1. Intestinal Obstruction
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
-Prerenal azotemia(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
Pneumatosis intestinalis (air in the bowel wall)
Portal venous gas
Mesenteric haziness
Poor uptake of IV contrast into 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
nasoenteric catheter
- 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 ?

51. Management
NGT (Decreased Nausea, Distention, Risk of vomiting and Aspiration)
Urinary Catheter(urine output:0.5-1ml/kg/h)
+ Broad – Spectrum antibiotics

52. Surgical Therapy Complete small bowel obstruction Colon Obstruction
-R/O: Pseudo obstruction

53. Conservative Therapy Partial small bowel obstruction (48 h)
Early postoperative (3-5 days after abdominal surgery) obstruction (2-3 weeks) + TPN
Crohn’s disease obstruction
Carcinomatosis

54. Ileus Temporary impaired intestinal motility
Absence of a lesion-causing mechanical obstruction
Reversed with time as the inciting factor is corrected

55. Causes of ileus Post laparotomy Metabolic&electrolyte derangements
Hospitalized patients
Uremia,Diabetic coma
Drugs:opiates,psychotropic agents,anticholinergic agents
Retroperitoneal hemorrhage or inflammation
Intraabdominal sepsis,systemic sepsis
Intestinal ischemia

56. Post op Ileus Surgical-induced sympathetic reflexes
Inflammatory response mediator release
Anesthetic/Analgesic effect

57. Return of normal motility
Small bowel motility 24h
Gastric motility h
Colonic motility days
Listening of bowel sounds is not a reliable indicator that ileus has fully resolved
Passing flatus or bowel movement is more useful

58. Clinical Presentation
Nausea, Vomiting
Lack of faltus or bowel movements
Abdominal distention
Diminished or absent bowel sounds

59. Diagnosis Ileus occurs in the absence of abdominal surgery
Ileus persist beyond 3-5 days postoperatively

60. Imaging
Abdominal radiographs: distinction between ileus & mechanical obstruction is difficult
Small bowel loops distention + air in the colon & rectum :possibility of adynamic ileus

61. CT: test of choice
- Exclude complete
mechanical obstruction
- presence of intra-abdominal
abscess or peritoneal sepsis

62. Management Fluid resuscitation NGT Drugs/Opiates
Hypokalemia/Hypocalcemia
Hypomagnesemia/Hypermagnesemia