Editor- Sajjad Rahnama’i
Last Updated- June 1, 2018
Overactive bladder syndrome (OAB) is defined as urinary urgency, usually with urinary frequency and nocturia, with or without urgency urinary incontinence [1,2].
In 2014 the International Consultation on Incontinence Research Society (ICI-RS) proposed that the terminology is slightly rephrased as: "overactive bladder syndrome (OAB) is characterized by urinary urgency, with or without urgency urinary incontinence, usually with increased daytime frequency and nocturia, if there is no proven infection or other obvious pathology .
Previously, OAB symptoms were described as associated with the unstable bladder (A bladder contracting involuntarily during the filling phase of a cystometrogram)  also referred to as detrusor hyperreflexia  (if neurological disease was present) or detrusor overactivity  (if the cause was unknown or non-neurogenic).
OAB is a symptom-based definition and a widely used term. It is a pragmatic approach to categorizing a recognized group of patients, and is understood by the patients. However, expert opinion suggested several issues for which additional evidence should be sought . Naming an organ (bladder) in the condition may suggest underlying mechanism, when contributory aspects may lie outside the bladder. No severity thresholds are set, which can cause uncertainty. Urgency is prominent in the definition, but may not be prominent in patients whose adaptive behaviour reduces their propensity to urgency.
OAB occurs in both men and women. In some patients, it is accompanied by uncontrolled contractions of the detrusor muscle during bladder filling, called detrusor overactivity (DO). However, patients with OAB do not always present with DO. DO is detected in only about half of patients with OAB by conventional techniques. But up to 50% of patients presenting with DO on urodynamics do not complain of clinical symptoms [4,5]. The differences in the relationship between sensation and bladder activity may be indicative of different clinical states. However, it is more likely that we don’t understand the true nature of the clinical condition yet. Urgency incontinence is the most bothersome symptom of overactive bladder and is reported in around 20% of men and 40% of women with overactive bladder symptoms [6-8].
The diagnosis of OAB is made on the basis of symptoms alone. However, cystometry can be used to verify that uncontrolled contractions during bladder filling are responsible for the OAB symptoms. OAB is a symptom (complaint by the patient). DO is a diagnosis (confirmed by urodynamics). Nevertheless, it appears some practitioners consider OAB a diagnosis and treat it as if it were confirmed DO. It does appear they share a common patho-physiological mechanisms [4,5]. However, OAB can co-exist with other common conditions, such as benign prostate enlargement (BPE), stress incontinence or nocturnal polyuria.
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