Crystallizing the Definition of Underactive Bladder Syndrome, a Common but Under-recognized Clinical Entity

Detrusor underactivity (DU) is an important contributor to lower urinary tract symptoms (LUTS). While DU has been defined in the literature in urodynamic terms, current definitions lack specific parameters. In addition, the clinical syndrome associated with and manifesting itself as DU, underactive bladder (UAB), has not been well defined in the literature. In the absence of a precise definition of UAB, it is difficult to appreciate the true nature and burden of this condition. We review the evidence regarding the epidemiology, pathogenesis, diagnosis, and treatment of DU and UAB and discuss the challenges in gathering data in the absence of precise definitions. DU may be idiopathic or caused by ageing, medications, or a number of causes of neurogenic, myogenic, or iatrogenic origin. Treatments are largely palliative due to a lack of curative options, and include watchful waiting, catheterization, medications, and surgical interventions. In light of the evidence available in the literature, we propose that a new symptom-based definition of UAB syndrome should be developed as a first step in furthering more standardized research. Further discussion on this proposed definition to reach expert consensus will enable researchers to gather more robust data, allowing greater insights into DU and UAB diagnosis and treatment.