Pain
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Review Comparative Study
Imaging vs quantitative sensory testing to predict chronic pain treatment outcomes.
In this article, I review the concept of personalized pain management and consider how brain imaging and quantitative sensory testing can be used to derive biomarkers of chronic pain treatment outcome. I review how different modalities of brain imaging can be used to acquire information about brain structure and function and how this information can be linked to individual measures of pain.
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Neurofibromatosis type 1 (NF1) is the most common of a group of rare diseases known by the term, "Neurofibromatosis," affecting 1 in 3000 to 4000 people. NF1 patients present with, among other disease complications, café au lait patches, skin fold freckling, Lisch nodules, orthopedic complications, cutaneous neurofibromas, malignant peripheral nerve sheath tumors, cognitive impairment, and chronic pain. Although NF1 patients inevitably express pain as a debilitating symptom of the disease, not much is known about its manifestation in the NF1 disease, with most current information coming from sporadic case reports. ⋯ As therapy for NF1 pain remains in various clinical and preclinical stages, we present current treatments available for patients and highlight the importance of future therapeutic development. Equally important, NF1 pain is accompanied by psychological complications in comorbidities with sleep, gastrointestinal complications, and overall quality of life, lending to the importance of investigation into this understudied phenomenon of NF1. In this review, we dissect the presence of pain in NF1 in terms of psychological implication, anatomical presence, and discuss mechanisms underlying the onset and potentiation of NF1 pain to evaluate current therapies and propose implications for treatment of this severely understudied, but prevalent symptom of this rare disease.
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Diabetes mellitus (DM) is a major global health concern, affecting more than 9% of the world population. The most common complication of DM is diabetic peripheral neuropathy (DPN), which leads to neuropathic pain in as many as 50% of patients. Despite its prevalence, there is neither good prevention of nor treatments for DPN, representing a major gap in care for the many who are afflicted. ⋯ It then discusses structural changes in Aβ, Aδ, and C fibers throughout the progression of DPN and their respective contributions to painful DPN in both human patients and DM mouse models. Finally, it highlights remaining questions on sensory neuron structure-function relationships in painful DPN and how we may address these in mouse models by using technological advances in cell-specific modulation. Only when these structure-function relationships are understood, can novel targeted therapeutics be developed for DPN.
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Small families carrying rare mutations, which I call "pointer-kindreds," can teach us important lessons. Here, I provide some examples from the field of pain.
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Quantitative sensory testing (QST) is a formal variant of a time-honoured clinical examination technique in neurology, the sensory examination. Prototypical QST profiles have been found in human surrogate models of peripheral sensitization, central sensitization, and deafferentation. Probabilistic sorting of individual patients to any combination of these profiles has been developed, and there is emerging evidence for the predictive value of such sensory profiles for treatment efficacy. ⋯ Several psychological factors had previously been found to be predictors of pain chronicity (catastrophizing, self-efficacy, and neuroticism). The relative importance of psychological vs sensory testing predictors has not been evaluated. It is likely that both will have differential roles in clinical practice.