6 Intestinal Obstruction.pptx
- 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
- 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.
- 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