GI -- Bowel obstruction
Terms
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- When you come upon a case of bowel obstruction, what are the things YOU must assess for?
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Level of obstruction
Cause of obstruction
Presence of enhancement of all small bowel loops (can always see enhancement in normal small bowel), and in large bowel if possible. - What are the three most common causes of small bowel obstruction in adult?
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1) Adhesions (65%)
2) External hernia (15%)
3) Neoplasm (15%) - What are they in the colon?
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1) Colon CA (65%)
2) Diverticulitis (20%)
3) Volvulus (10%) - What is the point then?
- Colonic obstruction and SBO have totally different etiologies, with SBO being benign causes usually, and colonic obstr malignant usually.
- What is a common cause of bowel obstruction in younger patients (i.e. 20s)?
- Inflammatory pseudotumor (inflammatory myofibroblastic tumor)
- What do you do when encountered with SBO in a "virgin" abdomen?
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Pretty much rules out adhesions. Must search hard for a cause, because there is always a good reason.
Hernia, mass, midgut volvulus with congenital Ladd bands, patient with cystic fibrosis with inspissated feces. - What additional abdominal finding do CF patients get?
- FATTY replacement of pancreas
- What is the cause of small bowel feces sign?
- Stasis of material in the small bowel
- What are the bowel obstruction situations most likely to result in strangulation?
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1) Closed loop obstructons
2) Volvulus
3) High grade obstructions (due to increased perfusion pressure) -- high grade obs happens with CA - What is sufficient to make dx of closed loop obstruction?
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1) Small bowel obstruction
2) U-shaped loop of distended bowel
3) Clouding of the adjacent mesentery
OR
See distended loop of bowel with two limbs in close contiguity and obstruction proximal to this region. - What is a sign of bowel ischemia that predates absence of enhancement?
- Target sign: See mural stratification or just see thickening and prominent enhancement of the mucosal surface.
- When the ischemia progresses to infarction, what occurs?
- The wall goes from thickened and enhancing to non-enhancing and almost paper thin. Next comes pneumatosis.
- Post-op patient with dilated ascending colon and SBO with collapsed descending colon. You want to r/o an obstructing lesion. CT is indeterminate. What do you do?
- Put patient on fluoro table, do single contrast BE just to demonstrate normal transverse colon. If normal, you know patient just has a variant pattern of adynamic ileus.
- When is enteroclysis preferred over CT?
- Chronic recurrent obstruction. Enteroclysis is good for challenging the small bowel to look for areas of poor dilation, which may reflect adhesions that can be removed laparoscopically.