1. Small Bowel, SBO, IBD Outline Small bowel physiology SBO physiology
Absorption
Barrier
SBO physiology
Hyperperistalsis
Decreased absorption
Increased secretion
Clinical aspects

2. Small Bowel, SBO, IBD Outline (cont’d) Crohn’s disease
Epidemiology
Pathology
Indications for operation
Ulcerative colitis

3. Small Bowel Physiology
Small Bowel, SBO, IBD
Small Bowel Physiology
Absorbs water, electrolytes, nutrients
Varies between jejunum and ileum
Compromised in certain disease states
Requires glutamine as energy source
Barrier function
Requires enteral nutrition for maintenance
Compromised by lack of feeding
?Leads to nosocomial infection

4. Layers of the small intestine
Layers of the small intestine. A large surface is provided by villi for the absorption of required nutriments. The solitary lymph follicles in the lamina propria of the mucous membrane are not labeled. In the stroma of both sectioned villi are shown the central chyle (lacteal) vessels or the villous capillaries. (From Sobotta J, Figge FHJ, Hild WJ: Atlas of Human Anatomy. New York, Hafner, 1974, with permission.)

5. Digestion and absorption of proteins.

6. Absorption of water and electrolytes in the small bowel and colon
Absorption of water and electrolytes in the small bowel and colon. (Adapted from Westergaard H: Short bowel syndrome. In Feldman M, Scharschmidt BF, Sleisenger MH [eds]: Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. Philadelphia, WB Saunders, 1998, p 1549.)

7. The mucosal barrier of the gut
The mucosal barrier of the gut. Antigens contact specialized microfold (M) cells overlying Peyer’s patches, which then process and present the antigen to the immune system. When B lymphocytes are stimulated by antigenic material, the cells develop into antibody-forming cells that secrete various types of immunoglobulins (Igs), the most important of which is IgA. (Adapted from Duerr RH, Shanahan F: Food allergy. In Targan SR, Shanahan F [eds]: Immunology and Immunopathology of the Liver and Gastrointestinal Tract. New York, Igaku-Shoin, 1990, p 510.)

8. Small Bowel, SBO, IBD SBO Physiology Global hyperperistalsis
Decreased absorption of H2O & lytes
Increased secretion of protein rich fluid
Hypoperistalsis in late stages

9. Small Bowel, SBO, IBD SBO Physiology
Pain and tenderness doesn’t differentiate type
Simple SBO
Usually partial
Differentiation by plain X-ray or CT
May resolve
Strangulated SBO
Usually complete
Often “closed loop”
Requires urgent operation

10. Common causes of small bowel obstruction in industrialized countries.

11. FIGURE 46-13A. Plain abdominal radiographs of a patient with a complete small bowel obstruction. A, Supine film shows dilated loops of small bowel in an orderly arrangement, without evidence of colonic gas. B, Upright film shows multiple, short, air-fluid levels arranged in a stepwise pattern. (Courtesy of Melvyn H. Schreiber, M.D., The University of Texas Medical Branch.)

12. CT scan through the mid abdomen shows dilated small bowel loops filled with fluid and decompressed ascending and descending colon. These are typical CT findings in small bowel obstruction. (Courtesy of Eric Walser, M.D., The University of Texas Medical Branch.)

13. Crohn’s Disease Epidemiology Disease of young adults
Peak incidence in late teens and 20’s
Smaller peak in 50’s & 60’s
Incidence varies amongst ethnic groups
Cause unknown
?Autoimmune
?Infectious
?Genetic

14. Crohn’s Disease Pathology Full-thickness involvement
Thickened bowel wall and mesentery
50% with non-caseating granulomas
May involve any portion of GI tract

15. Gross pathologic features of Crohn’s disease
Gross pathologic features of Crohn’s disease. A, Serosal surface demonstrates extensive “fat wrapping” and inflammation. B, Resected specimen demonstrates marked fibrosis of the intestinal wall, stricture, and segmental mucosal inflammation. (Courtesy of Mary R. Schwartz, M.D., Baylor College of Medicine.)

16. Crohn’s colitis with noncaseating granuloma.

17. Crohn’s Disease Pathology (cont’d) Ileal involvement most common
Colon-only involvement seen
Peri-rectal disease common
Extra-intestinal manifestations
Surgery not curative
Malignancy uncommon

18. Crohn’s colitis. This barium enema demonstrates segmental inflammation of the left colon, characteristic of Crohn’s disease. The rectum is spared, a clinical finding that is useful in distinguishing Crohn’s colitis from ulcerative colitis. The rectal mucosa is virtually always affected in patients with ulcerative colitis, whereas the pattern of colonic inflammation is variable in Crohn’s colitis.

19. Small bowel contrast study demonstrating “string sign” caused by inflammation and narrowing of the terminal ileum.

20. Crohn’s colitis. Linear ulceration of the mucosa, giving appearance of “railroad track” or “bear claw ulcers.”

21. Indications for Operation
Crohn’s Disease
Indications for Operation
Abscess
Certain fistulae
Obstruction
Intractability

22. Elective operations for Crohn’s colitis.

23. Surgical Considerations
Crohn’s Disease
Surgical Considerations
Important aspect of overall care
Bowel conservation important
Limited resection
Resect, don’t bypass
Long-term risk of short-gut is low
J-pouch not an option in colonic disease

24. Ulcerative Colitis Epidemiology Similar to Crohn’s disease
Early and late incidence peaks
Variable incidence among ethnic groups

25. Ulcerative Colitis Pathology Involves only mucosa and submucosa
Involves only colon and rectum
Serosa normal
Normal bowel wall thickness
Normal mesentery

26. Ulcerative colitis, macroscopic appearance of pancolitis
Ulcerative colitis, macroscopic appearance of pancolitis. Because the entire colon is involved with inflammatory changes, this specimen represents a case of universal colitis or pancolitis. The distal colon shows a large longitudinal ulcer with heaped-up adjacent mucosa. In the midportion of the colon, the mucosa is relatively flat and featureless. In the right side of the colon, there are multiple projections, or pseudopolyps, creating a cobblestone appearance. The ileocecal valve is edematous and irregular, whereas the terminal ileum is spared. (Courtesy of M. Markowitz Haber, M.D., Hahnemann University Hospital.)

27. Ulcerative colitis, macroscopic appearance of left-sided colitis
Ulcerative colitis, macroscopic appearance of left-sided colitis. The left side of the colon displays continuous disease manifested as erythema and granularity of the mucosal surface, whereas the right colon appears normal. (Courtesy of M. Markowitz Haber, M.D., Hahnemann University Hospital.)

28. Active ulcerative colitis
Active ulcerative colitis. The glands are irregular with branching, and, focally, the long axis of the gland is horizontal rather than perpendicular. A central crypt abscess is present. There are increased numbers of chronic inflammatory cells throughout the lamina propria. (Courtesy of M. Markowitz Haber, M.D., Hahnemann University Hospital.)

29. Barium enema demonstrating stricture in transverse colon of patient with ulcerative colitis of 15 years’ duration.

30. Photograph of resected colon from patient in Figure 48-28, revealing the stricture (arrow) to be invasive cancer. The patient had liver metastases

31. Ulcerative Colitis Pathology (cont’d) Extraintestinal manifestations
Malignancy
Duration of disease
Extent of disease

32. Ulcerative Colitis Presentation Diarrhea, often bloody Abdominal pain
Constitutional symptoms
Weight loss
Fulminant colitis
Toxic megacolon

33. Indications for Operation
Ulcerative Colitis
Indications for Operation
Bleeding (uncommon)
Unresponsive fulminant colitis
Toxic megacolon
Intractability
Inability to wean steroids
Cancer prevention

34. Elective operations for ulcerative colitis
Elective operations for ulcerative colitis. IPAA, ileal pouch-anal anastomosis

35. Ulcerative Colitis Surgical Aspects Colectomy curative
Total proctocolectomy with ileostomy
Ileo-anal pouch pull-through

36. Creation of an ileal J pouch using a cutting linear stapler
Creation of an ileal J pouch using a cutting linear stapler. For replacement of the rectum, a reservoir is created from the distal ileum. The stapler joins two limbs of intestine with staples while dividing the intervening wall. The diameter of the pouch so created is twice as large as the original diameter of the ileum.

37. Hand-sewn ileal pouch anal anastomosis following anorectal mucosectomy.