The overactive bladder is defined as a bladder storage / filling disorder, where involuntary bladder contractions occur, causing patient’s symptoms. It is most commonly due to idiopathic detrusor overactivity; but in the presence of neurological diseases, it is known as neurogenic detrusor overactivity.
The overall prevalence in the general population is 10%. It increases with age; especially after the age of 30 years. It is much higher in menopausal, elderly, hospitalized or nursing home patients.
The typical clinical presentation includes urgency and/or urge incontinence, frequency and nocturia, with urgency being the commonest symptom. Any one or a combination of these symptoms can occur. The less common is the symptom of bed wetting (nocturnal enuresis). Abdominal pain and pain during urination (dysuria) are not common symptoms of OAB.
In 90% of women with OAB, no recognizable cause can be found – Idiopathic detrusor overactivity. Other known causes include neurologic disease, inflammation, previous pelvic surgery, pelvic organ prolapse, psychosomatic diseases and orgasm.
General physical and neurological examinations should be performed. It is unusual, however, for a neurological examination to reveal unsuspected neurological dysfunction.
An initial evaluation should include an assessment of the patient's symptoms, detailed physical examination and urinalysis.
Once urinary tract infection has been excluded, it is possible to establish a working diagnosis based on the patient's description of symptoms. In cases where there is uncertainty regarding the diagnosis, more advanced investigations should be carried out.
It constitutes a program of scheduled voiding with progressive increase in the interval between each void. The cure rate of 80% has been reported. A 12-week program is anticipated.
It stimulates the pelvic floor and urethral muscles, and inhibits detrusor muscle contractility. A 50% cure rate has been reported. The main difficulty is with patient acceptance.
It is the most popular mode of treatment in patients with overactive bladder. However, the response is often dose-related and side effects are common at effective doses. In general, drugs improve detrusor instability by inhibiting the contractile activity of the bladder.
The maximum dose is usually determined by patient tolerance to the side effects.
Imipramine hydrochloride: It improves bladder storage significantly. It appears to improve bladder hypertonicity or compliance rather than uninhibited contractions. It is useful in patients with enuresis. The side effects are anticholinergic, as well as tremor and fatigue. It can also cause orthostatic hypotension.
DDAVP: It decreases urine production. It is helpful in patients with troublesome nocturnal urinary symptoms. However, its use in the elderly and patients with heart problem is limited.
It is only used as a last resort in the management of overactive bladder.
Overactive bladder can co-exist with stress urinary incontinence / urodynamics stress incontinence in up to 30% of patients. Medical management of the overactive bladder reduces the need for bladder continence surgery. If patients fail medical treatment, bladder neck surgery may be recommended. However, patients should understand that the post-operative course of detrusor instability is somewhat unpredictable. They may need to continue medical treatment for their overactive bladder.
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