Aims
of study
To
quantitatively assess and compare involuntary
detrusor activity (IDA) detected during
ambulatory urodynamics (AUM) in symptomatic
patients and healthy female volunteers.
Methods
A
total of 80 AUM studies that showed phasic
involuntary detrusor activity (IDA) were
analysed. Of these, 70 studies had been
performed in women with symptoms of urinary
urgency and/or urge incontinence and 10
in asymptomatic volunteers. The conduct
and interpretation of AUM followed our standard
protocol. Symptoms (urgency and urge incontinence)
were recorded by the patient in a diary
and by pressing event buttons. Detrusor
instability (DI) was diagnosed when IDA
occurred in association with urgency and
/ or urge incontinence.
Results
Of
the 10 studies in asymptomatic volunteers,
IDA was associated with urgency in 7 (70%).
All 70 patients in whom IDA was detected
during AUM had coincident symptoms. The
characteristics of the first and maximum
involuntary detrusor contractions for the
2 groups are shown in tables 1 & 2.
Table 1 Characteristics
of IDA: First detected contraction
X squared*
Mann Whitney U**
|
|
Median
bladder vol at 1st
contraction (ml)
|
Proportion
of 1st contractions
of amplitude
<10 cmH2O
|
Proportion
of 1st contractions of
duration
<30 sec
|
Incidence
of associated
leakage
|
|
Controls
(n=7)
|
494
|
4(57%)
|
6 (86%)
|
0
|
|
Patients (n=70)
|
207
|
18 (25%)
|
23 (32%)
|
26(37%)
|
|
p=
|
0.001**
|
0.07*
|
0.02*
|
0.004*
|
Table
2
Characteristics of IDA: Maximum detected contraction
|
|
Median
bladder vol at max
IDC (ml)
|
Incidence
of
max contractions of amplitude
<10 cmH2O
|
Incidence
of max contractions of duration
<30 sec
|
Incidence
of associated
leakage
|
|
Controls
(n=7)
|
494
|
4(57%)
|
4(57%)
|
1(14%)
|
|
Patients (n=70)
|
312.5
|
7(10%)
|
7(10%)
|
40(57%)
|
|
p=
|
0.001**
|
0.001*
|
0.001*
|
0.03*
|
Conclusion
This
study demonstrates that the character of
IDA detected during AUM in asymptomatic
volunteers is quantitatively distinct from
that seen in patients with urgency and urge
incontinence. This overactivity occurs at
higher bladder volumes, is of shorter duration
and associated with milder symptoms than
that detected in women with urgency and
urge incontinence. These findings support
the view that, in contrast to conventional
static cystometry, AUM permits quantitative
interpretation of IDA (1). Such interpretation
allows distinction to be made between detrusor
activity which is clinically relevant and
that which can be reasonably regarded as
a variation of normal.
References
1. van Waalwijk
van Doorn ESC, Malone-Lee JG, Janknegt RA
(1995): The differentiation of normal and
abnormal contractions on ambulatory urodynamics. Neurourology and Urodynamics 14(5): 531-532.
