Parameters of bladder function in pre-, peri-, and postmenopausal continent women without detrusor overactivity

Nocturia in Menopausal Women: The Link Between Two Common Problems of the Middle Age

INTRODUCTION AND HYPOTHESIS

The aim of this review is to discuss the link between menopause and nocturia and to give an overview of the increasing prevalence, risk factors, causative factors, treatment needs and options for nocturia in peri-menopausal women.

METHODS

This opinion article is a narrative review based on the expertise and consensus of a variety of key opinion leaders, in combination with an extensive literature review. This literature search included a thorough analysis of potential publications on both the PubMed Database and the Web of Science and was conducted between November 2022 and December 2022. The following key words were used "nocturia" and "menopause" or "nocturnal frequency and menopause." Moreover, key words including "incidence," "prevalence," "insomnia," "estrogen therapy," "metabolic syndrome," and "hot flushes" were used in combination with the aforementioned key words. Last, the reference lists of articles obtained were screened for other relevant literature.

RESULTS

The perimenopause can be a trigger for inducing nocturia. Typically, obesity, body mass index (BMI), and waist circumference are risk factors for developing peri-menopausal nocturia. Presumably the development of peri-menopausal nocturia is multifactorial, with interplay among bladder, sleep, and kidney problems due to estrogen depletion after the menopause. First, impaired stimulation of estrogen receptors in the urogenital region leads to vaginal atrophy and reduced bladder capacity. Moreover, menopause is associated with an increased incidence of overactive bladder syndrome. Second, estrogen deficiency can induce salt and water diuresis through blunted circadian rhythms for the secretion of antidiuretic hormone and the activation of the renin-angiotensin-aldosterone system. Additionally, an increased incidence of sleep disorders, including vasomotor symptoms and obstructive sleep apnea signs, is observed. Oral dryness and a consequent higher fluid intake are common peri-menopausal symptoms. Higher insulin resistance and a higher risk of cardiovascular diseases may provoke nocturia. Given the impact of nocturia on general health and quality of life, bothersome nocturia should be treated. Initially, behavioral therapy should be advised. If these modifications are inadequate, specific treatment should be proposed. Systemic hormone replacement is found to have a beneficial effect on nocturia, without influencing sodium and water clearance in patients with nocturnal polyuria. It is presumed that the improvement in nocturia from hormonal treatment is due to an improvement in sleep disorders.

Loss of resilience contributes to detrusor underactivity in advanced age

Volume hyposensitivity resulting from impaired sympathetic detrusor relaxation during bladder filling contributes to detrusor underactivity (DU) associated with aging. Detrusor tension regulation provides an adaptive sensory input of bladder volume to the brainstem and is challenged by physiological stressors superimposed upon biological aging. We recently showed that HCN channels have a stabilizing role in detrusor sympathetic relaxation. While mature mice maintain homeostasis in the face of stressors, old mice are not always capable. In old mice, there is a dichotomous phenotype, in which resilient mice adapt and maintain homeostasis, while non-resilient mice fail to maintain physiologic homeostasis. In this DU model, we used cystometry as a stressor to categorize mice as old-responders (old-R, develop a filling/voiding cycle) or old-non-responders (old-NR, fail to develop a filling/voiding cycle; fluctuating high pressures and continuous leaking), while also assessing functional and molecular differences. Lamotrigine (HCN activator)-induced bladder relaxation is diminished in old-NR mice following HCN-blockade. Relaxation responses to NS 1619 were reduced in old-NR mice, with the effect lost following HCN-blockade. However, RNA-sequencing revealed no differences in HCN gene expression and electrophysiology studies showed similar percentage of detrusor myocytes expressing HCN (I_h) current between old-R and old-NR mice. Our murine model of DU further defines a role for HCN, with failure of adaptive recalibration of HCN participation and intensity of HCN-mediated stabilization, while genomic studies show upregulated myofibroblast and fibrosis pathways and downregulated neurotransmitter-degradation pathways in old-NR mice. Thus, the DU phenotype is multifactorial and represents the accumulation of age-associated loss in homeostatic mechanisms.

Treating Lower Urinary Tract Symptoms in Older Adults: Intravesical Options

This article provides an overview of the diagnosis and the treatment of lower urinary tract symptoms in older adults complicated by the neurodegenerative changes in the micturition reflex and further confounded by age-related decline in hepatic and renal clearance raising the propensity of adverse drug reactions. The first-line drug treatment for lower urinary tract symptoms, orally administered antimuscarinics, fails to reach the equilibrium dissociation constant of muscarinic receptors even at their maximum plasma concentration and tends to evoke a half-maximal response at a muscarinic receptor occupancy of just 0.206% in the bladder with a minimal difference from exocrine glands, which raises the adverse drug reaction risk. On the contrary, intravesical antimuscarinics are instilled at concentrations 1000-fold higher than the oral maximum plasma concentration and the equilibrium dissociation constant erects a downhill concentration gradient that drives passive diffusion and achieves a mucosal concentration around ten-fold lower than the instilled concentration for a long-lasting occupation of muscarinic receptors in mucosa and sensory nerves. A high local concentration of antimuscarinics in the bladder triggers alternative mechanisms of action and is supposed to engage retrograde transport to nerve cell bodies for neuroplastic changes that underlie a long-lasting therapeutic effect, while an intrinsically lower systemic uptake of the intravesical route lowers the muscarinic receptor occupancy of exocrine glands to lower the adverse drug reaction relative to the oral route. Thus, the traditional pharmacokinetics and pharmacodynamics of oral treatment are upended by intravesical antimuscarinics to generate a dramatic improvement (~ 76%) noted in a meta-analysis of studies enrolling children with neurogenic lower urinary tract symptoms on the primary endpoint of maximum cystometric bladder capacity as well as the secondary endpoints of filling compliance and uninhibited detrusor contractions. The therapeutic success of intravesical multidose oxybutynin solution or oxybutynin entrapped in the polymer for sustained release in the pediatric population bodes well for patients with lower urinary tract symptoms at the other extreme of the age spectrum. Though generally used to predict oral drug absorption, Lipinski's rule of five can also explain the ten-fold lower systemic uptake from the bladder of positively charged trospium over oxybutynin, a tertiary amine. Chemodenervation by an intradetrusor injection of onabotulinumtoxinA is merited for patients with idiopathic overactive bladder discontinuing oral treatment because of a lack of efficacy. However, age-related peripheral neurodegeneration potentiates the adverse drug reaction risk of urinary retention that motivates the quest of liquid instillation, delivering larger fraction of onabotulinumtoxinA to the mucosa as opposed to muscle by an intradetrusor injection can also probe the neurogenic and myogenic predominance of idiopathic overactive bladder. Overall, the treatment paradigm of lower urinary tract symptoms in older adults should be tailored to individual's overall health status and the risk tolerance for adverse drug reactions.

Artifacts and abnormal findings may limit the use of asymptomatic volunteers as controls for studies of multichannel urodynamics

BACKGROUND

Multichannel urodynamics is the gold standard for the evaluation of lower urinary tract symptoms (LUTS). When performing studies to validate new adjuncts to urodynamic testing with control patients undergoing urodynamic investigation, there is difficulty in the interpretation of urodynamic results in the asymptomatic patient due to artifacts and the invasive nature of the procedure. The purpose of this investigation was to examine urodynamics in asymptomatic volunteers in order to better understand the role of control participants in urodynamic research studies.

METHODS

Asymptomatic volunteers with no LUTS were recruited to undergo standard urodynamic testing as a comparison group in a study evaluating novel urodynamic techniques. To be eligible, participants had to report no LUTS, score ≤1 on all symptom questions of the International Consultation on Incontinence Questionnaire Overactive Bladder Module (ICIq-OAB) survey, have no medical conditions or to undergo any medications that affect bladder function. The urodynamics was done according to ICS standards. All tracings were evaluated by an expert neuro-urologist. Data were analyzed categorically for the presence or absence of low compliance (<30 mL/cmH20), detrusor overactivity, bladder outlet obstruction (Bladder Outlet Obstruction Index [BOOI]>40), weak contractility (bladder contractility index [BCI]<100), straining to void, poorly sustained detrusor contraction, uncoordinated EMG activity, and intermittent flow.

RESULTS

A total of 24 participants completed the study including 10 men and 14 women. All participants had at least 1 urodynamic abnormality/artifact with an average of 4.43±1.28 abnormalities/participant. The most common abnormalities included uncoordinated electromyography (EMG) activity (87.50%), straining to void (79.17%), and intermittent flow (70.83%). There were no significant differences for sex, age, Body Mass Index.

CONCLUSIONS

This study demonstrated that healthy, asymptomatic volunteers have high rates of abnormal urodynamic findings, suggesting that asymptomatic participants are not the ideal controls in research studies that involve urodynamic testing.

False-negative finding in urodynamic study for the chief complaint. Does it interfere with the clinical outcomes for the treatment of SUI or OAB syndromes?

PURPOSE

False-negative urodynamic findings may mislead or prevent planned treatments due to unmatched findings with the clinical presentation. We hypothesized that the absence of urodynamic demonstration of SUI or OAB on urodynamics would interfere with clinical outcomes.

MATERIALS AND METHODS

We prospectively studied 124 women with (94) or without (30) demonstrable SUI after sling operations. Similarly, 64 women with OAB syndrome with (38) or without (26) demonstrable DO were also compared after treatment with anticholinergic agents. Patients were assessed with the UDI-6 and IIQ-7 questionnaires 3 and 6 months after treatment.

RESULTS

Only 76% of SUI patients demonstrated urine leakage during urodynamics. The UDI-6 score was higher in the demonstrable-SUI and demonstrable-DO groups, while the IIQ-7 score was comparable within the incontinence or urgency/frequency groups. Demonstrable and non-demonstrable SUI-operated patients showed similar outcomes. Patients with urgency syndromes with or without demonstrable DO had a similar rate of improvement with anticholinergic therapy.

CONCLUSIONS

Women with clinical complaints of SUI objectively demonstrated on urodynamics presented the same subjective clinical outcome as those with SUI lacking objective demonstration when measured by the UDI-6 and IIQ-7 questionnaires. Similarly, patients with OAB syndrome with or without demonstrable DO had similar clinical improvement when treated with anticholinergics and measured using the same questionnaires.

Age-related reductions in the excitability of phasic dorsal root ganglion neurons innervating the urinary bladder in female rats

Previous studies have revealed an impairment in bladder sensory transduction in aged animals. To examine the contributions of electrical property changes of bladder primary afferents to this impairment, we compared the electrical properties of dorsal root ganglion (DRG) neurons innervating the bladder among young (3 months), middle-aged (12 months), and old (24 months) female rats. The DRG neurons were labeled using axonal tracing techniques. Whole-cell current-clamp recordings of small and medium-sized neurons were performed to assess their passive and active properties. Two patterns of firing were identified based on responses to super-threshold stimuli (1.5, 2.0, 2.5, and 3.0 × rheobase): tonic neurons fired more action potentials (APs), whereas phasic neurons fired only one AP at the onset of stimulus. Tonic neurons were smaller and had a slower rate of AP rise, longer AP duration, more depolarized voltage threshold, and greater rheobase than phasic neurons. In phasic neurons, there was an age-associated increase in voltage threshold and an increase of rheobase (P < 0.05), suggesting an age-related decrease in excitability. In addition, both middle-aged and old rats had longer AP durations and slower rates of AP rise than young rats (P < 0.05). In tonic neurons, old rats had a greater AP overshoot and greater rate of AP rise, but no age-associated changes were identified in any other electrical properties. Our results suggest that the electrical properties of tonic and phasic bladder afferents are differentially altered with aging. A decrease in excitability may contribute to age-related reductions in bladder sensory function.

Increasing Age Predicts Increasing Residual Urine Volume

OBJECTIVES

To determine reference values for postvoid residual (PVR) volume for patients referred to a tertiary urogynecology center.

METHODS

After Institutional Review Board approval, we performed a retrospective chart review of all new patients presenting to our referral center. We assessed associations between PVR and patient demographics, pelvic floor symptoms, and physical examination by Wilcoxon rank sum or Kruskal-Wallis tests as appropriate. A multivariable logistic regression model was used to calculate odds ratios for patient characteristics associated with PVR in the top age range-specific decile.

RESULTS

Three hundred sixty-one patients were included in the analysis. The median PVR was 20 mL (interquartile range, 1st, 3rd quartiles, 10, 50). Older age was associated with higher PVR (P < 0.001). The median PVR in participants younger than 40 years was 10 mL, ages 40 to 49 years was 18 mL, 50 to 69 years was 20 mL, 70 to 79 years was 38 mL and in women older than 79 years was 50 mL. A multivariable analysis showed that prolapse stage (odds ratio [OR], 3.46 with prolapse stage 2-4 vs stage 0-1; P = 0.001), history of stroke (OR, 7.62; [95% CI 2.17-26.77, P = 0.002]), narcotic use (OR, 2.45; [95% CI 1.01-5.92; P = 0.047]), and urinary frequency (OR, 2.61; [95% CI, 1.14-5.98; P = 0.024]) were risk factors for increased PVR (as defined at >90%ile for age), independent of the age-related elevation.

CONCLUSIONS

The majority of patients presenting for urogynecologic evaluation had a low PVR with a median of 20 mL. Postvoid residual was higher for older age groups but nearly all volumes were less than 100 mL. The utility of a PVR measurement is highest for patients with pelvic organ prolapse, urinary frequency, narcotic use, or history of stroke.

Views of Normal Bladder Function Among Women Experiencing Lower Urinary Tract Symptoms

OBJECTIVE

To explore the perspectives of normal bladder function among women with lower urinary tract symptoms.

METHODS

This was a secondary analysis of qualitative data from structured interviews with 50 adult women with lower urinary tract symptoms. A directed content analysis of the transcripts explored women's perspectives on normal bladder function.

RESULTS

Participants' descriptions of "normal" took many forms and were based on several aspects of bladder function. A prominent feature of normal was that voiding occurred as a seamless process, beginning with an urge sensation, followed by voiding with ease and to completion, and then "being done." Descriptions of normal were based largely on concepts of voiding regularity, including voiding frequency, intervals, and patterns during the day and night. Another aspect of normal bladder function was the notion of having control in terms of not leaking urine, as well as the ability to hold urine and defer urination. Views of normal bladder function extended to the absence of symptoms and the impact of being symptom-free on day-to-day life, including not having to think about or worry about the bladder or limit daily activities.

CONCLUSION

Women's perspectives on normal bladder function are multifaceted, reflecting attributes most salient to each individual and likely informed by their personal experience with symptoms and their influence on daily life. This work has implications for how clinicians might engage women in discussing bladder symptoms and can inform future research and public health messaging about normal bladder function.

Normative noninvasive bladder function measurements in healthy women: A systematic review and meta-analysis

AIM

To conduct an evidence synthesis of normative reference values for bladder function parameters in women.

METHODS

We conducted a systematic review and meta-analysis of studies reporting bladder function parameters obtained from noninvasive tests in healthy women. Seven databases were searched for relevant studies from inception through December 2018, with manual searching of reference lists. We included English language articles that provided quantitative data on urination frequency, voided and postvoid residual volumes, and uroflowmetry results in women without lower urinary tract symptoms. Study selection, data extraction, and quality assessment were undertaken by at least two independent reviewers. Random-effects meta-analytic models were used to derive study-level pooled mean estimates and 95% confidence intervals.

RESULTS

A total of 24 studies (N = 3090 women, age range, 18-91 years) met eligibility criteria. Pooled mean estimates of bladder function parameters were: 6.6 daytime voids (95% confidence interval (95% CI), 6.2, 7.0), 0.4 nighttime voids (95% CI, 0.0, 0.8), 1577 mL for 24-hour voided volume (95% CI 1428,1725); 12 mL for postvoid residual volume (95% CI, 4, 20); and 28 mL/sec for maximum flow rate (95% CI, 27,30). Between-study heterogeneity was high for all outcomes (I²  = 61.1-99.6%), but insufficient data were available to explore reasons for this high heterogeneity (eg, differences by age).

CONCLUSION

Although summary mean estimates of bladder function parameters were calculated, the wide heterogeneity across studies precludes generalization of these estimates to all healthy women. Further research is needed to determine normative reference values within specific groups, such as those defined by age.

The aging bladder phenotype is not the direct consequence of bladder aging

AIMS

The prevalence of urinary dysfunction increases with age, yet therapies are often suboptimal. Incomplete understanding of the linkages between system, organ, and tissue domains across lifespan remains a knowledge gap. If tissue-level changes drive the aging bladder phenotype, parallel changes should be observed across these domains. In contrast, a lack of inter-domain correlation across age groups would support the hypothesis that urinary performance is a measure of the physiologic reserve, dependent on centrally-mediated adaptive mechanisms in the aging system.

METHODS

Male and female mice across four age groups underwent sequential voiding spot assays, pressure/flow cystometry, bladder strip tension studies, histology, and quantitative PCR analyses. The primary objective of this study was to test the impact of age on the cortical, autonomic, tissue functional and structural, and molecular domains, and identify inter-domain correlations among variables showing significant changes with age within these domains.

RESULTS

Behavior revealed diminished peripheral voiding and spot size in aged females. Cystometry demonstrated increased postvoid residual and loss of volume sensitivity, but the preservation of voiding contraction power, with almost half of oldest-old mice failing under cystometric stress. Strip studies revealed no significant differences in adrenergic, cholinergic, or EFS sensitivity. Histology showed increased detrusor and lamina propria thickness, without a change in collagen/muscle ratio. Adrb2 gene expression decreased with age. No consistent inter-domain correlations were found across age groups.

CONCLUSIONS

Our findings are consistent with a model in which centrally-mediated adaptive failures to aging stressors are more influential over the aging bladder phenotype than local tissue changes.

Reduced bladder responses to capsaicin and GSK-1016790A in retired-breeder female rats with diminished volume sensitivity

Literature documents an age-related reduction of bladder sensory function. Transient receptor potential vanilloid (TRPV)1 or TRPV4 channels have been implicated in bladder mechanotransduction. To investigate contributions of TRPV1 or TRPV4 to the age-related reduction of bladder sensory function, bladder responses to capsaicin (CAP; TRPV1 agonist) and GSK-1016790A (GSK; TRPV4 agonist) in retired breeder (RB; 12-15 mo) and young adult (2-3 mo) female rats were compared using multiple methods. Metabolic cage and continuous infusion cystometry [cystometrogram (CMG)] recordings revealed that RB rats exhibit larger bladder capacity and lower voiding frequency. RB rats also have a greater intravesical pressure threshold for micturition; however, the voiding contraction strength was equivalent to that in young rats. CAP (1 μM) or GSK (20 nM) administered intravesically evoked smaller changes in all CMG parameters in RB rats. In vitro, CAP (1 μM) or GSK (20 nM) evoked smaller enhancement of bladder strip contractions, while the muscarinic receptor agonist carbachol (at 100, 300, and 1,000 nM) elicited greater amplitude contractions in RB rats. Patch-clamp recording revealed smaller CAP (100 nM) induced inward currents in bladder primary sensory neurons, and Ca²⁺ imaging revealed smaller GSK (20 nM) evoked increases in intracellular Ca²⁺ concentration in urothelial cells in RB rats. These results suggest that RB rats have a decreased bladder sensory function commonly observed in elderly women, and could be used as an animal model to study the underling mechanisms. Reduced functional expression of TRPV1 in bladder afferents or reduced functional expression of urothelial TRPV4 may be associated with the diminished sensory function.

Pathophysiology of the Underactive Bladder: Evolving New Concepts

PURPOSE OF REVIEW

Underactive Bladder (UAB) is an emerging concept of voiding dysfunction, building on a tradition of often overlapping and confusing terminologies describing the patient experience, urodynamic function, and pathophysiology. This confusion of symptoms with function with pathology has hampered development of an effective disease model.

RECENT FINDINGS

As with other urinary symptoms, the relationship of voiding symptoms to urodynamic dysfunction is variable. Efforts are underway to formally define UAB as a collection of symptoms related to voiding. Defined as voiding symptoms, UAB cannot be reliably linked to detrusor underactivity (DU) nor to detrusor weakness.

SUMMARY

Progress will be made by characterizing the functional disorders underlying UAB symptoms, examining the biology of these linkages, re-conceptualizing urinary control as one part of a more global biologic adaptive physiology, and determining the relationships of central and peripheral pathologies leading to disrupted control mechanisms.

Can we define and characterize the aging lower urinary tract?-ICI-RS 2015

The prevalence of lower urinary tract (LUT) symptoms increases with age but the etiology is unknown. This article aims to identify research directions that clarify the basis of this association. The initial question is whether biological age is the variable of interest or a time-dependent accumulation of factors that impact on LUT function at rates that differ between individuals. In particular, the accumulation of conditions or agents due to inflammatory states or tissue ischemia is important. Much of the above has been concerned with changes to bladder function and morphology. However, the outflow tract function is also affected, in particular changes to the function of external sphincter skeletal muscle and associated sacral motor nerve control. Nocturia is a cardinal symptom of LUT dysfunction and is more prevalent with aging. Urine production is determined by diurnal changes to the production of certain hormones as well as arterial blood pressure and such diurnal rhythms are blunted in subjects with nocturia, but the causal links remain to be elucidated. Changes to the central nervous control of LUT function with age are also increasingly recognized, whether in mid-brain/brainstem regions that directly affect LUT function or in higher centers that determine psycho-social and emotional factors impinging on the LUT. In particular, the linkage between increasing white matter hyperintensities and LUT dysfunction during aging is recognized but not understood. Overall, a more rational approach is being developed to link LUT dysfunction with factors that accumulate with age, however, the precise causal pathways remain to be characterized. Neurourol. Urodynam. 36:854-858, 2017. © 2017 Wiley Periodicals, Inc.

Stimulation of the pelvic nerve increases bladder capacity in the prostaglandin E2 rat model of overactive bladder

Overactive bladder (OAB) syndrome is a highly prevalent condition that may lead to medical complications and decreased quality of life. Emerging therapies focusing on selective electrical stimulation of peripheral nerves associated with lower urinary tract function may provide improved efficacy and reduced side effects compared with sacral neuromodulation for the treatment of OAB symptoms. Prior studies investigating the effects of pelvic nerve (PelN) stimulation on lower urinary tract function were focused on promoting bladder contractions, and it is unclear whether selective stimulation of the PelN would be beneficial for the treatment of OAB. Therefore our motivation was to test the hypothesis that PelN stimulation would increase bladder capacity in the prostaglandin E₂ (PGE₂) rat model of OAB. Cystometry experiments were conducted in 17 urethane-anesthetized female Sprague-Dawley rats. The effects of intravesical PGE₂ vs. vehicle and PelN stimulation after intravesical PGE₂ on cystometric parameters were quantified. Intravesical infusion of PGE₂ resulted in decreased bladder capacity and increased voiding efficiency without a change in bladder contraction area under the curve, maximum contraction pressure, or contraction duration. Bladder capacity was also significantly decreased compared with vehicle (1% ethanol in saline) confirming that the change in bladder capacity was mediated by PGE₂ PelN stimulation reversed the PGE₂-induced change in bladder capacity and increased the external urethral sphincter electromyogram activity at a specific stimulation condition (amplitude of 1.0 times threshold at 10 Hz). These results confirm that the urodynamic changes reported in conscious rats are also observed under urethane anesthesia and that PelN stimulation is a novel and promising approach for the treatment of the symptoms of OAB.

Urodynamic Investigation: A Valid Tool to Define Normal Lower Urinary Tract Function?

Objectives

To evaluate whether urodynamic investigation (UDI), the gold standard to assess refractory lower urinary tract symptoms (LUTS), is appropriate to select healthy volunteers with apparent normal lower urinary tract function as control subjects for comparative studies.

Subjects and Methods

42 healthy subjects (22 women, mean age 32±10 years; 20 men, mean age 37±12 years) without LUTS were included into this prospective single-centre cohort study. All subjects recorded a 3-day bladder diary, completed validated questionnaires regarding LUTS, and underwent neuro-urological assessment as well as free uroflowmetry. Same session repeat UDI was performed according to “Good Urodynamic Practice” recommended by the International Continence Society, but using an air-charged instead of a water-filled catheter, and evaluated by a blinded investigator.

Results

All 3-day bladder diaries, LUTS questionnaires, neuro-urological assessments and free uroflowmetries were within normal limits. Overall (either during the first or second UDI), same session repeat UDI revealed pathological findings in 71% (30/42): Detrusor overactivity was detected in 14% (3/22) and 30% (6/20), post void residual >100mL in 14% (3/22) and 25% (5/20), bladder outlet obstruction in 9% (2/22) and 20% (4/20) and detrusor sphincter dyssynergia in 77% (17/22) and 65% (13/20) of our women and men, respectively.

Repeatability of detrusor overactivity (κ = 0.78, 95% CI: 0.54–1.02) and detrusor sphincter dyssynergia (κ = 0.77, 95% CI: 0.55–0.98) showed substantial agreement between both UDIs. All other assessed urodynamic parameters had wide 95% limits of agreement for differences in the parameters indicating poor repeatability.

Conclusions

More than 70% of our healthy subjects showed pathological urodynamic findings. Although UDI is the gold standard to assess refractory LUTS, it seems not to be applicable in healthy subjects to define normal lower urinary tract function. Therefore, we do not recommend using UDI to select healthy control subjects.

Evaluation of female overactive bladder using urodynamics: relationship with female voiding dysfunction

Purpose:

To investigate the role of urodynamic study (UDS) in female patients with overactive bladder (OAB) analyzing the relationship between OAB symptoms and female voiding dysfunction (FVD).

Materials and Methods:

We analyzed the clinical and urodynamic data of 163 women with OAB symptoms. OAB symptoms were categorized as dry and wet. FVD was described as detrusor underactivity (DUA), which was defined as a maximum flow rate (Q_max) of ≤15mL/s associated with a detrusor pressure at Q_max (PdetQ_max) of ≤20cmH₂O, along with bladder outlet obstruction (BOO), which was defined as a Q_max of ≤15mL/s with a PdetQ_max of >20cmH₂O. Clinical and urodynamic results were compared between patients with dry and wet symptoms and between those with and without FVD.

Results:

78 (47.9%) had dry, and 85 (52.1%) had wet symptoms. The entire group had a relatively low Q_max (15.1±6.6mL/s) and relatively high number of BOO (42.9%, 70/163) and DUA (8.6%, 14/163). A significantly higher number of patients with wet symptoms had detrusor overactivity compared to those with dry, as detected by the UDS (p<0.05). No significant differences were found in BOO and DUA number between dry and wet groups. Further, the international prostate symptom score did not different significantly between patients with and without FVD.

Conclusion:

A significant number of women with OAB had voiding dysfunction. However, the OAB symptoms themselves were not useful for predicting the presence of FVD. Therefore, UDS may be necessary for accurate diagnosis in women with OAB symptoms.

Underactive bladder in women: is there any evidence?

PURPOSE OF REVIEW

Underactive bladder (UAB) is a clinical symptom complex only recently gaining recognition as a clinical diagnosis. Lack of consensus agreement on a definition of UAB has limited its recognition and diagnosis in clinical practice. The purposes of this review are to: present existing definitions of UAB, review recent data regarding clinical and urodynamic diagnosis of the condition, and examine up-to-date hypotheses regarding its pathophysiology, with a focus on women.

RECENT FINDINGS

The process to develop a consensus definition for UAB as a clinical symptom complex is ongoing. Symptoms associated with UAB, such as weak stream, straining to void, and history of urinary retention are well correlated to detrusor underactivity on urodynamics, which frequently develops in elderly women. In addition to aging, UAB may be the end stage of a variety of contributing pathologic conditions such as diabetes and ischemic disease. In some women, UAB may result from a progression from overactive bladder to UAB.

SUMMARY

Existing evidence supports UAB in women as a symptom complex with a clinical and pathophysiologic profile distinguishable from other lower urinary tract-associated clinical conditions. Consensus definitions of clinical and urodynamic diagnostic parameters will be essential to more widespread recognition of UAB.

Predictors for de novo stress urinary incontinence following extensive pelvic reconstructive surgery

INTRODUCTION AND HYPOTHESIS

The aim of this study was to look for possible predictors preoperatively for the development of de novo stress urinary incontinence (SUI) in urodynamically continent women who underwent pelvic reconstructive surgery (PRS).

MATERIALS AND METHODS

Medical records of 637 continent women who underwent PRS for severe prolapse from January 2005 to December 2013 in our institutions were included in this study. We excluded women who had urodynamic stress incontinence (UDI) either occult or overt, detrusor overactivity, neurogenic bladder-voiding dysfunction, and previous anti-incontinent surgery. Primary outcome measure was the development of de novo SUI at 6 months to 1 year post operation.

RESULTS

Of women in this study, 11 % developed postoperative de novo SUI at 6 months to 1 year of follow-up. Women older than 66 years were 2.86 times [95 % confidence interval (CI) 1.01-2.53, p = 0.14], diabetes mellitus (DM) 2.18 times (95 % CI 1.63-4.21, p = 0.002), certain type of transvaginal mesh procedure 3.5 times (95 % CI, p < 0.001), maximum urethral closure pressure (MUCP) < 60 mmH20 4.65 times (95 % CI, 2.87-8.64, p < 0.001), and functional urethral length (FUL) < 2 cm 3.48 times (95 % CI, 2.13-5.83, p < 0.001) at greater risk of developing de novo SUI.

CONCLUSIONS

Continent women with advanced pelvic organ prolapse (POP) > 66 years, with DM or low MUCP and FUL values during preoperative urodynamic evaluation have higher risk of developing de novo SUI; therefore, we suggest counselling such women for concomitant PRS and anti-incontinent surgery.

Voiding dysfunction in older women with overactive bladder symptoms: A comparison of urodynamic parameters between women with normal and elevated post-void residual urine

AIMS

To compare urodynamic parameters in two groups of older women who have overactive bladder (OAB) symptoms: those with normal and those with elevated post-void residual (PVR).

METHODS

Secondary data analyses were conducted on medical record data from 203 women who were 65 years or older and who completed urodynamic testing. Of these, 151 (74%) medical records met the study criteria. A PVR of 100 ml or greater during the pressure-flow study was considered elevated for this study. Maximal flow rate (Qmax ) and detrusor pressure at Qmax , bladder capacity, voiding volume, and voiding pattern were compared between these two groups.

RESULTS

The mean Qmax and detrusor pressure at Qmax were 19.63 ml/sec (SD = 8.74) and 16.15 cmH2 O (SD = 11.19) for the overall sample, respectively. The elevated PVR group (n = 54) had significantly higher detrusor pressure at Qmax and bladder capacity than the normal PVR group (n = 97) (P < 0.05, P < 0.01, respectively). An interrupted voiding pattern accounted for 47.4% of the normal PVR group and 77.4% of the elevated PVR group, respectively (P < 0.01).

CONCLUSIONS

Older women with an elevated PVR required on average a higher detrusor pressure at Qmax and greater bladder capacity than women with a normal PVR. Although an interrupted voiding pattern was more prevalent in the elevated PVR group, many women in the normal PVR group also had an interrupted voiding pattern. These findings indicate that many women may habitually strain to void as well as strain due to inadequate detrusor function.

Contemporary concepts in the aetiopathogenesis of detrusor underactivity

Detrusor underactivity (DUA) is a poorly understood, yet common, bladder dysfunction, referred to as underactive bladder, which is observed in both men and women undergoing urodynamic studies. Despite its prevalence, no effective therapeutic approaches exist for DUA. Exactly how the contractile function of the detrusor muscle changes with ageing is unclear. Data from physiological studies in animal and human bladders are contradictory, as are the results of the limited number of clinical studies assessing changes in urodynamic parameters with ageing. The prevalence of DUA in different patient groups suggests that multiple aetiologies are involved in DUA pathogenesis. Traditional concepts focused on either efferent innervation or myogenic dysfunction. By contrast, contemporary views emphasize the importance of the neural control mechanisms, particularly the afferent system, which can fail to potentiate detrusor contraction, leading to premature termination of the voiding reflex. In conclusion, the contemporary understanding of the aetiology and pathophysiology of DUA is limited. Further elucidation of the underlying mechanisms is needed to enable the development of new and effective treatment approaches.

Does defective volume sensation contribute to detrusor underactivity?

AIMS

The urodynamic finding of detrusor underactivity (DU) in neurologically intact unobstructed patients may relate to impaired volume sensations rather than detrusor contractile defects. We hypothesized that DU patients would demonstrate higher volumes but similar wall stress at sensation thresholds, and similar voiding contractility, compared to other groups.

METHODS

Chart review of urodynamic studies in neurologically normal, nonobstructed symptomatic patients. Urodynamic studies having the primary findings of DU, stress urinary incontinence (SUI), detrusor overactivity (DO), and increased sensations without detrusor overactivity (IS) were abstracted. Age, gender, and pressure/volume data associated with sensations and voiding parameters were collected. Wall stress at sensations was calculated. Urodynamic variables at standard sensations and progression across standard sensations were compared among the four groups.

RESULTS

Fifty-one urodynamic studies were analyzed for comparison. Mean age did not differ between groups. The DU group was predominantly male versus the other groups. DU, SUI, and DO had higher volume thresholds for strong desire than did IS. DU and DO demonstrated higher wall stress at strong desire than did IS and SUI. Watts factor was not significantly different between groups, however, DU had a smaller voided volumes and a higher post-void residuals.

CONCLUSION

Increased volume and wall stress at strong desire, and similar contractility but the smaller voided volumes and elevated PVRs in DU suggest that diminished central sensitivity to volume afferent activity contributes to DU in nonobstructed, non-neurogenic symptomatic patients.

The effect of age on pressure flow parameters in women with lower urinary tract symptoms

This study aimed to evaluate changes in voiding with age in women with different urodynamic diagnoses. Correlation was used to analyse the association between age and voiding parameters (maximum flow rate, voided volume, flow rate centile and maximum detrusor pressure - PdetMax) in 896 datasets. Multivariate analysis was used to analyse the data further by age group and diagnosis - urodynamic stress incontinence (USI); detrusor overactivity (DO); mixed USI and DO; no urodynamic abnormality. Results showed that diagnosis accounts for a significant amount of variation in all four of the dependent variables Age group shows a significant effect on voiding volume but does not show significant effects on any other variable studied. There is no significant interaction term in any of the analyses, meaning that age and diagnosis do not appear to function together, e.g. age does not relate to flow rate centile, maximum flow rate or PdetQMax. It was concluded that the data suggest that there is no significant change in voiding function related to age. In the elderly, the main alteration in voiding is due to a higher prevalence of DO.

Can intrinsic sphincter deficiency be diagnosed by urodynamics?

Intrinsic sphincter deficiency (ISD) is a pathologic condition that is diagnosed by using urodynamics to measure Valsalva leak point pressure and maximal urethral closure pressure. The diagnosis can be difficult to reach given natural discrepancies in these values in women of different age groups and with varying degrees of incontinence. By standardizing urodynamic methodologies and interpretations to better diagnosis women with ISD, it may be possible to improve preoperative planning and outcomes for these patients treated surgically with synthetic midurethral slings.

Pathophysiology of idiopathic overactive bladder and the success of treatment: a systematic review from ICI-RS 2013

AIMS

To investigate the frequency of phenotype profiling of patients with idiopathic overactive bladder (OAB) syndrome, and to determine the effectiveness of treatment among individuals with different pathophysiologic profiles.

METHODS

The electronic databases MEDLINE, EMBASE, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, and CINAHL were searched from January 1, 1980 to August 12, 2013 for interventional randomized controlled treatment trials (RCTs) of idiopathic OAB. Phenotying for pathophysiologies originating in the urothelial/mucosal layer of the bladder, the detrusor muscle cell layer, and the central nervous system were sought. Articles that analyzed urgency outcomes based on pathophysiologic profiling were selected. Due to the heterogeneity of the included interventions and outcome assessment measures, meta-analysis was not appropriate and a qualitative synthesis was undertaken.

RESULTS

Of 239 original RCTs of idiopathic OAB, 48 (20%) profiled participants on underlying pathophysiology. Less than half of these (n = 20) reported treatment efficacy for urgency symptoms by pathophysiological sub-type. One examined the effect of botulinum A toxin on interstitial cell protein expression. Four compared treatment efficacy in OAB patients with and without involuntary detrusor contractions. Fifteen compared the effect of treatment on urgency reduction in patients with detrusor overactivity. There were no consistent trends in treatment efficacy according to pathophysiologic sub-type. No studies examined urothelial dysfunction or abnormal central processing of bladder afferent signaling in response to treatment.

CONCLUSIONS

In order to advance the field of idiopathic OAB, more trials are needed that profile and test urgency outcomes in participants according to suspected underlying pathophysiology. Neurourol. Urodynam. 33:611-617, 2014. © 2014 Wiley Periodicals, Inc.

Bladder health across the life course

Influences on bladder health begin during infancy and continue throughout the lifespan. Bladder anatomy and physiology change as individuals age, and the risk and propensity for bladder conditions, including lower urinary tract symptoms, throughout life are related to factors specific to age, sex, and life events. Bladder habits and dysfunctions at one stage of life may affect bladder health in subsequent stages. However, bladder problems are neither a normal part of aging nor inevitable at any stage of life. Many of the factors that negatively impact bladder health at all ages may be modifiable, and healthy bladder habits may prevent or reverse bladder dysfunctions that can occur naturally or in response to life events. There are opportunities to further define and promote healthy bladder habits through focused research and heightened public awareness of the importance of bladder health, which may lead to improvements in overall health and quality of life. It is our hope that this paper will inform and encourage public health initiatives and research programs aimed at this goal.

Bladder contractility and urethral resistance relation: what does a pressure flow study tell us?

Hydrodynamic analysis of a pressure flow study is the only reliable method to determine the presence or absence of a bladder outlet obstruction, especially benign prostatic obstruction. To interpret the results of pressure flow study in benign prostatic obstruction, understanding the outlines of the basic theory about evaluation of the relationship between bladder contractility and urethral resistance relation is of paramount importance. In contrast, hydrodynamic analysis of pressure flow study in conditions other than benign prostatic obstruction is complicated by the limits of theories about the hydrodynamics of the lower urinary tract. In this review, the proposed hydrodynamic theories about the relationship between bladder contractility and urethral resistance relation are outlined. Then, problems encountered in the application of hydrodynamic analysis of pressure flow study to diseases other than benign prostatic obstruction are discussed.

[Urinary bladder function in young and elderly women]

AIM

To identify the effect of aging on urinary bladder function, the maximal volume, post-voiding residual of the urinary bladder, mean urine flow rate, and urine volume were examined during micturition after drinking water (500-700 ml).

METHODS

Bladder volume, post-voiding residual, mean urine flow rate, and urine volume during micturition were measured in young (22±3 yr, n=12) and elderly women (64±3 yr, n=6).

RESULTS

The maximal urinary bladder volume was not significantly different (P>0.05) between young and elderly women (576±158 vs. 505±119 ml). In contrast, post-voiding residual volume was greater (88±52 ml, P<0.05) in elderly than in 34±40 ml in young women. Accordingly, urine volume was decreased to 418±155 ml in elderly compared to the volume in young women (556±141 ml). Although mean urine flow rate of 16 ml/s was equivalent between young and elderly women, the time period necessary for voiding was 27±6 s in elderly women, shorter (p<0.05) than the period for 43±24 s in young women.

CONCLUSION

It is suggested that contraction of the urinary bladder in elderly women is not so sustained as in young women, causing a greater post-voiding residual volume of the urinary bladder.

Normal urodynamic parameters in women: part II--invasive urodynamics

INTRODUCTION AND HYPOTHESIS

This literature review, providing reference ranges of normal variability in urodynamic parameters, is the second part of a two-part article. The first part addresses non-invasive urodynamics (UDS), while the second part addresses invasive techniques.

METHODS

Data were obtained through MEDLINE from articles published between January 1956 and February 2011, International Continence Society meeting abstracts, and standardization reports. Search terms included cystometry, urethral pressure profilometry, leak point pressure, video UDS, normal volunteer, pressure flow studies, and electromyography.

RESULTS

Normal values varied widely in the literature. However, with the help of clinical data, it was possible to define "normality" ranges for most of the different parameters.

CONCLUSIONS

Urodynamic evaluation of lower urinary tract (LUT) function is not a physiological test. However, it is still the best available tool for LUT function assessment. Even if normality in UDS can be defined, tests must always be interpreted against patient characteristics, complaints, and symptoms.

Clinical significance of postvoid residual volume in older ambulatory women

OBJECTIVES

To examine the prevalence, natural history, and clinical significance of high postvoid residual (PVR) volume in ambulatory older women.

DESIGN

Prospective cohort study.

SETTING

Group health plan in Washington state.

PARTICIPANTS

Nine hundred eighty-seven ambulatory women aged 55 to 75.

MEASUREMENTS

PVR was measured using bladder ultrasonography at baseline, 1 year, and 2 years. Participants completed questionnaires about urinary symptoms and provided urine samples for microbiological evaluation.

RESULTS

Of the 987 participants, 79% had a PVR less than 50 mL, 10% of 50 to 99 mL, 6% of 100 to 199 mL, and 5% of 200 mL or greater at baseline. Of women with a PVR less than 50 mL, 66% reported at least one urinary symptom at baseline. Of women with a PVR of 200 mL or greater, 27% reported no significant symptoms at baseline. In adjusted analyses using data from all study visits, women with a PVR of 100 mL or greater were more likely to report urinating more than eight times during the day (odds ratio (OR)=1.42, 95% confidence interval (CI)=1.07-1.87), and women with a PVR of 200 mL or greater were more likely to report weekly urgency incontinence (OR=1.50, 95% CI=1.03-2.18) than those with a PVR less than 50 mL. High PVR was not associated with greater risk of stress incontinence, nocturnal frequency, or urinary tract infection in adjusted analyses. Forty-six percent of those with a PVR of 200 mL or greater and 63% of those with a PVR of 100 to 199 mL at baseline had a PVR less than 50 mL at 2 years.

CONCLUSION

More than 10% of ambulatory older women may have a PVR of 100 mL or greater, which is associated with greater risk of some urinary symptoms, but many with high PVR are asymptomatic, and high PVR frequently resolves within 2 years. Symptom-guided management of urinary symptoms may be more appropriate than PVR-guided management in this population.

Aging and the underactive detrusor: a failure of activity or activation?

AIMS

To examine the known and potential contributions of motor, sensory, and biomechanical dysfunctions to the clinical problems of detrusor underactivity and detrusor hyperactivity/impaired contractility.

METHODS

A review of the current literature on non-obstructive voiding dysfunction associated with aging was conducted. The functional impact of age-induced biomechanical tissue change via alterations in sensory transduction is considered.

RESULTS

Impaired contractility has been regarded as etiologic of detrusor underactivity. However, an age-related degradation in detrusor contractility as the primary contributor to impaired bladder emptying has not been conclusively demonstrated. To the extent that detrusor contraction force and duration are dependent upon efferent nerve activity and thus reflex responses to sensory activity, there is a potential impact of impaired sensory function on voiding efficiency. Structural and functional tissue changes accompanying aging may result in altered bladder afferent function, with subsequent reflex impairment of detrusor voiding function.

CONCLUSIONS

The relative contributions of motor, sensory, and biomechanical dysfunctions to impaired voiding performance independent of outlet obstruction associated with aging remain to be elucidated.

The evolution of surgical treatment for female stress urinary incontinence: era of mid-urethral slings

Based on the integral theory, tension-free placement of a mid-urethral sling (MUS) for female stress urinary incontinence (SUI) has gained substantial popularity owing to the ease of the procedure and its effectiveness. Published series with long-term follow-up show continence rates after the MUS procedure ranging from 70% to 80%. Complication rates after MUS procedures are usually low. This review aimed to describe the historical change and the current use of the MUS. We discuss the efficacy and complications of various MUS procedures and the current strategies for managing failed slings.

Establishing a Mean Postvoid Residual Volume in Asymptomatic Perimenopausal and Postmenopausal Women

OBJECTIVE

To estimate mean postvoid residual (PVR) volumes among perimenopausal and postmenopausal women without significant lower urinary tract or pelvic organ prolapse symptoms.

METHODS

Patients presenting for well-women encounters were offered study participation. Women with a history of urinary incontinence greater than twice per week, urinary retention, symptomatic pelvic organ prolapse, or neurologic disorders were excluded. Pelvic relaxation, if present, was characterized according to the pelvic organ prolapse quantification system. Within 10 minutes of spontaneously voiding, PVR volume was assessed with bladder ultrasonography.

RESULTS

A total of 96 patients were enrolled; mean age was 60+/-11 years. The majority (80%) were postmenopausal; 30% had a previous hysterectomy. Most women (92%) had some degree of prolapse; the median stage was one, most commonly involving the anterior compartment (70%). The median PVR volume was 19 mL (range 0-145 mL); the mean PVR volume was 24+/-29 mL. Only 15% of patients had a PVR volume greater than 50 mL, and 95% had a PVR volume 100 mL or less. Only age 65 years or older was associated with a higher mean PVR volume; hormone therapy, vaginal atrophy, parity, and stage of asymptomatic prolapse did not affect PVR volumes.

CONCLUSION

Most asymptomatic perimenopausal and postmenopausal women had a PVR volume less than 50 mL, which was unaffected by multiple factors that were thought to potentially affect bladder function. Establishing "normal" volumes in this population may aid in developing recommendations regarding appropriate bladder function and retention criteria for women who are symptomatic or those who have had pelvic floor surgery.