This document provides an overview of intestinal obstruction, including its anatomy, causes, types, pathophysiology, clinical features, investigations, radiological features, and management. The key points are: - Intestinal obstruction occurs when there is a restriction to the normal passage of intestinal contents, which can be paralytic or mechanical. - Mechanical obstructions are further classified by site (small vs large bowel) and nature (simple vs strangulating). - Clinical features include colicky abdominal pain, distension, constipation, and vomiting. Specific investigations include abdominal X-rays and CT scanning. - Management depends on the cause but generally involves resuscitation, surgery for acute/strangulating

1. Intestinal Obstruction
Col G Sandala
Bsc Cli Med. BA (AE). Cert Mil
CHRESO UNIVERSITY

2. Objectives
• Introduction
• Anatomy of intestines
• Causes
• Types of Intestinal Obstructions
• Pathophysiology
• Clinical Features

3. • Specific Investigations
• Radiological Features
• Management
• Summary
• References

4. Anatomy of Intestines

6. General structure of GIT
• GIT- tube with varying
diameter of the lumen
• Wall made up of 4 main layers:
• Mucosa
• Submucosa
• Muscularis externa
• Serosa

7. The Small Intestines
• Its the longest part of the GIT
• Extends from the pyloric orifice of the stomach to the ileocecal fold.
• Its approximately 6-7 m long with a narrowing diameter from beginning
to end.
• It consists of the duodenum, the jejunum, and the ileum.

8. Duodenum
• Its the first part of the small intestine.
• It is C-shaped and is adjacent to the head of the pancreas.
• Its 20-25 cm long and is above the level of the umbilicus
• its lumen is the widest of the small intestine.
• It is retroperitoneal except for its beginning

10. • Arterial blood supply is by branches of gastroduodenal branch of the
celiac trunk and branches of the Superior Mesenteric Artery .

11. Jejunum
• The jejunum and ileum make up the last two sections of the small
intestine.
• The jejunum represents the proximal two-fifths.
• It is mostly in the left upper quadrant of the abdomen
• It is larger in diameter and has a thicker wall than the ileum.
• The arterial supply to the jejunum includes jejunal arteries from the
superior mesenteric artery.

12. Ileum
• Makes up the distal three-fifths of the small intestine
• is mostly in the right lower quadrant.

14. Large Intestines
• Extends from the distal end of the ileum to the anus.
• approximately 1.5 m in adults.
• It absorbs fluids and salts from the gut contents, thus forming feces.
• consists of the cecum, appendix, colon, rectum, and anal canal

19. Rectum and anal canal
• Extending from the sigmoid colon is the rectum. The rectosigmoid
junction is usually described as being at the level of vertebra SIII or at the
end of the sigmoid mesocolon because the rectum is a retroperitoneal
structure.
• The anal canal is the continuation of the large intestine inferior to the
rectum

21. Introduction
• Intestinal obstruction happens when there is restriction
to the normal passage of intestinal contents
• It may be divided into two main groups/classifications
as
 Paralytic (adynamic)
 Mechanical (dynamic)

22. Mechanical Obstruction
Some are classified according to the following:
• Site: High (small bowel obstruction) or
Low (Large bowel obstruction)
• Nature: Simple (when bowel is occluded without damage to its
blood supply) OR
Strangulation (when the blood supply of the involved
segment of intestine is cut off e.g. Strangulated hernia,
Volvulus, Intussusception or Adhesive band. Gangrene may
ensue if untreated).

23. Aetiology - 3
• Causes in the lumen –
Fecal impaction, food bolus, parasites, intussusception,
pedunculated tumour
• Causes in the wall –
Congenital atresia, tumours, Crohn’s disease
• Causes outside the wall –
Strangulated hernia, volvulus, adhesions.

25. Strangulated Hernia

31. • Fluid in the intestines is made up of two
sources:
 What the patient ingests or drinks; and
 Digestive secretion (saliva, gastric juice, bile, and
pancreatic secretion).

32. Pathophysiology
• Bowel distal to the obstruction rapidly empties and
becomes collapsed
• Above the obstruction becomes dilated with gas
(swallowed air) and fluid poured from gastric, biliary
and pancreatic secretions
• Increased peristalsis to overcome obstruction causing
intestinal colic

33. Pathology of obstruction
• As bowel distends blood supply becomes impaired
with mucosal ulceration, perforation.
• Perforation may occur due to pressure by a band
causing ischaemic necrosis or pressure from within the
gut

34. • In strangulating obstruction the integrity of the mucosal
barrier is lost due to ischaemia
• Bacteria and toxins can no longer be contained within
the lumen
• Transudation of bacteria into peritoneal cavity takes
place with secondary peritonitis

35. Effects of obstruction
• Fluid and electrolyte depletion (shock) due to copious
vomiting and loss into the bowel lumen
• Protein loss into the gut
• Toxaemia due to migration of toxin and bacteria into
the blood system.
• Septicaemia (shock).

36. Clinical Features
Four cardinal symptoms of intestinal obstruction
• Colicky abdominal pain
• Distension
• Absolute constipation
• Vomiting
NB: Not all may be present

37. Clinical Features
Pain
• Usually the first symptom
• Small bowel obstruction - peri-umbilical
• Distal obstruction – suprapubic

38. Clinical features
Distension
• Marked in large bowel obstruction, Sigmoid volvulus
• Not so marked in small bowel obstruction

39. Clinical features
Absolute constipation
• Failure to pass either flatus or faeces
• Its an early feature of large bowel obstruction but late
feature of small bowel obstruction
• Patient may pass one or two motions early after onset of
obstruction
• Partial or chronic obstruction may have passage of small
amounts of flatus

40. Clinical Features
Vomiting
• Early in high obstruction
• Late or absent in chronic or low obstruction
• Late stages - faeculent because of decomposing of
stagnant contents and altered blood transudating into the
lumen

41. P/Examination
• Dehydration
• In pain, may be rolling about with colic
• Tachycardia
• Afebrile, if fever may suggest strangulation
• Abdominal distention
• May have visible peristalsis

42. • Rectal examination (DRE, ?PR) – should always be
done. It may reveal a mass in the Pouch of Douglas, the
apex of an intussusception or faecal impaction
• Bowel sounds are increased in early stages of
obstruction but later on decrease and even stops

43. Investigations
• Abdominal X-Rays (Erect and supine).
• Computerised tomography (CT Scan)
• Water soluble contrast studies

47. Radiological features
Paralytic ileus
- Gas in both large and small
bowel
- No “cut-off” sign

48. Treatment – General Principles
• Specific treatment is according to the cause
Chronic large bowel obstruction, slowly progressing
obstruction can be investigated at some leisure with
sigmoidoscopy, colonoscopy and barium enema and
treated electively
Acute obstruction, of sudden onset, complete and
with risk of strangulation is an urgent problem
requiring emergency surgical intervention

49. Preoperative Preps in Acute Obstruction
• Gastric aspiration by nasogastric suction
• Intravenous fluid replacement
• Antibiotic therapy
• Catheterise

50. Treatment
• Resuscitation- (ABC…)
• Fluids, Blood
• Monitor urine output
• Prepare for laparotomy
• Type of option for definitive treatment depends on the
findings
Conservative
Operative

51. Conservative
Conservative treatment is by means of iv fluids and NG
aspiration. This is indicated
• Post operative paralytic ileus
• Repeated episodes of obstruction due to massive intra-
abdominal adhesions
• Chronic large bowel obstruction, remove faeces by enema,
prepare bowel and do elective operation

52. Volvulus

53. Volvulus
• Obstruction caused by twisting of the
intestines more than 180 degrees about
the axis of the mesentery
• 1-5% of large bowel obstructions
Sigmoid ~ 65%
Cecum ~25%
Transverse colon ~4%
Splenic Flexure

54. Sigmoid Volvulus
• Worldwide - up to 50% of obstruction
• More commonly seen in elderly patients in western
societies
• Redundant colon, mesocolon narrowed, twisting at
mesentery
• Risk factors
• Chronic constipation

55. Presentation
•Abdominal pain
•Distension
•No flatus or bowel movements
•Tympanitic abdomen
•Mild tenderness
•Palpable mass

56. Barium Enema
• Contraindicated in
patients with free air
on AXR, clinical signs
of peritonitis, or
suspicion for necrosed
bowel
• Bird’s beak
• Can decompress

57. Treatment
• Endoscopic decompression:
• Rigid or flexible proctosigmoidoscope
inserted into rectum
Gush of air/feces --> successful
• Rectal tube
Successful in 85-90% of cases
• Recurrence rate >60%
• Decreased risk for bowel necrosis if
treated early
• Elective resection

58. Operative
• Elective resection
• Emergent laparotomy
Operation depends on
viability of the bowel
Resection and anastomosis

59. Cecal Volvulus
• Less common than sigmoid volvulus
• Parietal peritoneum fails to connect with the cecum and
right colon
• Increased mobility of bowel, resulting in it folding on its axis
or upward
• Torsion occurs proximal to cecum

60. • Abdominal pain, colicky
• Distention
• Twist 180-360 degrees on
longitudinal axis of
ascending colon
• Associated with bowel
compromise, ischemia, and
perforation

61. X-rays
•“comma” shaped
•Convexity toward right
and downward

62. Treatment
•Decompression with
colonoscope
•Less successful than
with sigmoid volvulus
•Emergent operation if
signs of vascular
compromise

63. END