Scandinavian journal of rheumatology. Supplement
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Scand. J. Rheumatol. Suppl. · Jan 2000
ReviewNeuroimaging of chronic pain: phantom limb and musculoskeletal pain.
New developments in brain imaging lead to a better understanding of cortical and subcortical processes involved in pain perception and the establishment of chronic pain. For different forms of chronic pain long-term changes in cortical structures have been described. In patients with phantom limb pain and back pain alterations in the somatotopic organization of the primary somatosensory (SI) could be observed. ⋯ These changes, which are based on processes of neuronal plasticity, can partially be reversed by analgesic interventions. For the investigation of cortical processes concerning reorganization, EEG and MEG methods are most suitable because of their high temporal and spatial resolution. In conclusion, these findings open a new way for therapeutic interventions to prevent the development of chronic pain.
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Scand. J. Rheumatol. Suppl. · Jan 2000
ReviewPresent state of medication therapy in fibromyalgia syndrome.
For the treatment of primary fibromyalgia syndrome (FMS) the low dose application of tri- and tetracyclic antidepressive drugs was often studied. Up to now from all those drugs the effects of amitriptyline (AMI) are best documented. Because of its sedative properties it doesn't only influence pain but also improves the often disturbed sleep. ⋯ Although often used, we have only small information about the effectiveness of opioids. No beneficial effect could be attributed to the muscle relaxant chlormezanone. In conclusion, although only about 1/3 of the patients respond, AMI remains the drug of first choice in the conventional medication treatment of FMS.
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Scand. J. Rheumatol. Suppl. · Jan 2000
ReviewFibromyalgia-symptom or diagnosis: a definition of the position.
According to the American College of Rheumatology the diagnosis of fibromyalgia is based on criteria for the classification of fibromyalgia consisting entirely of clinical signs and symptoms. For diagnostic reasons autonomic disturbances and mental features have to be considered. The distinction between fibromyalgia (tender points) and myofascial pain syndrome (trigger points) is essential. ⋯ The myopathological patterns in fibromyalgia are non-specific: type II fiber atrophy, an increase of lipid droplets, a slight proliferation of mitochondria, and a slightly elevated incidence of ragged red fibers. Initial reports on some allelic abnormalities in the serotonin system seem to highlight the important role of serotonin already presumed earlier. Significantly high levels of substance P in the cerebrospinal fluid of FM patients additionally support the impact of these neurotransmitters on both nociceptive and antinociceptive mechanisms.
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Repetitive synaptic excitation or the application of L-glutamate into the vicinity of multireceptive neurons in the dorsal horn of the spinal cord and corresponding structures of the trigeminal nucleus increases neuronal excitability, which is then reflected by an expansion of the receptive field (Fig. 1). Similar alterations of the receptive field of neurons have been observed in various other brain regions. The receptive fields of multireceptive neurons also expand their size following mechanical, chemical, inflammatory or nerve injuries. ⋯ There is evidence from recent research that this facilitatory effect on glutamatergic synaptic transmission involves membrane receptor phosphorylation, and enhances activity-dependent gene expression (Fig. 3). In order to investigate the time-dependent processing of ongoing afferent noxious stimulation in the central nervous system we recently employed the quantitative autoradiographic 14C-2-deoxyglucose technique in a model of chronic monoarthritic pain in the rat. A synopsis of these most recent experimental data and results from previous electrophysiological in vivo and in vitro studies suggests that dorsal horn neurons and probably also other neurons in pain-related structures become spontaneously active and can maintain their activity without further noxious peripheral input.