Intestinal Obstruction

1. Dr. Rezvan Mirzaei Intestinal Obstruction

4. Pathophysiology Gas & Fluid Accumulation within the proximal Gas Accumulation • Swallowed Air (most) • Produced within the intestine Fluid Accumulation • Swallowed Liquids • GI secretions

5. Gas & Fluid Accumulation • Bowel distends => intraluminal & intramural pressure rise => microvascular perfusion impaired => intestinal ischemia => necrosis (strangulated bowel obstruction) • Luminal flora change => translocation of bacteria

6. Small intestine necrosis

7. Small Bowel Obstruction • Ethiologies 1- Intraluminal 2- Intramural 3- Extrinsic

8. Extrinsic • Adhisions • Hernias - External (inguinal, femoral) - Internal (following surgery) • Carcinomatosis

9. Intra-abdominal Adhisions • % 75 of the cases of small bowel obstruction

11. Intraluminal • Foreign Bodies • Bezoars • Gallstones • Meconium

12. Bezoar

13. What is cause?

14. Intramural • Tumors • Crohn’s Disease(inflammatory strictures) • Intussusceptions

15. Intussusceptions

16. Clinical Presentation • Intestinal activity increases => colicky abdominal pain & diarrhea • Nausea • Obstipation • Vomiting - More prominent with proximal obstruction - More Feculent: bacterial over growth: more established obstruction

17. History • Prior Abdominal Operations • Presence of Abdominal disorders(ca-IBD) • Search for hernia

18. Signs • Abdominal distention (more in distal obstruction) • Bowel Sounds - Hyperactive initially: peristalsis is increased - Minimal in late stage: as the bowel distends ,reflex inhibition of bowel motility results in a quiet abdomen

19. P/E • Dehydration • Low grade fever • Abdominal scar • Hernia • Bowel sounds • Tenderness • Digital rectal exam(Check stool for blood)

20. Lab test - Hemoconcentration(mildly elevated hematocrit) - Electrolyte abnormalities: Na,K,BUN,Cr,ABG - Mild leukocytosis -Prerenalazotemia(BUN/Cr ratio above 20)

21. Diagnosis • Mechanical/Ileus • Etiology • Partial/Complete • Simple/Strangulated • Colon/Small Bowel

22. Partial Small Bowel Obstruction • A portion of lumen is occluded • Allowing passage of Gas & Fluid • Development of strangulation is less likely Continued passage of flatus and/or stool beyond 6 to 12 hours after onset of symptoms

23. Strangulated Obstruction • Abdominal pain disproportionate to abdominal findings (suggestive of intestinal ischemia) • Tachycardia • Localized abdominal tenderness • Fever • Marked Leukocytosis • Acidosis

24. Radiographic Examination • Abdominal series - Supine abdomen - Upright abdomen - Upright chest • Triad for Small Bowel Obstruction - Dilated small bowel loops( > 3cm in diameter) - Air-Fluid levels (upright) - Lack of air in the colon

25. Small intestinal obstruction: supine

26. Small intestinal obstruction: upright

27. Sensitivity of Abdominal radiographs in small bowel obstruction %70~80 • Specificity is low - Ileus - Colonic Obstruction can mimic findings

29. Possibility of large bowel obstruction • Small bowel loops distention + distended cecum & colon+no rectal air or stool

31. False-Negative Findings on Radiography • Proximal Obstruction • Bowel lumen is filled with Fluid but no gas (Preventing Visualization of air-fluid levels or bowel distention) • Closed loop obstruction

32. Closed Loop Obstruction • Dangerous form • Both proximal & distal obstructed (volvulus) • Accumulated Gas & Fluid can not escape • Rapid rise in luminal pressure • Rapid progression to strangulation

33. Computed Tomographic (CT) Scan • %80~90 sensitivity • %70~90 specificity < %50 Sensitivity: low grade or partial small bowel obstruction

34. CT Scan Transition Zone • Proximal dilatation • Distal decompression • Intraluminal contrast does not pass beyond the transition zone • Colon containing little gas or fluid

35. SB loops filled with fluid & decompressed colon

37. CT Scan • Closed loop obstruction U-Shaped or C-Shaped dilated bowel loop associated with a radial distribution of mesenteric vessels converging toward a torsion point

38. CT Scan Strangulation • Thickening of the bowel wall • Pneumatosisintestinalis (air in the bowel wall) • Portal venous gas • Mesenteric haziness • Poor uptake of IV contrastinto the wall of the affected bowel

40. CT Scan • Global evaluation of the abdomen • May reveal etiology • Water soluble contrast - Therapeutic: Reduce the overall length of hospital stay - Prognostic: appearance of the contrast in the colon within 24 hours is predictive of none surgical resolution of bowel obstruction

41. SBO secondary to an abscesses

42. Small bowel series (small bowel follow through) • Enteroclysis - Contrast Solution via a long nasoentericcatheter - Double contrast technique (mucusal surface & small lesions) - Rarely performed in the acute setting • C.T enteroclysis

44. Jejunojejenal intussusceptions

45. Indications of contrast studies • There is not enough clinical indication for immediate operation but symptoms of obstruction continue

50. Management • Fluid resuscitation - Depletion of intravascular volume - Decreased oral intake - Vomiting - Sequestration of Fluid in bowel lumen & wall - Isotonic Fluid - C.V.P ?