OBJECTIVES: To evaluate the role of cystometry in the diagnostic evaluation of 
patients with symptoms of overactive bladder, by comparing the treatment outcome 
in those with and without urodynamically proven bladder instability.
METHODS: Prospective observational study performed at Urogynaecology Division, 
the Kidney Center Post-Graduate institute of nephro-urology, Karachi. Forty six 
patients with symptoms of overactive bladder, i.e., frequency (> or =8 voids/24 
hours), nocturia, urgency with or without urge incontinence, were included. 
Patients were recruited solely on their symptoms of overactive bladder. All 
patients, irrespective of the results of cystometry were subsequently treated 
with oxybutynin 2.5 mg twice daily along with bladder training. Involuntary 
detrusor contraction over base line during filling are considered significant 
(AUA Update series). Following variables were compared in those with or without 
urodynamically proven bladder instability: the bladder volume and amplitude of 
detrusor contraction at first and maximum detrusor contractions, the treatment 
outcome and relapse rate The complications of the procedure were noted.
RESULTS: Total number of 46 women, aged between 21-74 years with symptoms of 
overactive bladder were subjected to cystometry. The audit of cystometry showed 
unstable bladder in 17 (36.9%), while rest of the patients 29 (63%) had normal 
stable bladder with normal emptying. The comparison of treatment outcome in the 
urodynamically stable and unstable bladder revealed out of 17 unstable bladder 
with symptoms of OAB in 09 (60%) and 05 (29.4%), a 100% cure rate was observed 
after 3 and 6 months of treatment respectively. Of the 29 patients with stable 
bladder and symptoms of OAB, 100% cure rate was achieved in 20 (68.9%) and 06 
(20.6%) patients respectively. While in 3 patients in both groups, decrease of 
symptoms upto 75% after 6 months of treatment was observed. The median volume 
was less and amplitude of first and maximum detrusor contraction were more in 
unstable than stable bladder but it was not significant statistically.
CONCLUSION: Conventional Cystometry showed poor co-relation with Lower urinary 
tract symptoms (LUT). Both urodynamically proven unstable and stable bladder 
showed nearly equal improvement with treatment