Available via license: CC BY-NC-ND 4.0
Content may be subject to copyright.
Neurogastroenterology & Motility. 20 18; e1 34 37.
|
1 of 6
https://doi.org/10.1111/nmo.13437
wileyonlinelibrary.com/journal/nmo
1 | INTRODUCTION
Many patients with irritable bowel syndrome (IBS) complain of ab‐
dominal bloating which is defined as the sensation of an increase in
pressure within their abdomen. In approximately 50% of individu‐
als who complain of bloating1 this sensation can be accompanied
by an increase in abdominal girth which is referred to as visible
abdominal distension. Many patients with either bloating or vis‐
ible abdominal distension often rank this problem as their most
intrusive symptom.2,3 Patients are at their most comfortable
in the
morning and become more distended throughout the day, espe‐
cially in response to eating or drinking. In women with particularly
Received:11May2018
|
Revised:27J une2018
|
Accepted:2July2018
DOI : 10.1111 /nmo .134 37
ORIGINAL ARTICLE
Abdominal distension in health and irritable bowel syndrome:
The effect of bladder filling
Basma Issa1 | Julie Morris2 | Peter J Whorwell1
Thisisanop enaccessa rticleunderthetermsoftheC reativeCommonsAt tribution‐Non Commercial‐NoD erivsLicense,whichpermitsuseandd istrib utionin
any medium, provided the original work is properly cited, the use is non‐commercial and no mo difications or ad aptations are made.
©2018TheAut hors.Neurogastroenterology & MotilityPublishe dbyJohnWiley&Sons,Ltd.
1NeurogastroenterologyUnit,University
Hospit al of South M anches ter, Manchester,
UK
2Department of Medical
Statistics,Universit yHospit alofSouth
Manche ster,Manchester,UK
Correspondence: ProfessorPeterJ
Whorwell,MD,PhD,Neurogastroenterolog y
Unit,Wythens haweHospital,Man chester,
M239LT,UK(peter.whorwell@mft .nhs.uk).
Funding information
The study was supp orted by a n internal
grantfromtheUHSMGastroenterolo gy
ResearchFundJF3SW1.
Abstract
Background & Aims: Abdominal distension is a commonfeature of irritable bowel
syndrome (IBS), which is difficult to treat and can have the appearance of late preg‐
nancy. It results from an abnormality of the normal accommodation reflex which
keeps abdominal girth constant despite changes in gastrointestinal volume resulting
from food ingestion or gasaccumulation.Wespeculated thatbladder filling might
also trigger this abnormal reflex in IBS and this study tested this hypothesis.
Methods: Eight females with IBS (aged 21‐43, mean 34) were compared with seven fe‐
malecontrols(aged19‐56,mean31)atthesametimeinthemenstrualcycle.Abdominal
girth in response to maximum tolerated bladder filling following ingestion of 1500 mls
of water was measured using abdominal inductance plethysmography. Symptoms, girth
change after bladder emptying, and urine volumes were also recorded.
Key Results: Baseline gir th of patients and controls was 84.8 and 79.9 cm respec‐
tively.Afterreachingmaximumtoleratedbladderfilling,girthincreasedbyameanof
6.4 (Standard deviation (SD) 2.1) cm in patients compared with 3.5 (1.1) in controls
(P=0.006),withpatientshavingsymptomsofbladderhypersensitivity.Aftervoiding
urine, girth reduced by 5.3 (3.1) and 1.9 (1.2) in patients vs controls (P = 0.018), de‐
spite passing similar mean urine volumes, 789 (364) mls vs 671(286) (P = 0.50).
Conclusions & Inferences: Bladder filling contributes to abdominal distension in IBS
and is unrelated to urine volume suggesting that bladder stretch or hypersensitivity
might trigger this response. Frequent bladder emptying may help control this intru‐
sive problem which is very challenging to manage.
KEYWORDS
bladder, bloating, distension, hypersensitivity, irritable bowel syndrome
2 of 6
|
ISSA et Al.
severe
distension, it is not unusual for people to ask t hem whether
they are pregnant.
Techniques such as the gas infusion technique, abdominal induc‐
tanceplethysmography,electromyography(EMG),andCTscanning,
have allowed the pathophysiology to be more clearly understood.
Visible abdominal distension is more associated with constipation,1
delayed gastrointestinal transit,4 weak abdominal musculature,5
probable changes in the gastrointestinal flora,6 and an abnormal
accommodation reflex.7‒12 Bloating is more often associated with
visceral hypersensitivity and a tendency to a loose bowel habit.13
However, it is likely that none of these mechanisms are mutually ex‐
clusive and their relative contribution to the problem in any particu‐
lar individual varies.
Azpiroz a nd colleagu es have been st udying the a ccommoda‐
tion reflex for many years and have shown that in healthy peo‐
ple this reflex allows an individual to accommodate an increase in
the volume of their abdominal contents without any appreciable
change in abdominal girth. This is achieved by a degree of dia‐
phragmatic relaxation in conjunction with an increase in tone of
the anterior abdominal musculature. They have shown that this
reflex may be reversed in patients with IBS accompanied by ab‐
dominal distension, so that an increase in abdominal volume re‐
sults in contraction of the diaphragm coupled with relaxation of
the anterior abdominal wall,7‒12 leading to an increase in abdomi‐
nal girth. Interestingly, they have also shown that this abnormality
can be reversed by biofeedback which suggests that it might be a
conditioned response rather than necessarily an alteration in re‐
flex pathways. These observations were made using CT scanning
or diaphragmatic electromyography in response to a colonic gas
challenge and, therefore, the fact that the infusion of gas triggers
this abnormal reflex, suggests that an increase in colonic volume
might be one of t he activat ors of this reac tion. A simil ar mech‐
anism might explain why distension is more common in patients
with constipation and this hypothesis is supported by the observa‐
tion that relieving constipation can lead to a reduction in abdom‐
inal distension.6
We have developed a technique called abdominalinduc tance
plethysmography(AIP) which allows the measurementof abdom‐
inal girth in an ambulatory fashion over a 24‐hour period. The
equipment consists of a soft, expandable belt containing a wire,
the inductance of which changes with the shape of the abdomen
and can be captured by a data logger for 30 seconds every minute
and subsequently, transposed into a measurement accurate down
to one millimetre.14 During studies using abdominal inductance
plethysmography, we have noticed that, in some individuals, disten‐
sion seems to be exacerbated by a full bladder. This has led us to
speculate that an increase in the volume of any abdominal viscus,
especially the bladder in which large volume changes occur, might
result in distension in a patient in whom the accommodation reflex
is already abnormal, such as in IBS. This study was designed to test
this hypothesis by establishing whether bladder filling has any ef‐
fect on abdominal distension in patients with IBS compared with
healthy controls.
2 | METHODS
2.1 | Participants
Eight female patients with ROME III defined IBS15 with constipation
(mean age 34, range 21‐43) were compared with seven healthy con‐
trols without any evidence of bowel problems (mean age 31, range
19‐56). Females were used because of their tendency to suffer from
abdominal distension more than males. Those over the age of 55
were excluded to rule out any chance of confounding of the results
as a consequence of the possibility of abdominal muscles weakening
with age. Following initial screening, suitable potential participants
were sent a patient information sheet and subsequently, attended
the Neurogastroe nterology Unit in the afternoon, in order to go
through the informed consent procedure and symptom checking.
2.2 | Procedure
If found to be suitable, all participants completed a questionnaire de‐
tailing any urological symptoms and the IBS patients had the severity
of their condition assessed using the IBS symptom severity score
(IBS SSS).16 This instrument consists of five components which are
each scored out of 100 giving a maximum total score of 500, with a
score of less than 175 indicating mild IBS, 175‐30 0 moderate IBS and
greater th an 300 seve re IBS. All pa rticipant s were fit ted with the
abdominal inductance plethysmography device, in order for them to
become familiar with the equipment before starting the study on the
following day. Participants were then asked to refrain from smoking,
alcohol, caffeine, and any strenuous physical activity prior to partici‐
pating in the study and those patients with IBS were also asked to
discontinueanyoftheirIBSmedication.Allparticipantswerestud‐
ied when they were in the middle of their menstrual cycle depending
on the length of their cycle.
The following day, participants were asked to return to the unit
the following morning without having had anything to eat or drink
sincemidnight.Allsub jec tswereaskedtoemptyt heirbl add eronar‐
rival and then sit in a comfortable chair for the duration of the study.
During this time they were asked to drink one and a half liters of
Key Points
• AbdominaldistensionisamajorprobleminIBS.Itistrig‐
gered by a variety of fac tors but the effect of bladder
filling has not been assessed.
• IBS patients became much more distended than the nor‐
mal people in response to a bladder filled with a similar
amount of urine. This suggests that their bladder might
be over‐sensitive and triggering this response.
• Abdominaldistensionisnotoriouslydifficulttotreatand
advising frequent emptying of the bladder might help
patients to control this symptom.
|
3 of 6
ISSA et Al .
water over the course of the first hour and remain in the sitting posi‐
tion and refrain from emptying their bladder for as long as possible,
during which time the abdominal girth was continuously recorded.
When they f elt a strong need to e mpty their bla dder, they were
asked to fill in a further questionnaire recording any symptoms and
theirseverity,scoredonazerotoonehundredscale,andwerethen
allowed to pass urine into a toilet that was equipped to collect their
urine so that the volume could be recorded. The participant was
then instructed to return to their seat and girth was measured for a
further 30 minutes following emptying their bladder after which the
study was terminated.
2.3 | Ethical statement
The stu dy was approved by Natio nal Research Ethic s Committee
North West—Greater Manchester South, REF: 12/NW/0667 and
all participant s gave informed consent. All patient data were a n‐
onymizedandparticipantsallocated auniquestudynumberforthe
purposes of analysis.
2.4 | Power calculation
Based on previous research in our department, a difference in
change of gir th of 5 centimeters between IBS patients and controls
was regarded as meaningful.
Sample size calculation: Withsevensubjectsineach group the
study would have 80% power to detect a difference of 4.5 cm or
more in the change in distension between a patient and control
group (using a simple t‐test with an estimated common standard de‐
viation of 2.5, derived from a previous study, with the conventional
5% significance level).
2.5 | Statistical analysis
Age,bodymassindex(BMI),andgirthmeasurement swerecom‐
pared bet ween the t wo groups using the simple two tailed t‐
test. Frequency and severity of symptoms were compared with
Fisher’sExact test and the Mann–WhitneyU‐test, respectively.
The conventional two‐sided 5% significance level was used
throughout.
3 | RESULTS
All patie nts with IBS m et the ROME III cr iteria. Table 1 compar es
the baseline characteristics of IBS patients and controls in terms of
age, BMI and abdominal girth. In addition, for patient s with IBS, it
documents the score of each component of the IBS symptom sever‐
ity score (SSS) and the total score. The mean IBS symptom severity
score for the IBS group was 255 with two patients being classified
as mild, four as moderate, and two as severe. The IBS patients and
controls had similar BMI values (23.3 and 23.9) and were of similar
age (34.3 and 31.4).
Table 2 compares the baseline urological symptoms in patients
and contro ls. As can b e seen all pat ients with I BS tended to have
more symptoms, with urgency of micturition reaching significance.
Figure 1 is an example of the actual output from the abdomi‐
nal induc tance plethysmography belt in a patient with IBS during
bladder filling and emptying. For comparison, Figure 2 shows the
output fromthebeltina healthy control.Ascanbe seen, inboth
subjects girth increases with time but the curve is much steeper
with bladder filling and declines more sharply after bladder emp‐
tying in the IBS patient. Table 3 shows the mean changes in girth
for all the IBS patients and controls following the consumption
of1.5liters ofwater.Whenthebladder was full,themeangirth
measurement in IBS patients increased by 6.4 cm compared with
only 3.5 cm in controls, which is a highly significant dif ference
(P=0.00 6).W hen the bladd er was emptied , girth measu rement
TABLE 1 Baseline characteristics of participants in terms of age,
BMI, and girth and symptom severity scores in irrit able bowel
syndrome (IBS) patients
Mean (SD)
P valueIBS (n = 8) Controls (n = 7)
Age 3 4.3 (7. 8) 31.4 (12.4) 0.60
BMI 23.3 (2.6) 23.9 (3.3) 0.72
Abdominalgirth 8 4. 8 (9.7 ) 7 9.9 (6 .8) 0.29
Abdominalpain
severity
38.6 (25.9) – –
Abdominalpain
frequency
37. 6 (2 8.9 ) – –
Bloating severity 49.0 (18.0) – –
Satisfaction with
Bowel habit
64.5 (15 .8) – –
How much IBS
affecting life
50.1 (15.3) – –
Total IBS score 255.2 (84.1) – –
TABLE 2 Baseline urological symptoms in irritable bowel
syndrome (IBS) patients and healthy controls
Urological symptoms
Median (range) or % (n)
P
valueIBS (n = 8) Controls (n = 7)
Numberoftimes
urinate during day
9 (5.22) 5 (5.9) 0.06
Numberoftimes
urinate during night
1 (1. 2) 0 (0.2) 0.06
Do you have urgency
associated with
passing water?
75% (6) 43% (3) 0.32
How often do you have urgency?
Occasionally 17% (1) 100% (3)
Usually/often 83% (5) 0% (0) 0.05
How severe is your
urgency?
56 (31.75) 37 (35.42) 0.38
4 of 6
|
ISSA et Al.
subsided by 5.3 cm in IBS patients compared to only 1.9 cm in con‐
trols (P = 0.018). However, there was no significant difference in
the mean volume of urine passed by IBS patients and controls on
emptying their bladders (mean (SD) volume: 789 (364) mls, range:
190‐1250 vs 671 (286) mls, range: 225‐1000, (P = 0.50). Figure 3
is a graphical representation of the mean change in girth measure‐
ment from baseline in all patients and controls.
Table 4 compares the symptoms induced by a full bladder and
their severity in IBS patients and controls and again shows that IBS
patients tended to be more symptomatic.
4 | DISCUSSION
The results of this study show that in patients with IBS and healthy
controls, filling of the bladder with similar volumes of urine leads
to a substantial increase in abdominal girth in patients with IBS but
not in healthy controls. Furthermore, the fact that a relatively small
number of patients were required to detect a significant effect in‐
dicates that the differences were clear‐cut and unequivocal. This
observation supports the hypothesis that, on the assumption that
the accommodation reflex is disordered in some individuals with IBS,
an increase in the volume of any abdominal viscus might result in a
similar reaction.
Obviously, the bladder is the intra‐abdominal organ which un‐
dergoes the widest range of volume changes and it is, therefore,
likely to have the greatest effect. There is already evidence that the
colon is involved in this reflex and our dat a would support the notion
that similarly, changes in the volume of the small bowel and stom‐
ach might also be impor tant. Indeed, a response to an increase in
volume of the stomach in a patient with IBS could explain why so
many patients with this condition complain of an almost instanta‐
neous increase of girth within minutes of starting a meal or even just
FIGURE 1 Abdominalinductanceplethysmographytracefrom
an irritable bowel syndrome patient showing a steady increase in
girth af ter drinking 1500 cc of water followed by a sharp decline
after bladder emptying (arrow)
85
84
83
82
81
80
79
78
77
76
75
09:21 09:51 10:21 10:5111:21 11:51
Girth (cm)
Time
Bladder emptying
FIGURE 2 Abdominalinductanceplethysmographytracefrom
a healthy control showing a slight increase in girth after drinking
1500 cc of water followed by a small decline after bladder emptying
(arrow)
89
88
87
86
85
84
83
82
81
80
79
09:37 10:07 10:47 11:1811.51 12:27
Girth (cm)
Time
Bladder emptying
TABLE 3 Changes in abdominal girth in irritable bowel
syndrome (IBS) patients and healthy controls after maximum
bladder filling and following bladder emptying
Time
Mean change in girth (SD) in
cms
P valueIBS (n = 8) Controls (n = 7)
Change from baseline
to full bladder
6.4 (2.1) 3.5 (1.1) 0.006
Change from full to
empty bladder
5.3 (3.1) 1.9 (1.2) 0.018
FIGURE 3 Comparison of the mean change in girth from
baseline and 95% confidence intervals resulting from bladder filling
in irritable bowel syndrome patients and healthy controls
–4
Baseline 30
min
60
min
Full
bladder
Patients
Volunteers
Change in girth (cm)
End
of test
0
–2
2
6
4
8
10
|
5 of 6
ISSA et Al .
drinkinga glass ofwater.Whether more subtle changesin volume,
especially in the presence of visceral hypersensitivity, can initiate
this response in these patients is less clear, but it would be of inter‐
esttoinvestigatethepossibilitythatanincreaseinuterinesizeatthe
time of menstruation might partly explain the exacerbation of IBS
symptoms, including bloating and distension, with menses that many
women with this condition report.17,1 8
It would be useful to understand what leads to a disturbance of
the accommodation reflex in the first place and whether it is a con‐
ditioned response or an alteration of reflex pathways. Furthermore,
once initiated how do changes in intra‐abdominal volume mediate
this effect? The most likely explanations are either as a result of
pressure changes within the viscus or in response to stretching of
the mucosa or serosa. Visceral hypersensitivity is one of the most
common physiological abnormalities described in patients with IBS
and it is temp ting to attribute a role to this phe nomenon in the patho‐
genesis of distension. However, this abnormality seems to be more
common in patients with bloating in the absence of distension,13 al‐
though this is not a clear‐cut difference and there is some overlap.
Whatever mechanismsare involved,aclearer understandingwould
be useful because bloating and distension are notoriously difficult
symptoms to treat and better management strategies are needed.
Patients with IBS frequently complain of bladder symptoms sug‐
gestive of an irritable bladder and are certainly over‐represented
in urology clinics.19 In addition, urodynamic studies in IBS patients
have shown that approximately 50% have a demonstrable abnormal‐
it y.20 In the current study we have again confirmed that IBS patients
have a propensity to have symptoms suggestive of an irritable blad‐
der (Table 2). Furthermore, when their bladders were full, IBS pa‐
tients also complained of more symptoms (Table 4). However, we did
not obser ve any differences in the volume of urine passed between
patients and healthy controls, which suggests that the observed dif‐
ferences in the change in abdominal girth with bladder filling were
not related to the amount of urine in the bladder. To investigate this
further, it would have been interesting to establish whether there
was a relationship between any urodynamic abnormality and the
observed distension response. However, it was felt that the incor‐
poration of urodynamic investigation was not ethically justified in
this study, when it was not even known whether there would be a
distension response to bladder filling.
Withrespecttothetreatmentofdistensionassociatedwitha
disordered accommodation reflex, it is possible that, as with anis‐
mus, biofeedback might have therapeutic potential and this has
been confirmed by the Barcelona group.21 In addition, some life‐
style approaches may be worthy of consideration. For instance,
patients with constipation should be encouraged to keep their
bowel as empt y as possible and this may even be worth consider‐
ing when the constipation is relatively mild. Furthermore, as gas
insufflation studies have been shown to have an effect, dietary
manipulation aimed at reducing fermentation should also be ad‐
vised.Withregardtoanypossibleeffectfromsmallbowelorgas‐
tric filling, it would be of interest to know whether slowing the
speed of fluid or food int ake might have an ameliorating effec t.
Lastl y,in t he light of our find ings, it would se em reasonable t o
recommend that patients with abdominal distension should be ad‐
vised to keep their bladders as empty as possible, especially as it
appears that distension starts to be triggered by even mild blad‐
der filling (Figures 1 and 3). Consequently, we now recommend
that patients with troublesome distension try to pass urine on a
reasonably regular basis. In addition, in the design and conduct of
any future clinical studies or trials on abdominal distension, the
possible confounding effect s of bladder filling need to be taken
into consideration.
In conclusion, the mechanisms leading to the enigmatic symptom
of abdominal distension are gradually being unraveled, but we still
do not have all the answers.
Symptoms IBS Controls P value
Do you have pain in your bladder? %
answering yes
88% 43% 0.12
Howsevereist hepain(0−100sclae)?
Median (range)
59 (33.94) 30 (8.38) *
Do you have a tight feeling in your
tummy? % answering yes
100% 71% 0.20
How severe is t his feeling? Median
(range)
74 (4 5.9 2) 57 (36.93) *
Do you have a bloated feeling? %
answering yes
88% 43% 0.12
How severe is t his feeling? Median
(range)
69 (50.92) 28 (25.46) *
Do you feel distended? % answering yes 88% 43% 0.12
How severe is t his feeling? Median
(range)
73 (52.93) 28 (25.46) *
*P‐values relating to severity comparisons not included because numbers with each particular sy mp‐
tom in the control group are too small.
TABLE 4 Comparison of symptoms
induced by a full bladder in irritable bowel
syndrome (IBS) patients and healthy
controls and their severity
6 of 6
|
ISSA et Al.
DISCLOSURES
BIandJMhavenocompetingInterests.Overthelast5yearsPJWhas
acted as a consultant for, or received research grant support from,
the following companies: Almirall Pharma, Chr. Hansen, Danone
Research, Ironwood Pharmaceuticals, Sucampo Pharmaceuticals,
andAllerganPharma.
AUTHOR CONTRIBUTIONS
BIandPJWconceivedtheideaandBIcondu ctedthes tudy;JMcon‐
ducted the statistical analysis; PJW and BI reviewed the literature
and drafted the manuscript and all authors approved the final ver‐
sion of the paper.
ORCID
Peter J Whorwell http://orcid.org/0000‐0002‐5220‐8474
REFERENCES
1. Houghto n LA, L ea R, Ag rawal A , et al. Relat ionship of ab dominal
bloating to distention in irritable bowel syndrome and effect of
bowel habit. Gastroenterology. 2006;131:100 3‐1010.
2. Maxton DG, Morris JA, Whorwell PJ. Ranking of symp‐
toms by patients with the irrit able bowel syndrome. BMJ.
1989; 299 :1138 .
3. Ringel Y,W illiams RE,Kalilani L, et al. Prevalence, char acteristics,
and impact of bloating symptoms in patients with irritable bowel
syndrome. Clin Gastroenterol Hepatol. 2009;7:68 ‐72.
4. Agraw al A, Whor well P, Houghton L . Is abdomi nal distens ion re‐
lated to delayed small and large bowel transit in patients with con‐
stipation predominant irritable bowel syndrome. Gastroenterology.
2006;130:632.
5. SullivanSN. Ap rospec tivestudy ofunexplainedvisibleabdominal
bloating. N Z Med J. 1994;107:428‐43 0.
6. AgrawalA , HoughtonL A, MorrisJ,et al. Clinical trial:theef fect s
of a fermented milk product containing Bifidobacterium lactis
DN‐173‐010onabdominaldistensionandgastrointestinaltransitin
irritable bowel s yndrome with constipation. Aliment Pharmacol Ther.
2009;29:104‐114.
7. VilloriaA,AzpirozF,BurriE,etal.Abdomino‐phrenicdyssynergiain
patients with abdominal bloating and distension. Am J Gastroentero l.
2011;106:815‐819.
8. VilloriaA,AzpirozF,SoldevillaA,etal.Abdominalaccommodation:
a coordinated adapt ation of the abdominal wall to its content. Am J
Gastroenterol. 20 08;103:2807‐2815.
9. Burri E , Cisternas D, V illoria A , et al. Accommo dation of the a b‐
domen to its content: integrated abdomino‐thoracic response.
Neurogastroenterol Motil. 2012;24:312.‐e162.
10. Burri E, B arba E, Hu aman JW, et al. Mec hanisms of pos tprand ial
abdominal bloating and distension in functional dyspepsia. Gut.
2014;63:395‐400.
11. Burri E, C isternas D, V illoria A , et al. Abdom inal accommo dation
induced by meal inges tion: dif ferential responses to gastric and co‐
lonic volume loads. Neurogastroenterol Motil. 2013;25:339.‐e253.
12. AccarinoA ,PerezF,AzpirozF,etal.Abdominal distention results
from caudo‐ventral redistribution of contents. Gastroenterology.
2009;136:1544‐1551.
13. A grawal A , Houghton LA, Lea R, et al. Bloating and disten‐
tion in irritable bowel syndrome: the role of viscer al sensation.
Gastroenterology. 2008;134:1882‐1889.
14. ReillyBP,BoltonMP,LewisMJ,etal. Adevicefor24hourambula‐
tory monitoring of abdominal girth using inductive plethysmogra‐
phy. Physiol Meas. 2002;23:661‐670.
15. Longstreth GF,Thompson WG, Chey WD, et al. Functionalbowel
disorders. Gastroenterology. 20 06 ;130 :148 0‐1491.
16. Francis CY, Morris J, Whorwell PJ. The irritable bowel severity
scoring system: a simple method of monitoring irritable bowel syn‐
drome and its progress. Aliment Pharmacol Ther. 1997;11:395‐402 .
17. WhiteheadWE,CheskinLJ,HellerBR,etal.Evidenceforexacerba‐
tion of irritable bowel syndrome during menses. Gastroenterology.
1990 ;98 :1485‐1489.
18. Houghton LA ,Lea R,Jackson N,etal. Themenstrualcycleaffects
rectal sensitivity in patients with irritable bowel syndrome but not
healthy volunteers. Gut. 2002;50:471‐474.
19. Francis CY,Duf fy JN, WhorwellPJ, et al. Highprevalenceofirri‐
table bowel syndrome in patients attending urological outpatient
departments. Dig Dis Sci. 1997;42:404‐407.
20 . W horwel l PJ,Lup ton EW, Erdur an D, et al. Bla dder smoot h mus‐
cle dysfunction in patient s with irritable bowel syndrome. Gut.
1986;27:1014‐1017.
21. BarbaE,BurriE,AccarinoA,etal. Abdominothoracicmechanisms
of functional abdominal dis tension and correc tion by biofe edback.
Gastroenterology. 2015;148:732‐739.
How to cite this article:IssaB,MorrisJ,WhorwellPJ.
Abdominaldistensioninhealthandirritablebowelsyndrome:
The effect of bladder filling. Neurogastroenterol Motil.
20 18; e13 437. https://doi.o rg/10.1111/nmo.134 37
