Subtypes of complex regional pain syndrome-a systematic review of the literature.

To systematically identify and summarize possible subtypes of complex regional pain syndrome (CRPS), we searched MEDLINE, Embase, Cochrane, Scopus, and Web of Science for original studies reporting or investigating at least one subtype within a group of patients with CRPS. The search retrieved 4239 potentially relevant references. Twenty-five studies met our inclusion criteria and were included in the analysis.

Global series: Complex regional pain syndrome: abstracts from the International Association for the Study of Pain complex regional pain syndrome SIG virtual symposia 2021.

The aim of this IASP complex regional pain syndrome (CRPS) SIG Global Series 2021 was to bring together clinicians including those from developing countries to better understand the clinical presentation of complex regional pain syndrome in countries with less well-published patient populations. The purpose was to learn from each other about the range of treatments, successful outcomes, and challenges experienced. These meeting proceedings comprise abstracts from nine countries that span 4 continents and are summaries of online presentations delivered by speakers representing these countries over the course of 2 symposia.

'It becomes the new everyday life' - experiences of chronic pain in everyday life of people with limb-girdle muscular dystrophy.

Purpose: To investigate experiences and reflections on challenges in everyday life of people living with limb-girdle muscular dystrophy (LGMD) and chronic pain in order to improve rehabilitation services.

Materials And Methods: The design for this study was qualitative using the Interpretive Description methodology and the salutogenic theory of Sense of Coherence as the theoretical framework. Four semi-structured focus group interviews were conducted with 19 adults with LGMD from April to May 2021.

Prevalence of chronic pain in a national cohort of patients with limb-girdle muscular dystrophy: a cross-sectional study.

Purpose: The aim was to investigate the prevalence, characteristics, predictors, and consequences of chronic pain in a national cohort of patients with limb-girdle muscular dystrophy (LGMD).

Materials And Methods: Questionnaires were sent to all Danish LGMD patients (≥18 years of age) registered with the National Rehabilitation Center for Neuromuscular Diseases.

Results: Of 209 patients, 121 responded.

Impact of the COVID-19 pandemic on biopsychosocial health and quality of life among Danish children and adults with neuromuscular diseases (NMD)-Patient reported outcomes from a national survey.

The purpose was to investigate the impact of the COVID-19 pandemic on biopsychosocial health, daily activities, and quality of life among children and adults with neuromuscular diseases, and to assess the prevalence of COVID-19 infection and the impact of this in patients with neuromuscular diseases. The study was a national questionnaire survey. Responses were obtained from 811 adults (29%) and 67 parents of children (27%) with neuromuscular diseases.

Complex regional pain syndrome: a focus on the autonomic nervous system.

Purpose: Although autonomic features are part of the diagnostic criteria for complex regional pain syndrome (CRPS), the role of the autonomic nervous system in CRPS pathophysiology has been downplayed in recent years. The purpose of this review is to redress this imbalance.

Methods: We focus in this review on the contribution of the autonomic nervous system to CRPS pathophysiology.

Bilaterally Reduced Intraepidermal Nerve Fiber Density in Unilateral CRPS-I.

Objective: Findings regarding small nerve fiber damage in complex regional pain syndrome type I (CRPS-I) are not uniform, and studies have not included a matched healthy control group. The aim was to assess intraepidermal nerve fiber density (IENFD) in relation to thermal sensitivity of the same skin areas in CRPS-I patients and a gender- and age-matched healthy control group.

Methods: IENFD was investigated in skin biopsies from the CRPS-affected and contralateral limbs of eight CRPS-I patients and from an equivalent site in eight gender- and age-matched healthy controls (HCs).

Complex regional pain syndrome: intradermal injection of phenylephrine evokes pain and hyperalgesia in a subgroup of patients with upregulated α1-adrenoceptors on dermal nerves.

The aim of this study was to determine whether upregulated cutaneous expression of α1-adrenoceptors (α1-AR) is a source of pain in patients with complex regional pain syndrome (CRPS). Immunohistochemistry was used to identify α1-AR on nerve fibres and other targets in the affected and contralateral skin of 90 patients, and in skin samples from 38 pain-free controls. The distribution of α1-AR was compared between patients and controls, and among subgroups of patients defined by CRPS duration, limb temperature asymmetry, and diagnostic subtype (CRPS I vs CRPS II).

Review of neuroimaging studies related to pain modulation.

Background And Purpose: A noxious stimulus does not necessarily cause pain. Nociceptive signals arising from a noxious stimulus are subject to modulation via endogenous inhibitory and facilitatory mechanisms as they travel from the periphery to the dorsal horn or brainstem and on to higher brain sites. Research on the neural structures underlying endogenous pain modulation has largely been restricted to animal research due to the invasiveness of such studies (e.

Hemisensory disturbances in patients with complex regional pain syndrome.

Sensory disturbances often spread beyond the site of injury in complex regional pain syndrome (CRPS) but whether this applies equally to CRPS I and II, or changes across the course of the disease, is unknown. Establishing this is important, because different symptom profiles in CRPS I and II, or in acute vs chronic CRPS, might infer different pathophysiology and treatment approaches. To explore these questions, sensory disturbances were assessed in the limbs and forehead of 71 patients with CRPS I and 33 patients with CRPS II.

The effects of capillary dysfunction on oxygen and glucose extraction in diabetic neuropathy.

Diabetic neuropathy is associated with disturbances in endoneurial metabolism and microvascular morphology, but the roles of these factors in the aetiopathogenesis of diabetic neuropathy remain unclear. Changes in endoneurial capillary morphology and vascular reactivity apparently predate the development of diabetic neuropathy in humans, and in manifest neuropathy, reductions in nerve conduction velocity correlate with the level of endoneurial hypoxia. The idea that microvascular changes cause diabetic neuropathy is contradicted, however, by reports of elevated endoneurial blood flow in early experimental diabetes, and of unaffected blood flow when early histological signs of neuropathy first develop in humans.

Cutaneous noradrenaline measured by microdialysis in complex regional pain syndrome during whole-body cooling and heating.

Complex regional pain syndrome (CRPS) is characterised by autonomic, sensory, and motor disturbances. The underlying mechanisms of the autonomic changes in CPRS are unknown. However, it has been postulated that sympathetic inhibition in the acute phase with locally reduced levels of noradrenaline is followed by an up-regulation of alpha-adrenoceptors in chronic CRPS leading to denervation supersensitivity to catecholamines.

The specificity and mechanisms of hemilateral sensory disturbances in complex regional pain syndrome.

Unlabelled: Hyperalgesia often extends from the affected limb to the ipsilateral forehead in patients with complex regional pain syndrome (CRPS). To investigate whether this is more common in CRPS than other chronic pain conditions, pressure-pain thresholds and sharpness to a firm bristle were assessed on each side of the forehead, at the pain site, and at an equivalent site on the contralateral side in 32 patients with chronic pain other than CRPS (neuropathic or nociceptive limb pain, radicular pain with referral to a lower limb or postherpetic neuralgia), and in 34 patients with CRPS. Ipsilateral forehead hyperalgesia to pressure pain was detected in 59% of CRPS patients compared with only 13% of patients with other forms of chronic pain.

Cutaneous limb inflammation produces analgesia to pressure pain in the ipsilateral forehead of healthy volunteers.

Unlabelled: To investigate the pain-modulatory effects of a local inflammatory stimulus on pain elsewhere in the body, capsaicin was applied topically to the forearm of 14 healthy female volunteers. Pressure-pain thresholds and sensitivity to sharpness were assessed on each side of the forehead twice per day during 48 hours of capsaicin treatment, and in the treated and contralateral forearm before and at the end of treatment. Heat was applied to the treated area to rekindle pain at times of forehead assessment.

Central pain modulation and scalp tenderness in frequent episodic tension-type headache.

Objective: To determine whether the inhibitory effect of acute limb pain on pain to mechanical stimulation of the forehead is compromised in individuals with frequent episodes of tension-type headache.

Background: Central pain modulation processes are disrupted in patients with chronic tension-type headache. This deficit in pain modulation might be a predisposing characteristic that increases vulnerability to tension-type headache and to symptoms such as scalp tenderness, or could be a feature that develops secondarily during attacks and that persists for a few days afterward.

Reduction of allodynia in patients with complex regional pain syndrome: A double-blind placebo-controlled trial of topical ketamine.

A double-blind placebo-controlled crossover trial was used to determine the effects of topical ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, on the sensory disturbances in 20 patients with complex regional pain syndrome (CRPS). On two occasions separated by at least one week, sensory tests to light touch, pressure, punctate stimulation, light brushing and thermal stimuli were performed in the symptomatic and contralateral limb and on each side of the forehead before and 30min after 10% ketamine cream was applied to the symptomatic or healthy limb. Venous blood for the plasma estimations of ketamine and norketamine was obtained 1h after application of the creams.

Cold-induced limb pain decreases sensitivity to pressure-pain sensations in the ipsilateral forehead.

The aim of this study was to investigate the effect of unilateral limb pain on sensitivity to pain on each side of the forehead. In the first experiment, pressure-pain thresholds and sharpness sensations were assessed on each side of the forehead in 45 healthy volunteers before and after a 10 degrees C cold pressor of the hand and in 18 controls who were not subjected to the cold pressor. In a second experiment, forehead sensitivity was assessed in 32 healthy volunteers before and after a 2 degrees C cold pressor.

HuMax-CD4: a fully human monoclonal anti-CD4 antibody for the treatment of psoriasis vulgaris.

Background: Psoriasis is characterized by infiltration with mononuclear cells. Especially activated memory CD4+ T cells are critical in the pathogenesis. Interaction between the CD4 receptor and the major histocompatibility complex class II molecule is important for T-cell activation.