Overactive bladder

Overactive bladder (OAB) is a urological condition defined by a set of symptoms: "urgency, with or without urge incontinence, usually with frequency and nocturia." The International Continence Society(ICS) is responsible for this definition. There exists, however, some controversy over the use of this term because these symptoms taken in isolation may overlap with those of other bladder conditions, including interstitial cystitis, or rarely even bladder tumours.

The etiology of OAB is unclear, and indeed there may be multiple possible causes. It is often associated with detrusor overactivity, a pattern of bladder muscle contraction observed during urodynamics, and treatments for OAB, are usually synonymous with treatments for detrusor overactivity. OAB is distinct from stress urinary incontinence, but when they occur together is usually known as mixed incontinence.

Earlier reports estimated that about one in six adults in the United States or Europe had OAB. Because the average age of people in the developed world is increasing, it is expected that OAB will become more common in the future as the prevalence of OAB increases with age. However, a recent Finnish population-based survey showed that the prevalence had been largely overestimated due to methodological shortcomings regarding age distribution and low participation (in earlier reports). OAB affects approximately half of that proposed earlier.

In 2008 researchers found that simulating the condition in rats caused overactivation of their locus caeruleus, and it is thought this could cause anxiety and disrupted sleep in humans.

Treatment for OAB includes lifestyle modification (fluid restriction, avoidance of caffeine), bladder retraining, antimuscarinic drugs (darifenacin, hyoscyamine, oxybutynin, tolterodine, solifenacin, trospium), and various devices (Urgent PC Neuromodulation System, InterStim). Intravesical botulinum toxin A is also used in some intractable cases, although not with formal FDA approval. The antimuscarinic fesoterodine was recommended for approval by the European Medicines Agency in February 2007, and will become available for use during 2008.