|
The bladder detrusor muscle is normally relaxed
and it expands to accommodate increasing volumes of
urine during filling until the need to void, at
which time it contracts to empty the urine out of
the bladder. The sensation of “fullness” typically occurs
when the bladder is about 50% full and the urge to
urinate (void) occurs when the bladder is about 75%
full.
In healthy people, the initiation of voiding is
controllable even when the bladder holds more than
75% of its maximum capacity.
In people with overactive bladder (OAB), the
detrusor muscle contracts spastically, resulting in
high bladder pressure and a sudden urge to
urinate (urgency). When the urge is not suppressed, it leads to
involuntary loss of urine (incontinence). There
are many causes of OAB and timely and correct
diagnosis is often hard to achieve.
There are three symptoms associated with an
overactive bladder:
- Frequency (frequent urination, including at night)
- Urgency (urgent need to urinate)
- Urge incontinence (strong need to urinate
followed by leaking or involuntary emptying)
People with OAB often experience urgency and
incontinence at inconvenient and unpredictable
times. It interferes with work, daily routine, intimacy and
sexual function. It
can cause embarrassment, social isolation, and can
diminish self-esteem and quality of life.
OAB affects millions of people
worldwide, and both sexes and all age groups may be
affected. The overall prevalence of OAB in the US is
similar between men (16.0%) and women (16.9%), but
with different symptoms and severity [1].
OAB affects as many as 34 million
people in the United States and its socioeconomic
burden is estimated to be more than 12.6 billion
dollars annually [2].
Diagnosis
Detrusor overactivity is a urodynamic observation
characterized by involuntary detrusor contractions
during the filling phase. The cystometrography (CMG), also known as
filling cystometry, is the component of the
urodynamic test that is used to assess the bladder
during filling. A
CMG provides information on the pressure/volume
relationship of the bladder when you first feel the
need to urinate, when you are able to sense
fullness, and when your bladder is completely full.
NIRS Application
Urodynamix is currently conducting studies to
examine the use of near infrared spectroscopy (NIRS)
technology to aid in the diagnosis of OAB.
References:
[1] Stewart WF, Van Rooyen JB, Cundiff GW, Abrams P, Herzog AR, Corey R, Hunt TL, Wein AJ.
Prevalence and burden of overactive bladder in the
United States. World J Urol. 2003 May;20(6):327-36. Epub
2002 Nov 15.
[2] Tubaro A, Palleschi G. Overactive
bladder: epidemiology and social impact.
Curr Opin Obstet Gynecol. 2005
Oct;17(5):507-11.
|
