Transcript TB or CD? A Aljebreen, MD, Assistant Professor, Colrectum Forum 2007

TB or CD?
A Aljebreen, MD, Assistant Professor,
department of Medicine, KKUH
Colrectum Forum 2007
Overview
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TB and CD epidemiology
How to diagnose?
Introduction
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In geographical regions where both intestinal
tuberculosis (TB) and Crohn’s disease (CD) coexist, the
differential diagnosis of these two conditions poses a
challenge to clinicians.
The ultimate course of these two disorders is different.
Intestinal TB is entirely curable, provided that the
diagnosis is made early enough and appropriate
treatment is instituted.
In contrast, CD is a progressive relapsing illness.
Unfortunately, it is difficult to differentiate intestinal TB
from CD because of similar clinical, pathological,
radiological, and endoscopic findings.
Epidemiology of TB
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Annual incidence rates of extrapulmonary
tuberculosis have been increasing to 4.7 cases
per 100,000 population in 1997 in Saudi Arabia.
Extrapulmonary TB represented 28.2% of all
reported TB cases.
Abdominal TB accounted for 16% of all
extrapulmonary TB in 2 large series from Riyadh
and Jeddah.
Ministry of Health. Tuberculosis. Annual Health Report, 1997. p. 46-49.
Epidemiology of TB
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Gastrointestinal TB was the 2nd most common
type of TB after pulmonary disease among 820
patients with TB between 1982 and 1990 (small
bowel involvement in 34% of them)
Al-Karawi. J Clin Gastroenterol 1995; 20: 225-232.
CD in Saudi Arabia
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Very scarce data
It was considered an area “without IBD”
1982, the first 2 cases reported.
In 2003, Al-Ghamdi reported the first study about CD
where they collected 77 cases from 1983-2002.
Concluded there was a definite increase in the incidence
of CD
At KKUH we have collected 79 new IBD cases within
the last 2 years
So, there is a definite surge of IBD
Al-Ghamdi et al, WJG 2003
Extrapulmonary TB: difficult to
diagnose??
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Several forms of extrapulmonary TB lack any of
the localizing symptoms or signs.
Cutaneous anergy to PPD was noted in 35-50%
of patients.
No clinical or radiological evidence of
pulmonary TB could be found in up to one 3rd
of these patients.
Diagnosis: intestinal TB or CD
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They can present exactly with same clinical
pictures (same age group, symptoms and signs)
Same radiological findings and same endoscopic
findings
Mostly with same pathological findings
So how can we make the diagnosis?
? Other features
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History of previous TB
CXR findings of TB
The tuberculin skin test is less helpful, because a
positive test does not necessarily mean active
disease.
Perianal fistulae and extraintesitnal
manifestations of CD
If all negative: any other clues??
Multiple attempts!!
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Endoscopic findings?
Laproscopic findings?
Histological findings?
PCR?
Empirical TB?
Endoscopic diagnosis?
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CD (4 parameters)
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Anorectal lesions,
longitudinal ulcers,
aphthous ulcers, and
cobblestone appearance
Intestinal TB (4 parameters)
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involvement of fewer than four segments,
a patulous ileocecal valve,
transverse ulcers, and
scars or pseudopolyps
Endoscopy. 2006 Jun;38(6):592-7.
Endoscopic diagnosis?
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Lee et al hypothesized that a diagnosis of Crohn's
disease could be made when the number of parameters
characteristic of Crohn's disease was higher than the
number of parameters characteristic of intestinal
tuberculosis, and vice versa.
Making these assumptions, the diagnosis of either
intestinal tuberculosis or Crohn's disease would have
been made made correctly in 77 of our 88 patients
(87.5 %), incorrectly in seven patients (8.0 %), and
would not have been made in four patients (4.5 %).
Endoscopy. 2006 Jun;38(6):592-7.
Endoscopic findings: TB
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In tuberculosis patients, transverse ulcers
with surrounding hypertrophic mucosa and
multiple erosions were usual colonoscopic
findings.
Am J Gastroenterol 1998;93: 606–609.
Gastrointest Endosc 2004;59:362-8.
Typical transverse ulcer
Gastrointest Endosc 2004;59:362-8.
Radiology
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SBFT reveals a thickened bowel wall with
distortion of the mucosal folds and ulcerations.
CT may show preferential thickening of the
ileocecal valve and medial wall of the cecum and
massive lymphadenopathy with central necrosis.
Calcified mesenteric lymph nodes and an
abnormal chest film are other findings that aid
in the diagnosis of intestinal tuberculosis.
At surgery: TB
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Reduced largely since introduction of colonoscopy
Indications:
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Mass lesions associated with the hypertrophic form, because
they can lead to luminal compromise with complete
obstruction.
Surgery also may be necessary when free perforation,
confined perforation with abscess formation, or massive
hemorrhage occur.
Findings:
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The bowel wall appears thickened with an inflammatory mass
surrounding the ileocecal region.
The serosal surface is covered with multiple tubercles.
The mesenteric lymph nodes frequently are enlarged and
thickened.
Histologically
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Intestinal TB: granulomas are
Large,
 multiple,
 confluent with
 caseation
 Ulcers lined by epitheliod histiocytes
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CD
Fissuring ulcer,
 lymphoid aggregates,
 transmural inflammation, and
 Infrequent, small, noncaseating granulomas.
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Am J Gastroenterol 2002;97:1446 –1451.
Pulimood et al. Gut 1999
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Multiple confluent
granulomas, one of
which exhibits
necrosis.
There is almost no
infiltration of
neutrophils.
PCR: rapid and accurate?
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The positivity rate by PCR in 39 intestinal tuberculosis
specimens was 64.1% (25/39), but was zero by PCR in
30 Crohn’s disease specimens.
Moreover, in the tissues of intestinal tuberculosis with
granulomas similar to those of Crohn’s disease, there
were 71.4% (10/14) positive by PCR, and there were
61.1% (11/18) positive in intestinal tuberculosis tissues
without granulomas.
Am J Gastroenterol 2002;97:1446 –1451.
Empirical anti-TB
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If intestinal TB still possibility, give 4-6 weeks
of anti-TB
30% of CD patietns at China receives anti-TB
before final diagnosis
? Saudi
ASCA?
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ASCA (IgG and IgA) does not differentiate
between CD and intestinal TB
No correlation between ASCA and duration,
location and behaviour of CD and intestinal TB
Makhania et al. Digestive disease & Science. Jan 2007
Microbiology
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Finding Acid-fast bacilli in one third of patients.
The organism also can be recovered in a culture
of the involved tissues (up to 50% of pts but
need 8 weeks)
Horvath et al, AJG 1998
Intestinal TB: when to call?
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The definitive diagnosis of intestinal
tuberculosis is made by
identification of the organism in tissue, either by
direct visualization with an acid-fast stain,
 by culture of the excised tissue, or
 by a PCR assay.
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Presumptive diagnosis
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can be established in
A patient with active pulmonary tuberculosis and
radiologic and clinical findings that suggest
intestinal involvement.
 Response to anti-TB
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Summary
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In geographical regions where both intestinal tuberculosis (TB)
and Crohn’s disease (CD) coexist, the differential diagnosis of
these two conditions poses a challenge to clinicians.
Unfortunately, it is difficult to differentiate intestinal TB from
CD because of similar clinical, pathological, radiological, and
endoscopic findings.
Although attempts have been made to distinguish them, there
are still no specific differential diagnostic methods up to now.
Polymerase chain reaction (PCR) assay, which allows highly
specific and sensitive detection of Mycobacterium tuberculosis has
been developed (9 –11), and may provide a novel means for
differentiating between these two conditions.