Pain
-
Randomized Controlled Trial Multicenter Study
Prevention of medication overuse in patients with migraine.
This multi-center study compared the therapeutic effect of a cognitive-behavioral minimal contact program (MCT) to the effect of a brochure (bibliotherapy) for the prevention of medication overuse headache (MOH) in migraine patients. Seven German headache centers recruited 182 migraine patients with high triptan or analgesic intake frequency. Patients were randomly allocated to either the MCT-group, receiving both an MCT program and an educational brochure or to the biblio-group receiving only the brochure. ⋯ Psychological improvements remained stable in both groups at short- and long-term follow-up. During the study, none of the patients developed an MOH. MCT- and bibliotherapy are useful in migraine patients to prevent medication overuse headache or the transition of episodic to chronic headache.
-
The ability of a painful stimulus to suppress pain in another, remote area (DNIC) has been intensely studied. However, the effect of the distance between the two painful stimuli and the attentional factors during the measurement of pain perception received minimal treatment. We evaluated the effect of these factors on DNIC and on the interaction between DNIC and spatial summation (SS) of pain. ⋯ However, the instruction to summate attenuated DNIC and the DNIC instruction attenuated SS of pain. Attention to the conditioning stimulus induced a stronger DNIC than attention to the test stimulus (p<0.001). We conclude that (1) DNIC and SS of pain appear to be antagonistic processes. (2) DNIC is affected by the distance between two noxious stimuli and to a lesser extent, by attention. (3) The interaction between DNIC, SS and attention is complex and reflects the role of sensory-cognitive integration in pain perception.
-
Many chronic pain conditions including complex regional pain syndrome are exacerbated by sympathetic activity. In animal models, sympathetic fibers sprout into the dorsal root ganglia (DRG) after peripheral nerve injury, forming abnormal connections with sensory neurons. However, functional studies of sympathetic-sensory connections have been limited largely to in vivo studies. ⋯ In whole DRG isolated 3 days after SNL, microelectrode recordings of sensory neurons showed that repeated stimulation of the dorsal ramus enhanced spontaneous activity in large and medium diameter neurons and reduced rheobase in large neurons. These effects, which were slow and long lasting, were attributed to stimulation of the sympathetic sprouts because: stimulation had no effect in uninjured DRG; and effects could be reduced or eliminated by a "cocktail" of antagonists of norepinephrine and ATP receptors, by pretreatment with the sympathetic release blocker bretylium, or by pre-cutting the grey ramus through which sympathetic fibers coursed to the ligated DRG. The latter treatment, a relatively minimal form of sympathectomy, was also highly effective in reducing mechanical pain ipsilateral to the SNL.
-
Cannabinoids are analgesic in man, but their use is limited by their psychoactive properties. One way to avoid cannabinoid receptor subtype 1 (CB1R)-mediated central side-effects is to develop CB1R agonists with limited CNS penetration. Activation of peripheral CB1Rs has been proposed to be analgesic, but the relative contribution of peripheral CB1Rs to the analgesic effects of systemic cannabinoids remains unclear. ⋯ Similarly, intraplantar AZ11713908 was also sufficient to induce robust analgesia. These results demonstrate that systemic administration of AZ11713908, produced robust analgesia in rodent pain models via peripheral CB1R. Peripherally restricted CB1R agonists provide an interesting novel approach to analgesic therapy for chronic pain.
-
Rural residency and low socioeconomic status (SES) are associated with increased likelihood of chronic pain. Other demographics are also differentially associated with the experience of pain. This study examines the relations between demographic and pain-related variables in a virtually unstudied population of rural Alabama chronic pain patients. ⋯ Pain catastrophizing was uniquely associated with pain intensity, pain interference, and perceived disability; depression was uniquely associated with pain interference and life satisfaction. Pain catastrophizing mediated the relation between primary literacy and pain intensity; age effects were differentially mediated by either pain catastrophizing or depression. These analyses provide an insight into the specific demographic and psychosocial factors associated with chronic pain in a low-literacy, low-SES rural population.