Digestive Endoscopy Unit, “Lorenzo Bonomo” Hospital, Andria,
Giovanni Brandimarte, Walter Elisei, Department of Internal
Medicine, Division of Gastroenterology, “Cristo Re” Hospital,
Gian Marco Giorgetti, Clinical Nutrition Unit, “S. Eugenio”
Hospital, Rome, Italy
Correspondence to: Dr. Antonio Tursi, Galleria Pisani, 4,
70031 Andria, Italy. email@example.com
intestinal bacterial overgrowth (SIBO) may contribute to the
appearance of several gastrointestinal nonspecific symptoms. Acute
diverticulitis is affected by some similar symptoms and bacterial
colonic overgrowth. We assessed the prevalence of SIBO in acute
uncomplicated diverticulitis and evaluated its influence on the
clinical course of the disease.
studied 90 consecutive patients (39 males, 51 females, mean age 67.2
years, range 32-91 years). Sixty-one patients (67.78%) and 29
patients (32.22%) were affected by constipation-or
diarrhea-prevalent diverticulitis respectively. All subjects were
investigated by lactulose H2-breath
test at the entry and at the end of treatment. We also studied a
control group of 20 healthy subjects (13 males, 7 females, mean age
53 years, range 22-71 years).
transit time (OCTT) was delayed in 67/90 patients (74.44%) (range
115-210 min, mean 120 min). Fifty-three of ninety patients (58.88%)
showed SIBO, while OCTT was normal in 23/90 patients (25, 56%). In
the control group, the mean OCTT was 88.2 min (range 75-135 min).
The difference between diverticulitic patients and healthy subjects
was statistically significant (P<0.01). OCTT was longer in
constipation-prevalent disease than in diarrhea-prevalent disease
[180.7 min (range 150-210 min) vs 121 min (range 75-180 min)
(P<0.001)], but no difference in bacterial overgrowth was
found between the two forms of diverticulitis.After treatment with
rifaximin plus mesalazine for 10 d, followed by mesalazine alone for
8 wk, 70 patients (81.49%) were completely asymptomatic, while 16
patients (18.60%) showed only slight symptoms. Two patients (2.22%)
had recurrence of diverticulitis, and two other patients (2.22%)
were withdrawn from the study due to side-effects. Seventy-nine of
eighty-six patients (91.86%) showed normal OCTT (range 75-105\ min,
mean 83 min), while OCTT was longer, but it was shorter in the
remaining seven (8.14%) patients (range 105-115 min, mean of 110
min). SIBO was eradicated in all patients, while it persisted in one
patient with recurrence of diverticulitis.
affects most of the patients with acute diverticulitis. SIBO may
worsen the symptoms of patients and prolong the clinical course of
the disease, as confirmed in the case of persistence of SIBO and
diverticulitis recurrence. In this case, we can hypothesize that
bacteria from small bowel may re-colonize in the colon and provoke
recurrence of symptoms.
© 2005 The WJG Press and Elsevier Inc. All rights reserved.
Key words: Small intestinal bacterial overgrowth; Oro-cecal
Tursi A, Brandimarte G, Giorgetti GM, Elisei W. Assessment of small
intestinal bacterial overgrowth in uncomplicated acute
diverticulitis of the colon. World J Gastroenterol
2005; 11(18): 2773-2776
Diverticular disease of the colon is the most common disease
affecting the large bowel in the Western world.
This disease is correlated with the aging process and a low-fiber
diet and bears a considerable amount of morbidity.
The continuous aging process of the population also leads to an
increase of this disease. To refer to an acquired deformity present
in perhaps two-thirds of the elderly as a “disease” may be
inaccurate, particularly as a large majority of those affected will
remain entirely asymptomatic. Nonetheless, 20% of patients may
manifest clinical illness.
The true incidence of colonic diverticulosis is
difficult to measure, mainly because most patients are asymptomatic.
The incidence clearly increases with age, varying from less than 10%
in those under 40 years, to 50-66% of patients over 80 years[4-6].
Only a small proportion (5-10%) of patients who develop
diverticulitis are younger than 50 years,
and the course of the disease in these patients does not seem more
aggressive than that in older patients.
It is commonly thought that multiple factors
(anatomic features intrinsic to the colon, alterations in colonic
wall with aging, dietary fiber, motor dysfunction, abnormal
intraluminal pressure, and possible genetic influences) including
altered motility of the large bowel play a great role in the genesis
of colonic diverticula. Motility disorders of the gut are a
predisposing factor in development of small intestinal bacterial
that may contribute to the appearance of several
gastrointestinal nonspecific symptoms, such as bloating, abdominal
pain, flatulence and diarrhea.
Since acute diverticulitis is affected by some similar symptoms,
and diverticulitis is affected by bacterial colonic overgrowth, the
aim of this study was to assess the prevalence of SIBO in acute
uncomplicated diverticulitis and its influence on the clinical
course of the disease.
MATERIALS AND METHODS
A prospective study was conducted on 90 consecutive patients (39
males, 51 females, mean age 67.2 years, range 32-91 years) with
acute uncomplicated diverticulitis of the colon to assess the
oro-cecal transit time (OCTT) and SIBO.
Diagnosis of diverticulitis, defined as inflammation and/or
infection associated with diverticula of the colon,
was performed by colonoscopy.
We assessed the following symptoms in all the
enrolled patients: constipation, diarrhea, abdominal pain, rectal
bleeding, and mucus passage with the stools. The intensity of the
symptoms was quantified with a quantitative scale (0-10 according to
increasing worsening of symptoms): 0: absence; 1-2: slight; 3-5:
mild; 6-7: moderate; 8-10: severe.
In order to assess the prevalence of SIBO, all
subjects were studied after an overnight fast for 24 h before the
test. They were requested not to smoke on the morning of the test.
End expiratory samples were collected before the patients drank the
test solution (10 g of lactulose suspended in 100 mL of tap water)
and at 15 min-intervals thereafter, for 240 min. Hydrogen
concentrations in each collected sample were measured with a
breath-hydrogen analyzer (EC60 gastrolyzer breath hydrogen monitor,
Bedfont Scientific Ltd, Upchurch, Kent, UK). OCTT was defined as the
time elapsing between lactulose ingestion and a sustained increase
of 10 ppm or more of H2
excretion above the baseline value, which was about 75±15 min.
We also evaluated the presence of bacterial overgrowth, which was
defined by the presence of a peak >20 ppm occurring >15 min
before the colonic peak. The patients with an elevated fasting H2
combined with an early increase in H2
after lactulose ingestion were considered positive for bacterial
We compared the results obtained in a control group, comprising of
20 healthy subjects (13 males, 7 females, and mean age 53 years,
range 22-71 years).
All patients were treated with rifaximin (Rifacolâ,
Formenti SpA, Milano, Italy) 800 mg/d plus mesalazine (Pentacolâ
800, Sofar SpA, Trezzano Rosa [MI], Italy) 2.4 g/d for 10 d,
followed by mesalazine 1.6 g/d for 8 wk.
Medical control visit and a new lactulose H2-breath
were performed at the end of the 8th
wk of treatment with mesalazine alone, and the presence of possible
side-effects was evaluated. Moreover, the patients were invited to a
control visit whenever they considered necessary.
Data were analyzed by c2
test. P<0.05 was considered statistically significant.
Diverticulitis was localized in the overall colon of 10 patients
(11.11%), in the transverse-descending-sigma of 13 patients
(14.45%), in the left-sided colon of 12 patients (13.33%), in the
descending colon-sigma of 45 cases (50%), in the sigma-rectum of 7
cases (7.78%) and in the rectum of 3 patients (3.33%). Sixty-one
patients (67.78%) and 29 patients (32.22%) were affected by
constipation-or diarrhea-prevalent diverticulitis respectively.
OCTT was delayed in 67/90 patients (74.44%),
ranging from 115 to 210 min, averaged 120 min (Figure 1).
Fifty-three of ninetypatients (58.88%) showed bacterial overgrowth,
while OCTT was normal in 23/90 CD patients (25, 56%), ranging from
75 to 90 min averaged 82.5 min.
1 (PDF) OCTT
before and after treatment.
In the control group, the mean OCTT was 88.2 min,
ranging from 75 to 135 min. The difference between patients with
diverticulitis and healthy subjects was statistically significant (P<0.01).
When we subdivided the studied population
according to bowel movements (constipation-or diarrhea-prevalent
colonic diverticulitis), we could note that OCTT was longer in
constipation-prevalent disease than in diarrhea-prevalent disease.
OCTT was 180.7 min (range 150-210 min), 121 min (range 75-180 min)
in constipation- and diarrhea-prevalent colonic diverticulitis,
respectively with a statistically significant difference (P<0.001,
(PDF) OCTT in constipation-or diarrhea-prevalent
Interestingly, we did not find any difference in
bacterial overgrowth between patients. In fact, 26/53 (49.05%)
patients and 27/53 (50.95%) patients with SIBO were affected by
constipation-prevalent and diarrhea- prevalent colonic
Seventy patients (per-protocol: 81.49% [CI:
67-94%]; on intention-to-treat: 77.78% [CI: 60-85%]) were completely
asymptomatic after the 8th
wk of treatment with mesalazine alone (overall symptomatic score:
0), while 16 patients (per-protocol: 18.60%; on intention-to-treat:
17.77%) showed only mild symptoms (overall symptomatic score: 44).
Two patients (2.22%) had recurrence of diverticulitis (abdominal
pain, constipation, and fever) after 4 and 6 wk of treatment with
mesalazine alone, and two other patients (2.22%) showed severe
side-effects (severe diarrhea [more than 8 bowel movements/day]),
and they were withdrawn from the study. The overall score of
patients decreased from 1 439 to 44 (P<0.001).
was re-evaluated at the end of the 8th
wk of treatment with mesalazine alone. Seventy-nine of eighty-six
(91.86%) patients showed normal OCTT, ranging from 75 to 105 min,
averaged 83 min, while OCTT was longer but it was shorter in the
remaining seven (8.14%) patients, ranging from 105 to 115 min,
averaged 110 min. SIBO was eradicated in all patients. In contrast,
a new lactulose H2-BT
showed persistence of SIBO in one patient with recurrence of
Abnormal intraluminal pressure and disordered colonic motility have
been implicated as pathogenetic factors in diverticulosis. In
particular, alteration of colonic motility has been described as the
pathophysiological mechanism in diverticular disease. It has been
reported that colonic motility is influenced by the aging process,
as shown by the decrease of high-amplitude propagated contraction
frequency with the age, whereas segmental contractile activity
This study showed clearly that most of the
patients with acute diverticulitis showed a high prevalence of SIBO.
The mechanisms underlying the genesis of SIBO in uncomplicated
diverticulitis of the colon may be as follows. The first involved
mechanism may be the fecal stasis. In fact, the muscle thickening
observed in affected bowel segments was thought to be obstructive,
and to contribute to the delayed transit of feces.
Studies with intracolonic displacement tools suggested that an
accentuation of segmentary motor activity (as observed in
diverticular disease) could abolish oro-aboral progression of
thereby facilitating retropulsion and drying of the semiliquid fecal
matter. These findings have led to the second mechanism causing SIBO
that may be the colonic bacterial overgrowth. Changes in intestinal
microflorae may be one of the putative mechanisms responsible for
colonic inflammation, and could be the key point in the development
of symptoms in acute uncomplicated diverticulitis. Acute
diverticulitis is a condition characterized by abnormal bacterial
colonic overgrowth. This last condition, associated with the reverse
peristalsis affecting the colon in diverticular disease, may then
favor a small bowel colonization by colonic bacterial florae,
provoking SIBO. This hypothesis was confirmed by this study as most
patients with acute diverticulitis of the colon showed delayed OCTT
(74.44%) and SIBO (58.88%).
The reason why SIBO evaluation is important in
acute uncomplicated diverticulitis of the colon is that SIBO is a
small bowel disease that has never been investigated in patients
with acute uncomplicated diverticulitis, but it may play a role in
the genesis of the symptoms experienced by these patients. SIBO is
characterized by nonspecific GI complaints, ranging from mild
symptoms such as bloating, abdominal pain and flatulence to a severe
malabsorption syndrome with diarrhea, steatorrhea and weight loss,
and small intestinal mucosal lesions in some cases.
Bacteria are responsible for intraluminal sugar fermentation with
the production of a great amount of H2 and CH4 (causing bloating,
abdominal pain and flatulence). Furthermore, they could cause bile
salt deconjugation and dehydroxylation of fatty acids with
consequent fat malabsorption and impaired ileal resorption of bile
acids, which have irritative and cathartic effects on colonic mucosa.
The final consequence of these events is the development of
diarrhea, abdominal pain and mucus passage with stools. These
symptoms are indistinguishable from those of acute uncomplicated
diverticulitis, and may then worsen patient symptoms. Moreover, it
may prolong the clinical course of the disease. This last hypothesis
has been confirmed by the patients with diverticulitis recurrence
and persistence of SIBO. In this case we can hypothesize that
bacteria from the small bowel may re-colonize in the colon and
provoke recurrence of symptoms.
Fortunately, the main treatment for SIBO and
acute uncomplicated diverticulitis is the same. In fact, rifaximin
has been effectively used both in the treatment of diverticular
and in the treatment of SIBO.
On the other hand, delayed colonic motility persisted despite
resolution of acute episodes. This colonic alteration may then
persist as a risk factor for SIBO recurrence in patients with
colonic diverticulitis. Persistence or recurrence of symptoms often
indistinguishable from those of diverticulitis, may lead to
unnecessary diagnostic examinations to exclude recurrence of
diverticulitis. However, a correct exclusion of SIBO by lactulose
breath test may contribute to the correct diagnosis and exclusion of
diverticulitis recurrence in most of the cases.
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