title: Comparative assessment of maximal bladder capacity, 0.9% NaCl versus 0.2 M Kcl, for the diagnosis of interstitial cystitis: a prospective controlled study.
abstract: OBJECTIVE
  Increased urothelial permeability has been proposed as a cause of interstitial cystitis (IC). The potassium sensitivity test assesses bladder discomfort after instillation of 0.4 M KCl for identification of increased urothelial permeability. Since exposure to 0.4 M KCl may be extremely painful for patients with IC we investigated a less traumatic alternative.
  
  
  METHODS
  The study comprised 38 controls and 40 patients with IC. In all subjects cystometry was performed with 0.9% NaCl followed by 0.2 M KCl, and filling volume at first urge and maximum bladder capacity (Cmax) were assessed for both solutions.
  
  
  RESULTS
  Controls did not show a significant change in Cmax. KCl decreased Cmax in 37 of 40 (92%) patients with IC with a mean decrease of 30%. The examination was painless in all controls and in 33 of 40 (82%) patients with IC, and was moderately painful in 7.
  
  
  CONCLUSIONS
  For demonstration of increased potassium sensitivity and diagnosis of IC, comparative assessment of Cmax is a well tolerated alternative to the 0.4 M potassium sensitivity test. Statistical evaluation of these results suggests that a decrease in Cmax greater than 30% is indicative of IC.
authors.affiliation: Department of Urology, Ludwig Bolzmann Institute of Urology and Andrology, Municipal Hospital Lainz, Vienna, Austria.
authors.forename: Lukas K
authors.initials: LK
authors.lastname: Daha
authors.forename: Claus R
authors.initials: CR
authors.lastname: Riedl
authors.forename: Gero
authors.initials: G
authors.lastname: Hohlbrugger
authors.forename: Marlies
authors.initials: M
authors.lastname: Knoll
authors.forename: Paul F
authors.initials: PF
authors.lastname: Engelhardt
authors.forename: Heinz
authors.initials: H
authors.lastname: Pflüger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018856:Cystitis, Interstitial / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011189:Potassium Chloride; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012965:Sodium Chloride; D001743:Urinary Bladder / Q000503:physiopathology*
chemical_list: D012965:Sodium Chloride; D011189:Potassium Chloride