Supplemental Digital Content is Available in the Text. An original tool to distinguish Parkinson disease-related from non-Parkinson disease-related pain and to classify it into 3 mechanistic pain descriptors.

Opsoclonus-myoclonus-ataxia (OMA) syndrome is a debilitating autoimmune neurological disorder. Post-infectious opsoclonus-myoclonus-ataxia syndrome has been described with varying bacterial, spirochetal, and viral infections including several patients with HIV. However, specific immunopathological mechanisms that may lead to opsoclonus-myoclonus in HIV-positive patients are unknown.We report a case of HIV-associated opsoclonus-myoclonus and early HIV infection. A review of published literature shows opsoclonus-myoclonus can occur during early infection, in immune reconstitution syndrome or in association with other infections, especially tuberculosis.

BackgroundThe different phenotypic presentations of fibromyalgia (FM) have been infrequently studied and may have diagnostic and therapeutic implications. The aim of this study was to explore differences between FM patients with classical symmetric (s‐FM) presentation and FM patients with marked asymmetric (a‐FM) pain.MethodsWe performed two consecutive cross‐sectional studies on FM patients and matched healthy volunteers (HV). FM patients were divided into a‐FM (and s‐FM groups according to their score of pain intensity on each body side; patients with a difference of ≥40 mm in VAS between left and right sides were classified as a‐FM, otherwise classified as s‐FM. Participants (FM = 32; HV = 31) were assessed for clinical, cortical excitability (CE), quantitative sensory testing (QST; study 1), and intraepidermal nerve fibre density (IENFD) determinations (study 2).ResultsWhile pain intensity did not significantly differ between s‐FM and a‐FM patients, pain interference in daily activities was significantly higher in the a‐FM as compared to the s‐FM group (54.7 ± 8.9 and 37.6 ± 13.5; p < .0001). PPT was significantly lower in the more painful side of a‐FM as compared to the HV (27.7 ± 7.9 and 49.9 ± 13.0; p < .0001), while PPT in the less painful side of a‐FM was significantly higher than PPT values in the s‐FM (35.8 ± 8.3 and 27.7 ± 5.5; p = .031). S‐FM and a‐FM had significantly abnormal intracortical inhibition values on CE measurements compared to HV. There were no significant differences in IENFD between groups.ConclusionsWithin the current FM criteria, there exist different phenotypes with clinical, psychophysics, and neurophysiological findings that are not related to peripheral IENFD abnormalities.SignificanceCurrent fibromyalgia criteria may contain different phenotypes of fibromyalgia based on the lateralization of pain.

Introduction:The question of whether the human fetus experiences pain has received substantial attention in recent times. With the advent of high-definition 4-dimensional ultrasound (4D-US), it is possible to record fetal body and facial expressions. Objective: To determine whether human fetuses demonstrate discriminative acute behavioral responses to nociceptive input. Methods: This cross-sectional study included 5 fetuses with diaphragmatic hernia with indication of intrauterine surgery (fetoscopic endoluminal tracheal occlusion) and 8 healthy fetuses, who were scanned with 4D-US in 1 of 3 conditions: (1) acute pain group: Fetuses undergoing intrauterine surgery were assessed in the preoperative period during the anesthetic injection into the thigh; (2) control group at rest: Facial expressions at rest were recorded during scheduled ultrasound examinations; and (3) control group acoustic startle: Fetal facial expressions were recorded during acoustic stimulus (500-4000 Hz; 60-115 dB). Results: Raters blinded to the fetuses' groups scored 65 pictures of fetal facial expressions based on the presence of 12 items (facial movements). Analyses of redundancy and usefulness excluded 5 items for being of low discrimination capacity (P.0.2). The final version of the pain assessment tool consisted of a total of 7 items: brow lowering/eyes squeezed shut/deepening of the nasolabial furrow/open lips/horizontal mouth stretch/vertical mouth stretch/neck deflection. Odd ratios for a facial expression to be detected in acute pain compared with control conditions ranged from 11 (neck deflection) to 1,400 (horizontal mouth stretch). Using the seven-item final tool, we showed that 5 is the cutoff value discriminating pain from nonpainful startle and rest. Conclusions: This study inaugurates the possibility to study pain responses during the intrauterine life, which may have implications for the postoperative management of pain after intrauterine surgical interventions

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Background: Central neuropathic pain (CNP) is often refractory to available therapeutic strategies and there are few evidence-based treatment options. Many patients with neuropathic pain are not diagnosed or treated properly. Thus, consensus-based recommendations, adapted to the available drugs in the country, are necessary to guide clinical decisions. Objective: To develop recommendations for the treatment of CNP in Brazil. Methods: Systematic review, meta-analysis, and specialists opinions considering efficacy, adverse events profile, cost, and drug availability in public health. Results: Forty-four studies on CNP treatment were found, 20 were included in the qualitative analysis, and 15 in the quantitative analysis. Medications were classified as first-, second-, and third-line treatment based on systematic review, meta-analysis, and expert opinion. As first-line treatment, gabapentin, duloxetine, and tricyclic antidepressants were included. As second-line, venlafaxine, pregabalin for CND secondary to spinal cord injury, lamotrigine for CNP after stroke, and, in association with first-line drugs, weak opioids, in particular tramadol. For refractory patients, strong opioids (methadone and oxycodone), cannabidiol/delta-9-tetrahydrocannabinol, were classified as third-line of treatment, in combination with first or second-line drugs and, for central nervous system (CNS) in multiple sclerosis, dronabinol. Conclusions: Studies that address the treatment of CNS are scarce and heterogeneous, and a significant part of the recommendations is based on experts opinions. The CNP approach must be individualized, taking into account the availability of medication, the profile of adverse effects, including addiction risk, and patients' comorbidities.

Background Unlike motor symptoms, the effects of deep brain stimulation (DBS) on non‐motor symptoms associated with dystonia remain unknown. Methods The objective of this study was to assess the effects of DBS on evoked experimental pain and cutaneous sensory thresholds in a crossover, double‐blind on/off study and compare these results with those of healthy volunteers (HV). Results Sixteen patients with idiopathic dystonia (39.9 ± 13 years old, n = 14 generalized) with DBS of the globus pallidus internus underwent a battery of quantitative sensory testing and assessment using a pain top‐down modulation system (conditioned pain modulation, CPM). Results for the more and less dystonic body regions were compared in on and off stimulation. The patients' results were compared to age‐ and sex‐matched HV. Descending pain modulation CPM responses in dystonic patients (on‐DBS, 11.8 ± 40.7; off‐DBS, 1.8 ± 22.1) was abnormally low (defective) compared to HV (−15.6 ± 23.5, respectively p = .006 and p = .042). Cold pain threshold and cold hyperalgesia were 54.8% and 95.7% higher in dystonic patients compared to HV. On‐DBS CPM correlated with higher Burke‐Fahn‐Marsden disability score (r = 0.598; p = .014). While sensory and pain thresholds were not affected by DBS on/off condition, pain modulation was abnormal in dystonic patients and tended to be aggravated by DBS. Conclusion The analgesic effects after DBS do not seem to depend on short‐duration changes in cutaneous sensory thresholds in dystonic patients and may be related to changes in the central processing of nociceptive inputs.

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