人们普遍认为,这些疾病的主要“病变”存在于中枢神经系统(即脑和脊髓),涉及疼痛和/或感觉放大。这些疾病(包括纤维肌痛、肠易激综合征、头痛、颞下颌关节紊乱)的一个标志是个体存在广泛痛觉过敏(对疼痛刺激的反应增强)和/或异常性疼痛(正常的非疼痛刺激引起疼痛)。[24]Maixner W, Fillingim R, Booker D, et al. Sensitivity of patients with painful temporomandibular disorders to experimentally evoked pain. Pain. 1995;63:341-351.http://www.ncbi.nlm.nih.gov/pubmed/8719535?tool=bestpractice.com[25]Naliboff BD, Derbyshire SW, Munakata J, et al. Cerebral activation in patients with irritable bowel syndrome and control subjects during rectosigmoid stimulation. Psychosom Med. 2001;63:365-375.http://www.ncbi.nlm.nih.gov/pubmed/11382264?tool=bestpractice.com[26]Giesecke T, Gracely RH, Grant MA, et al. Evidence of augmented central pain processing in idiopathic chronic low back pain. Arthritis Rheum. 2004;50:613-623.http://onlinelibrary.wiley.com/doi/10.1002/art.20063/fullhttp://www.ncbi.nlm.nih.gov/pubmed/14872506?tool=bestpractice.com[27]Giesecke J, Reed BD, Haefner HK, et al. Quantitative sensory testing in vulvodynia patients and increased peripheral pressure pain sensitivity. Obstet Gynecol. 2004;104:126-133.http://www.ncbi.nlm.nih.gov/pubmed/15229011?tool=bestpractice.com[28]Moshiree B, Price DD, Robinson ME, et al. Thermal and visceral hypersensitivity in irritable bowel syndrome patients with and without fibromyalgia. Clin J Pain. 2007;23:323-330.http://www.ncbi.nlm.nih.gov/pubmed/17449993?tool=bestpractice.com[29]Greenspan JD, Slade GD, Bair E, et al. Pain sensitivity risk factors for chronic TMD: descriptive data and empirically identified domains from the OPPERA case control study. J Pain. 2011;12(11 Suppl):T61-T74.http://www.jpain.org/article/S1526-5900%2811%2900739-5/fulltexthttp://www.ncbi.nlm.nih.gov/pubmed/22074753?tool=bestpractice.com这表明,这些个体的枢神经系统 (CNS) 存在的放大疼痛或感觉处理(即疼痛强化)方面的基础问题,而不是位于身体目前疼痛区域的病理异常。疼痛“向心化”的这些发现可通过功能神经影像学检查上的相同表现来证实,似乎部分原因在于影响疼痛和感觉传导的神经递质水平失衡。因此,中枢神经系统介导的非疼痛症状(疲劳、记忆困难、睡眠和情绪障碍)是其常见合并症。
对于这些疾病,类似的治疗是有效的,包括药物治疗(例如,升高抗伤害性神经递质 [如 5-羟色胺和去甲肾上腺素] 的药物或下调促痛神经递质 [如谷氨酸、P 物质] 的药物)和非药物治疗(例如,运动、认知行为疗法 [cognitive behavioural therapy, CBT])。
一些研究表明,部分纤维肌痛患者可能存在结构异常,但是目前尚不清楚这些研究结果的意义。例如,研究表明这些个体的外周神经小纤维可能是异常的(例如数目减少、曲度增加)。[30]Caro XJ, Winter EF, Dumas AJ. A subset of fibromyalgia patients have findings suggestive of chronic inflammatory demyelinating polyneuropathy and appear to respond to IVIg. Rheumatology (Oxford). 2008;47:208-211.http://rheumatology.oxfordjournals.org/content/47/2/208.longhttp://www.ncbi.nlm.nih.gov/pubmed/18208823?tool=bestpractice.com[31]Kim SH, Kim DH, Oh DH, et al. Characteristic electron microscopic findings in the skin of patients with fibromyalgia - preliminary study. Clin Rheumatol. 2008;27:407-411.http://www.ncbi.nlm.nih.gov/pubmed/18323007?tool=bestpractice.com[32]Oaklander AL, Fields HL. Is reflex sympathetic dystrophy/complex regional pain syndrome type I a small-fiber neuropathy? Ann Neurol. 2009;65:629-638.http://www.ncbi.nlm.nih.gov/pubmed/19557864?tool=bestpractice.com还有很多研究表明,纤维肌痛患者可能存在脑结构异常;这些研究显示慢性疼痛可能与显著的神经可塑性相关,与其他疼痛领域的研究是一致的。[33]Apkarian AV, Sosa Y, Sonty S, et al. Chronic back pain is associated with decreased prefrontal and thalamic gray matter density. J Neurosci. 2004;24:10410-10415.http://www.jneurosci.org/content/24/46/10410.longhttp://www.ncbi.nlm.nih.gov/pubmed/15548656?tool=bestpractice.com许多研究组使用基于体素的形态测量学或弥散张量成像来识别纤维肌痛患者的脑结构异常。[34]Sundgren PC, Petrou M, Harris RE, et al. Diffusion-weighted and diffusion tensor imaging in fibromyalgia patients: a prospective study of whole brain diffusivity, apparent diffusion coefficient, and fraction anisotropy in different regions of the brain and correlation with symptom severity. Acad Radiol. 2007;14:839-846.http://www.ncbi.nlm.nih.gov/pubmed/17574134?tool=bestpractice.com[35]Kuchinad A, Schweinhardt P, Seminowicz DA, et al. Accelerated brain gray matter loss in fibromyalgia patients: premature aging of the brain? J Neurosci. 2007;27:4004-4007.http://www.jneurosci.org/content/27/15/4004.longhttp://www.ncbi.nlm.nih.gov/pubmed/17428976?tool=bestpractice.com[36]Luerding R, Weigand T, Bogdahn U, et al. Working memory performance is correlated with local brain morphology in the medial frontal and anterior cingulate cortex in fibromyalgia patients: structural correlates of pain-cognition interaction. Brain. 2008;131:3222-3231.http://brain.oxfordjournals.org/content/131/12/3222.longhttp://www.ncbi.nlm.nih.gov/pubmed/18819988?tool=bestpractice.com[37]Lutz J, Jäger L, de Quervain D, et al. White and gray matter abnormalities in the brain of patients with fibromyalgia: a diffusion-tensor and volumetric imaging study. Arthritis Rheum. 2008;58:3960-3969.http://onlinelibrary.wiley.com/doi/10.1002/art.24070/fullhttp://www.ncbi.nlm.nih.gov/pubmed/19035484?tool=bestpractice.com[38]Schmidt-Wilcke T. Variations in brain volume and regional morphology associated with chronic pain. Curr Rheumatol Rep. 2008;10:467-474.http://www.ncbi.nlm.nih.gov/pubmed/19007538?tool=bestpractice.com最大的一项此类研究结果表明,其中一些异常可能与表现出相同变化的频繁共存精神疾病相关。[39]Hsu MC, Harris RE, Sundgren PC, et al. No consistent difference in gray matter volume between individuals with fibromyalgia and age-matched healthy subjects when controlling for affective disorder. Pain. 2009;143:262-267.http://www.ncbi.nlm.nih.gov/pubmed/19375224?tool=bestpractice.com因此,如果纤维肌痛患者存在结构异常或组织损伤,则大部分证据表明这损伤涉及神经组织,而不是这些患者感觉疼痛的身体部位。