1. Inflammatory bowel disease and Ulcerative colitis
Dr Mamlook Elmagraby

2. Objectives of the lecture:
Upon completion of this lecture, students should be able to:
Know the two forms of idiopathic inflammatory bowel disease (IBD)
Describe Ulcerative Colitis with respect to: clinical features and extra-intestinal manifestations, pathogenesis, pathology (gross and microscopic features), complications (especially adenocarcinoma preceded by dysplasia)

3. Ulcerative Colitis

4. Ulcerative Colitis (UC)
UC is an ulceroinflammatory disease affecting the colon, which is limited to the mucosa and submucosa UC begins in the rectum and extends proximally in a continuous fashion UC is a systemic disorder in some persons (primary sclerosing cholangitis) The disease may arise at any age, with a peak incidence between ages 20 and 25 years

5. Ulcerative Colitis (UC)
Morphology
UC involves the rectum and sigmoid and may involve the entire colon
Colonic involvement is continuous from the distal colon
In active disease, mucosa shows hyperemia, edema, and granularity with friability and easy bleeding
With severe active disease, there is extensive and broad-based ulceration of the mucosa

6. Colon, chronic ulcerative colitis, colectomy specimen - mucosal surface
This large bowel has a diffusely inflamed mucosal surface, extending from the rectum to the cecum.
The right colon appears to be less involved

7. Ulcerative Colitis (UC)
Isolated islands of regenerating mucosa bulge upward to create pseudopolyps
Exposure of the muscularis propria and neural plexus to fecal material also may lead to toxic megacolon

8. Toxic megacolon.
Complete cessation of colon neuromuscular activity has led to massive dilatation of the colon and black-green discoloration signifying gangrene and impending rupture

9. Ulcerative Colitis (UC)
Microscopical features:
The pathologic features of UC are those of mucosal inflammation, ulceration, chronic mucosal damage
A diffuse, predominantly mononuclear inflammatory infiltrate in the lamina propria is present
Neutrophilic infiltration may produce collections of neutrophils in crypt lumina (crypt abscesses)
The most serious complication of ulcerative colitis is the development of colon carcinoma

10. Colon, chronic ulcerative colitis
This image shows an ulcer base with fibrin, capillaries, and inflammatory cells
Note the distorted regenerating crypts at the edge of the ulcer
Compare the shape of the regenerating crypts with that of the normal crypts

11. Ulcerative colitis.
Microscopic view of the mucosa, showing diffuse active inflammation with crypt abscess and glandular architectural distortion.

12. Colon, chronic ulcerative colitis
The lamina propria shows an increase in acute and chronic inflammatory cells
A mucosal crypt is distended by a collection of neutrophils, known as a crypt abscess

13. Ulcerative Colitis (UC)
Clinical Features
UC is characterized by chronic inflammation of the mucosa that involves the rectum and extends proximally through the colon  
The extent and severity of the colonic inflammation determine prognosis and presentation (insidious versus acute onset)
The typical clinical course of UC is one of chronic intermittent exacerbations followed by periods of remission
Most patients exhibit diarrhea, abdominal pain, rectal bleeding, and the passage of mucus per rectum
Exacerbation increase in severity of a disease

14. Ulcerative Colitis (UC)
These symptoms may persist for days, weeks, or months before they subside 
More than half of patients have mild disease
Colectomy cures intestinal disease, but extraintestinal manifestations may persist
Anemia commonly occurs and is caused by:
Chronic blood loss from the involved colonic mucosa
Bone marrow suppression from the inflammatory condition
Subside become less severe

15. Ulcerative Colitis (UC)
Perforation can occur in patients with severe or fulminant colitis, especially in the setting of toxic megacolon
Toxic megacolon is characterized by gross dilation of the large bowel associated with fever, abdominal pain, dehydration, bloody diarrhea, tachycardia
Perforation a hole in the containing walls of a structure
Fulminant Occurring suddenly, rapidly, and with great severity

16. Distribution of lesions in inflammatory bowel disease
Distribution of lesions in inflammatory bowel disease. The distinction between Crohn disease and ulcerative colitis is primarily based on morphology

17. Macroscopic Microscopic Feature Crohn Disease Ulcerative Colitis
Bowel region
Ileum ± colon
Colon only
Distribution
Skip lesions
Diffuse
Stricture
Yes
Rare
Wall appearance
Thick
Thin
Microscopic
Inflammation
Transmural
Limited to mucosa
Pseudopolyps
Moderate
Marked
Ulcers
Deep, knife-like
Superficial, broad-based
Lymphoid reaction
Fibrosis
Mild to none
Serositis
Granulomas
Yes (~35%) No
Fistulae/sinuses
Features of Crohn Disease and Ulcerative Colitis

18. Clinical Feature Crohn Disease Ulcerative Colitis Perianal fistula
Yes (in colonic disease) No
Fat/vitamin malabsorption
Yes
Malignant potential
With colonic involvement
Recurrence after surgery
Common
Toxic megacolon
Features That Differ between Crohn Disease and Ulcerative Colitis