Pain
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Postherpetic neuralgia is an exceptionally drug-resistant neuropathic pain. To investigate the pathophysiological mechanisms underlying postherpetic neuralgia we clinically investigated sensory disturbances, pains and itching, with an 11-point numerical rating scale in 41 patients with ophthalmic postherpetic neuralgia. In all the patients we recorded the blink reflex, mediated by non-nociceptive myelinated Abeta-fibers, and trigeminal laser evoked potentials (LEPs) related to nociceptive myelinated Adelta- and unmyelinated C-fiber activation. ⋯ Our study shows that postherpetic neuralgia impairs all sensory fiber groups. The neurophysiological-clinical correlations suggest that constant pain arises from a marked loss of nociceptive afferents, whereas paroxysmal pain is related to Abeta-fiber demyelination. These findings might be useful for a better understanding of pain mechanisms in postherpetic neuralgia.
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The trapezius muscle often develops pain as the result of repetitive and stressful work tasks although it is unclear to what extent this pain is due to alterations in muscle concentrations of algesic/nociceptive substances. Twenty women with chronic neck- and shoulder pain (TM) whose work required highly repetitive work tasks and 20 pain-free female colleagues (CON) were studied during and after a full 8-hour workday. We collected microdialysates from their dominant/most painful trapezius muscle; concentrations of serotonin, glutamate, lactate, pyruvate, potassium, bradykinin, and cytokines and blood flow were determined. ⋯ No differences in EMG, task exposure level, mental stress, or urine-cortisol in the groups were found. These findings support the idea that peripheral nociceptive processes are activated in occupationally active subjects, who are diagnosed with trapezius myalgia. In contrast, no sign of low blood flow or increased stress or muscle activity markers were found in TM.
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Patients who continue to suffer from lasting and severely disabling angina pectoris despite optimum drug treatment and who are not suitable candidates for invasive procedures, suffer from a condition referred to as "chronic refractory angina pectoris". Based on the available data, spinal cord stimulation, SCS, is considered as the first-line additional treatment for these patients by the European Society of Cardiology. However, no systematic review of randomised controlled studies has yet been published. ⋯ There is also a strong evidence that SCS can improve the functional status of these patients, as illustrated by the improved exercise time on treadmill or longer walking distance without angina. In addition, SCS does not seem to have any negative effects on mortality in these patients (limited scientific evidence). The complication rate was found to be acceptable.
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Central post-stroke pain (CPSP) is one of the most common types of intractable pain. We reported that repetitive transcranial magnetic stimulation (rTMS) of primary motor cortex relieves pain for patients who were refractory to medical treatment. But the mechanism is unclear. ⋯ The rTMS-effective group had higher delineation ratio of the CST (p=0.02) and the TCT (p=0.005) than the rTMS-ineffective group. Previous studies suggested that an intact CST allows pain control but did not discuss the TCT. Our results suggest that the TCT also plays a role in pain reduction by rTMS of the primary motor cortex and that the efficacy of rTMS for patients with CPSP is predictable by fiber tracking.