Pain
-
Afferents from the C2 spinal nerve (SN) and trigeminal nerve (TN) innervate neighboring cranial territories, and their convergence on the upper cervical dorsal horn neurons represents neural substrate of pain referral in primary headache disorders. Unfortunately, little is known about trigeminocervical input to the major spinal nociceptive projection area lamina I. Here, we used ex vivo brainstem-cervical cord preparation for the visually guided whole-cell recording from the upper cervical lamina I neurons. ⋯ Thus, trigeminocervical input in lamina I is processed in both nerve-specific and convergent circuitries. Afferent convergence on to inhibitory interneurons serves as a feedforward mechanism balancing excitatory drive to projection neurons. Disruption of this balance may cause pain in primary headache syndromes.
-
Different pathophysiological mechanisms contribute to the pain development in osteoarthritis (OA). Sensitization mechanisms play an important role in the amplification and chronification of pain and may predict the therapeutic outcome. Stratification of patients according to their pain mechanisms could help to target pain therapy. ⋯ The most adequate bedside tools to detect sensitization were pressure pain sensitivity (pain intensity at 4 mL pressure using a 10-mL blunted syringe), mechanical pinprick pain sensitivity (pain intensity of a 0.7 mm nylon filament) over the most affected knee, and extrasegmental pressure pain sensitivity (pain threshold). This pilot study presents a first attempt to develop an easy-to-use bedside test to probe sensitization in patients with chronic OA knee pain or chronic pain after TKR. This tool may be used to optimize individualized, mechanism-based pain therapy.
-
A significant proportion of children/adolescents report chronic widespread pain (CWP), but little is known about clinically relevant CWP or what factors lead to onset in this population. Objectives were to report the primary care consultation prevalence of CWP and investigate risk factors associated with onset. A validated algorithm for identifying CWP status from primary care electronic healthcare records was applied to a child or adolescent population (aged 8-18 years). ⋯ Findings show a significant proportion of the child or adolescent primary care population has CWP. Most risk factors involved pain-related conditions, suggesting potential pathways of pain development. Further work is now needed to better understand the development of CWP in children and adolescents.
-
Observational Study
The beneficial effect of positive treatment expectations on pharmacological migraine prophylaxis.
Migraine is one of the leading causes of years lived with disability and considered to be a major global health concern. Pharmacological preventive treatment often causes side effects that limit the adherence to longer-term treatment regimens. Both experimental and clinical evidence suggests that positive expectations can modulate pain and analgesic treatment effects. ⋯ Positive treatment expectation was associated with a generally lower number of headache and migraine days and a stronger reduction in headache days over the course of the treatment in chronic but not in episodic migraine patients. Moreover, patients with prior treatment showed a stronger reduction in headache days with higher expectation as compared to patients without prior experience. Our results underscore the relevance of further exploring the role of treatment expectation and its systematic modulation in patients with migraine and other pain conditions.
-
A key clinical problem is identifying the patient with endometriosis whose pain is complicated by central nervous system sensitization, where conventional gynecologic treatment (eg, hormonal therapy or surgery) may not completely alleviate the pain. The Central Sensitization Inventory (CSI) is a questionnaire previously validated in the chronic pain population. The objective of this study was an exploratory proof-of-concept to identify a CSI cutoff in the endometriosis population to discriminate between individuals with significant central contributors (identified by central sensitivity syndromes [CSS]) to their pain compared to those without. ⋯ Receiver operating characteristic analysis indicated that a CSI cutoff of 40 had a sensitivity of 78% (95% CI: 72.7%-84.6%) and a specificity of 80% (95% CI: 70.3%-84.5%) for identifying a patient with endometriosis with ≥3 CSS. In the group with CSI ≥ 40, 18% retrospectively self-reported pain nonresponsive to hormonal therapy and 40% self-reported daily pain, compared with 6% and 20% in the CSI < 40 group (P = 0.003 and 0.002, respectively). In conclusion, a CSI ≥ 40 may be a practical tool to help identify patients with endometriosis with pain contributors related to central nervous system sensitization.