Pain
-
Comparative Study
Visceral and cutaneous hypersensitivity in Persian Gulf war veterans with chronic gastrointestinal symptoms.
Approximately 697000 United States military personnel participated in the Persian Gulf War (PGW) between August 1990 and March 1991. By April 1997, over 25% of veterans reported chronic health complaints of underdetermined etiology. Gastrointestinal symptoms were among the most frequently reported symptoms including abdominal pain and diarrhea. ⋯ Results of the hierarchical regressions indicated that the psychological measures (i.e. anxiety, somatic focus) accounted for a significant amount of variance in each of the pain measures. PGW veterans who developed chronic abdominal pain and diarrhea during their tour of duty exhibit visceral hypersensitivity similar to patients with the irritable bowel syndrome. These veterans also have cutaneous hypersensitivity and higher levels of anxiety and somatic focus accounting for these differences in pain reporting.
-
Several theories about musculoskeletal pain syndromes such as whiplash-associated disorder (WAD) suggest that pain and muscle activity interact and may contribute to the chronicity of symptoms. Studies using surface electromyography (sEMG) have demonstrated abnormal muscle activation patterns of the upper trapezius muscles in the chronic stage of WAD (grade II). There are, however, no studies that confirm that these muscle reactions are initiated in the acute stage of WAD, nor that these muscle reactions persist in the transition from acute neck pain to chronic neck pain disability. ⋯ Furthermore, follow-up assessments of the EMG level during these two tasks, did not show a time related change. In conclusion, in subjects with future disability, the acute stage is characterized by a reorganization of the muscular activation of neck and shoulder muscles, possibly aimed at minimizing the use of painful muscles. This change of motor control, is in accordance with both the (neurophysiological) 'pain adaptation model' and (cognitive behavioral) 'fear avoidance model'.
-
Comparative Study
Affective associative learning modifies the sensory perception of nociceptive stimuli without participant's awareness.
The present experiment examined the possibility to change the sensory and/or the affective perception of thermal stimuli by an emotional associative learning procedure known to operate without participants' awareness (evaluative conditioning). In a mixed design, an aversive conditioning procedure was compared between subjects to an appetitive conditioning procedure. Both groups were also compared within-subject to a control condition (neutral conditioning). ⋯ This experiment shows that it is possible to modify the perception of intensity of thermal stimuli by a non-conscious learning procedure based on the transfer of the valence of the unconditioned stimuli (pleasant or unpleasant slides) towards the conditioned stimuli (non-painful and painful thermal stimuli). These results plead for a conception of pain as a conscious output of complex informational processes all of which are not accessible to participants' awareness. Mechanisms by which affective input may influence sensory experience and clinical implications of the present study are discussed.
-
Case Reports
Management of chronic intractable angina - spinal opioids offer an alternative therapy.
The successful treatment of chronic intractable angina by spinally administered opioids via an Algomed drug delivery device (hereinafter called the pump) is reported in seven patients. All patients had at least two prior cardiac surgeries and the duration of minimally controlled chronic intractable angina varied from 5 to 19 years prior to spinally administered opioids. ⋯ The opioid used was either morphine or fentanyl and the dose increase (either mg/year or microg/year, respectively) varied from 1.2 to 16. We suggest that bolus spinal morphine or fentanyl administered via the pump is a viable alternative for the effective control of angina when more established therapies have been found to provide insufficient pain relief.