODS

The patients underwent ultrasound-guided single-injection PNB (lidocaine + epinephrine [1: 200,000]) according to the primary site of pain. The level of pain (measured using a numeric rating scale) was recorded before and after the PNB, and the occurrence of adverse events were also measured. The primary outcome of this study was the amount of pain reduction after PNB. Secondary outcome measures obtained 1 month after the PNB included the pain reduction rate 1 month after the PNB, the patient-reported satisfaction and effectiveness regarding the PNB, intention for re-injection, and the patients' willingness to recommend this procedure to others.

RESULTS

The mean pain reduction after PNB was 3.3 ± 2.8. PNB was associated with pain reduction that persisted for greater than 1 month in 68% (15/22) of the patients. Thirteen of 22 patients reported a pain reduction of 50% or more. The mean pain reduction rate was 43.6%. Of the 22 patients, 13 were willing to undergo a second round of treatment with PNB. Nine of them underwent the procedure. No adverse events were observed in this study.

CONCLUSIONS

Our study provides preliminary data suggesting that PNB could be an effective and feasible method to treat CPSP.

[Central Post-Stroke Pain at the Tingandogo University Teaching Hospital of Ouagadougou (Burkina Faso): Frequency, Clinical Profile, Quality of Life of Patients and Associated Factors]

Objective

Few studies have been done on central post-stroke pain (CPSP) in Sub-Saharan Africa, while taking it into account would improve the quality of life of stroke survivors. The purpose of this study was to determine the prevalence of CPSP, to describe its clinical profile, to assess the quality of life of patients and to identify the factors associated with its occurrence, from a prospective hospital series in Ouagadougou, Burkina Faso.

Methodology

It was a prospective, descriptive and analytical longitudinal follow-up study, conducted from January 2015 to March 2020, at the Tingandogo University Hospital, in Ouagadougou, Burkina Faso. The study involved all patients over the age of 16, consecutively hospitalized for stroke confirmed by CT and / or brain MRI, then reviewed every three months in outpatient Neurology, during at least 9 months after their stroke. The sociodemographic and clinical characteristics of the patients, the nature of the stroke, the existence of CPSP and, if applicable, its clinical characteristics, its treatment and its impact on the quality of life of the patients were recorded; a bivariate then multivariate analysis with logistic regression step by step, made it possible to search for the factors associated with the occurrence of CPSP. The significance threshold used was p < 0.05.

Results

A total of 236 patients were collected, out of which 28 patients presented a CPSP (11.9%), after a mean duration of post-stroke follow-up of 12.9 months. Cerebral infarction, intracerebral hemorrhage and cerebral venous thrombosis accounted for 69.5%, 29.7% and 0.8% respectively. The mean age of patients with CPSP was 54.6 years, with a male predominance (53.6%). The mean time to onset for CPSP was 3.8 months after stroke. Pains such as burning (75%) and allodynia (67.8%) were the most common. The average CPSP intensity was 7.6 / 10 on the visual analog scale. Hypoaesthesia (96.4%) and paraesthesia (71.4%) were the signs or symptoms most commonly associated with CPSP. CPSP had a moderate to severe negative impact on usual work, general activity and mood of patients in 60.7%, 50% and 46.4% of patients, respectively. Amitriptyline (75%) and / or level II analgesics (60.7%,) were the most used molecules, and effective in 57% of cases. Only age ≤ 50 years was independently associated with the occurrence of CPSP (OR 2.86; p = 0.03).

Conclusion

CPSP affects more than 1 in 10 stroke patients and moderately to severely affects the quality of life for most of these patients. Screening and adequate management of CPSP as part of multidisciplinary post-stroke follow-up will contribute to improve the quality of life of stroke patients and will facilitate their social and professional reintegration.

Opioids in Post-stroke Pain: A Systematic Review and Meta-Analysis

Background: Post-stroke pain is one of the most common sequelae of stroke, which stands among the leading causes of death and adult-acquired disability worldwide. The role and clinical efficacy of opioids in post-stroke pain syndromes is still debated.

Objectives: Due to the important gap in knowledge on the management of post-stroke pain, this systematic review aimed at assessing the efficacy of opioids in post-stroke pain syndromes.

Methods: A literature search was conducted on databases relevant for medical scientific literature, i.e. PubMed/MEDLINE, Scopus, Web of Science and Cochrane Library databases from databases inception until August 31^st, 2020 for clinical trials assessing the effects of opioids and opioid antagonists on pain reduction and pain related symptoms in patients with post-stroke pain syndromes. Studies assessing the effects of other medications (e.g., tricyclic antidepressant, pregabalin) or non - pharmacological management strategies (e.g., neurostimulation techniques) were excluded. The selected studies have been subjected to examination of the risk of bias.

Results: The literature search retrieved 83,435 results. After duplicates removal, 34,285 articles were title and abstract screened. 25 full texts were assessed and 8 articles were identified to be eligible for inclusion in the qualitative summary and narrative analysis, of which three were placebo-controlled and two were dose-response. Among placebo-controlled studies, two evaluated the analgesic effect of morphine and one assessed the effects of the opioid antagonist naloxone on patients with central post-stroke pain. With regard to dose-response studies, both were on patients with central post-stroke pain, one assessing the efficacy of levorphanol, and the other on naloxone. Seven out of eight included studies showed an overall slight analgesic effect of opioids, with less consistent effects on other pain-related symptoms (e.g., mood, quality of life). The randomized controlled trials were subjected to meta-analysis and rating of the quality of evidence for the two outcomes considered according to GRADE (Grading of Recommendations, Assessment, Development and Evaluations) system. The overall results are inconclusive because of the small number of studies and of patients.

Conclusions: The limited number of the included studies and their heterogeneity in terms of study design do not support the efficacy of opioids in post-stroke pain and in pain-related outcomes. Large double-blind randomized clinical trials with objective assessment of pain and related symptoms are needed to further investigate this topic.

The cornucopia of central disinhibition pain - An evaluation of past and novel concepts

Central disinhibition (CD), as applied to pain, decreases thresholds of endogenous systems. This provokes onset of spontaneous or evoked pain in an individual beyond the ability of the nervous system to inhibit pain resulting from a disease or tissue damage. The original CD concept as proposed by Craig entails a shift from the lateral pain pathway (i.e. discriminative pain processing) towards the medial pain pathway (i.e. emotional pain processing), within an otherwise neurophysiological intact environment. In this review, the original CD concept as proposed by Craig is extended by the primary "nociceptive pathway damage - CD" concept and the secondary "central pathway set point - CD". Thereby, the original concept may be transferred into anatomical and psychological non-functional conditions. We provide examples for either primary or secondary CD concepts within different clinical etiologies as well as present surrogate models, which directly mimic the underlying pathophysiology (A-fiber block) or modulate the CD pathway excitability (thermal grill). The thermal grill has especially shown promising advancements, which may be useful to examine CD pathway activation in the future. Therefore, within this topical review, a systematic review on the thermal grill illusion is intended to stimulate future research. Finally, the authors review different mechanism-based treatment approaches to combat CD pain.

Effects of Non-Invasive Brain Stimulation on Clinical Pain Intensity and Experimental Pain Sensitivity Among Individuals with Central Post-Stroke Pain: A Systematic Review

Purpose

Central post-stroke pain (CPSP) is a neuropathic disorder resulting in pain and disability. An emerging treatment for CPSP is non-invasive brain stimulation including direct current stimulation [tDCS] and repetitive transcranial magnetic stimulation [rTMS]. This systematic review analyzes the efficacy and quality of non-invasive brain stimulation intervention studies for CPSP.

Methods

Studies were sought from three research databases published between 2007 and 2017. Studies were included if the sole intervention was non-invasive brain stimulation and the primary outcome either clinical or experimental pain intensity. Studies were qualitatively assessed for risk of bias.

Results

Of 1107 articles extracted, six met eligibility criteria. Five studies found a decrease in pain intensity (p<0.05) immediately and 3 weeks after rTMS or tDCS was delivered over the primary motor cortex. For experimental pain, one study found thermal pain thresholds improved for those receiving tDCS compared to sham (p<0.05), while another found normalization of the cold detection threshold only after rTMS (p<0.05). Qualitative assessment revealed only one study rated as "excellent/good" quality, while the other five were rated as "fair" or "poor".

Conclusion

Non-invasive brain stimulation may have a therapeutic effect on pain level for individuals with CPSP, as evidenced by significant decreases in clinical and experimental pain scores. However, despite the impact of CPSP and the promise of non-invasive brain stimulation, few rigorous studies have been performed in this area. Future studies should aim to standardize treatment parameters, measure both clinical and experimental pain, and include long-term follow-up.

Diffusion Tensor Tractography Studies of Central Post-stroke Pain Due to the Spinothalamic Tract Injury: A Mini-Review

Elucidation of the pathophysiological mechanism of central post-stroke pain (CPSP) is essential to the development of effective therapeutic modalities for CPSP. However, the pathophysiological mechanism of CPSP has not yet been clearly elucidated. The recent development of diffusion tensor tractography (DTT), derived from diffusion tensor imaging (DTI), has allowed visualization and estimation of the spinothalamic tract (STT), which has been considered the most plausible neural tract responsible for the pathogenesis of CPSP. In this mini-review, six DTT studies in which CPSP due to STT injury in stroke patients was demonstrated are reviewed. The information provided in the reviewed studies suggests that DTT is useful in the elucidation of the pathophysiological mechanism associated with CPSP. We believe that the reviewed studies will facilitate neurorehabilitation of stroke patients with CPSP. However, DTT studies of CPSP are still in the beginning stage because the total number (six studies) of the reviewed studies is very low and half were case reports. Therefore, further studies involving large numbers of subjects are warranted.

Central post-stroke pain: predictors and relationship with magnetic resonance imaging and somatosensory evoked potentials

BACKGROUND

Central post-stroke pain (CPSP) is an under-recognized complication of stroke although it can lead to deterioration in quality of life and impairment in activities of daily living. Its estimated prevalence varies between 18.6 and 49%.

OBJECTIVE

To investigate the prevalence and predictors of CPSP in ischemic stroke patients and to find its relationship with somatosensory evoked potentials (SSEPs) and magnetic resonance imaging.

PATIENTS AND METHODS

Sixty five consecutive patients with recent first attack of ischemic stroke who were admitted to the Neurology Department, Suez Canal University Hospitals were recruited. Patients were subjected to clinical assessment, Hamilton depression rating scale, brain MRI, short-form McGill Pain Questionnaire (SF-MPQ), daily pain rating scale (DPRS), stimulus evoked pain, and SSEPs.

RESULTS

The total prevalence rate of CPSP was 35.4% (n = 23). The mean age of the patients developed CPSP was significantly lower than those without CPSP (p = 0.004). Deep sensory dysfunction was statistically significantly higher among CPSP group than non-CPSP group (p = 0.001). CPSP group showed statistically significant higher prevalence of thalamic stroke (p = 0.007), as well as significant abnormalities in inter-peak interval (IPL) of median and tibial nerves SSEPs (p < 0.05). Thalamic group showed higher abnormalities in IPL of median and tibial nerves compared to extra-thalamic group, but without statistically differences.

CONCLUSION

The prevalence of CPSP was found to be 35.4%. Predictors of CPSP include; deep sensory dysfunction, prolongation of tibial N21-P40 IPL, smoking history, age < 50 years, presence of thalamic stroke and prolongation of median N9-N20 IPL.

Thalamic pain: anatomical and physiological indices of prediction

Thalamic pain is a severe and treatment-resistant type of central pain that may develop after thalamic stroke. Lesions within the ventrocaudal regions of the thalamus carry the highest risk to develop pain, but its emergence in individual patients remains impossible to predict. Because damage to the spino-thalamo-cortical system is a crucial factor in the development of central pain, in this study we combined detailed anatomical atlas-based mapping of thalamic lesions and assessment of spinothalamic integrity using quantitative sensory analysis and laser-evoked potentials in 42 thalamic stroke patients, of whom 31 had developed thalamic pain. More than 97% of lesions involved an area between 2 and 7 mm above the anterior-posterior commissural plane. Although most thalamic lesions affected several nuclei, patients with central pain showed maximal lesion convergence on the anterior pulvinar nucleus (a major spinothalamic target) while the convergence area lay within the ventral posterior lateral nucleus in pain-free patients. Both involvement of the anterior pulvinar nucleus and spinothalamic dysfunction (nociceptive thresholds, laser-evoked potentials) were significantly associated with the development of thalamic pain, whereas involvement of ventral posterior lateral nucleus and lemniscal dysfunction (position sense, graphaesthesia, pallaesthesia, stereognosis, standard somatosensory potentials) were similarly distributed in patients with or without pain. A logistic regression model combining spinothalamic dysfunction and anterior pulvinar nucleus involvement as regressors had 93% sensitivity and 87% positive predictive value for thalamic pain. Lesion of spinothalamic afferents to the posterior thalamus appears therefore determinant to the development of central pain after thalamic stroke. Sorting out of patients at different risks of developing thalamic pain may be achievable at the individual level by combining lesion localization and functional investigation of the spinothalamic system. As the methods proposed here do not need complex manipulations, they can be added to routine patients' work up, and the results replicated by other investigators in the field.

A Medication Combination for the Treatment of Central Poststroke Pain via the Adjuvant Use of Prednisone With Gabapentin: A Case Report

Central poststroke pain is a neuropathic pain syndrome that can occur from pathology of the brain. The case presented is of a woman with multiple comorbidities who was found to have an acute infarct in the left middle and anterior cerebral artery territories. She began to complain of worsening diffuse right upper and lower extremity pain, and central poststroke pain was diagnosed. First-line agents were contraindicated as the result of medical comorbidities, and chronic kidney disease only permitted the use of low-dose gabapentin. The patient's morbid obesity inspired the use of an adjunct medication protocol of a prednisone taper for proper treatment. After starting this treatment regimen, the patient experienced significant pain relief with eventual resolution. A steroid-based treatment protocol was used successfully in the early stages of central poststroke pain with proper side effect management and may have prevented difficult treatment management in the outpatient setting.

A Comprehensive Review of Central Post-Stroke Pain

Although central post-stroke pain is widely recognized as a severe chronic neuropathic pain condition, its consolidated definition, clinical characteristics, and diagnostic criteria have not been defined due to its clinically diverse features. The present study was undertaken to comprehensively review current literature and provide a more complete picture of central post-stroke pain with respect to its definition, prevalence, pathophysiology, clinical characteristics, and diagnostic problems, and to describe the range of therapies currently available. In particular, nursing care perspectives are addressed. It is hoped that this review will help nurses become knowledgeable about central post-stroke pain and provide valuable information for the drafting of effective nursing care plans that improve outcomes and quality of life for patients with central post-stroke pain.

Post stroke pain: identification, assessment, and therapy

BACKGROUND

Pain is a common complication after stroke and is associated with the presence of depression, cognitive dysfunction, and impaired quality of life. It remains underdiagnosed and undertreated, despite evidence that effective treatment of pain may improve function and quality of life.

SUMMARY

We provide an overview of the means for clinical assessment and risk factors for the development of post-stroke pain, then review the newest available literature regarding the commonest post-stroke pain syndromes, including central post-stroke pain, complex regional pain syndrome, musculoskeletal pain including shoulder subluxation, spasticity-related pain, and post-stroke headache, as well as the available epidemiology and current treatment options. Key Messages: In the best interests of optimizing quality of life and function after stroke, clinicians should be aware of pain as a common complication after stroke, identify those patients at highest risk, directly inquire as to the presence and characteristics of pain, and should be aware of the options for treatment for the various pain syndromes.

Usage of Pain Medications During Stroke Rehabilitation: The Post-Stroke Rehabilitation Outcomes Project (PSROP)

Pain remains one of the most common, yet most challenging, medical problems in health care today, and it is one of the most common complications that occurs after a stroke. Pain can affect the course of stroke rehabilitation adversely, and it occasionally may be a cause for transfer back to an acute care hospital. The Post-Stroke Rehabilitation Outcomes Project (PSROP) database was used to describe the incidence of pain by body location and trends in the use of different classifications of medications to treat pain. Of the 1,122 participants in the PSROP database, the most common locations of pain in stroke survivors were the head, leg, back, and shoulder. The most frequently prescribed classifications of pain medications were other analgesics (acetaminophen and tramadol), followed by narcotic analgesics, non-steroidal antiinflammatory drugs (NSAIDs), anticonvulsants, and tricyclic antidepressants. After acetaminophen, the most frequently prescribed medications in each classification, respectively, include hydrocodone APAP, cox-2 inhibitors, gabapentin, and amitriptyline. Other frequently prescribed pain medications included sumatriptan (migraine analgesic), cyclobenzaprine (muscle relaxant), and baclofen (antispasticity muscle relaxant). Medications should be chosen based upon the medical condition causing pain, the ability of the stroke survivor to comply with administration of the medication, and the cost of the medication. Appropriate and timely treatments of painful conditions result in maximum function and the ability to lead active lives and maintain an adequate quality of life.

Pharmacological management of central post-stroke pain: a practical guide

Pain is one of the most troublesome sequelae of stroke. Some of this post-stroke pain is caused by the brain lesion itself; this is called central post-stroke pain (CPSP). Although the prevalence of CPSP is low (1-8 %), persistent, often treatment-resistant, painful sensations are a major problem for stroke patients. The pathogenesis of CPSP remains unknown, but suggested underlying causes include hyperexcitation in the damaged sensory pathways, damage to the central inhibitory pathways, or a combination of the two. For pharmacological treatment, amitriptyline, an adrenergic antidepressant, is currently the first-line drug for CPSP. However, its effect is frequently incomplete and a high dose is commonly not tolerated in stroke patients. Lamotrigine, an antiepileptic, was also found to be effective in a controlled trial and can be used as an alternative or additive therapy. GABAergic drugs with potential calcium channel-blocking effects, such as gabapentin or pregabalin, have recently emerged as a potentially useful therapy. These drugs are effective in various neuropathic pain syndromes, but their effect on CPSP remains to be proven. Pregabalin may improve pain-related anxiety and sleep disturbances. Fluvoxamine and mexiletine may be used adjunctively in some patients. Non-pharmacological treatments such as motor cortex stimulation or deep brain stimulation are used in some centers, but are not proven to be effective. Further well designed clinical trials as well as basic research should be performed to improve our understanding of the pathophysiology of CPSP and to develop better treatment strategies.

Chronic post-traumatic headache: clinical findings and possible mechanisms

Chronic post-traumatic headache (CPTHA), the most frequent complaint after traumatic brain injury (TBI), dramatically affects quality of life and function. Despite its high prevalence and persistence, the mechanism of CPTHA is poorly understood. This literature review aimed to analyze the results of studies assessing the characteristics and sensory profile of CPTHA in order to shed light on its possible underlying mechanisms. The search for English language articles published between 1960 and 2013 was conducted in MEDLINE, CINAHL, and PubMed. Studies assessing clinical features of headache after TBI as well as studies conducting quantitative somatosensory testing (QST) in individuals with CPTHA and in individuals suffering from other types of pain were included. Studies on animal models of pain following damage to peripheral tissues and to the peripheral and central nervous system were also included. The clinical features of CPTHA resembled those of primary headache, especially tension-type and migraine headache. Positive and negative signs were prevalent among individuals with CPTHA, in both the head and in other body regions, suggesting the presence of local (cranial) mechanical hypersensitivity, together with generalized thermal hypoesthesia and hypoalgesia. Evidence of dysfunctional pain modulation was also observed. Chronic post-traumatic headache can result from damage to intra- and pericranial tissues that caused chronic sensitization of these tissues. Alternatively, although not mutually exclusive, CPTHA might possibly be a form of central pain due to damage to brain structures involved in pain processing. These, other possibilities, as well as risk factors for CPTHA are discussed at length.

Gabapentin reverses central pain sensitization following a collagenase-induced intrathalamic hemorrhage in rats

PURPOSE

The treatment of central neuropathic pain remains amongst the biggest challenges for pain specialists. The main objective of this study was to assess gabapentin (GBP), amitriptyline (AMI), and carbamazepine (CARBA) for the treatment of a rodent central neuropathic pain model.

METHODS

Male Sprague Dawley rats were trained on the rotarod, Hargreaves, Von Frey and acetone behavioral tests, and baseline values were obtained prior to surgery. A stereotaxic injection of either a collagenase solution or saline was made in the right ventral posterolateral thalamic nucleus. The rats were tested on days 2, 4, 8, and 11 postsurgery. They were retested at regular intervals from day 15 to day 25 postsurgery, after oral administration of either the vehicle (n=7 and n=8 rats with intracerebral injections of collagenase and saline, respectively) or the different drugs (GBP [60 mg/kg], AMI [10 mg/kg], CARBA [100 mg/kg]; n=8 rats/drug).

RESULTS

A significant decrease in the mechanical thresholds and no change in heat threshold were observed in both hind limbs in the collagenase group, as we had previously shown elsewhere. Reversal of the mechanical hypersensitivity was achieved only with GBP (P<0.05). AMI and CARBA, at the dosages used, failed to show any effect on mechanical thresholds. Transient cold allodynia was observed in some collagenase-injected rats but failed to be statistically significant.

CONCLUSION

Intrathalamic hemorrhaging in the ventrolateral thalamic nucleus induced a bilateral mechanical allodynia, which was reversed by GBP but not AMI or CARBA.

Population-based study of central post-stroke pain in Rimini district, Italy

Central post-stroke pain (CPSP) is still an underestimated complication of stroke, resulting in impaired quality of life and, in addition to the functional and cognitive consequences of stroke, the presence of CPSP may be associated with mood disorders, such as depression, anxiety, and sleep disturbances. This type of pain may also impair activities of daily living and further worsen quality of life, negatively influencing the rehabilitation process. The prevalence of CSPS in the literature is highly variable (1%-12%) according to different studies, and this variability could be influenced by selection criteria and the different ethnic populations being investigated. With this scenario in mind, we performed a population-based study to assess the prevalence of CPSP and its main features in a homogeneous health district (Rimini, Italy), including five hospitals for a total population of 329,970 inhabitants. From 2008 to 2010, we selected 1,494 post-stroke patients and were able to interview 660 patients, 66 (11%) of whom reported pain with related tactile and thermal hyperesthesia, accompanied by needle puncture, tingling, swelling, and pressure sensations. Patients reported motor impairment and disability, which influenced their working ability, rehabilitation, and social life. Despite this severe pain state, there was a high percentage of patients who did not receive adequate treatment for pain.

Stroke syndromes and clinical management

The knowledge of brain syndromes is essential for stroke physicians and neurologists, particularly those that can be extremely difficult and challenging to diagnose due to the great variability of symptom presentation and yet of clinical significance in terms of potential devastating effect with poor outcome. The diagnosis and understanding of stroke syndromes has improved dramatically over the years with the advent of modern imaging, while the management is similar to general care as recommended by various guidelines in addition to care of such patients on specialized units with facilities for continuous monitoring of vital signs and dedicated stroke therapy. Such critical care can be provided either in the acute stroke unit, the medical intensive care unit or the neurological intensive care unit. There may be no definitive treatment at reversing stroke syndromes, but it is important to identify the signs and symptoms for an early diagnosis to prompt quick treatment, which can prevent further devastating complications following stroke. The aim of this article is to discuss some of the important clinical stroke syndromes encountered in clinical practice and discuss their management.

Central poststroke pain: current diagnosis and treatment

Central post-stroke pain syndrome (CPSP) is a debilitating sequel that can follow thalamic sensory stroke. Less well recognized, CPSP follows lateral medullary stroke and parietal cortical stroke and may develop anywhere along the spinothalamic or trigemino-thalamic pathways. Patients describe sharp, stabbing, or burning pain and experience hyperpathia and especially allodynia. Although CPSP was first described over 100 years ago, CPSP is too frequently underrecognized. It is treatable disorder. Pharmacological therapy, magnetic stimulation, and invasive electrical stimulation are reviewed and recommendations made.

Is pain associated with suicidality in stroke?

OBJECTIVE

To evaluate the relation between poststroke pain and suicidality (SI) in Chinese patients with first or recurrent stroke.

DESIGN

Cross-sectional survey.

SETTING

Acute stroke unit of a university-affiliated general hospital.

PARTICIPANTS

Patients (N=496) with acute ischemic stroke admitted to the Acute Stroke Unit.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Patients were interviewed 3 months after the index stroke. SI was assessed with the Geriatric Mental State Examination. Pain was evaluated with the Faces Pain Rating Scale-Revised (FPS-R). The association between FPS-R scores and SI was examined and adjusted for potential confounders, including marital status, depression, neurologic deficits assessed by the National Institute of Health Stroke Scale, and functioning measured by the Barthel Index.

RESULTS

Thirty-seven (7.5%) of the patients had SI (the SI group). Compared with the non-SI group, patients in the SI group were more likely to experience pain (59.5% vs 37.7%), had a higher mean FPS-R score (6.0±2.5 vs 4.5±2.3), and had an FPS-R score of >4 (43.2% vs 15.9%). After adjustment for possible confounders, the FPS-R score of >4 (odds ratio=2.9) remained a significant predictor of SI in the subsequent forward logistic regression models.

CONCLUSIONS

These findings should alert clinicians that the early identification and treatment of pain may reduce suicide risk in patients with stroke.

The prevalence of central poststroke pain according to the integrity of the spino-thalamo-cortical pathway

OBJECTIVES

Little is known about the prevalence of central poststroke pain (CPSP) according to the integrity of the spino-thalamo-cortical pathway (STP). Using diffusion tensor tractography, we investigated the prevalence of CPSP according to the integrity of the STP in patients with intracerebral hemorrhage.

METHODS

We recruited 52 consecutive chronic patients and 10 normal control subjects. Patients were classified into two groups according to preservation of the integrity of the STP. Each group was divided into two subgroups according to the presence of CPSP.

RESULTS

The preserved group included 34 patients [CPSP subgroup, 16 (47%) patients; non-CPSP subgroup, 18 (53%) patients], and 18 patients were enrolled into the disrupted group [CPSP subgroup, 3 (17%) patients; non-CPSP subgroup, 15 (83%) patients]. The fractional anisotropy and mean diffusivity values of the CPSP and non-CPSP subgroups of the preserved group were decreased and increased when compared with those of the control group, respectively (p < 0.05).

CONCLUSIONS

We found that the prevalence of CPSP in patients with partial injury of the STP was higher than that of patients with complete injury of the STP. Partial injury of the STP appears to be more vulnerable to development of CPSP than complete injury of the STP in patients with intracerebral hemorrhage.

Antiepileptic drugs for central post-stroke pain management

Antiepileptic drugs (AEDs) are commonly prescribed for a wide range of disorders other than epilepsy, including both neurological and psychiatric disorders. AEDs play also a role in pharmacological management of neuropathic pain. Central post-stroke pain (CPSP) is a disabling morbidity occurring in 35% of patients with stroke. The pathophysiology of CPSP is not well known but central disinhibition with increased neuronal excitability has been suggested. AEDs include many different drugs acting on pain through several mechanisms, such as reduction of neuronal hyperexcitability. To our knowledge conclusive evidence has not been published yet. The aim of this review is to delineate efficacy and safety of AEDs in CPSP.

Safety and efficacy of pregabalin in patients with central post-stroke pain

Pregabalin has demonstrated efficacy in several forms of neuropathic pain, but its long-term efficacy in central post-stroke pain (CPSP) is unproven. We evaluated the efficacy and safety of pregabalin versus placebo in patients with CPSP. A 13-week, randomized, double-blind, multicenter, placebo-controlled, parallel group study of 150 to 600 mg/day pregabalin was conducted in patients aged ≥18 years with CPSP. The primary efficacy endpoint was the mean pain score on the Daily Pain Rating Scale over the last 7 days on study drug up to week 12 or early termination visit. Secondary endpoints included other pain parameters and patient-reported sleep and health-related quality-of-life measures. A total of 219 patients were treated (pregabalin n=110; placebo n=109). A mean pain score at baseline of 6.5 in the pregabalin group and 6.3 in the placebo group reduced at endpoint to 4.9 in the pregabalin group and 5.0 in the placebo group (LS mean difference=-0.2; 95% CI=-0.7, 0.4; P=0.578). Treatment with pregabalin resulted in significant improvements, compared with placebo, on secondary endpoints including MOS-sleep, HADS-A anxiety, and clinician global impression of change (CGIC) P<0.05. Adverse events were more frequent with pregabalin than with placebo and caused discontinuation in 9 (8.2%) of pregabalin patients versus 4 (3.7%) of placebo patients. Although pain reductions at endpoint did not differ significantly between pregabalin and placebo, improvements in sleep, anxiety, and CGIC suggest some utility of pregabalin in the management of CPSP.

Neurological complications of acute ischaemic stroke

Complications after ischaemic stroke, including both neurological and medical complications, are a major cause of morbidity and mortality. Neurological complications, such as brain oedema or haemorrhagic transformation, occur earlier than do medical complications and can affect outcomes with potential serious short-term and long-term consequences. Some of these complications could be prevented or, when this is not possible, early detection and proper management could be effective in reducing the adverse effects. However, there is little evidence-based data to guide the management of these neurological complications. There is a clear need for improved surveillance and specific interventions for the prevention, early diagnosis, and proper management of neurological complications during the acute phase of stroke to reduce stroke morbidity and mortality.

Abnormal activity of primary somatosensory cortex in central pain syndrome

Central pain syndrome (CPS) is a debilitating and chronic pain condition that results from a lesion or dysfunction in the CNS. The pathophysiological mechanisms underlying CPS are poorly understood. We recently demonstrated that CPS is associated with suppressed inputs from the inhibitory nucleus zona incerta to the posterior thalamus (PO). As a consequence, activity in PO is abnormally increased in CPS. Because the perception of pain requires activity in the cerebral cortex, CPS must also involve abnormal cortical activity. Here we test the hypothesis that CPS is associated with increased activity in the primary somatosensory cortex (SI), a major projection target of PO that plays an important role in processing sensory-discriminative aspects of pain. We recorded activity of single units in SI in rats with CPS resulting from spinal cord lesions. Consistent with our hypothesis, SI neurons recorded from lesioned rats exhibited significantly higher spontaneous firing rates and greater responses evoked by innocuous and noxious mechanical stimulation of the hindpaw compared with control rats. Neurons from lesioned rats also showed a greater tendency than controls to fire bursts of action potentials in response to noxious stimuli. Thus, the excruciatingly painful symptoms of CPS may result, at least in part, from abnormally increased activity in SI.