URODYNAMIC STUDY OF LOWER URINARY TRACT

XI. Clinical Significance of Unstable Bladder

Abstract

45 cases of unstable bladder excluding patients with an apparent outlet obstruction were clinically evaluated. Bladder instability was assessed by urodynamic examination. The presence of uninhibited detrusor contraction with urgency during filling on the supine position was considered unstable bladder type I. The uninhibited contraction provoked by cough or abdominal strain during isovolumetric study on the supine was type II, and the uninhibited contraction provoked by postural change from supine to either sitting-up or standing position was type III.
The majority of patients (42%) were found in the age group of less than 10 years. The most frequent complaint was urge incontinence followed by pollakisuria, bed wetting and so forth. Urinary tract infection and vesicoureteral reflux were coexisted in 31% and 24% of cases, respectively. The cystometric examination disclosed unstable bladder type I in 31 (69%), type II in 2 (4%) and type III in 12 patients (27%). The bladder capacity studied by our method was not significantly different between type I and III.
It is probable that the decreased threshold of exteroceptive and proprioceptive receptors in detrusor muscle and the acquired or congenital dysfunction of cortical perception causes involuntary detrusor contraction. It has been well understood and should be stressed that an unstable bladder is a frequent unrecognized pathogenesis which is responsible for the various disorders in the lower urinary tract. When the ordinary cystometry fails to disclose uninhibited contraction in a patient who complains of bladder urgency and/or its related symptoms, the provocative procedure should be attempted. Otherwise approximately one third of unstable bladder could not be properly recognized.