Comparative assessment of maximal bladder capacity, 0.9% NaCl versus 0.2 M Kcl, for the diagnosis of interstitial cystitis: a prospective controlled study.
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.
Daha
Lukas K
LK
Department of Urology, Ludwig Bolzmann Institute of Urology and Andrology, Municipal Hospital Lainz, Vienna, Austria.
Riedl
Claus R
CR
Hohlbrugger
Gero
G
Knoll
Marlies
M
Engelhardt
Paul F
PF
Pflüger
Heinz
H
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*
D012965:Sodium Chloride; D011189:Potassium Chloride