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Small Bowel, Obstruction and Inflammatory Bowel Disease. Albert Einstein College of Medicine Medical Student Lecture Series Jessica Schnur , MD. Physiology. Nutrient and water absorption Absorbs ~ 80% of the 9L of fluid that passes through daily, leaving approx 1.5 L for the colon
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Small Bowel, Obstruction and Inflammatory Bowel Disease Albert Einstein College of Medicine Medical Student Lecture Series Jessica Schnur, MD
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 enterokinasetrypsinogentrypsin all other pepsinogens) • Glutamine is major source of energy for enterocytes
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
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??
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
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
Gut Hormones • Somatostatin: inhibits secretions, motility and splanchnic perfusion • Carcinoid syndrome, post-gastrectomy dumping syndrome, EC fistulas, variceal hemorrhage • Secretin: stimulates pancreatic/intestinal secretion • Secretinstim test • CCK: stimulates pancreas/GB emptying; inhibits Oddi contraction • Evaluate GB EF%
Small Bowel Anatomy • Arterial supply • Layers of small bowel wall
Small Bowel Obstruction • Most common causes without previous surgery and with previous surgery??
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
Treatment • NGT, IVF, foley, electrolye correction • Indications for surgery? • Serial abdominal exams
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
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
Crohn’s Pathology • Transmural inflammation, skipped areas • Aphthous or linear ulcers, granulomas, fibrosis/strictures, abscess, fistulas, perforation • Creeping fat
Presentation • Abdominal pain, weight loss, diarrhea, fever, perianal abscesses, peritonitis • Extraintestinal manifestations (25%): • Erythemanodosum; pyodermagangrenosum • Arthritis; ankylosingspondylitis; sacroiliitis • conjuctivitis; uveitis • PSC; steatosis, cholelithiasis • Nephrolithiasis • Thromboembolism; vasculitis; osteoporosis; pancreatitis; endocarditis
Diagnosis • Differentiate Crohn’s from UC, IBS, infectious and ischemic etiologies • Radiography, endoscopy, pathology
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
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
Outcome for UC • Risk of colon cancer 1-2% per year starting 10 years after dx