title: Hypoalgesia to experimental visceral and somatic stimulation in painful chronic pancreatitis.
abstract: OBJECTIVE
  To gain more information of the pain mechanisms in chronic pancreatitis we applied standardized experimental pain stimulation of the duodenum, oesophagus and the skin in 12 healthy controls and 13 patients with chronic pancreatitis and typical pain attacks.
  
  
  METHODS
  Using endoscopy a guide wire was positioned into the horizontal part of the duodenum, and a probe with a distal balloon was introduced over the guide wire. Mechanical stimuli were given as tonic (38 ml/min) or phasic (increasing volume steps of 5 ml delivered for 60 s) distensions of the balloon. After stimulation of the duodenum, the distal oesophagus was stimulated with the same protocol. Finally, the skin was stimulated with 'single and repeated burst' electrical stimuli reflecting activation of peripheral and central pain mechanisms.
  
  
  RESULTS
  The stimuli reliably evoked both painful and non-painful local and referred sensations. The patients had hyposensitivity to both tonic and phasic mechanical stimuli of the duodenum and the oesophagus (P=0.001). Hypoalgesia was also observed to single and repeated electrical skin stimuli in the patients, most evident for repeated stimuli (P=0.001). The evoked referred pain did not differ between the groups, but the patients used on average more words from the McGill Pain Questionnaire to describe the pain evoked in the duodenum (P=0.02).
  
  
  CONCLUSIONS
  Generalized hypoalgesia to experimental visceral and somatic stimulations was found in chronic pancreatitis. The findings suggest that the activation and modulation of central mechanisms is fundamental in pancreatic pain, and future studies should address the effect of analgesics with central effects in the treatment of these patients.
authors.affiliation: Centre for Visceral Biomechanics and Pain, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Georg
authors.initials: G
authors.lastname: Dimcevski
authors.forename: Klaus P
authors.initials: KP
authors.lastname: Schipper
authors.forename: Ulrik
authors.initials: U
authors.lastname: Tage-Jensen
authors.forename: Peter
authors.initials: P
authors.lastname: Funch-Jensen
authors.forename: Anne L
authors.initials: AL
authors.lastname: Krarup
authors.forename: Egon
authors.initials: E
authors.lastname: Toft
authors.forename: Niels
authors.initials: N
authors.lastname: Thorsgaard
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
authors.forename: Asbjørn M
authors.initials: AM
authors.lastname: Drewes
mesh_terms: D015746:Abdominal Pain / Q000209:etiology* / Q000503:physiopathology; D000328:Adult; D004386:Duodenum / Q000503:physiopathology; D004558:Electric Stimulation / Q000379:methods; D004947:Esophagus / Q000503:physiopathology; D005260:Female; D006339:Heart Rate; D006801:Humans; D006987:Hypesthesia / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D050500:Pancreatitis, Chronic / Q000150:complications* / Q000503:physiopathology; D010812:Physical Stimulation / Q000379:methods; D012677:Sensation