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  enterokinase  trypsinogen  trypsin  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 – Secretin stim 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; % 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

Inflammatory Bowel Disease

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%): – Erythema nodosum; pyoderma gangrenosum – Arthritis; ankylosing spondylitis; 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

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