Pain
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Chronic dry eye disease (DE) is associated with an unstable tear film and symptoms of ocular discomfort. The characteristics of symptoms suggest a key role for central neural processing; however, little is known about central neuroplasticity and DE. We used a model for tear deficient DE and assessed effects on eye blink behavior, orbicularis oculi muscle activity (OOemg), and trigeminal brainstem neural activity in male rats. ⋯ Synaptic blockade at the Vi/Vc transition or the Vc/C1 region greatly reduced hypertonic saline-evoked OOemg activity in DE and sham rats. These results indicated that persistent tear deficiency caused sensitization of ocular-responsive neurons at multiple regions of the caudal trigeminal brainstem and enhanced OOemg activity. Central sensitization of ocular-related brainstem circuits is a significant factor in DE and likely contributes to the apparent weak correlation between peripheral signs of tear dysfunction and symptoms of irritation.
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Randomized Controlled Trial Multicenter Study
Imipramine and Pregabalin Combination for Painful Polyneuropathy. A Randomized Controlled Trial.
Monotherapy with first-line drugs for neuropathic pain often fails to provide sufficient pain relief or has unacceptable side effects because of the need for high doses. The aim of this trial was to test whether the combination of imipramine and pregabalin in moderate doses would relieve pain more effectively than monotherapy with either of the drugs. This was a randomized, double-blind, placebo-controlled, crossover, multicenter trial consisting of four 5-week treatment periods in patients with painful polyneuropathy. ⋯ During combination therapy, the dropout rate was higher and the patients reported a higher rate and severity of side effects. Combination of moderate doses of the tricyclic antidepressant imipramine and pregabalin could be considered as an alternative to high-dosage monotherapy. However, the trial also emphasized that balance between efficacy and safety is an issue.
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Complaints of the arm, neck, or shoulder are common musculoskeletal disorders. To gain insight in prognostic factors of complaints of the arm, neck, or shoulder that are associated with recovery, we conducted a systematic review. We included longitudinal prognostic cohort studies that investigated associations between prognostic factors and recovery in terms of symptoms, disability, or sickness absence. ⋯ The results of our best evidence synthesis showed that for short-term follow-up (<6 months), longer duration of complaints, higher symptom severity, more functional limitations, the use of specific coping styles, and accident as "patients' opinion regarding cause" were negatively associated with recovery. For long-term follow-up, we found that longer duration of complaints at presentation had an unfavorable prognostic value for recovery. Our evidence synthesis revealed strong evidence for no prognostic impact of many factors that are suggested to be associated with recovery according to the primary studies.
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Topical high-concentration L-menthol is the only established human experimental pain model to study mechanisms underlying cold hyperalgesia. We aimed at investigating the combinatorial effect of cold stimuli and topical L-menthol on cold pain and secondary mechanical hyperalgesia. Analogue to the heat-capsaicin model on skin sensitization, we proposed that cold/menthol enhances or prolong L-menthol-evoked sensitization. ⋯ Skin blood flow increased after L-menthol (P < 0.001) and stayed stable after cold cycles. Repeated application of cold on skin treated by L-menthol facilitated and prolonged L-menthol-induced cold pain and hyperalgesia. This model may prove beneficial for testing analgesic compounds when a sufficient duration of time is needed to see drug effects on CPT or mechanical hypersensitivity.
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The primary objective of this study was to assess the impact of pediatric pain-related conditions on health care expenditures. We analyzed data from a nationally representative sample of 6- to 17-year-old children captured in the 2007 National Health Interview Survey and 2008 Medical Expenditure Panel Survey. Health care expenditures of children with pain-related conditions were compared with those of children without pain-related conditions. ⋯ The incremental health care expenditures associated with pediatric pain-related conditions were similar to those of attention deficit and hyperactivity disorder ($9.23 billion; 95% CI, $1.89-$18.1 billion), but more than those associated with asthma ($5.35 billion; 95% CI, $0-$12.3 billion) and obesity ($0.73 billion; 95% CI, $6.28-$8.81 billion). Health care expenditures for pediatric pain-related conditions exert a considerable economic burden on society. Efforts to prevent and treat pediatric pain-related conditions are urgently needed.