OBJECTIVES: To investigate if interstitial cystitis/bladder pain syndrome (IC/BPS) subjects demonstrate mechanical or thermal hyperalgesia, and whether the hyperalgesia is segmental or generalized (global).
MATERIALS AND METHODS: 10 female IC/BPS subjects and 10 age-matched female controls without co-morbid fibromyalgia or narcotic use were recruited for quantitative sensory testing. Using the Method of Limits, pressure pain and heat pain thresholds were measured. Using the Method of Fixed Stimulus, the visual analog scale (VAS) pain experienced was recorded when a fixed pressure/temperature was applied.
RESULTS: The VAS pain rated by female IC/BPS subjects was significantly higher than the VAS pain rated by female control subjects when a fixed mechanical pressure (2 kg or 4 kg) was applied to the suprapubic (T11) area (p=0.028). There was an up-shift of the stimulus-response curve, which corresponded to the presence of mechanical hyperalgesia in the suprapubic area in IC/BPS. However, the VAS pain rated by IC/BPS subjects was not different from those rated by controls when a fixed pressure was applied at the other body sites (T1 arm, L4 leg, S2-3 sacral). No difference in VAS pain rating was noted when a fixed heat stimulus (35°C or 37°C) was applied to any of the body sites tested (T1, T11, L4, S2). There was no difference in pressure pain thresholds or thermal pain thresholds between IC/BPS and controls.
CONCLUSIONS: Female subjects with IC/BPS showed segmental hyperalgesia to mechanical pressure stimulation in the suprapubic area (T10-T12). This segmental hyperalgesia may be explained in part by spinal central sensitization.
Lai HH, Gardner V, Ness TJ, Gereau RW 4th. Are you the author?
Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, MO; Washington University Pain Center, Washington University School of Medicine, St Louis, MO.
Reference: J Urol. 2013 Dec 5. pii: S0022-5347(13)06071-0.