Detrusor underactivity and the underactive bladder: Symptoms, function, cause-what do we mean? ICI-RS think tank 2014

Abstract

Impaired bladder emptying is a well-recognized cause of lower urinary tract symptoms. However, the symptoms produced do not always relate to voiding, and may include frequency, urgency and incontinence. Conversely, the etiology of symptoms of disturbed voiding is not necessarily dependent upon objectively impaired voiding. Terms including underactive bladder, detrusor underactivity, and impaired contractility describe aspects of these problems, and have been used somewhat interchangeably. It is possible that the present lack of effective therapy in many cases relates to both etiologic and diagnostic uncertainty stemming from terminologic imprecision. Detrusor underactivity has a standardized definition, unlike underactive bladder and impaired contractility. The relationships of symptoms, function, and cause were the focus of a 2014 ICI-RS Think Tank entitled Does Detrusor Underactivity Exist, and if so it is neurogenic, myogenic, or both? This review presents a summary of the problem and the Think Tank conclusions. A terminologic hierarchy and specific research goals are presented.

Urothelial ATP signaling: what is its role in bladder sensation?

“…DU/UAB is defined as contraction of reduced strength and/or duration, resulting in prolonged bladder emptying and/or failure to achieve complete bladder emptying within a normal time span. Although the pathophysiology of DU/UAB remains unclear, neurogenic and myogenic hypotheses have been suggested as the underlying mechanisms . Based on the neurogenic hypothesis that the inadequate afferent input leads to poor efferent output and impaired detrusor contraction, enhanced urothelial ATP signaling could stimulate detrusor contraction via activation of bladder afferent pathways.…”

Phenotyping women with detrusor underactivity by presumed etiology: Is it plausible?

“…Since there is not currently a universal measurement to define DU, our use of P det @ Q max as an index of bladder contractility may have also limited our findings. Men were excluded from the study due to the potentially different pathophysiologies in men and women, as in the case of BOO secondary to benign prostatic enlargement in men …”

Pathophysiology of the Underactive Bladder: Evolving New Concepts

“…Patients reporting voiding symptoms consistent with UAB have higher volume sensory thresholds and PVRs compared to non-UAB patients, but UAB is not associated with impaired contractility [19]. Sensory, central control, and detrusor motor factors must all be considered [6•]. …”

“…Of 53 publications containing the term “underactive bladder,” the majority (31) are reviews and opinion pieces; lots of smoke, not enough fire, and what exists is complicated by terminologic confusion. Fortunately, in the interests of clarity and hopefully progress in understanding the symptoms of impaired voiding and their causes, both the ICI Research Society [6•] and the International Continence have considered UAB. An Underactive Bladder committee of the ICS is formulating a formal definition (based on expert opinion), to be included in an updated terminology document.…”