Pain
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Ocular pain is a core symptom of inflammatory or traumatic disorders affecting the anterior segment. To date, the management of chronic ocular pain remains a therapeutic challenge in ophthalmology. The main endogenous opioids (enkephalins) play a key role in pain control but exhibit only transient analgesic effects due to their rapid degradation. ⋯ Chronic PL265 topical administration also decreased Iba1 and neuronal injury marker (ATF3) staining in the nucleus of primary sensory neurons of ipsilateral trigeminal ganglion. These results open a new avenue for ocular pain treatment based on the enhancement of endogenous opioid peptides' analgesic effects in tissues of the anterior segment of the eye. Dual enkephalinase inhibitor PL265 seems to be a promising topical treatment for safe and effective alleviation of ocular pain and inflammation.
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Changes in facial expression are an essential form of social communication and in nonverbal infants are often used to alert care providers to pain-related distress. However, studies of early human brain development suggest that premature infants aged less than 34 weeks' gestation do not display discriminative brain activity patterns to equally salient noxious and innocuous events. Here we examine the development of facial expression in 105 infants, aged between 28 and 42 weeks' gestation. ⋯ In a subset of 49 infants, we also recorded EEG brain activity and demonstrated that the temporal emergence of facial discrimination mirrors the developmental profile of the brain's ability to generate discriminative responses. Furthermore, within individual infants, the ability to display discriminative facial expressions is significantly related to brain response maturity. These data demonstrate that the emergence of behavioural discrimination in early human life corresponds to our brain's ability to discriminate noxious and innocuous events and raises fundamental questions as to how best to interpret infant behaviours when measuring and treating pain in premature infants.
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The diagnosis of distal symmetric polyneuropathies (DSPs) relies on the presenting symptomatology and neurological sensory examination, supported by objectively quantified structural and functional changes in sensory nerves. Although these separate components have important diagnostic utility, the associations between the structural vs the symptomatic and functional findings in painful DSP are still unclear. It is assumed that delineation of the correlations, or lack of such, between structure, clinical presentation, and function will contribute to a better understanding and treatment of DSP. ⋯ Among various psychophysical sensory measures, warmth detection and heat pain thresholds correlated best with intraepidermal nerve fiber density, particularly when assessed at the same anatomical site. The observed sources of heterogeneity, and the lack of associations between structural and functional measures in several studies are discussed. A framework is proposed for uniform assessment of nerve fiber parameters for investigating clinically relevant mechanisms of neuropathic pain in DSP.
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The patients with multiple sclerosis (MS) are at greater risk of pain than people without the disease; however, the occurrence and characteristics of pain among these patients are incompletely described. We aimed to assess characteristics of pain amongst MS patients using MS patients who were recruited to participate in 3 studies in Sweden (n = 3877) and were matched with individuals without MS (n = 4548) by sex, year of birth, and region of residence. The Prescribed Drugs Register identified prescribed pain medication, overall and restricted to those given 4 or more prescriptions in 1 year to assess chronic pain. ⋯ The HR for chronic pain treatment was 3.55 (3.27-3.84), indicating an increased effect size relative to any pain treatment. Chronic neuropathic pain showed the largest HR at 7.43 (6.21-8.89). Neuropathic pain was shown to be the primary mechanism leading to increased risk of pain in patients with MS.