Presence of SARS-CoV-2 RNA in COVID-19 survivors with post-COVID symptoms 2 years after hospitalization: The VIPER study.

The SARS-CoV-2 VIrus PERsistence (VIPER) study investigated the presence of long-lasting SARS-CoV-2 RNA in plasma, stool, urine, and nasopharyngeal samples in COVID-19 survivors. The presence of SARS-CoV-2 RNA reverse transcription polymerase chain reactions (RT-PCR) were analyzed within plasma, stool, urine, and nasopharyngeal swab samples in COVID-19 survivors with post-COVID symptoms and a comparison group of COVID-19 survivors without post-COVID symptoms matched by age, sex, body mass index and vaccination status. Participants self-reported the presence of any post-COVID symptom (defined as a symptom that started no later than 3 months after the initial infection). Fifty-seven (57.9% women, age: 51.1, standard deviation [SD]: 10.4 years) previously hospitalized COVID-19 survivors with post-COVID symptoms and 55 (56.4% women, age: 50.0, SD: 12.8 years) matched individuals who had a past SARS-CoV-2 infection without post-COVID symptoms were evaluated 27 (SD 7.5) and 26 (SD 8.7) months after hospital discharge, respectively. The presence of SARS-CoV-2 RNA was identified in three nasopharyngeal samples of patients with post-COVID symptoms (5.2%) but not in plasma, stool, or urine samples. Thus, SARS-CoV-2 RNA was not identified in any sample of survivors without post-COVID symptoms. The most prevalent post-COVID symptoms consisted of fatigue (93%), dyspnea, and pain (both, 87.7%). This study did not find SARS-CoV-2 RNA in plasma, stool, or urine samples, 2 years after the infection. A prevalence of 5.2% of SARS-CoV-2 RNA in nasopharyngeal samples, suggesting a potential active or recent reinfection, was found in patients with post-COVID symptoms. These results do not support the association between SARS-CoV-2 RNA in plasma, stool, urine, or nasopharyngeal swab samples and post-COVID symptomatology in the recruited population.

Profiling migraine patients according to clinical and psychophysical characteristics: clinical validity of distinct migraine clusters.

AIMS: Investigate if different clinical and psychophysical bedside tools can differentiate between district migraine phenotypes in ictal/perictal (cohort 1) and interictal (cohort 2) phases. METHOD: This observational study included two independent samples in which patients were subgrouped into distinct clusters using standardized bedside assessment tools (headache frequency, disability, cervical active range of motion, pressure pain threshold in different areas): (A) cohort 1-ictal/perictal migraine patients were subgrouped, based on previous studies, into two clusters, i.e., Cluster-1.1 No Psychophysical Impairments (NPI) and Cluster-1.2 Increased Pain Sensitivity and Cervical Musculoskeletal Dysfunction (IPS-CMD); (B) cohort 2-interictal migraine patients were subgrouped into three clusters, i.e., Cluster-2.1 NPI, Cluster-2.2 IPS, and Cluster-2.3 IPS-CMD. Clinical characteristics (multiple questionnaires), somatosensory function (comprehensive quantitative sensory testing (QST)), and cervical musculoskeletal impairments (cervical musculoskeletal assessment) were assessed and compared across headache clusters and a group of 56 healthy controls matched for sex and age. RESULTS: Cohort 1: A total of 156 subjects were included. Cluster-1.2 (IPS-CMD) had higher headache intensity (p = 0.048), worse headache-related (p = 0.003) and neck-related disability (p = 0.005), worse quality of life (p = 0.003), and higher symptoms related to sensitization (p = 0.001) and psychological burden (p = 0.005) vs. Cluster-1.1(NPI). Furthermore, Cluster-1.2 (IPS-CMD) had (1) reduced cervical active and passive range of motion (p < 0.023), reduced functionality of deep cervical flexors (p < 0.001), and reduced values in all QST(p < 0.001) vs. controls, and (2) reduced active mobility in flexion, left/right lateral flexion (p < 0.045), and reduced values in QST (p < 0.001) vs. Cluster-1.1 (NPI). Cohort 2: A total of 154 subjects were included. Cluster-2.3 (IPS-CMD) had (1) longer disease duration (p = 0.006), higher headache frequency (p = 0.006), disability (p < 0.001), and psychological burden (p = 0.027) vs. Cluster-2.2 (IPS) and (2) higher headache-related disability (p = 0.010), neck-related disability (p = 0.009), and higher symptoms of sensitization (p = 0.018) vs. Cluster-2.1 (NPI). Cluster-2.3(IPS-CMD) had reduced cervical active and passive range of motion (p < 0.034), and reduced functionality of deep cervical flexors (p < 0.001), vs. controls, Custer-2.1 (NPI), and Cluster-2.2 (IPS). Cluster-2.2 (IPS) and 2.3 (IPS-CMD) had reduced QST values vs. controls (p < 0.001) and Cluster-2.1 (p < 0.039). CONCLUSION: A battery of patient-related outcome measures (PROMs) and quantitative bedside tools can separate migraine clusters with different clinical characteristics, somatosensory functions, and cervical musculoskeletal impairments. This confirms the existence of distinct migraine phenotypes and emphasizes the importance of migraine phases of which the characteristics are assessed. This may have implications for responders and non-responders to anti-migraine medications.

Intra-articular injection of gold micro-particles with hyaluronic acid for painful knee osteoarthritis.

BACKGROUND: Recently, in an open pilot study, we found up to two years, a potential pain-relieving effect of intra-articular gold micro-particles using the patient's synovial fluid for patients with knee osteoarthritis (KOA). During the study the excluded group of patients, due to multisite pain, co-morbidities, and other exclusion criteria., received intra-articular gold micro-particles using hyaluronic acid,. We aimed to identify if pre-treatment characteristics influence the global outcome two years after intra-articular treatment for painful KOA with gold microparticles using hyaluronic acid. METHODS: Using hyaluronic acid as the carrier, 136 patients with KOA received intraarticular injections with 20 mg gold microparticles (72.000 particles, 20-40 µm in diameter). In the analysis, we included the Global Rating of Change Scale, Pain Detect Questionnaire (PDQ), Body Mass Index (BMI), and Kellgren & Lawrence score at the inclusion, Western Ontario, and McMaster Universities Osteoarthritis Index (WOMAC) sub-scores for pain, stiffness, and function at inclusion and two years. RESULTS: On the Global Rating Change Scale, 69.1% of patients reported a positive effect, 28.7% no effect, and 2.2% worse. PDQ and the three WOMAC subscores all improved at two years of follow-up. PDQ ≥ 13 (P = 0.028), BMI (P = 0.022) and Kellgren & Lawrence grade 4 (P = 0.028) at inclusion reduced the effect with a minor odds ratio compared to the baseline effect of treatment (P = 0.025). WOMAC subscores at inclusion did not influence the outcome (P > 0.5). CONCLUSIONS: Severe osteoarthritis, obesity, and neuropathic pain, reduced the effect of intra-articular gold microparticles for knee OA. TRIAL REGISTRATION: The study followed the principles of the Declaration of Helsinki and was approved by the local ethics committee of the North Denmark Region by 27/07/2016 (N-20,160,045). The regional data protection agency approved the project by 06/07/2016 (2008-58-0028, ID 2016 - 116) and registered in ClinicalTrial.Gov by 04/01/2018 (NCT03389906).

Optimizing examination time and diagnostic performance of the histamine-induced axon-reflex flare response in diabetes.

INTRODUCTION/AIMS: The axon-reflex flare response is a reliable method for functional assessment of small fibers in diabetic peripheral neuropathy (DPN), but broad adoption is limited by the time requirement. The aims of this study were to (1) assess diagnostic performance and optimize time required for assessing the histamine-induced flare response and (2) associate with established parameters. METHODS: A total of 60 participants with type 1 diabetes with (n = 33) or without (n = 27) DPN participated. The participants underwent quantitative sensory testing (QST), corneal confocal microscopy (CCM), and flare intensity and area size assessments by laser-Doppler imaging (FLPI) following an epidermal skin-prick application of histamine. The flare parameters were evaluated each minute for 15 min, and the diagnostic performance compared to QST and CCM were assessed using area under the curve (AUC). Minimum time-requirements until differentiation and to achieve results comparable with a full examination were assessed. RESULTS: Flare area size had better diagnostic performance compared with CCM (AUC 0.88 vs. 0.77, p < 0.01) and QST (AUC 0.91 vs. 0.81, p = 0.02) than mean flare intensity, and could distinguish people with and without DPN after 4 min compared to after 6 min (both p < 0.01). Flare area size achieved a diagnostic performance comparable to a full examination after 6 and 7 min (CCM and QST respectively, p > 0.05), while mean flare intensity achieved it after 5 and 8 min (CCM and QST respectively, p > 0.05). DISCUSSION: The flare area size can be evaluated 6-7 min after histamine-application, which increases diagnostic performance compared to mean flare intensity.

Profiling migraine patients according to clinical and psychophysical characteristics: a cluster analysis approach.

AIM: This study aims to profile migraine patients according clinical and psychophysical characteristics. METHOD: In this observational study, two cohorts of migraine patients(episodic/chronic) were included. Cohort-1: ictal/perictal phase; Cohort-2: interictal phase.The following variables were assessed: headache frequency; disability; cervical active range of motion(AROM) in flexion, extension, right/left lateral flexion, right/left rotation; pressure-pain threshold(PPT) over: temporalis, two cervical areas(C1/C4 vertebral segments), and two distal pain-free areas(hand/leg). Cluster analysis was performed using the K-means algorithm. Differences across clusters were investigated. RESULTS: Cohort-1: 100 patients were included, and two clusters were identified. Cluster-1.1 (19%), Cluster-1.2 (81%). Cluster 1.1 had a higher percentage of men (P = .037) and higher disability (P = .003) compared to Clusters 1.2. Cluster 1.2 had reduced AROM in flexion, extension, and left/right lateral flexion (P < .037), and lower PPT value in all areas (P < .001) compared to Cluster 1.1. Cohort-2: 98 patients were included and three clusters were identified. Cluster-2.1(18%), Cluster-2.2(45%), and Cluster-2.3(37%). Cluster-2.1 had a higher percentage of men compared to clusters-2.2 and 2.3 (P = .009). Cluster-2.3 had higher headache frequency, and disability compared to Cluster-2.2 (P < .006), and higher disability compared to Cluster-2.1 (P = .010). Cluster-2.3 had reduced AROM in all directions compared to Clusters-2.1 and 2.2 (P < .029). Clusters-2.2 and 2.3 have lower PPT values in all areas compared to Cluster-1.1 (P < .001). CONCLUSION: In the Ictal/perictal phase, two clusters were identified according to clinical and psychophysical characteristics, with one group showing no psychophysical impairment and one with increased pain-sensitivity and cervical musculoskeletal-dysfunctions.In the interictal phase, three clusters could be identified, with one group showing no psychophysical impairment, one increased pain-sensitivity, and one increased pain sensitivity and cervical musculoskeletal-dysfunctions.

Clustering analysis identifies two subgroups of women with fibromyalgia with different psychological, cognitive, health-related, and physical features but similar widespread pressure pain sensitivity.

OBJECTIVE: Given that identification of groups of patients can help to better understand risk factors related to each group and to improve personalized therapeutic strategies, this study aimed to identify subgroups (clusters) of women with fibromyalgia syndrome (FMS) according to pain, pain-related disability, neurophysiological, cognitive, health, psychological, or physical features. METHODS: Demographic, pain, sensory, pain-related disability, psychological, health, cognitive, and physical variables were collected in 113 women with FMS. Widespread pressure pain thresholds were also assessed. K-means clustering was used to identify groups of women without any previous assumption. RESULTS: Two clusters exhibiting similar widespread sensitivity to pressure pain (pressure pain thresholds) but differing in the remaining variables were identified. Overall, women in one cluster exhibited higher pain intensity and pain-related disability; more sensitization-associated and neuropathic pain symptoms; higher kinesiophobia, hypervigilance, and catastrophism levels; worse sleep quality; higher anxiety/depressive levels; lower health-related function; and worse physical function than women in the other cluster. CONCLUSIONS: Cluster analysis identified one group of women with FMS exhibiting worse sensory, psychological, cognitive, and health-related features. Widespread sensitivity to pressure pain seems to be a common feature of FMS. The present results suggest that this group of women with FMS might need to be treated differently.

Trigeminocervical pain sensitivity during the migraine cycle depends on headache frequency.

OBJECTIVE: This experimental study aimed to assess pain sensitivity in low-frequency episodic migraine (LFEM), high-frequency episodic migraine (HFEM), and chronic migraine (CM) patients across the different phases of the migraine cycle. METHOD: In this observational, experimental study, clinical characteristics (diary and time from the last/next headache attack), and quantitative sensory testing (QST) (wind-up pain ratio (WUR) and pressure pain threshold (PPT) from the trigeminal area and PPT from the cervical spine) was performed. LFEM, HFEM, and CM were assessed in each of the 4 migraine phases (HFEM and LFEM: interictal, preictal, ictal, and postictal; CM: interictal and ictal) and compared vs. each other's (matched for the phase) and controls. RESULTS: A total of 56 controls, 105 LFEM, 74 HFEM, and 32 CM were included. No differences in QST parameters were observed between LFEM, HFEM, and CM in any of the phases. During the interictal phase and when comparing with controls the following were found: 1) LFEM had lower trigeminal PPT (p = 0.001) and 2) lower cervical PPT (p = 0.001). No differences were observed between HFEM or CM and healthy controls. During the ictal phase and when comparing with controls the following were found: HFEM and CM had 1) lower trigeminal PPTs (HFEM p = 0.001; CM = p < 0.001), 2) lower cervical PPT s (HFEM p = 0.007; CM p < 0.001), and 3) higher trigeminal WUR (HFEM p = 0.001, CM p = 0.006). No differences were observed between LFEM and healthy controls. During the preictal phase and when comparing with controls the following were found: 1) LFEM had lower cervical PPT (p = 0.007), 2) HFEM had lower trigeminal (p = 0.013) and 3) HFEM had lower cervical (p = .006) PPTs. During the postictal phase and when comparing with controls the following were found: 1) LFEM had lower cervical PPT (p = 0.003), 2) HFEM had lower trigeminal PPT (p = 0.005), and 3) and HFEM had lower cervical (p = 0.007) PPTs. CONCLUSION: This study suggested that HFEM patients have a sensory profile matching CM better than LFEM. When assessing pain sensitivity in migraine populations, the phase with respects to headache attacks is of utmost importance and can explain the inconsistency in pain sensitivity data reported in the literature.

Sensitization symptoms are associated with psychological and cognitive variables in COVID-19 survivors exhibiting post-COVID pain.

OBJECTIVE: To investigate the association between demographic, clinical, psychological, cognitive, and health-related variables and the Central Sensitization Inventory (CSI) in previously hospitalized COVID-19 survivors exhibiting "de novo" post-COVID pain. METHODS: Seventy-seven (n = 77) COVID-19 survivors with "de novo" post-COVID pain completed demographic (age, height, and weight), clinical (duration and intensity of the pain), psychological (depressive/anxiety levels and sleep quality), cognitive (catastrophizing and kinesiophobia levels), and health-related quality of life variables as well as the CSI. A multivariable correlation analysis was conducted to determine the association between variables, and a stepwise multiple linear regression model was performed to identify CSI predictors. RESULTS: Patients were assessed a mean of 6.0 (SD 0.8) months after hospital discharge. Twenty-six (33.7%) individuals showed indications of sensitization-associated symptoms (CSI score ≥40 points). The CSI score was positively associated with pain intensity (r: 0.371), anxiety (r: 0.784), depressive (r: 0.709), catastrophizing (r: 0.620), and kinesiophobia (r: 0.359) levels (all, p < 0.001). The stepwise regression analysis revealed that 60.2% of CSI was explained by anxiety levels and pain intensity. CONCLUSION: This study found that psychological and cognitive variables were associated with the CSI score in previously hospitalized COVID-19 survivors with "de novo" post-COVID pain. Anxiety levels and the intensity of pain symptoms were independently associated with CSI score suggesting a significant overlap with psychological construct. The "de novo" post-COVID pain association with CSI may indicate changes in the pain processing important for managing the pain.

Priming of central and peripheral mechanisms with heat and cutaneous capsaicin facilitates secondary hyperalgesia to high-frequency electrical stimulation.

Heat/capsaicin sensitization and electrical high-frequency stimulation (HFS) are well-known models of secondary hyperalgesia, a phenomenon related to chronic pain conditions. This study investigated whether priming with heat/capsaicin would facilitate hyperalgesia to HFS in healthy subjects. Heat/capsaicin priming consisted of a 45°C heat stimulation for 5 min followed by a topical capsaicin patch (4 × 4 cm) for 30 min on the volar forearm of 20 subjects. HFS (100 Hz, 5 times 1 s, minimum 1.5 mA) was subsequently delivered through a transcutaneous pin electrode approximately 1.5 cm proximal to the heat/capsaicin application. Two sessions were applied in a crossover design; traditional HFS (HFS) and heat/capsaicin sensitization followed by HFS (HFS + HEAT/CAPS). Heat pain threshold (HPT), mechanical pain sensitivity (MPS), and superficial blood perfusion were assessed at baseline, after capsaicin removal, and up to 40 min after HFS. MPS was assessed with pin-prick stimulation (128 mN and 256 mN) in the area adjacent to both HFS and heat/capsaicin, distal but adjacent to heat/capsaicin and in a distal control area. HPT was assessed in the area of heat/capsaicin. Higher sensitivity to 128 mN pin-prick stimulation (difference from baseline and control area) was observed in the HFS + HEAT/CAPS session than in the HFS session 20 and 30 min after HFS. Furthermore, sensitivity was increased after HFS + HEAT/CAPS compared with after heat/capsaicin in the area adjacent to both paradigms, but not in the area distal to heat/capsaicin. Results indicate that heat/capsaicin causes priming of the central and peripheral nervous system, which facilitates secondary mechanical hyperalgesia to HFS.NEW & NOTEWORTHY High-frequency electrical stimulation (HFS) and heat/capsaicin sensitization are well-known models of secondary hyperalgesia. The results from the current study indicate that increased sensitivity to 128 mN pin-prick stimulation can be obtained when HFS is delivered following an already established heightened central hyperexcitability provoked by heat/capsaicin sensitization.

Evaluation of itch and pain induced by bovine adrenal medulla (BAM)8-22, a new human model of non-histaminergic itch.

Chronic itch is a socioeconomic burden with limited management options. Non-histaminergic itch, involved in problematic pathological itch conditions, is transmitted by a subgroup of polymodal C-fibres. Cowhage is traditionally used for studying experimentally induced non-histaminergic itch in humans but encounters some limitations. The present study, therefore, aims to design a new human, experimental model of non-histaminergic itch based on the application of bovine adrenal medulla (BAM)8-22, an endogenous peptide that activates the MrgprX1 receptor. Twenty-two healthy subjects were recruited. Different concentrations (0.5, 1 and 2 mg/ml) of BAM8-22 solution and vehicle, applied by a single skin prick test (SPT), were tested in the first session. In the second session, the BAM8-22 solution (1 mg/ml) was applied by different number of SPTs (1, 5 and 25) and by heat-inactivated cowhage spicules coated with BAM8-22. Provoked itch and pain intensities were monitored for 9 min, followed by the measurement of superficial blood perfusion (SBP) and mechanical and thermal sensitivities. BAM8-22 induced itch at the concentration of 1, 2 mg/ml (p < 0.05) and with the significantly highest intensity when applied through BAM8-22 spicules (p < 0.001). No concomitant pain sensation or increased SBP was observed. SBP increased only in the 25 SPTs area probably due to microtrauma from the multiple skin penetrations. Mechanical and thermal sensitivities were not affected by any of the applications. BAM8-22 applied through heat-inactivated spicules was the most efficient method to induce itch (without pain or changes in SBP and mechanical and thermal sensitivities) suggesting BAM8-22 as a novel non-histaminergic, human, experimental itch model.

Cervical musculoskeletal impairments in the 4 phases of the migraine cycle in episodic migraine patients.

OBJECTIVE: To assess cervical musculoskeletal impairments during the 4 phases of a migraine cycle in episodic migraine patients, controlling for the presence of concomitant neck pain. METHODS: Differences in cervical musculoskeletal impairments were assessed during the 4 migraine phases in episodic migraine patients and compared with healthy controls controlling for concomitant neck pain. Cervical musculoskeletal impairments were assessed as follow: cervical active range of motion; flexion rotation test; craniocervical flexion test and calculation of activation pressure score; the total number of myofascial trigger points in head/neck muscles; the number of positivevertebral segments (headache's reproduction) during passive accessory intervertebral movement; pressure pain thresholds over C1, C2, C4, C6 vertebral segments bilaterally, trigeminal area, hand, and leg. Signs of pain sensitization were assessed by evaluating mechanical pain threshold over trigeminal area and hand, pressure pain thresholds, and the wind-up ratio. The Bonferroni-corrected p-value (05/4 = 0.013) was adopted to assess the difference between groups, while a p-value of 0.05 was considered significant for the correlation analysis. RESULTS: A total of 159 patients and 52 controls were included. Flexion rotation test and craniocervical flexion test were reduced in all 4 phases of the migraine cycle versus healthy controls (p < 0.001). The number of myofascial trigger points and positive vertebral segments was increased in all 4 phases of the migraine cycle versus healthy controls (p < 0.001). Flexion, extension, and total cervical active range of motion and cervical pressure pain thresholds were reduced in episodic migraine in the ictal phase versus controls (p < 0.007) with no other significant differences. Outside the ictal phase, the total cervical active range of motion was positively correlated with trigeminal and leg pressure pain threshold (p < 0.026), the number of active myofascial trigger points and positive positive vertebral segments were positively correlated with higher headache frequency (p=0.045), longer headache duration (p < 0.008), and with headache-related disability (p = 0.031). Cervical pressure pain thresholds were positively correlated with trigeminal, hand, and leg pressure pain threshold (p < 0.001), and trigeminal and leg mechanical pain thresholds (p < 0.005), and negatively correlated with the wind-up ratio (p < 0.004). CONCLUSION: In all phases of the migraine cycle, independent of the presence of concomitant neck pain, episodic migraine patients showed reduced flexion rotation test and craniocervical flexion test and an increased number of myofascial trigger points and passive accessory vertebral segments. These impairments are correlated with enhanced headache duration, headache-related disability, and signs of widespread pain sensitization. Reduction in active cervical movement and increased mechanical hyperalgesia of the cervical was consistent in ictal episodic migraine patients and the subgroups of episodic migraine patients with more pronounced widespread sensitization.

Trigeminal and cervical sensitization during the four phases of the migraine cycle in patients with episodic migraine.

OBJECTIVE: Assessing mechanical pain thresholds from trigeminal, cervical, and distal pain-free areas during the four phases of a migraine cycle in patients with episodic migraine (EM). METHODS: This multicenter, cross-sectional, observational study conducted in Parma and Genoa's Headache Centers assessed quantitative sensory tests during the four migraine phases in patients with EM compared to controls. Temporal summation of pain (TSP), static pressure pain threshold (sPPT), and mechanical pinprick pain threshold (MPT) were assessed from the trigeminal area, sPPT and dynamic PPT (dPPT) from the cervical area, sPPT and MPT over the hand, and sPPT from the tibialis anterior. RESULTS: A total of 135 patients and 46 controls were included. TSP was facilitated in ictal EM (EM vs. controls: mean [standard deviation] 2.7 [2.0] vs. 1.4 [1.8]; p = 0.004); trigeminal sPPT and MPT were reduced in interictal (sPPT: 198.5 [79.3] kPa; p = 0.021; MPT: 12.6 [15.7] g; p = 0.001), preictal (sPPT: 200.6 [71.6] kPa; p = 0.033; MPT: 10.7 [12.4] g; p < 0.001), ictal (sPPT: 171.4 [95.9] kPa; p < 0.001; MPT: 7.3 [12.0] g; p < 0.001), and postictal EM (sPPT: 182.2 [76.3] kPa; p = 0.006; MPT: 10.1 [14.9] g; p = 0.001), compared to controls (sPPT: 238.3 [73.8] kPa; MPT: 21.9 [17.3] g). Cervical sPPTs and dPPT were reduced in interictal (sPPT upper cervical spine: 420.5 [176.7] kPa; p = 0.031; sPPT lower cervical spine: 458.6 [207.3] kPa; p = 0.002; dPPT: 4826.5 [2698.0] g; p < 0.001), preictal (sPPT upper cervical spine: 389.3 [133.4] kPa; p = 0.006; sPPT lower cervical spine: 450.8 [174.3] kPa; p = 0.005; dPPT: 4184.2 [2628.3] g; p < 0.001), ictal (sPPT upper cervical spine: 379.9 [205.6] kPa p = 0.003; sPPT lower cervical spine: 436.3 [271.1] kPa; p = 0.001; dPPT: 3838.3 [2638.7] g; p < 0.001), and postictal EM (sPPT upper cervical spine: 385.5 [131.6] kPa; p = 0.020; sPPT lower cervical spine: 413.0 [150.3] kPa; p = 0.002; dPPT: 4679.6 [2894.9] g; p = 0.001), compared to controls (sPPT upper cervical spine: 494.9 [171.5] kPa; sPPT lower cervical spine: 586.9 [210.8] kPa; dPPT: 7693.9 [2896.8] g). Preictal EM had reduced hand sPPT and MPT (sPPT: 248.8 [96.6] kPa vs. 319.8 [112.3] kPa; p = 0.006; MPT: 23.6 [12.2] g vs. 32.5 [14.4] g; p = 0.035), while EM in the other phases showed reduction in hand MPT (interictal: 22.3 [15.6] g vs. 32.5 [14.4] g; p = 0.002; ictal: 22.4 [17.0] g vs. 32.5 [14.4] g; p = 0.004; postictal: 24.2 [18.8] g vs. 32.5 [14.4] g; p = 0.003) without significant reduction in hand sPPT. No difference in sPPT over the tibialis anterior was found. Hand MPT was negatively correlated with longer disease duration (r = -0.25; p = 0.011) and hand sPPT was negatively correlated with higher drug usage (r = -0.31; p = 0.002). TSP during the ictal phase was positively correlated with the physical (r = 0.38; p = 0.040) and emotional headache-related disability (r = 0.53; p = 0.003). CONCLUSION: In all phases of the migraine cycle, patients with EM show signs of sensitization in the trigeminocervical area, with patients with the most prominent sensitization in the ictal phase. Signs of widespread sensitization were consistent in the preictal phase in patients with EM and in the subgroups of patients with EM with the longest disease duration and more usage of symptomatic drugs.

Headache as a COVID-19 onset symptom and post-COVID-19 symptom in hospitalized COVID-19 survivors infected with the Wuhan, Alpha, or Delta SARS-CoV-2 variants.

OBJECTIVE: This study looked at differences in the presence of headache as an onset symptom of coronavirus disease 2019 (COVID-19) and as a post-COVID-19 symptom in individuals previously hospitalized owing to infection with the Wuhan, Alpha, or Delta variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). BACKGROUND: Headache can be present in up to 50% of individuals during the acute phase of SARS-CoV-2 infection and in 10% of subjects during the post-COVID-19 phase. There are no data on differences in the occurrence of headache in the acute- and post-COVID-19 phase according to the SARS-CoV-2 variants. METHODS: A cross-sectional cohort study was conducted. Unvaccinated subjects previously hospitalized for COVID-19 caused by the Wuhan (n = 201), Alpha (n = 211), or Delta (n = 202) SARS-CoV-2 variants were scheduled for a telephone interview 6 months after hospital discharge. Hospitalization data were collected from hospital medical records. RESULTS: The presence of headache as a COVID-19 onset symptom at hospitalization was higher in subjects with the Delta variant (66/202, 32.7%) than in those infected with the Wuhan (42/201, 20.9%; odds ratio [OR] 1.83, 95% confidence interval [CI] 1.17-2.88) or Alpha (25/211, 11.8%; OR 3.61, 95% CI, 2.16-6.01) variants. The prevalence of post-COVID-19 headache 6 months after hospital discharge was higher in individuals infected with the Delta variant (26/202, 12.9%) than in those infected with the Wuhan (11/201, 5.5%; OR 2.52, 95% CI 1.22-5.31) or Alpha (eight of 211, 3.8%; OR 3.74, 95% CI 1.65-8.49) variants. The presence of headache as a COVID-19 onset symptom was associated with post-COVID-19 headache in subjects infected with the Wuhan (OR 7.75, 95% CI 2.15-27.93) and Delta variants (OR 2.78, 95% CI 1.20-6.42) but not with the Alpha variant (OR 2.60, 95% CI 0.49-13.69). CONCLUSION: Headache was a common symptom in both the acute- and post-COVID-19 phase in subjects infected with the Wuhan, Alpha, and Delta variants but mostly in those infected with the Delta variant.

The Role of TRP Channels in Nicotinic Provoked Pain and Irritation from the Oral Cavity and Throat: Translating Animal Data to Humans.

Tobacco smoking-related diseases are estimated to kill more than 8 million people/year and most smokers are willing to stop smoking. The pharmacological approach to aid smoking cessation comprises nicotine replacement therapy (NRT) and inhibitors of the nicotinic acetylcholine receptor, which is activated by nicotine. Common side effects of oral NRT products include hiccoughs, gastrointestinal disturbances and, most notably, irritation, burning and pain in the mouth and throat, which are the most common reasons for premature discontinuation of NRT and termination of cessation efforts. Attempts to reduce the unwanted sensory side effects are warranted, and research discovering the most optimal masking procedures is urgently needed. This requires a firm mechanistic understanding of the neurobiology behind the activation of sensory nerves and their receptors by nicotine. The sensory nerves in the oral cavity and throat express the so-called transient receptor potential (TRP) channels, which are responsible for mediating the nicotine-evoked irritation, burning and pain sensations. Targeting the TRP channels is one way to modulate the unwanted sensory side effects. A variety of natural (Generally Recognized As Safe [GRAS]) compounds interact with the TRP channels, thus making them interesting candidates as safe additives to oral NRT products. The present narrative review will discuss (1) current evidence on how nicotine contributes to irritation, burning and pain in the oral cavity and throat, and (2) options to modulate these unwanted side-effects with the purpose of increasing adherence to NRT. Nicotine provokes irritation, burning and pain in the oral cavity and throat. Managing these side effects will ensure better compliance to oral NRT products and hence increase the success of smoking cessation. A specific class of sensory receptors (TRP channels) are involved in mediating nicotine's sensory side effects, making them to potential treatment targets. Many natural (Generally Recognized As Safe [GRAS]) compounds are potentially beneficial modulators of TRP channels.

Painful cold-heat segmental pulse stimulation provokes the thermal pain illusion.

PURPOSE/AIM: The thermal grill illusion is a paradoxical pain sensation induced by simultaneous exposure to spatially separated, non-painful, cold, and warm stimuli. This study aimed to determine whether paradoxical sensations are also evoked by simultaneous exposure to painful cold-heat stimuli and whether the mechanism involves modulation by segmental and extra-segmental spatial integration. MATERIALS AND METHODS: Sensory perceptions were triggered by simultaneous application of painful cold-heat pulse stimuli using a developed bedside tool equipped with quantitative thermal stimulator devices. Four conditions were investigated: (1) one device placed on the forearm (condition 1, control); (2) two devices placed on the forearm (condition 2, ipsilateral segmental integration); (3) two devices placed on the forearm and ipsilateral thigh (condition 3, extra-segmental integration); and (4) two devices placed bilaterally on the forearms (condition 4, contralateral segmental integration). The evoked perceptions of paradoxical heat sensation and the loss of cold or heat sensation were evaluated. RESULTS: The aforementioned phenomena were experienced by 11(35.4%), 3(9.7%), 3(9.7%), and 0(0.0%) subjects for conditions 1-4, respectively. Fisher's exact test revealed significant differences (p=.001) among the four conditions. However, Bonferroni post hoc analysis revealed significant differences only between conditions 1 and 4 (p=.005). CONCLUSIONS: Simultaneous painful cold-heat pulse stimulation can induce paradoxical sensations similar to those shown for non-painful thermal (cold and heat) stimuli. They were predominantly evoked by ipsilateral integration. Paradoxical sensations have diagnostic value, and quantifying them using a simple bedside tool may be useful in the clinical setting.

Functional and Structural Neuroplastic Changes Related to Sensitization Proxies in Patients with Osteoarthritis: A Systematic Review.

OBJECTIVE: Several reports in literature have identified sensitization as a possible basis for the enhanced pain reactions associated with osteoarthritis (OA). The aim of this current systematic review is to summarize functional and structural brain changes associated with surrogate sensitization parameters assessed in patients with OA-related pain. DESIGN: Systematic review. SUBJECTS: Patients with OA related pain. METHODS: A literature search was conducted systematically in MEDLINE, CINAHL, EMBASE databases for human studies up to December 2019. Articles were included if they assessed brain imaging and sensitization parameters (quantitative sensory testing and questionnaires) in adults with OA-related pain. Methodological quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) score. RESULTS: Five studies reporting on 138 patients were included in this review. The MINORS scale yielded mean scores of 8.5/16 and 12.3/24, for the cohort and case-control studies respectively. Four low-quality studies suggest a greater pain matrix activation associated with clinical measures of sensitization in patients with OA, while another study underlined the presence of structural changes (reduced gray matter volume) in the cortical areas involved in the nociceptive processing possible also related to sensitization. CONCLUSIONS: This review shows conflicting evidence for structural and functional neuroplastic brain changes related to sensitization proxies in patients with OA.

Mild Skin Heating Evokes Warmth Hyperknesis Selectively for Histaminergic and Serotoninergic Itch in Humans.

Chronic itch can severely affect quality of life. Patients report that their chronic itch can be exacerbated by exposure to warm conditions ("warmth hyperknesis"). The aim of this mechanistic study was to investigate the effect of mild heating of the skin in humans on various experimental models of itch. A total of 18 healthy subjects were recruited to the study. Itch was provoked by histamine, serotonin, or cowhage in 3 different sessions. The provoked area was heated with an infrared lamp, and the skin temperature was either not altered, or was increased by 4°C or 7°C. Subsequent to induction of itch, the itch intensity was recorded for 10 min while the skin was heated continuously throughout the entire period of itch induction. Heating the skin resulted in a significant increase in itch intensity when provoked by histamine or serotonin. It is possible that thermoception and pruriception interact and selectively produce a higher itch intensity in histaminergic and serotoninergic itch.

Serological Biomarkers at Hospital Admission Are Not Related to Long-Term Post-COVID Fatigue and Dyspnea in COVID-19 Survivors.

OBJECTIVE: The aim of this study was to investigate the association between serological biomarkers at the acute phase of infection at hospital admission with the development of long-term post-COVID fatigue and dyspnea. METHODS: A cohort study including patients hospitalized due to COVID-19 in one urban hospital of Madrid (Spain) during the first wave of the outbreak (from March 20 to June 30, 2020) was conducted. Hospitalization data, clinical data, and eleven serological biomarkers were systematically collected at hospital admission. Patients were scheduled for an individual telephone interview after hospital discharge for collecting data about the presence of post-COVID fatigue and dyspnea. RESULTS: A total of 412 patients (age: 62 years, standard deviation: 15 years; 47.5% women) were assessed with a mean of 6.8 and 13.2 months after discharge. The prevalence of post-COVID fatigue and dyspnea was 72.8% and 17.2% at 6 months and 45.4% and 13.6% at 12 months after hospital discharge, respectively. Patients exhibiting post-COVID fatigue at 6 or 12 months exhibited a lower hemoglobin level, higher lymphocyte count, and lower neutrophil and platelets counts (all, p < 0.05), whereas those exhibiting post-COVID dyspnea at 6 or 12 months had a lower platelet count and lower alanine transaminase, aspartate transaminase, and lactate dehydrogenase (LDH) levels (all, p < 0.05) than those not developing post-COVID fatigue or dyspnea, respectively. The multivariate regression analyses revealed that a lower platelet count and lower LDH levels were associated but just explaining 4.5% of the variance, of suffering from post-COVID fatigue and dyspnea, respectively. CONCLUSION: Some serological biomarkers were slightly different in patients exhibiting post-COVID fatigue or dyspnea, but they could not explain the long-COVID problems in those patients.

Fatigue and Dyspnoea as Main Persistent Post-COVID-19 Symptoms in Previously Hospitalized Patients: Related Functional Limitations and Disability.

BACKGROUND: Multicentre studies focussing on specific long-term post-COVID-19 symptoms are scarce. OBJECTIVE: The aim of this study was to determine the levels of fatigue and dyspnoea, repercussions on daily life activities, and risk factors associated with fatigue or dyspnoea in COVID-19 survivors at long term after hospital discharge. METHODS: Age, gender, height, weight, symptoms at hospitalization, pre-existing medical comorbidity, intensive care unit admission, and the presence of cardio-respiratory symptoms developed after severe acute respiratory syndrome coronavirus 2 infection were collected from patients who recovered from COVID-19 at 4 hospitals in Madrid (Spain) from March 1 to May 31, 2020 (first COVID-19 wave). The Functional Impairment Checklist was used for evaluating fatigue/dyspnoea levels and functional limitations. RESULTS: A total of 1,142 patients (48% women, age: 61, standard deviation [SD]: 17 years) were assessed 7.0 months (SD 0.6) after hospitalization. Fatigue was present in 61% patients, dyspnoea with activity in 55%, and dyspnoea at rest in 23.5%. Only 355 (31.1%) patients did not exhibit fatigue and/or dyspnoea 7 months after hospitalization. Forty-five per cent reported functional limitations with daily living activities. Risk factors associated with fatigue and dyspnoea included female gender, number of pre-existing comorbidities, and number of symptoms at hospitalization. The number of days at hospital was a risk factor just for dyspnoea. CONCLUSIONS: Fatigue and/or dyspnoea were present in 70% of hospitalized COVID-19 survivors 7 months after discharge. In addition, 45% patients exhibited limitations on daily living activities. Being female, higher number of pre-existing medical comorbidities and number of symptoms at hospitalization were risk factors associated to fatigue/dyspnoea in COVID-19 survivors 7 months after hospitalization.

Increased nerve growth factor expression in the synovial tissues of patients with rotator cuff tears.

BACKGROUND: Rotator cuff tears (RCTs) are often associated with severe shoulder pain. Non-steroidal anti-inflammatory drugs, not recommended for long-term use, do not effectively manage RCT-induced pain, resulting in reduced quality of life. To improve management, a better understanding of the fundamental properties of RCT pain is needed. Here, we aimed to compare the expression levels of nerve growth factor (NGF) and cyclooxygenase-2 (COX-2) mRNA in the synovial tissues of patients with RCT-induced pain and patients with non-painful recurrent shoulder dislocation (RSD). METHODS: The study included 32 patients with RCT who underwent arthroscopic rotator cuff repair and 28 patients with non-painful RSD who underwent arthroscopic Bankart repair. Synovial tissue samples were harvested from subacromial bursa and rotator interval of RCT patients and from the rotator interval of RSD patients. Samples were analyzed quantitatively expression levels for NGF and COX2 mRNA and NGF protein. RESULTS: NGF mRNA and protein levels were significantly higher in the rotator interval of RCT patients than in the rotator interval of RSD patients (p = 0.0017, p = 0.012, respectively), while COX2 mRNA levels did not differ significantly between the two patient groups. In RCT patients, COX2 mRNA was more highly expressed in the rotator interval than in the subacromial bursa (p = 0.038), whereas the mRNA and protein levels of NGF did not differ between the two tissues. The expression of NGF mRNA in the synovium of the rotator interval was significantly correlated with the numeric rating scale of pain (ρ = 0.38, p = 0.004). CONCLUSION: NGF mRNA and protein levels were elevated in patients with painful RCT compared with those in patients with non-painful RSD, whereas COX-2 levels were comparable in the two patient groups. These findings provide insights into novel potential strategies for clinical management of RCT.