Review of underactive bladder

Abstract

In clinical practice, many patients cannot empty their bladders within an acceptable duration. Common complaints include weak urinary stream and incomplete emptying, which may affect quality of life. Bladder emptying requires sufficient detrusor contractile power, velocity, and durability. The urodynamic term for inadequate detrusor contraction is detrusor underactivity (DU). Although this definition was provided by the ICS, it may not be clinically practical. Analogous to the relationship between overactive bladder (OAB) and detrusor overactivity (DO), the symptom complex caused by DU is termed underactive bladder (UAB). Many conditions lead to UAB, such as advanced age, neurogenic bladder and BOO, but the definite pathophysiology directly leading to UAB is still being widely studied without a widely-accepted consensus. The preferred mainstream treatment for increased residual urine volume caused by UAB is intermittent catheterization, while pharmacotherapy is still disappointing after decades of development. There are no studies on surgical treatment for UAB with an acceptable level of evidence. We reviewed the recent literature on UAB and DU to provide a comprehensive discussion of the related presentation, etiology, diagnosis and management.

Detrusor underactivity versus bladder outlet obstruction clinical and urodynamic factors

“…According to these criteria, BCI <100 corresponds to weak detrusor, between 100-150, normal detrusor, and >150, strong detrusor (12). As observed in Table 2, there is a statistically difference between the groups for BCI, showing that this could be a good parameter, in opposition to what has been presented in other articles that BCI is not able to differentiate patients with DU from those with BOO (8,20).…”

“…One study compared Schafer Nomogram, BCI and WF, and showed that only Schafer Nomogram would be able to identify BOO, however, we could observe from the data presented that both BCI and WF were able to differentiate DU from BOO (8).…”

“…Schafer nomogram has been used to differentiate patients with DU from patients with BOO (7,8). BCI is calculated using a simple formula and can be used as screening method for DU, although it may be a method that is not able to differentiate patients with DU from those with BOO (7,9).…”

Underactive bladder in aging rats is associated with a reduced number of serotonin‐expressing cells in the urethra and is improved by serotonin application to the urethra

“…Already recognized mechanisms underlying DU include degeneration of bladder smooth muscle cells, disorders affecting central nervous system control of the voiding reflex, and disruption of the efferent–afferent nerves of the lower urinary tract . A less explored mechanism is modification of the urethra–bladder reflex .…”

“…2 Already recognized mechanisms underlying DU include degeneration of bladder smooth muscle cells, 3 disorders affecting central nervous system control of the voiding reflex, and disruption of the efferent-afferent nerves of the lower urinary tract. 4 A less explored mechanism is modification of the urethra-bladder reflex. 5,6 Urethral anesthesia with lidocaine inhibits subepithelial afferent nerves and prevents the occurrence of effective bladder contractions in humans and other mammals.…”