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M is a 52-year-old woman with a two-year history of urinary incontinence. She works as an accountant and is distressed with the impact this is having on her work and social life. She experiences frequency every 30 minutes to one hour during the day and gets up around four times at night. She gets a sudden urge to void and loses moderate-to-large amounts, especially at night. She has to wear pads whenever she leaves home due to some accidents she has before getting to the toilet.
She had a hysterectomy at age 50 years. Her BMI is 32, she has a grade II cystocele. Urinary tract infection has been ruled out. She is a smoker and drinks alcohol.
She was asked to keep a bladder diary.
Based on her symptoms of frequency, urgency and nocturia, a diagnosis of overactive bladder (OAB) was made.
She underwent conservative management with bladder training and physiotherapy, but without any improvement.
She then underwent urodynamic testing, which showed evidence of detrusor over-activity.
The International Continence Society (ICS) defines OAB as symptoms of urgency with or without urge incontinence, usually associated with urinary frequency and nocturia in the absence of local pathology and significant endocrine factors. It can be associated with detrusor overactivity on urodynamic testing.
The prevalence of OAB is reported at 12-17 per cent and significantly increases with age. It affects approximately 350,000 of people over the age of 40 years in Ireland. OAB has a greater impact on life than stress urinary incontinence and is responsible for several other comorbidities. Up to 67 per cent of women with OAB report a negative effect on daily living. Significant comorbidities of OAB include depression, falls and fractures and increased admission to hospitals and nursing homes.
For most people, the cause of an overactive bladder is unknown. Stress can make the problem worse and the types of fluid can also influence the symptoms. OAB can be a problem for many people of all ages.
OAB is a diagnosis of exclusion. When eliciting the history, a wide differential must be considered, which may be contributing to the symptoms. A number of points should be elucidated from the patient’s history, such as:
Do you ever have the sudden urge to urinate and feel you can barely make it to the bathroom?
Do you ever have leaking/wetting during day/night?
How often do you urinate during the day?
How often do you get up to go to the bathroom after going to sleep?
Does the need to urinate wake you?
Do you ever leak urine during sex?
An examination should be conducted on all patients and include assessment of urinary, gynaecological and neurological systems. Abdominal palpation and vaginal examination will enable identification of a palpable bladder, prolapse or pelvic mass, as well as determine the patient’s oestrogen status.
In addition, a voiding diary spanning a 48- to 72-hour period is an invaluable tool in OAB, as it gives a better picture of the pattern of voiding than can be obtained from the history alone.
Information obtained should include number of fluids consumed (types and volume), voids in daytime, night-time, 24-hour period, volume of urine over 24 hours, maximum voided volume, average voided volume, median maximum voided volume and nocturnal urine volume.
A urinalysis should be done to exclude a urinary tract infection, and glycosuria, which might indicate the presence of diabetes.
Secondary investigations include urodynamic testing, a cystoscopy, and imaging of the upper urinary tract.
Secondary investigations should be considered in patients with neurological disease, refractory OAB, or those in whom initial investigations raise the suspicion of an underlying problem that may require further evaluation or treatment.
Urodynamic testing aims to demonstrate incontinence objectively and differentiate between different types of incontinence, so that the most effective method of treatment can be selected.
An important part in the management of OAB is advising the patient to make some lifestyle changes. These include adjusting volume, timing and types of fluids; this involves maintaining an adequate intake of six-to-eight cups (1,500-2,000ml) per day, decreasing evening fluid intake, especially if the patient complains of nocturia, and decreasing intake of caffeine and other fluids that cause irritation to the bladder, such as alcohol, carbonated drinks, citrus, tomato and spicy food. Some drinks that are not an irritant to the bladder include water, fruit teas, caffeine-free tea, coffee and milk.
It is also important to ask the patient to lose weight, as this has a significant effect on leakage, quit smoking, and avoid constipation by increasing dietary fibre.
Pelvic floor exercises
Along with these lifestyle changes, another key part of the management is behavioural therapy, which includes pelvic floor muscle training, urge suppression and bladder retraining. Pelvic floor rehabilitation programmes are aimed at strengthening the pelvic floor musculature. The rehabilitation programmes may include simple oral or written information, exercises performed with biofeedback, pelvic muscle contractions stimulated by functional electrical stimulation (FES), motor-relearning exercises, or any combination of the above.
Success is dependent on a continuous, regular home exercise programme to avoid deconditioning.
Bladder training is also called ‘bladder drill’. It works by activating cortical inhibition over the sacral micturition reflex centre. Bladder training is aimed at increasing the voiding interval and decreasing urgency and associated urge incontinence. There are usually three components to the training: patient education, scheduled voiding, and positive reinforcement.
Bladder retraining should be undertaken in small stages. For example, if the patient is going to the toilet every half an hour, they should try extending the time (or ‘holding on’) by 10 minutes for a week, then by 15 minutes for a week, and then 30 minutes, etc. Ideally, they should be able to hold on for three-to-four hours between toilet visits.
Learn to suppress the urgency
There are different techniques for this. What works for one person may not work for another. Some suggestions include sitting straight on a hard seat, distracting one’s self by reading a newspaper, doing crosswords, etc, and contracting the pelvic floor muscles. These techniques may help gradually, but patience is needed, as it may take weeks or months before noticing any significant improvement.
In the primary care setting, patients presenting with typical OAB symptoms can be treated empirically with an anticholinergic agent and obtain clinical benefit without the need for invasive urodynamic procedures.
There are many options of anticholinergic medications to choose from and these are demonstrated in Table 2.
Another relatively new drug used is mirabegron, which is a β3-adrenoceptor agonist, with a mechanism of action that is distinct from anticholinergics. Hence, it has fewer side-effects and is considered as a second-line therapy when patients are intolerant to anticholinergics.
The choice of anticholinergic therapy should be guided by individual patient comorbidities, as objective efficacy of anticholinergic drugs is similar. Dose escalation does not improve objective parameters and causes more anticholinergic adverse effects. It is, however, associated with improved subjective outcomes. To decrease side-effects, switching to a lower dose or using an extended-release formulation or a transdermal delivery mechanism should be considered.
Absolute contraindications to anticholinergic use include urinary retention, gastric retention, uncontrolled narrow-angle glaucoma, and known hypersensitivity to the individual drugs or any of their ingredients.
Relative contraindications that warrant cautious use include partial bladder outlet obstruction (borderline or high post-void residuals), controlled narrow-angle glaucoma, impaired cognitive function, reduced renal or hepatic function, concomitant excessive alcohol use (added sedating effects), decreased gastrointestinal motility, constipation, and myasthenia gravis.
Elderly patients in particular should be monitored for drug interactions or polypharmacy of drugs with anticholinergic effect (eg, antidepressants, antipsychotics, anxiolytics), as the overall anticholinergic load is associated with confusion, falls and fractures.
Anticholinergics are category C drugs in pregnancy, to be used only if the benefits clearly outweigh the risk.
When to refer to secondary care
Patients would usually attend primary care to seek help for their OAB symptoms, however a GP must identify certain ‘red flags’ that warrant referral to a specialist urogynaecologist. These include:
Failed medical treatment.
Voiding difficulty or chronic urinary retention.
Recurrent urinary tract infections.
Significant vaginal prolapse.
What if medications do not work?
In cases where medications do not work, one of the options includes intravesical Botox injections. Intravesical botulinum toxin-A prevents acetylcholine release at the neuromuscular junction, resulting in temporary chemodenervation and muscle relaxation for up to six months. The technique is to place multiple injections under cystoscopic guidance directly into the detrusor.
Complete continence can be achieved in 40-80 per cent of patients and bladder capacity improved by 56 per cent for up to six months. Maximal benefit is between two and six weeks, maintained over six months. The injections can be repeated according to degree of improvement or relief of symptoms.
Other options include posterior tibial nerve stimulation and sacral nerve stimulation, which involves an implantable electrode in the S3 foramen continuously stimulating the S3 nerve root, in order to stimulate the pudendal nerve. A temporary wire is initially placed under local anaesthetic for five-to-seven days in both sides and a voiding diary is kept. An improvement of >50 per cent in any parameters will enable a permanently-implanted S3 lead on the side with the best clinical response. There is a potential benefit for up to five years in patients with OAB.
Current indications for sacral nerve stimulation include refractory urge incontinence, refractory urgency and frequency and idiopathic urinary retention.
Some more radical methods of treatment include augmentation cystoplasty and urinary diversion. In augmentation cystoplasty, the bladder is enlarged by incorporating a variety of different patches into the native bladder, usually patches of bowel still attached to their mesentery (ileum, caecum or sigmoid colon). Indications for bladder augmentation include a small, contracted bladder and a dysfunctional bladder with poor compliance.
Urinary diversion should be considered only when conservative treatments have failed, and if sacral nerve stimulation and augmentation cystoplasty are not appropriate or unacceptable to the patient.
OAB is a common, bothersome condition. A thorough history and physical examination are imperative in reaching a diagnosis, along with proper investigations, if necessary. The role of behavioural therapy and lifestyle modifications should not be overlooked, as it has almost equal efficacy to pharmacological treatment. Careful monitoring of the patient’s progress in therapy helps in addressing their specific problems, and trying different methods if previous ones do not work or have considerable side-effects.
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