Flashcards in Small Intestine Deck (67):
What comprises the small bowel?
Duodenum, jejunum, and ileum
How long is the duodenum?
What marks the end of the duodenum and the start of the jejunum?
Ligament of Treitz
What is the length of the small bowel?
What provides blood supply to the small bowel?
Branches of the SMA
What are the plicae circulares?
Circular folds of mucosa in small bowel lumen
What are the major structural differences between the jejunum and the ileum?
Jejunum: long vasa recta, large plicae circulares, thicker wall
Ileum: shorter vasa recta, smaller plicae circulares, thinner wall
What does the terminal ileum absorb?
B12, fatty acids, bile salts
What is an SBO?
Small Bowel Obstruction.
Mechanical obstruction to the passage of intraluminal contents.
What are the signs and symptoms of SBO?
Abdominal discomfort, cramping, nausea, abdominal distention, emesis, high-pitched bowel sounds
What lab tests are performed with SBO?
Electrolytes, CBC, T&S, UA
What are the classic electrolyte findings with proximal obstruction?
Hypovolemic, hypochloremic, hypokalemic alkalosis
What must be ruled out on PE in patients with SBO?
What major AXR findings are associated with SBO?
Distended loops of small bowel air-fluid levels on upright film
What is a complete SBO?
Complete obstruction of the lumen usually paucity or no colon gas
What is the danger of complete SBO?
Closed loop strangulation of the bowel leading to bowel necrosis
What is a partial SBO?
Incomplete SBO; some colon gas
What is the initial management of all patients with SBO?
NPO, NGT, IVF, Foley
What tests can differentiate partial from complete SBO?
CT with oral contrast, small bowel follow-through
What are the ABCs of SBO?
2. Bulge (hernias)
3. Cancer and tumors
What are other causes (not ABCs) of SBO?
GIVES BAD CRAMPS:
Gallstone ileus, Intussusception, Volvulus, External compression, SMA syndrome, Bezoars, Bowel wall hematoma, Abscesses, Diverticulitis, Crohn's disease, Radiation enteritis, Annular pancreas, Meckel's diverticulum, Peritoneal adhesions, Stricture
What is SMA syndrome?
SMA compresses duodenum, causing obstruction.
Seen with weight loss.
What is the treatment of complete SBO?
Laparotomy and lysis of adhesions
What is LOA?
Lysis Of Adhesions
What is the treatment of partial SBO?
Initially, conservative treatment with close observation plus NGT decompression
Intra-operatively, how can the level of obstruction be determined in patients with SBO?
Transition from dilated bowel proximal to the decompressed bowel distal to the obstruction
What is the most common indication for abdominal surgery in patients with Crohn's disease?
Can a patient have complete SBO and bowel movements and flatus?
Yes; the bowel distal to the obstruction can clear out gas and stool
After a small bowel resection, why should the mesenteric defect always be closed?
To prevent an internal hernia
What may cause SBO if a patient is on coumadin?
Bowel wall hematoma
What is the most common cause of SBO in adults?
What is the most common cause of SBO around the world?
What is the most common cause of SBO in children?
What are the signs of strangulated bowel with SBO?
Fever, severe/continuous pain, hematemesis, shock, gas in the bowel wall or portal vein, abdominal free air, peritoneal signs, acidosis (lactic acid)
What are the clinical parameters that will lower the threshold to operate on a partial SBO?
Increasing WBC, fever, tachycardia, tachypnea, abdominal pain
What is an absolute indication for operation with partial SBO?
Peritoneal signs, free air on AXR
What classic saying is associated with complete SBO?
"Never let the sun set or rise on complete SBO"
What condition commonly mimics SBO?
Paralytic ileus (AXR reveals gas distention throughout, including the colon)
What is the differential diagnosis of paralytic ileus?
Post-operative ileus after abdominal surgery (usually resolves in 3-5 days); Electrolyte abnormalities (hypokalemia most common); Medications (anticholinergic, narcotics); Inflammatory intra-abdominal process; Sepsis or shock; Spine injury; Retroperitoneal hemorrhage
What tumor classically causes SBO due to mesenteric fibrosis?
What is the differential diagnosis of benign tumors of the small intestine?
Leiomyoma, lipoma, lymphangioma, fibroma, adenoma, hemangioma
What are the signs and symptoms of small bowel tumors?
Abdominal pain, weight loss, SBO, perforation
What is the most common benign small bowel tumor?
What is the most common malignant small bowel tumor?
What is the differential diagnosis of malignant tumors of the small intestine?
Adenocarcinoma, carcinoid, lymphoma, sarcoma
What is the workup of a small bowel tumor?
UGI with small bowel follow-through, enteroclysis, CT, enteroscopy
What is the treatment for malignant small bowel tumor?
Resection and removal of mesenteric draining lymph nodes
What malignancy is classically associated with metastasis to small bowel?
What is Meckel's diverticulum?
Remnant of the vitelline duct, which connects the yolk sac with the primitive midgut in the embryo
What is the most common small bowel congenital abnormality?
What is the usual location of Meckel's diverticulum?
Within 2 feet of the ileocecal valve on the anti-mesenteric border of the bowel
What is the major differential diagnosis for Meckel's diverticulum?
Is Meckel's diverticulum a true diverticulum?
What is the incidence of Meckel's diverticulum?
What is the gender ratio for Meckel's diverticulum?
M:F = 2:1
What is the average age at onset of symptoms of Meckel's diverticulum?
Within the first 2 years of life, but can occur at any age
What are the possible complications of Meckel's diverticulum?
Intestinal hemorrhage (painless); intestinal obstruction; inflammation/perforation
What are the signs and symptoms of Meckel's diverticulum?
Lower GI bleeding, abdominal pain, SBO
What is the most common complication of Meckel's diverticulum in adults?
What heterotopic tissue type is most often found in Meckel's diverticulum?
Gastric mucosa, but duodenal, pancreatic, and colonic are also found
What is the "rule of 2s" for Meckel's diverticulum?
2% of patients are symptomatic
Found 2 feet from the ileocecal valve
Found in 2% of the population
Most symptoms occur by 2 years
Ectopic tissue found in 1 of 2 patients
Most diverticula are 2 inches long
2:1 = M:F
What is the role of incidental Meckel's diverticulectomy?
Most experts would remove in children (controversial in adults)
What is a Meckel's scan?
Scan for ectopic gastric mucosa in Meckel's diverticulum.
Uses technetium pertechnetate IV, which is preferentially taken up by gastric mucosa.
What is the treatment of a Meckel's diverticulum that is causing bleeding and obstruction?
Surgical resection with small bowel resection, as the actual ulcer is usually on the mesenteric wall opposite the diverticulum
What is the name of the hernia associated with incarcerated Meckel's diverticulum?
In patients with guaiac-positive stools and a negative upper and lower GI workup, what must be ruled out?
Small bowel tumor.
Evaluate with enteroclysis.