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1. PATHOLOGY OF INFLAMMATORY BOWEL DISEASE
AND DIVERTICULAR DISEASE OF THE COLON
Moderator: Dr. Zelalem Assefa
(Consultant Colorectal and General Surgeon)
Presenter: Dr. fikreyohanis .s (GSR1)
Aug , 2021

2. OUTLINE
INFLAMMATORY BOWEL
DISEASE(IBD)
 Introduction
 Epidemiology
 Etiology and Pathophysiology
 Extra Intestinal Manifestation
of IBD
 Crohn’s Disease(CD)
 Ulcerative Colitis(UC)
 Indetereminate Colitis
DIVERTICULAR DISEASE OF
THE COLON (DDC)
 Introduction
 Epidemiology
 Pathophysiology
 Uncomplicated DDC
 Complicated DDC

3. Inflammatory Bowel Disease
• IBD is a chronic condition resulting from complex interactions between
intestinal microbiota and host immunity in genetically predisposed
individuals resulting an inappropriate mucosal immune activation
It comprises :
» Ulcerative colitis
» Crohn’s disease, and
» Indeterminate colitis

4. Epidemiology:
• UC - 8 to15 /100,000 and CD - 1 to 5/100,000 in USA and Northern
Europe, Lower in Asia, Africa and South America
Bimodal age distribution
• UC - Peaks in 3rd - 7th decades
• CD - peaks in 15- 30 then 60 -70 years
• Higher among Caucasians and White than Blacks, Hispanics and
Asians

5. Pathophysiology
 Under physiologic conditions, homeostasis normally exists between
• The commensal microbiota
• Epithelial cells
• Immune cells within the tissues
A consensus hypothesis is that each of these three major host
compartments that function together are affected by
 specific environmental (e.g., smoking, antibiotics, enteropathogens)
 genetic factors that, in a susceptible host, cumulatively and interactively
disrupt homeostasis

6. Genetics
• Risk for disease is increased when there is an affected family
member
• In Crohn disease, the concordance rate for monozygotic
twins is approximately 50% and only 16% in UC

7. • over 200 genes associated with IBD identified Among
these, NOD2, ATG16L1 and IRGM
• The presence of NOD2 gene on IBD1 locus on chromosome
16 has been linked to Crohn’s disease
• Persons with allelic variants on both have a 40-fold relative
risk of Crohn’s disease

8. COMMENSAL MICROBIOTA AND IBD
• The endogenous commensal microbiota within the intestines plays a
central role in the pathogenesis of IBD
• The establishment and maintenance of the intestinal microbiota
composition and function is under the control of host, environmental &
genetic (e.g., NOD2)
• The commensal microbiota in patients with both UC and CD is
demonstrably different from non-affected individuals, a state of
dysbiosis

9. DEFECTIVE IMMUNE REGULATION IN IBD
• The mucosal immune system does not normally elicit an inflammatory
immune response to luminal contents due to oral (mucosal) tolerance
• Oral tolerance may be responsible for the lack of immune
responsiveness to dietary antigens and the commensal microbiota in the
intestinal lumen
• In IBD this suppression of inflammation is altered, leading to
uncontrolled inflammation. The mechanisms of this regulated immune
suppression are incompletely known

10. Cont…
3/25/2024 Tesfaye.N 10

11. • Epithelial defects - a variety of epithelial defects have
been described in Crohn disease, ulcerative colitis. For
example, defects in intestinal epithelial tight barrier function
occur in patients with Crohn

12. CROHN’S DISEASE
• Crohn’s disease is a chronic, idiopathic transmural
inflammatory disease with skip lesions that may affect any
part of the GI tract,
 Small intestine alone - 30% of cases
 Small intestine and colon - 40%
 The colon alone - 30%
• CD may involve the duodenum, stomach, esophagus,

13. GROSS PATHOLOGY

14.  The earliest lesion characteristic of Crohn’s disease is the aphthous
ulcer. These superficial ulcers are up to 3 mm in diameter and are
surrounded by a halo of erythema. In the small intestine, aphthous ulcers
typically arise over lymphoid aggregates
 As disease progresses, aphthae coalesce into larger, stellate shaped
ulcers. Linear or serpiginous ulcers may form when multiple ulcers fuse
in a direction parallel to the longitudinal axis of the intestine. With
transverse coalescence of ulcers, a cobblestone appearance of the
mucosa may arise

15.  A pathognomonic feature of Crohn’s disease that is grossly evident
and helpful in identifying affected segments of intestine during surgery is
the presence of fat wrapping, which represents encroachment of
mesenteric fat onto the serosal surface of the bowel

16. Features that allow for differentiation between Crohn’s disease
of the colon and ulcerative colitis include
 The layers of the bowel wall affected in UC is limited to the
mucosa and sub mucosa but may involve the full-thickness in
Crohn’s disease
 The longitudinal extent of inflammation is continuous and
characteristically affects the rectum in UC but may be
discontinuous and spare the rectum in Crohn’s disease

17. Microscopic feature
 crypt abscess
 distortion of mucosal architecture
 Paneth cell metaplasia
 Non- caseating granulomas(hallmark)
- only found in 35 %

18. Clinical presentation CD
Depending on :-
o The segment of intestine involved
o Features of the disease:
 Fibrostenotic
 Inflammatory
 fistulizing

19. Fibrostenotic patterns
 occurs in any location, most commonly in the terminal ileum
 patients present with obstructive symptoms such as nausea,
vomiting, and decreased oral intake
 medical management is unsuccessful and surgical
intervention is required

20. Inflammatory
 It is characterized by mucosal ulceration and bowel wall
thickening
 This pattern often gives rise to obstructive symptoms in the
small intestine and diarrhea in the colon
 Inflammatory pattern is much more likely to respond to
medical therapy

21. penetrating or fistulizing
• Patients may be completely asymptomatic, as in the case of
many entero-enteral fistulas, present with anorectal
abscesses or fistulas
• Symptom depend on Involvement of the secondarily organ –
» recurrent UTI or pneumaturia
» vaginal discharge
» diarrhea
» cutaneous feculent drainage

22. Classification of CD

23. ILEOCOLITIS
Terminal ileum is the most common site of inflammation
o presented with -:
 Right lower quadrant pain and Palpable mass
 Diarrhea
 Fever
 Leukocytosis
 Pain is usually colicky relieved by defecation
 Weight loss

24. o persistent inflammation, gradually progresses to fibrostenotic
narrowing , stricture and chronic bowel obstruction
o Severe inflammation may lead to localized wall thinning, with
microperforation and fistula formation

25. JEJUNOILEITIS
• Extensive inflammatory disease is associated with a loss of
digestive and absorptive surface, resulting in malabsorption
and steatorrhea
• Intestinal malabsorption can cause anemia,
hypoalbuminemia, hypocalcemia, hypomagnesemia,
coagulopathy

26. COLONIC
 Distribution
– 1/3 total colonic involvement,
– 40% segmental disease
– 30% left-sided only
 Patients with colitis present with low grade fevers, malaise,
diarrhea, crampy abdominal pain, and sometimes
hematochezia

27. Anorectal
• perianal involvement is clearly more common in those with
concomitant rectal or colonic disease
• CD patients may also manifest
 edematous (elephant ear) skin tags
 blue discoloration of the anus
 abscesses and fistulas that are often recurrent, multiple

28. INVESTIGATION
Serologic marker
• The most commonly tested antibodies are (pANCA) and (ASCA)
• ASCA+/pAaNCA–, is associated with a diagnosis of Crohn’s disease
• ASCA–/pANCA+, correlates with ulcerative colitis
• Although these antibody tests have high specificity, their use has been
hampered by low test sensitivities

29. Plain Films
 plain films is often a routine part of the diagnosis
 An abdominal plain film may help in the setting of –
» Bowel obstruction
» To exclude toxic megacolon, or
» To evaluate for pneumoperitoneum

30. CONTRAST STUDIES
 barium studies helped diagnose CD by identifying longitudinal and
transverse linear ulcerations that create cobblestone and nodular
patterns, skip lesions, fistulas, and strictures
 with newer studies such as CT and MRE traditional barium studies are
becoming less favorable

31. Computed Tomography
 In many centers, CT has now largely replaced the barium studies
 with the added ability to identify the extent of the disease and
involvement of surrounding structures, manifested by
 segmental bowel thickening
 mesenteric fat stranding
 intra-abdominal fluid &
 presence of fistula

32. Magnetic Resonance Imaging
• MRE is over 85% accurate in predicting stenosis, abscess, and fistula
• Its sensitivity (85–90%), specificity (100%), and negative predictive
value (77%)
• MRI has also been particularly useful in the evaluation of complex
perianal fistulas seen in CD

33. Endoscopy
• To identify the extent and severity of the disease and perform biopsies to
aid in diagnosis
• Endoscopic evaluation includes colonoscopy,
esophagogastroduodenoscopy (EGD), enteroscopy, and capsule
endoscopy

35. Ulcerative colitis
• It is characterized by recurring episodes of inflammation
limited to the mucosal layer of the colon
• It commonly involves the rectum and may extend in a proximal
and continuous fashion to involve other parts of the colon

36. Gross pathology
 Early UC - the mucosa grossly appear edematous, with confluent
erythema and a loss of vascular markings
 Intermediate - the mucosa will develop granularity with micropurulence
and bleeding
 Advanced UC - will be marked by pseudo-polyp formation, deep
ulcerations, gross purulence, mucosal bridging, and varied mucosal
thickness

37. Microscopic feature
• Early disease - characterized by mucosal inflammation, crypt distortion,
goblet cell mucin depletion, and vascular congestion
• Intermediate disease - is associated with crypt abscesses and loss of
mucosa with preservation of the crypts themselves
• Advanced disease- hallmarks are Crypt destruction, pseudopolyps, and
deeper invasion of inflammation

38. • It is in late disease where we tend to identify dysplasia;
however, it can only be interpreted when identified in non-
inflamed bowel, as many dysplastic features are similar to
inflammation

39. • The risk of colorectal carcinoma among UC patients is approximately
3.7%, with pancolitis conferring an even higher risk of 5.4%
• The same study found the cumulative risk of colorectal carcinoma by
decade was 2% at 10 years, 8% at 20 years, and18% at 30 years

40. Clinical Manifestations
Signs and symptoms depend on the severity and location
The most common findings are -:
 Blood and mucus in the stools
 Tenesmus
 Urgency
 Increased stool frequency
 Fecal incontinence, and
 pain with defecation
 Fecal incontinence

41. systemic symptoms including-
• fever, fatigue, weight loss, and anemia from blood loss
Physical examination
Mild disease- it is often normal
Moderate to severe UC - have abdominal tenderness, fever,
hypotension, tachycardia, and pallor, evidence of blood on DRE

43. DIAGNOSIS
Serologic Testing
 CRP and ESR are the only two widely used tests for assessing general
systemic inflammation
 pANCA and ASCA, may help differentiate CD from UC
 pANCA is more frequently identified in UC patients(50–70% of UC vs.
20–30% of CD)
 ASCA is more frequently associated with CD, although it may be present
in 10 to 15% of UC patients as well

44. Endoscopy
 Endoscopy is the GOLD STANDARD for diagnosis of UC
 Colonoscopic examination alone is generally enough to diagnose UC ,
allows for tissue biopsy as well as assessment of the gross appearance
and specific pattern of inflammation
 The entire extent of the disease process can effectively be surveyed

45. Mucosal Biopsies
• During the procedure, multiple biopsies are necessary for diagnosing UC
and from six segments (the terminal ileum, the ascending, transverse,
descending and sigmoid colon and the rectum) should be obtained

46. Plain Film X-Rays
 X-rays still play a role when considering the patient who presents acutely
with abdominal pain
 We may see presence of free air or toxic megacolon

47. CT- SCAN
In UC, the indications for CT enterography and colonography are
currently
• strictures precluding endoscopic assessment
• patients with severe comorbidities where colonoscopy is contraindicated
• It also allows excluding small bowel involvement for the differential
diagnosis of CD or in the case of indeterminate colitis

48. Magnetic Resonance
• The role of MRI in IBD is still evolving. While less efficient
and more costly than CT for an abdominal survey

49. Indetereminate Colitis
• In 15% of patients with IBD, differentiating UC from CD is impossible
“indeterminate colitis”
• Their symptoms similar to ulcerative colitis
• Endoscopic and pathologic findings usually include features common to
both diseases
Serologic markers have been employed to differentiate UC from CD
• pANCA- 60% to 70% in UC, compared to 2% to 28% in CD
• ASCA-39% to 69% in CD, but only 5% to 15% of UC

50. Diverticular Disease of the Colon
• A diverticulum is a sac-like protrusion of the colonic wall
• Diverticulosis is defined by the presence of diverticula without
inflamation
• Diverticular disease - is defined as clinically significant and
symptomatic diverticulosis due to diverticular bleeding, diverticulitis,
segmental colitis

51. • The majority of colonic diverticula are false diverticulum which
the mucosa and muscularis mucosa have herniated through
the colonic wall
• These diverticula occur at the teniae coli, at points where
nutrient artery penetrate the colonic wall

52. EPIDEMOLOGY
The distribution of diverticulosis within the colon varies by geography
 Western and industrialized nations have prevalence rates of 50 %
above the age of 50
• Approximately 95 % of patients with diverticula have sigmoid diverticula
 In Asia, the prevalence of diverticulosis is between 13 and 25 % and
diverticulosis is predominantly right-sided

53. Pathophysiology

54. MORPHOLOGY
• Colonic diverticula are small, flasklike outpouchings, usually 0.5-1 cm in
diameter
• They are most common in the sigmoid colon, but other regions of the
colon may be affected
• Colonic diverticula have a thin wall composed of a flattened or atrophic
mucosa, compressed submucosa, and attenuated muscularis propria

55. RISK FACTORS
 Diet - Low fiber, high fat, and red meat
 Physical inactivity
 Obesity

56. Clinical Features

57. Uncomplicated Diverticulitis
 It is characterized by LLQ pain and tenderness
 CT findings include pericolic soft tissue stranding, colonic wall
thickening, and/or phlegmon
 Most patients will respond to outpatient therapy with broad-spectrum oral
antibiotics (7 to 10 D) and a low-residue diet
 10% to 20% of patients with more severe pain, tenderness, fever, and
leukocytosis are treated in the hospital with parenteral antibiotics

58. Complicated Diverticulitis
Abscess
 It occur in 17 % of patients hospitalized with acute diverticulitis
 The symptoms of a diverticular abscess are similar to acute diverticulitis
 CT is the imaging modality of choice
 It should be suspected in patients with uncomplicated diverticulitis who
have no improvement of symptoms despite of antibiotic treatment

59. FISTULA
 Acute diverticulitis may result in the formation of a fistula between the
colon and adjacent viscera
 Fistulas most commonly involve the bladder, and may have
pneumaturia, fecaluria, or dysuria
 Patients with a colovaginal fistula may report vaginal passage of feces or
flatus

60. Perforation
 Generalized peritonitis may result from rupture of a diverticular abscess
or free rupture of an inflamed diverticulum
 only 1 to 2 % of patients with acute diverticulitis have a perforation, but
mortality rates is about 20 %
 The abdomen is distended and diffusely tender to light palpation. There
is diffuse guarding, rigidity, and rebound tenderness, and bowel sounds
are absent

61. Hemorrhage
• Bleeding results from erosion of the peri-diverticular arteriole and may
result in massive hemorrhage
• Most significant LGIB occurs in elderly patients is due to diverticulosis
• The exact bleeding source may be difficult to identify, Fortunately, in 80%
of patients, bleeding stops spontaneously

62. Hinchey classification of Diverticulitis

63. REFERENCES
• Marvin L. Corman..etal,corman’s Colon And Rectal
Surgery,6th edition
• Jeffrey H. Peters…etal,Shackelford’s Surgery of the
Alimentary Tract,7th edition
• Brunicardi FC, Schwartz’s Principles of Surgery, 11th
edition
• Michael J. …etal,maingot’s Abdominal Surgery,13th
edition
• Uptodate 2018

64. THANK YOU