title: Segmental hyperalgesia to mechanical stimulus in interstitial cystitis/bladder pain syndrome: evidence of central sensitization.
abstract: OBJECTIVE
  We investigate if subjects with interstitial cystitis/bladder pain syndrome demonstrate mechanical or thermal hyperalgesia, and whether the hyperalgesia is segmental or generalized (global).
  
  
  METHODS
  Ten female subjects with interstitial cystitis/bladder pain syndrome and 10 age matched female controls without comorbid 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 pain experienced was recorded when a fixed pressure/temperature was applied.
  
  
  RESULTS
  The visual analog scale pain rated by female subjects with interstitial cystitis/bladder pain syndrome was significantly higher than that rated by female control subjects when a fixed mechanical pressure (2 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 interstitial cystitis/bladder pain syndrome. However, the visual analog scale pain rated by subjects with interstitial cystitis/bladder pain syndrome was not different from that rated by controls when a fixed pressure was applied at the other body sites (T1 arm, L4 leg, S2-3 sacral). No difference in visual analog scale pain rating was noted when a fixed heat stimulus (35C or 37C) 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 subjects with interstitial cystitis/bladder pain syndrome and controls.
  
  
  CONCLUSIONS
  Female subjects with interstitial cystitis/bladder pain syndrome 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.
authors: Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri; Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri. Electronic address: laih@wustl.edu.
authors: H Henry
authors: HH
authors: Lai
authors: Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri.
authors: Vivien
authors: V
authors: Gardner
authors: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama.
authors: Timothy J
authors: TJ
authors: Ness
authors: Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri.
authors: Robert W
authors: RW
authors: Gereau
mesh_terms: D000328:Adult; D000368:Aged; D059333:Central Nervous System Sensitization; D018856:Cystitis, Interstitial / Q000150:complications* / Q000503:physiopathology*; D006801:Humans; D006930:Hyperalgesia / Q000209:etiology*; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold; D055815:Young Adult
keywords: central nervous system sensitization; cystitis; hyperalgesia; interstitial; pain measurement