Best practice & research. Clinical rheumatology
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Best Pract Res Clin Rheumatol · Apr 2011
ReviewCentral pain mechanisms in chronic pain states--maybe it is all in their head.
Mechanisms underlying chronic pain differ from those underlying acute pain. In chronic pain states, central nervous system (CNS) factors appear to play particularly prominent roles. ⋯ The characteristic symptoms of these central pain conditions include multifocal pain, fatigue, insomnia, memory difficulties and a higher rate of co-morbid mood disorders. In contrast to acute and peripheral pain states that are responsive to non-steroidal anti-inflammatory drugs (NSAIDs) and opioids, central pain conditions respond best to CNS neuromodulating agents, such as serotonin-norepinephrine reuptake inhibitors (SNRIs) and anticonvulsants.
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Best Pract Res Clin Rheumatol · Apr 2011
ReviewPeripheral pain mechanisms in chronic widespread pain.
Clinical symptoms of chronic widespread pain (CWP) conditions like fibromyalgia (FM), include pain, stiffness, subjective weakness, and muscle fatigue. Muscle pain in CWP is usually described as fluctuating and often associated with local or generalised tenderness (hyperalgesia and/or allodynia). This tenderness related to muscle pain depends on increased peripheral and/or central nervous system responsiveness to peripheral stimuli, which can be either noxious (hyperalgesia) or non-noxious (allodynia). For example, patients with muscle hyperalgesia will rate painful muscle stimuli higher than normal controls, whereas patients with allodynia may perceive light touch as painful, something that a 'normal' individual will never describe as painful. The pathogenesis of such peripheral and/or central nervous system changes in CWP is unclear, but peripheral soft tissue changes have been implicated. Indirect evidence from interventions that attenuate tonic peripheral nociceptive impulses in patients with CWP syndromes like FM suggest that overall FM pain is dependent on peripheral input. More importantly, allodynia and hyperalgesia can be improved or abolished by removal of peripheral impulse input. Another potential mechanism for CWP pain is central disinhibition. However, this pain mechanism also depends on tonic impulse input, even if only inadequately inhibited. Thus, a promising approach to understanding CWP is to determine whether abnormal activity of receptors in deep tissues is fundamental to the development and maintenance of this chronic pain disorder. ⋯ Most CWP patients present with focal tissue abnormalities including myofascial trigger points, ligamentous trigger points or osteoarthritis of the joints and spine. While not predictive for the development of CWP, these changes nevertheless represent important pain generators that may initiate or perpetuate chronic pain. Local chemical mediators, including lactic acid, adenosine triphosphate (ATP) and cytokines, seem to play an important role in sensitising deep tissue nociceptors of CWP patients. Thus, the combination of peripheral impulse input and increased central pain sensitivity may be responsible for widespread chronic pain disorders including FM.
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Best Pract Res Clin Rheumatol · Apr 2011
ReviewTrauma and work-related pain syndromes: risk factors, clinical picture, insurance and law interventions.
In the past decade, major progress has been made in our understanding of fibromyalgia syndrome (FMS). Various triggers have been implicated as contributing to symptom development in FMS when genetically susceptible individuals are challenged. A substantial amount of data points towards the association between trauma and chronic widespread pain/fibromyalgia syndrome (CWP/FMS). ⋯ Furthermore, several persistent local pain conditions may progress to CWP/FMS. These conditions may share a common pathogenic mechanism namely, central sensitisation. Physical trauma and emotional trauma co-exist in many traumatic events and may interact in the pathogenesis of CWP/FMS.
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Best Pract Res Clin Rheumatol · Apr 2011
ReviewMultidisciplinary approach to fibromyalgia: what is the teaching?
Fibromyalgia (FM) is a rheumatic disease that is characterised by chronic musculoskeletal pain, stiffness, fatigue, sleep and mood disorder. FM patients demonstrate dysregulation of pain neurotransmitter function and experience a neurohormone-mediated association with sleep irregularities. ⋯ It has been shown that interdisciplinary treatment programmes lead to greater improvements in subjective pain and function than monotherapies. Physical exercise and multimodal cognitive behavioural therapy are the most widely accepted and beneficial forms of non-pharmacological therapy.
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Best Pract Res Clin Rheumatol · Apr 2011
ReviewClinimetric evaluations of patients with chronic widespread pain.
Assessing chronic widespread pain (CWP) and its impact on physical, emotional and social function requires multidimensional qualitative and health-related quality of life (HRQL) instruments. The recommendations of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) concerning outcome measurements for pain trials are useful for making routine assessments, the most significant of which include pain, fatigue, disturbed sleep, physical functioning, emotional functioning, patient global ratings of satisfaction and HRQL. ⋯ Clinicians need to be aware of the psychometric properties of the instruments used, including their levels of imprecision and minimum clinically important differences (those indicating a meaningful change in clinical status). This article reviews a selection of the instruments used to assess CWP patients, including validated newly developed and well-established screening instruments, and discusses their advantages and limitations.