Development of idiopathic detrusor underactivity in women: From isolated decrease in contraction velocity to obvious impairment of voiding function

OBJECTIVES To sequentially assess the evolution of urodynamic parameters in women who could be studied before and after the development of idiopathic detrusor underactivity (DUA). METHODS We assessed retrospectively 32 consecutive postmenopausal women seen during the period 1989 to 2006. They had invasive urodynamics (cystometry and pressure/flow study) performed when first referred (time 1) and then after several months (time 2). Group A, 17 women with a history of recurrent acute uncomplicated cystitis, had time 2 assessment performed a median of 24 months after time 1, following the discovery of large postvoid residual urine volumes at follow-up. As controls we took 15 age-matched women (group 13), referred to exclude anxiety as the main cause for lower urinary tract symptoms, who proved normal urodynamically at time 1, were then lost at follow-up, and proved still normal urodynamically when reassessed a median of 27 months later (time 2). RESULTS At time 1, group A showed normal urodynamic findings, except for a reduced detrusor contraction velocity. During the period between times I and 2, antimicrobial prophylaxis caused a 17% decrease in acute cystitis recurrences. At time 2, group A showed an obvious DUA, with reduced bladder emptying efficiency, lowered detrusor contraction strength, and a further decrease in detrusor contraction velocity. CONCLUSIONS An isolated decrease in detrusor contraction velocity showed as the early phase of the process leading to obvious DUA in the patients studied. This appeared to be a pathological process rather than a natural evolution due to aging.