Factors impacting bladder underactivity and clinical implications

Lower urinary tract symptoms in the voiding phase can be due to an underactive bladder, but are usually similar to symptoms of infravesical obstruction or dysfunctional voiding. The underactive bladder can be caused by an impaired detrusor contraction but also by a derangement of local and central neuro-cognitive regulatory systems or an impairment of bladder sensation. Potential risk factors of bladder underactivity include: ageing, diabetes, neurogenic disease, cardiovascular disease, obstruction and psychological causes. Comprehensive diagnostic and detection techniques for an underactive detrusor are necessary. To establish the diagnosis and follow up new treatments, useful urodynamic parameters and threshold values have to be determined. As neuro-cognitive regulation plays an important role in the control of voiding, psychological factors have to be taken into account during the assessment in these patients. Ambulatory urodynamic techniques therefore have to be considered. Voiding is determined by the balance of both the detrusor contraction and the resistance of the bladder outlet, a dysfunction in one factor can be compensated by a counter-acting function of the other factor. Therefore, to predict voiding problems in the future, it will be indicated to assess the compensatory capacity of the detrusor contractility, contractile reserve, and the outlet relaxation capacity. If novel treatments and evaluation techniques have become available, it is likely that in the future, many patients that get a TURP now, can be treated by pharmacological agents directed towards increasing the bladder contractility in a balanced combination with medication directed towards lowering the bladder outlet resistance.