Crohn's disease. Some key differentiating factors from ulcerative colitis include: - Patchy, skip lesions rather than continuous involvement from rectum up. - Transmural inflammation rather than limited to mucosa/submucosa. - Granulomas on histology. - Involvement can be anywhere from mouth to anus rather than limited to colon. Main contributing factors include genetic susceptibility, abnormal immune response to gut flora, and environmental triggers like stress, smoking, and diet. Underlying pathogenesis involves failure of immune regulation.

1. Inflammatory Bowel Disease
Crohn Disease
terminal ileitis” or
“regional enteritis
“
Lecture 12
by
Dr Mohammad Manzoor Mashwani BKMC Mardan

2. IIBD- Crohn’s Disease
Crohn’s Disease (CD)
• Crohn’s Disease is an idiopathic, chronic,
transmural inflammatory process of the bowel that
can affect any part of the gastro intestinal tract
from the mouth to the anus.
• Most cases involve the small bowel, particularly the
terminal ileum
.
Inflammatory
Chronic
Relapsing
Autoimmune ?
Idiopathic
A systemic
inflammatory
disease with
predominant
intestinal
involvement.
IBDcomprised of
two major
disorders:
Ulcerative Colitis
(UC)
Crohn’s Disease
(CD)

3. Burril
Bernard
Crohn

4. Epidemiology
• Higher number of cases of Crohn’s disease found in
western industrialized nations.
• Males and females are equally affected.
• Smokers are three times more likely to develop Crohn's
disease.
• Crohn's disease tends to present initially in the teens and
twenties (Young adults).

5. Classification of CD
On the area of the gastrointestinal tract which it affects:
• Ileocolic Crohn's disease: Affects both the ileum and
the large intestine (50%)
• Crohn's ileitis: Affects the ileum only (30%)
• Crohn's colitis: Affects the large intestine, accounts for
the remaining twenty percent of cases.

6. Classification of CD
On the behavior of disease as it progresses:
• Stricturing disease causes narrowing of the bowel which may
lead to bowel obstruction or changes in the caliber of the
feces.
Stricturing

7. Classification of CD
• Penetrating disease creates abnormal passage ways between the
bowel and other structures such as the skin.
• Inflammatory disease causes inflammation without causing strictures
or fistulae.
Inflammatory
Penetrating

8. They result from an abnormal local immune response against the normal flora
of the gut, and probably against some self antigens, in genetically susceptible
individuals.
The pathogenesis of IBD involves genetic susceptibility, failure of immune
regulation, and triggering by microbial flora.

9. Morphology
Location: (Any) terminal ileum, ileocecal valve, and cecum. Multiple, separate, sharply
delineated areas of disease, resulting in skip lesions/patchy/cobblestone
appearance. The intestinal wall is thickened and rubbery as a consequence of
transmural edema, inflammation, submucosal fibrosis, and hypertrophy of the
muscularis propria, all of which contribute to stricture formation.
aphthous ulcer-serpentine ulcers
Fissures, fistula ,perforation. mesenteric fat frequently extends around the serosal
surface (creeping fat) Clusters of neutrophils within a crypt (crypt abscesses)
destruct crypt leading to distortion of mucosal architecture; the normally straight
and parallel crypts take on bizarre branching shapes and unusual orientations to
one another. Epithelial metaplasia- gastric antral-appearing glandscalled
pseudopyloric metaplasia. Paneth cell metaplasia may also occur in the left colon,
where Paneth cells are normally absent. Noncaseating granulomas, a hallmark of
Crohn disease, are found in approximately 35% of cases. Granulomas may also be
present in mesenteric lymph nodes. Cutaneous granulomas form nodules that are
referred to as metastatic Crohn disease.
.

10. Morphology
• Location-any- terminal ileum, ileocecal valve, cecum
• Lesion- skip, patchy; stricture formation; serpentine ulcer;
• Fissure, fistula, perforation; creeping fat; crept abscessdistortion of mucosal architecture; pseudopyloric
metaplasia; Noncaseating granulomas.
A granuloma is a focus of chronic inflammation consisting of a microscopic aggregation of
macrophages that are transformed into epithelium-like cells, surrounded by a collar of
mononuclear leukocytes, principally lymphocytes and occasionally plasma cells.
Granuloma is a collection macrophages.

12. Gross pathology of Crohn disease. A, Small-intestinal stricture. B, Linear mucosal ulcers and
thickened intestinal wall. C, Perforation and associated serositis. D, Creeping fat.

13. Microscopic pathology of Crohn disease. A, Haphazard crypt organization results
from repeated injury and regeneration. B, Noncaseating granuloma. C, Transmural
Crohn disease with submucosal and serosal granulomas (arrows).

14. Symptoms- Extremely variable
Approximately 20% of patients present acutely
with right lower quadrant pain, fever, and
Positive String Sign
bloody diarrhea that may mimic acute
Age: 15-30 periods of flare-ups and remission,
appendicitis or bowel perforation. Periods of
active disease are typically interrupted by
Common symptoms of Crohn's disease: asymptomatic periods that last for weeks to
often recurs at
• abdominal pain Disease of anastamosis,
many months.
the site
and as many as 40% of
• diarrhoea
patients require
Disease re-activation can be associated with a variety
additional resections
• weight loss
within 10 years.
of external triggers, including physical or emotional
Less common symptoms include: stress, specific dietary items, and cigarette smoking.
• poor appetite
Smocking is a strong
Fistulae develop between loops of bowel and may
• fever, night sweats
exogenous risk factor for
also involve the urinary bladder, vagina, and
development of Crohn
• rectal pain/rectal bleeding abdominal or perianal skin.
disease and, in some
Some patients with Crohn's disease also develop symptoms outside of cases, disease onset is
associated with
the gastrointestinal tract; these symptoms include:
initiation of smoking.
sacroiliitis,
• arthritis ankylosing spondylitis,
Unfortunately, smoking
Iron-deficiency anemia may develop in
cessation does not
individuals with colonic disease, while extensive
• skin rash erythemaofnodosum
result in disease
small bowel disease may result in serum protein
clubbing the fingertips,
• inflammation of the iris of the eye. loss and hypoalbuminemia, generalized nutrient remission.
malabsorption, or malabsorption of vitamin B12
and bile salts.
Perforations and peritoneal abscesses are common.
Risk of colonic adenocarcinoma is increased in patients with long-standing colonic disease.
Fibrosing strictures,
particularly of the terminal
ileum, are common and
require surgical resection.

16. Paper Question Annual 2013
• A young emotionally stressed female presents
to medical OPD with complaints of
intermittent attacks of mild diarrhea,
abdominal pain and fever followed by
asymptomatic period lasting for weeks and
months. Positive String sign is seen.
Colonoscopy reveals patchy, deep intestinal
ulcers. Continue on next slide…..

17. • a. What is the most likely diagnosis?
1
• b. How would you differentiate the diagnosis
from other form of Irritable Bowl Disease
(IBD)?
6
• c. What are the main factors that contribute
to the above diagnose disease?
3