Discussion: Cellular physiology of detrusor smooth muscle and the development of bladder instability: Possible mechanisms

Etiology of overactive bladder: a diet and lifestyle model for diabetes and obesity in older women

OBJECTIVE

To evaluate a coherent, evidence-based hypothesis that specific modifiable lifestyle factors implicated in the development of diabetes and associated obesity are related to the onset of OAB.

METHODS

A hypothetical causative model for OAB involving modifiable lifestyle factors implicated in the development of diabetes and obesity was constructed, based on a systematic literature review. Secondary analysis of data was undertaken in a prospective cohort of women aged 40 and over, living in Leicestershire, UK. Subjects included 3,411 women free from OAB at baseline and 277 incident cases of OAB. Reported diet, lifestyle, morbid, and social factors were measured at baseline and incident cases at 1-year follow-up. Graphical chain modeling was used to estimate the associations between variables and identify likely pathways involved.

RESULTS

All hypothesized lifestyle factors (physical activity, high glycemic index, and high energy intake) plus diabetes and obesity were retained within the graph as potential contributors. However, low physical activity was the only direct risk factor linked prospectively to the onset of OAB (RR 2.47; 95% CI 1.82, 3.36), in addition to older age.

CONCLUSIONS

Poor lifestyle factors causally linked to diabetes and obesity may contribute to the onset of OAB; low physical activity appears to be an important modifiable causal factor for OAB operating directly as well as indirectly via pathways involving obesity or diabetes. Further research is needed to demonstrate a causal link between lifestyle and OAB.

Role of alpha adrenergic blocker in the management of posterior urethral valves

PURPOSE

To evaluate the effect of Terazosin (alpha1 adrenergic blocker) on bladder emptying in children with posterior urethral valves.

MATERIALS AND METHODS

Forty-two children with significant post void residual urine after valves ablation were placed on Terazosin ranging from 0.25 to 2 mg. Post void urine at the commencement and at follow up was monitored with abdominal ultrasound.

RESULTS

Post void residual urine significantly reduced in 40 patients (95%) who were put on Terazosin. Mean pretreatment PVR was 15.7 ml and mean PVR at the last follow up was 2.4 ml (P = 0.000). This was a reduction of 85% in the pretreatment post void residual urine volume. All the patients had improvement in urinary stream. One patient reacted to Terazosin with hypotension necessitating its withdrawal. Mean follow up was 17 months.

CONCLUSION

Terazosin has proved to be safe and results in significant improvement in bladder emptying in our patients with posterior urethral valves. Randomized controlled trial and long-term follow up are necessary to further define the role of alpha1 adrenergic blocker therapy in children with posterior urethral valves. This study will become the justification for such a study.

The elusive electromyogram in the overactive bladder: a spark of understanding

It has been said that a technique capable of recording a urinary bladder electromyogram could be useful in the clinical evaluation of the detrusor neuropathies and myopathies implicated in the generation of lower urinary tract symptoms. However, in contrast to electromyography of skeletal and cardiac muscle, detrusor smooth muscle electromyography has remained in its infancy despite 50 years of scientific effort. The principal problems appear to be isolation of the real signal from artefacts, and the doubtful existence of electromyographic activity during cholinergic muscle contraction. The discovery of purinergic neuromuscular transmission in the overactive human bladder has renewed interest in detrusor electromyography as, in contrast to cholinergic mechanisms, purinergic mechanisms can generate extracellular electrical activity. In this paper, the development and validation of a novel technique for recording electrical activity from neurologically intact guinea-pig and human detrusor in vitro is described. A purinergic electromyographic signal is characterised and it is shown that detrusor taken from overactive human bladders has a greater propensity to generate electromyographic activity than normal by virtue of an aberrant purinergic mechanism.

Urinary storage symptoms and comorbidities: a prospective population cohort study in middle-aged and older women

OBJECTIVE

to identify predictive morbidities for urinary storage syndromes including indicators for neurological, musculoskeletal, cardiovascular, immune, lower bowel and psychological systems. This is the first study to test prior hypotheses, based on a literature review.

DESIGN

this was a prospective cohort study involving 12,570 female respondents aged 40 or more registered with general practitioners and living at home in Leicestershire. Postal questionnaires were used at baseline and 1-year follow-up (response rates 65 and 79%, respectively).

MEASURES

pure stress urinary incontinence (SUI) and overactive bladder syndrome (OAB) were defined using standardised symptom indicators. Specific morbidities included reported medical diagnoses, standardised symptoms and general health indicators. Associations were identified using logistic regression, adjusting for age and physical impairment, with separate models for general and specific morbidities.

RESULTS

multivariate morbidities consistently associated (i.e. both longitudinally and cross-sectionally) were SUI-cystitis and obesity; and OAB-bowel urgency, osteoporosis, imbalance, ankle swelling, cystitis, poor health and old age. Other independent predictors were SUI-multiple sclerosis and joint pain; and OAB-deep vein thrombosis and diabetes. Consistent univariate indicators supported neurological, musculoskeletal, cardiovascular, immunological and psychological connections with both types of storage disorder plus an association with lower bowel problems for OAB.

CONCLUSIONS

abnormal urinary storage symptoms were predicted by obesity and poor general health, involving a range of systems of the body. OAB showed more extensive links than SUI with specific morbidities, including more medically diagnosed as opposed to symptom-based conditions. These findings were independent of problems with physical impairment.