1. Small Bowel, Obstruction and Inflammatory Bowel Disease Albert Einstein College of Medicine Medical Student Lecture Series Jessica Schnur, MD

3. Physiology Nutrient and water absorption Absorbs ~ 80% of the 9L of fluid that passes through daily, leaving approx 1.5 L for the colon Starch digestion with pancreatic amylase/hydrolases  glucose/galactose/fructose Protein digestion with pepsins (bile  enterokinase  trypsinogen  trypsin  all other pepsinogens) – Glutamine is major source of energy for enterocytes

4. Physiology continued Long-chain fatty acids absorbed via chylomicrons through lymphatics  thoracic duct Short/medium-chain fatty acids absorbed directly into portal venous system Important in control of chyle leaks

5. Vitamin absorption B12  intrinsic factor from stomach B12+R protein hydrolyzed in duodenum  binds with IF (escapes hydrolysis by pancreatic enzymes) B12+IF absorbed in terminal ileum Which surgeries cause B12 deficiency??

6. More Vitamins Water soluble: vit C, folate, thiamine, biotin Fat soluble: A, D, E & K Duodenum major site of absorption of iron and calcium T.I. major site of folate absorption

7. Bile Reabsorption 95% reabsorbed Majority in terminal ileum Conjugated bile only reabsorbed in the terminal ileum Gallstones can form after resection of T.I. due to malabsorption of bile

8. Gut Hormones Somatostatin: inhibits secretions, motility and splanchnic perfusion – Carcinoid syndrome, post-gastrectomy dumping syndrome, EC fistulas, variceal hemorrhage Secretin: stimulates pancreatic/intestinal secretion – Secretin stim test CCK: stimulates pancreas/GB emptying; inhibits Oddi contraction – Evaluate GB EF%

9. Small Bowel Anatomy Arterial supply Layers of small bowel wall

12. Small Bowel Obstruction Most common causes without previous surgery and with previous surgery??

13. SBO continued Other causes: – neoplasms, Crohn’s, volvulus, intussusception, RTX/ischemia, foreign body, gallstone ileus, diverticulitis, Meckel’s Laparotomy: 5% lifetime incidence of SBO; 20- 30% chance recurrence Presentation: nausea/vomiting, failure to pass gas/stool, crampy abdominal pain Diagnosis: obstruction vs. ileus, partial or complete, etiology, strangulation

16. Treatment NGT, IVF, foley, electrolye correction Indications for surgery? Serial abdominal exams

18. Inflammatory Bowel Disease

19. Crohn’s Disease Median age at dx: 30 Affects entire alimentary tract First degree relatives have 15x risk Smoking increases risk of relapse and need for surgery

20. Ulcerative Colitis Peak age of onset 30’s and 70’s 10-30% prevalence among family members Disease of mucosa/submucosa: atrophy, friable mucosa, crypt abscesses, pseudopolyps Continuous involvement, 90% rectal involvement; may have backwash ileitis Spares anus

21. Crohn’s Pathology Transmural inflammation, skipped areas Aphthous or linear ulcers, granulomas, fibrosis/strictures, abscess, fistulas, perforation Creeping fat

23. Presentation Abdominal pain, weight loss, diarrhea, fever, perianal abscesses, peritonitis Extraintestinal manifestations (25%): – Erythema nodosum; pyoderma gangrenosum – Arthritis; ankylosing spondylitis; sacroiliitis – conjuctivitis; uveitis – PSC; steatosis, cholelithiasis – Nephrolithiasis – Thromboembolism; vasculitis; osteoporosis; pancreatitis; endocarditis

24. Diagnosis Differentiate Crohn’s from UC, IBS, infectious and ischemic etiologies Radiography, endoscopy, pathology

25. Treatment Palliation rather than cure in Crohn’s Medical therapy, surgical therapy, nutritional support Medical: abx, steroids, aminosalicylates, immunomodulators Surgery: can be curative for UC patients

26. Outcome for Crohn’s Surgery for Crohn’s: 70-80% require once unresponsive to aggressive medical tx or develop complications (obstruction, hemorrhage, cancer, perforation, growth retardation) Postop complications 15-30%: wound infections, abscesses, leaks 85% endoscopic recurrence by 3 years Clinical recurrence: 60% by 5 years, 94% by 15 years 30% need reoperation within 5 years

27. Outcome for UC Risk of colon cancer 1-2% per year starting 10 years after dx

28. Crohn’s vs. UC CharacteristicCrohn’s DiseaseUlcerative Colitis Transmural inflammationYesUncommon LocationEntire alimentary tractColon (backwash ileitis) DistributionSkip lesionsContiguous Rectal involvement50%90% Gross Bleeding70-75%Universal Perianal disease75%Rare FistulizationYesNo Granulomas50-75%No