MCQ - Intestinal obstruction- Mesenteric ischemia, malrotation

  1. Classical picture of chronic mesenteric ischemia?
    • Postprandial abdominal pain (intestinal angina or intestinal claudication) leading to an aversion to food and weight lossQ.
    • Pain is characteristically diffuse, midabdominal, midepigastric, and crampy in nature.
    • Pain develops within 15–45 minutes after eating (severity related to the size of the meal ingested
  2. Definitive therapy for chronic mesenteric ischemia?
    Transaortic endarterectomy or bypass grafting
  3. Does occlusion of IMA cause irreversible ischemia?
    Occlusion of IMA does not always result in irreversible ischemia of the descending and sigmoid colon, because the marginal artery of colon usually receives an adequate supply from the left branch of the middle colic arteryQ
  4. Pathophysiology of Non occlusive mesenteric ischemia (NOMI)?
    Splanchnic vasoconstriction is the underlying pathophysiologic process and is precipitated by hypoperfusion from medications, depressed cardiac output, or renal or hepatic disease
  5. Arteriogram features of NOMI?
    Diffuse vasospasm with marked narrowing of the major branches of the SMA, often with the “string of lakes” appearanceQ with reflux of contrast into the aorta
  6. Most common site of lodgement of mesenteric emboli?
    • Most mesenteric emboli lodge in the SMA (branches from the aorta at an oblique angle)Q•
    • SMV is most commonly involved in venous thrombosis.
  7. IOC for Acute mesenteric ischemiam?
  8. IOC for Mesenteric venous thrombosis?
  9. IOC for Chronic mesenteric ischemiam?
  10. Return of normal motility of stomach, small and large bowel?
    • Small intestineQ (within 24 hours) >Gastric (48 hours)Q > Colonic (3-5 days)Q
    • Post-operative ileus is most pronounced in colonQ.
    • Because small bowel motility is returned before colonic and gastric motility, listening for bowel sounds is not a reliable indicator that ileus has fully resolved.
  11. What is catchpole regimen?
    Adrenergic blocking agent in association with cholinergic stimulation, e.g. neostigmineQ, in paralytic ileus
  12. MC cause of Large bowel obstruction?
    • Colorectal cancerQ (CA Rectum > sigmoid)
    • Adhesions (MC cause of small bowel obstruction) are rarely a cause of colonic obstruction
  13. What is Closed-loop obstruction?
    • When both the proximal and distal parts of the bowel are occluded.
    • For example - closed-loop obstruction is seen when a cancer occludes the lumen of the colon in the presence of a competent ileocecal valveQ. Increasing colonic distention- pressure in the cecum - vessels in the bowel wall are occluded, and necrosis and perforationQ can occur.
  14. Treatment of large bowel obstruction?
    • All patients with complete acute large bowel obstruction require prompt surgical interventionQ and should not undergo a trial of non-operative management.
    • Acute large bowel obstruction in patients with competent ileocecal valve is a true surgical emergency because of high chances of perforation (MC site: Cecum)Q.
  15. Diameter of loops in small and large bowel obstruction?
    • Small bowel obstruction - 3–5 cmQ
    • Large bowel obstruction - >5 cmQ
  16. What is Ogilvie’s syndromeQ?
    Acute colonic pseudo-obstruction
  17. MC site of volvulus?
    Sigmoid colon - more commonly anticlockwise (can be both clockwise or anticlockwise
  18. Contrast enema finding in volvulus?
    Demonstrates the point of obstruction with the pathognomic ‘birds beak’ or ‘bird of prey’ or ‘ace of spades’ signQ
  19. Management of sigmoid volvulus?
    • Initial management: ResuscitationQ followed by endoscopic decompression and detorsionQ.
    • Decompression/detorsionQ can be achieved by placement of rectal tube through a proctoscope or the use of a colonoscope
    • In case of failure - laparotomy with resections of the sigmoid colonQ
    • Even if detorsion of the sigmoid volvulus is successful, risk of recurrence is high (50%)Q - Sigmoid colectomy is indicated after the patient has stabilized
  20. What is Cecal volvulus?
    • Cecal volvulus is actually a cecocolic volvulusQ , occurs in clockwise directionQ
    • Axial rotation of the terminal ileum, cecum, and ascending colonQ with concomitant twisting of the associated mesentery.
    • Cause: Lack of fixation of the cecum to the retroperitoneum.Q
  21. What is Cecal bascule?
    A condition in which cecum folds in a cephalad direction anteriorly over a fixed ascending colonQ
  22. Normal location of ligament of treitz?
    Left of the vertebral column and posterior to the stomachQ
  23. Operative Treatment of Malrotation?
    • The standard approach via a right upper quadrant transverse incisionQ.
    • If volvulus is present, it should be reduced by counterclockwise rotationQ as necessary because volvulus usually occurs in a clockwise direction.
    • Ladd’s bands, which represent the posterior peritoneal attachments of the right colon that cross over the duodenum, should be divided on the lateral aspect of the duodenumQ.
    • Widening of the mesenteric base is necessary, and the duodenum is mobilized and straightened by dividing the abnormal ligament of Treitz and Ladd’s bands.
    • Incidental appendectomy should be performed to avoid diagnostic confusion in the future because the cecum will be placed in the left lower quadrantQ
    • Duodenum and proximal jejunum are placed on the right sideQ
    • Terminal ileum and cecum are placed in the left hypochondriumQ
  24. What are Ladd’s bands?
    Retroperitoneal attachments that normally fix the cecum and ascending colon to the posterior abdominal wall
  25. When do herniated intestinal loops return to abdominal cavity in embryo?
    10th week
  26. MC rotational abnormality?
  27. MC type of malrotation?
    Incomplete rotationQ - rotation is arrested at around 180 degreesQ.
  28. What is Spastic ileus or dynamic ileus?
    • It results from extreme and prolonged contraction of the intestine.
    • Spastic ileus is seen in
    • • Heavy metal poisoningQ
    • • PorphyriaQ
    • • UremiaQ
    • • Extensive intestinal ulcerationQ
Card Set
MCQ - Intestinal obstruction- Mesenteric ischemia, malrotation
Intestinal obstruction