“OAB is defined as urgency, with or without urge incontinence, and
usually with frequency and nocturia”
OAB = overactive bladder; ICS = International Continence Society.Abrams P. Urology. 2003;62(Suppl 5B):28-37.
l Urgency: The complaint of a sudden, compelling desire to pass
urine that is difficult to defer
l Urge incontinence: The complaint of involuntary leakage of
urine accompanied or immediately preceded by urgency
l Frequency: Usually accompanies urgency with or without urge
incontinence and is the complaint by the patient who considers
that he/she voids too often by day
l Nocturia: Usually accompanies urgency with or without urge
incontinence and is the complaint that the individual has to
wake at night one or more times to void
Abrams P, et al. Urology. 2003;61:37-49.
Reduced Volume Voided per Micturition
1. Proven direct effect
2. Effect correlated with urgency but inconsistent due to multifactorial etiology of the symptom
Reference: Chapple CR et al. Br J Urol (2005) 95: 335-340
Symptoms of OAB are due to involuntary contractions
of the detrusor muscles during the filling phase of the
Mediated by acetylcholine induced stimulation of
bladder muscarinic receptors
Muscarinic receptors M2 – M3 are demonstrated to
cause direct smooth muscle contraction
M3 receptor is responsible for the normal micturition
40–44 45–49 50–54 55–59 60–64 65–69 70–74 75+
EU SIFO Study
l 17% of the adult population have symptoms of OAB
l Prevalence of OAB increases with age
l Similar prevalence among men and women (women may
Source: Milsom et al. 2001
Prevalence of OAB in women of reproductive age is 16.9%,
30.9% women over 65 years.
Urinary Incontinence 36%
Outflow obstruction Hypothesis:
Outflow obstruction lead to partial denervation
Reduction in acetyl cholinesterase staining nerves in
obstructed human bladder.
Muscle strips from patient, with detrusor over activity
exhibit super-sensitivity to acetylcholine
It causes alteration of the contraction properties of
the detrusor muscle.
Individual cells are more irritable when synchronus
activation is damaged.
The patho-physiology of idiopathic and obstructive
overactive bladder is different
Neurogenic hypothesis is controversial
Detrusor develops post junctional super sensitivity due
to partial denervation, with reduced sensitivity to
stimulation to electrical stimulation of its nerve supply,
but a greater sensitivity to stimulation with Ach.
If obstruction is relieved the detrusor can return to
normal behaviour, renervation may also occur.
Relaxation of urethra is known to precede
contraction of the detrusor in women with detrusor
Not proved by experiments done by southerst &
Sutherst JR etal, The effect on the bladder pressure of sudden entry of fluid into
the posterior urethra. Br J Urol 1978; 50: 406-9.
Brading & Turner Suggested that common feature in
all cases of detrusor over-activity is partial
denervation of detrusor which alters the properties of
smooth muscle resulting in coordinated myogenic
contraction of the whole detrusor.
Charton etal suggested that primary defect in the
Idiopathic and neuropathic bladder is a loss of nerves
accompanied by hypertrophy of the cells and
increased production of elastin and collagen within
the muscle fascicles.
1. Brading AF, Turner WH. The unstable bladder: towards a common mechanism. Br. J
Urol 1994; 73: 3-8.
2. Charlton RG, Morley AR, etal, Focal changes in nerve, muscle and connective tissue in
normal and unstale human bladder. BJU Int 1999; 84 953-60.
The role of the afferent activation in the urothelium
and sub-urothelial myofibroblasts has been
investigated as a factor in pathophysiology of detrusor
Studies revealed that ATP is released from the
urothelium by bladder distension evoking neuronal
discharge leading to bladder contraction.
In addition prostanoids and nitric oxide are
synthesised locally in urothelium and also released by
Multiplicity of symptoms
Exclude other causes of frequency & urgency
demonstrable stress incontinence
oestrogen status, vulval excoriation
Rule out neurological lesion
Examine cranial nerves and S2, S3 & S4 outflow to rule
out multiple sclerosis
Idiopathic detrusor overactivity
Urinary tract infection
Stress urinary incontinence
Overflow incontinence with retention
External pressure (pregnancy, fibroids, pelvic mass)
Secondary to medical conditions (diabetes, myeloma)
Iatrogenic (diuretics and other drugs, post hysterectomy)
Psychosocial (dementia, physical disability)
Recurrent urinary tract infections
Haematuria – calculus, tumour
Short duration of symptoms
Symptoms persist inspite of treatment e.g. recurrent UTI
The International Continence Society (ICS) has defined
the following three types of urinary diary on the basis
of the recorded parameters:
Micturition charts record only the times of micturition, day
and night, for at least 24 h.
Frequency-volume charts record the volumes voided and the
time of each micturition, day and night, for at least 24 h.
Bladder diaries record the times of micturition and voided
volumes, as well as other information, such as incontinence
episodes, pad usage, fluid intake, degree of urgency, and the
degree of incontinence.
Total Voided Volume
Nocturnal Voided Volume
Functional Bladder Capacity
Mean Voided Volume
Type of fluid ingested
Modified bladder diary De Wachter and Wyndaele
No desire to void
Normal desire to void
Strong desire to void
Urgent desire to void
In order to measure urgency severity urgency scoring
systems can be used such as:
Patient perception of intensity of urgency score
Urgency perception score (UPS)
Indevus Urgency Severity Scale (IUSS)
Therapeutic Agents Side-effects
Diuretics urgency, frequency and UI
Some calcium antagonists urgency
Benzodiazepines sedation and confusion causing
Alcohol diuresis, impaired perception of
bladder filling, OAB
Antidepressants Opiates &
urinary retention with overflow
Bladder Retraining – first line treatment recommended by
AUA. First described by Jeffcoate & Francis
Pelvic Floor Muscle Retraining Detrusor muscle
contraction can be inhibited by pelvic floor muscle
A meta analysis has concluded that bladder retraining is
more useful than placebo.
Too few studies to evaluate PFMT.
NICE and ICI (International consultation on Incontinence)
recommend that bladder retraining should be considered
as first line treatment in all women with OAB.
Botulinium Toxin Botox A
In 2011 FDA approved Botox A injections use on bladder.
In 2013 approved for treatment of OAB.
100 units injected into bladder wall muscle at 30 sites
for OAB & 200 units for neurogenic bladder.
Acts by inhibiting the parasympathetic response of Ach
from the motor neurons and inhibits detrusor
Stop Aspirin 7 days before therapy
Antiplatelet therapy should be stopped
Do not give if nitrite +ve in dipstick of morning urine.
UTI should be excluded at the site of injection
No acute urinary retention at the time of treatment
Patient willing to initiate self catheterization as
there is significant risk of voiding diffeculties.
A small electrode is placed in both legs near medial
Electrode connected to stimulator which generates
Every 12th week 30 minutes session is required.
Acts by activation of affarent sacral nerve that
inhibit para sympathetic motor neuros there by
prevents detrusor contractions.
Requires O.T. fascilities
OAB, distressing condition affect QOL
The clinical diagnosis is of exclusion
Urodynamic investigations needed to demonstrate
detrusor over activity
Majority will benefit from conservative treatment
eventually requires drug therapy.
Refractory OAB treated with Botulinum Toxin, neuro
Reconstructive surgery for refractory patients – may
require ileal diversion, clam cystoplasty or detrusor
myectomy. A every small number will need with severe