Surgical Recall - Ch. 44 Small Intestine

Question 1

1. What comprises the small bowel?
2. How long is the duodenum?
3. What marks the end of the duodenum and the start of the jejunum?
4. What is the length of the entire small bowel?
5. What provides blood supply to the small bowel?
6. What does the small bowel do?
7. What are the plicae circulares?
8. What are the major structural differences between the jejunum and the ileum?
9. What does the terminal ileum absorb?

Answer 1

1. What comprises the small bowel? D, J, I
2. How long is the duodenum? 12 inches
3. What marks the end of the duodenum and the start of the jejunum? Ligament of Treitz
4. What is the length of the entire small bowel? 6 m (20 ft)
5. What provides blood supply to the small bowel? Branches of SMA
6. What does the small bowel do? Digestion and absorption
7. What are the plicae circulares? Circular folds of mucosa in small bowel lumen
8. What are the major structural differences between the jejunum and the ileum? Jejunum: long vasa rectae, large plicae circulares, thicker wall / Ileum: shorter vasa recta, smaller plicae circulares, thinner wall
9. What does the terminal ileum absorb? B12, fatty acids, bile salts

Question 2

SBO

1. What lab tests are performed with SBO?
2. What are classic electrolyte/acid-base findings with proximal obstruction?
3. What must be r/o on exam in patients with SBO?
4. What major AXR findings are associated with SBO?
5. What is the danger of complete SBO?
6. What is the initial mgmt of all pts with SBO?

Answer 2

1. What lab tests are performed with SBO? Electrolytes, CBC, type and screen, urinalysis
2. What are classic electrolyte/acid-base findings with proximal obstruction? Hypovolemic, hypochloremic, hypokalemia, alkalosis
3. What must be r/o on exam in patients with SBO?Incarcerated hernia (also look for surgical scars)
4. What major AXR findings are associated with SBO? Distended loops of small bowel air-fluid levels on upright film
5. Closed loop strangulation of the bowel leading to bowel necrosis
6. NPO, NGT, IVF, Foley

Question 3

SBO

1. What are the ABCs of SBO?
2. What are other causes of SBO?
3. What is SMA syndrome?
4. What is the tx of complete SBO?
5. What is LOA?
6. What is the tx of incomplete SBO?

Answer 3

SBO

1. What are the ABCs of SBO?
   
   1. Adhesions
   2. Bulge (hernias)
   3. Cancer and tumors
2. What are other causes of SBO? GIVES BAD CRAMPS
   
   1. Gallstone ileus
   2. Intussusception
   3. Volvulus
   4. External compression
   5. SMA syndrome
   6. Bezoars, Bowel wall hematoma
   7. Abscesses
   8. Diverticulitis
   9. Crohn’s disease
   10. Radiation enteritis
   11. Annular pancreas
   12. Meckel’s diverticulum
   13. Peritoneal adhesions
   14. Stricture
3. What is SMA syndrome? Seen with weight loss–SMA compresses duodenum, causing obstruction
4. What is the tx of complete SBO? Lapartomy and lysis of adhesions
5. What is LOA? Lysis of Adhesions
6. What is the tx of incomplete SBO? Initially, conservative tx with close observation + NGT decompression

Question 4

SBO

1. What is the most common indication for abdominal surgery in pts with Crohn’s disease?
2. Can a pt have complete SBO and bowel movements and flatus?
3. After a small bowel resection, why should the mesenteric defect always be closed?
4. What may cause SBO if pt is on coumadin?
5. What is the #1 cause of SBO in adults?
6. What is the #1 cause of SBO around the world?
7. What is the #1 cause of SBO in children?

Answer 4

SBO

1. What is the most common indication for abdominal surgery in pts with Crohn’s disease? SBO
2. Can a pt have complete SBO and bowel movements and flatus? Yes; the bowel distal to the obstruction can clear out gas and stool
3. After a small bowel resection, why should the mesenteric defect always be closed? To prevent an internal hernia
4. What may cause SBO if pt is on coumadin? Bowel wall hematoma
5. What is the #1 cause of SBO in adults? Post-op adhesions
6. What is the #1 cause of SBO around the world? Hernias
7. What is the #1 cause of SBO in children? Hernias

Question 5

SBO

1. What are the signs of strangulated bowel with SBO?
2. What are the clinical parameters that will lower the threshold to operate on a partial SBO?
3. What is an absolute indication for operation with partial SBO?
4. What classic saying is associated with complete SBO?
5. What condition commonly mimics SBO?
6. What is the differential diagnosis of paralytic (nonobstructive) ileus?
7. What tumor classically causes SBO due to “mesenteric fibrosis”?

Answer 5

1. Fever, shock, peritoneal signs, acidosis (increased lactic acid)
2. Increasing WBC, fever, tachycardia, abdominal pain
3. Peritoneal signs, free air on AXR
4. “Never let the sun set or rise on complete SBO”
5. Paralytic ileus (AXR reveals gas distension throughout, including the colon)
6. Differential:
   
   1. Post-op ileus after abdominal surgery (normally resolves in 3-5 days)
   2. Electrolyte abnormalities (hypokalemia = most common)
   3. Meds (anticholinergic, narcotics)
   4. Inflammatory intra-abdominal process
   5. Sepsis/shock
   6. Spine injury/spinal cord injury
   7. Retroperitoneal hemorrhage
7. Carcinoid tumor

Question 6

Meckel’s Diverticulum

1. What is it?
2. What is its claim to fame?
3. What is the usual location?
4. What is the major differential dx?
5. Is it a true diverticulum?
6. What are the possible complications?
7. What heterotopic tissue type is most often found?
8. What is the “rule of 2s”?

Answer 6

1. Remnant of omphalomesenteric duct/vitelline duct, which connects the yolk sac with the primitve midgut in the embryo
2. Most common small bowel congenital abnormality
3. Within ~2 ft of ileocecal valve on antimesenteric border of the bowel
4. Appendicitis
5. Yes; all layers of the intestine are fonud in the wall
6. Intestinal hemorrhage (painless)–50%; accounts for half of all lower GI bleeding in pts younger than 2 years –> bleeding results from ectopic gastric mucosa secreting acid –> ulcer –> bleeding
7. Gastric mucosa (60%), but duodenal, pancreatic, and colonic mucosa are also found
8. 2% of pts = symptomatic; found 2 ft from ileocecal valve, 2% of population, most sx occur before age 2, ectopic tissue, most diverticular are 2 inches long, 2 to 1 M:F ratio

Question 7

Meckel’s Diverticulum

1. What is the treatment of a Meckel’s diverticulum that is causing bleeding and obstruction?
2. What is the name of the hernia associated with incarcerated Meckel’s diverticulum?
3. What is the most common cause of small bowel bleeding?

Answer 7

1. Surgical resection, with small bowel resection as the actual ulcer is usually on the mesenteric wall opposite the diverticulum
2. Litter’s hernia
3. Small bowel angiodysplasia