Small Intestine, C44 P286-293 Flashcards
1
Q
SMALL BOWEL ANATOMY What comprises the small bowel? P286
A
Duodenum, jejunum, and ileum
2
Q
SMALL BOWEL
ANATOMY
How long is the duodenum?
P286
A
≈12 inches—thus the name: duodenum!
3
Q
SMALL BOWEL ANATOMY What marks the end of the duodenum and the start of the jejunum? P286
A
Ligament of Treitz
4
Q
SMALL BOWEL ANATOMY What is the length of the entire small bowel? P286
A
≈6 meters (20 feet)
5
Q
SMALL BOWEL ANATOMY What provides blood supply to the small bowel? P286
A
Branches of the superior mesenteric
artery
6
Q
SMALL BOWEL
ANATOMY
What does the small bowel do?
P286
A
Major site of digestion and absorption
7
Q
SMALL BOWEL ANATOMY What are the plicae circulares? P286
A
Plicae means “folds,” circulares means
“circular”; thus, circular folds of mucosa
(a.k.a. valvulae conniventes) in small bowel
lumen
8
Q
SMALL BOWEL ANATOMY What are the major structural differences between the jejunum and the ileum? P287
A
Jejunum—long vasa rectae, large plicae
circulares, thicker wall
Ileum—shorter vasa rectae, smaller
plicae circulares, thinner wall
(Think: Ileum = Inferior vasa rectae,
Inferior plicae circulares, and
Inferior wall thickness in comparison
to the jejunum)
9
Q
SMALL BOWEL ANATOMY What does the terminal ileum absorb? P287
A
B12, fatty acids, bile salts
10
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What is small bowel obstruction (SBO)? P287
A
Mechanical obstruction to the passage of
intraluminal contents
11
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What are the signs/ symptoms? P287
A
Abdominal discomfort, cramping,
nausea, abdominal distention, emesis,
high-pitched bowel sounds
12
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What lab tests are performed with SBO? P287
A
Electrolytes, CBC, type and screen,
urinalysis
13
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What are classic electrolyte/ acid-base findings with proximal obstruction? P287
A
Hypovolemic, hypochloremic,
hypokalemia, alkalosis
14
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What must be ruled out on physical exam in patients with SBO? P287
A
Incarcerated hernia (also look for surgical scars)
15
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What major AXR findings are associated with SBO? P287 (picture)
A
Distended loops of small bowel air-fluid
levels on upright film
16
Q
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
Define complete SBO.
P288
A
Complete obstruction of the lumen;
usually paucity or no colon gas
17
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What is the danger of complete SBO? P288
A
Closed loop strangulation of the bowel
leading to bowel necrosis
18
Q
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
Define partial SBO.
P288
A
Incomplete SBO; some colon gas
19
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What is initial management of all patients with SBO? P288
A
NPO, NGT, IVF, Foley
20
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What tests can differentiate partial from complete bowel obstruction? P288
A
CT with oral contrast, small bowel
follow-through
21
Q
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What are the ABCs of SBO?
P288
A
Causes of SBO:
- Adhesions
- Bulge (hernias)
- Cancer and tumors
22
Q
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What are other causes of SBO?
P288
A
The acronym “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
23
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What is superior mesenteric artery (SMA) syndrome? P288
A
Seen with weight loss—SMA compresses
duodenum, causing obstruction
24
Q
SMALL BOWEL SMALL BOWEL OBSTRUCTION What is the treatment of complete SBO? P288
A
Laparotomy and lysis of adhesions
25
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is LOA?
P288
Lysis Of Adhesions
26
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is the treatment of
incomplete SBO?
P289
```
Initially, conservative treatment with close
| observation plus NGT decompression
27
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
Intraoperatively, how can
the level of obstruction be
determined in patients with
SBO?
P289
```
Transition from dilated bowel proximal to
the decompressed bowel distal to the
obstruction
28
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is the most common
indication for abdominal
surgery in patients with
Crohn’s disease?
P289
```
SBO
29
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
Can a patient have complete
SBO and bowel movements
and flatus?
P289
```
Yes; the bowel distal to the obstruction
| can clear out gas and stool
30
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
After a small bowel resection,
why should the mesenteric
defect always be closed?
P289
```
To prevent an internal hernia
31
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What may cause SBO if
patient is on coumadin?
P289
```
Bowel wall hematoma
32
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is the #1 cause of SBO
in adults (industrialized
nations)?
P289
```
Postoperative adhesions
33
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is the #1 cause of SBO
around the world?
P289
```
Hernias
34
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is the #1 cause of SBO
in children?
P289
```
Hernias
35
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What are the signs of
strangulated bowel with
SBO?
P289
```
```
Fever, severe/continuous pain,
hematemesis, shock, gas in the bowel
wall or portal vein, abdominal free air,
peritoneal signs, acidosis (increased
lactic acid)
```
36
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What are the clinical
parameters that will lower
the threshold to operate on
a partial SBO?
P289
```
Increasing WBC
Fever
Tachycardia/tachypnea
Abdominal pain
37
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is an absolute
indication for operation
with partial SBO?
P290
```
Peritoneal signs, free air on AXR
38
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What classic saying is
associated with complete
SBO?
P290
```
“Never let the sun set or rise on complete
| SBO”
39
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What condition commonly
mimics SBO?
P290
```
```
Paralytic ileus (AXR reveals gas distention
throughout, including the colon)
```
40
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What is the differential
diagnosis of paralytic
(nonobstructive) ileus?
P290
```
```
Postoperative ileus after abdominal
surgery (normally resolves in 3–5 days)
Electrolyte abnormalities (hypokalemia is
most common)
Medications (anticholinergic, narcotics)
Inflammatory intra-abdominal process
Sepsis/shock
Spine injury/spinal cord injury
Retroperitoneal hemorrhage
```
41
```
SMALL BOWEL
SMALL BOWEL OBSTRUCTION
What tumor classically
causes SBO due to
“mesenteric fibrosis”?
P290
```
Carcinoid tumor
42
```
SMALL BOWEL
SMALL BOWEL TUMORS
What is the differential diagnosis
of benign tumors of
the small intestine?
P290
```
Leiomyoma, lipoma, lymphangioma,
| fibroma, adenomas, hemangiomas
43
```
SMALL BOWEL
SMALL BOWEL TUMORS
What are the signs and
symptoms of small bowel
tumors?
P290
```
Abdominal pain, weight loss, obstruction
| (SBO), and perforation
44
```
SMALL BOWEL
SMALL BOWEL TUMORS
What is the most common
benign small bowel tumor?
P290
```
Leiomyoma
45
```
SMALL BOWEL
SMALL BOWEL TUMORS
What is the most common
malignant small bowel tumor?
P290
```
Adenocarcinoma
46
```
SMALL BOWEL
SMALL BOWEL TUMORS
What is the differential
diagnosis of malignant
tumors of the small
intestine?
P290
```
1. Adenocarcinoma (50%)
2. Carcinoid (25%)
3. Lymphoma (20%)
4. Sarcomas (<5%)
47
```
SMALL BOWEL
SMALL BOWEL TUMORS
What is the workup of a
small bowel tumor?
P291
```
UGI with small bowel follow-through,
| enteroclysis, CT scan, enteroscopy
48
```
SMALL BOWEL
SMALL BOWEL TUMORS
What is the treatment for
malignant small bowel
tumor?
P291
```
Resection and removal of mesenteric
| draining lymph nodes
49
```
SMALL BOWEL
SMALL BOWEL TUMORS
What malignancy is
classically associated with
metastasis to small bowel?
P291
```
Melanoma
50
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is it?
P291 (picture)
Remnant of the omphalomesenteric duct/
vitelline duct, which connects the yolk sac
with the primitive midgut in the embryo
51
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is its claim to fame?
P291
Most common small bowel congenital
| abnormality
52
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the usual location?
P291
Within ≈2 feet of the ileocecal valve on
| the antimesenteric border of the bowel
53
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the major
differential diagnosis?
P291
```
Appendicitis
54
SMALL BOWEL
MECKEL’S DIVERTICULUM
P291
Is it a true diverticulum?
55
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the incidence?
P291
≈2% of the population at autopsy
56
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the gender ratio?
P292
Twice as common in men
57
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the average age at
onset of symptoms?
P292
```
Most frequently in the first 2 years of
| life, but can occur at any age
58
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What are the possible
complications?
P292
```
```
Intestinal hemorrhage (painless)—
50%; accounts for half of all lower
GI bleeding in patients younger than
2 years
Bleeding results from ectopic gastric
mucosa secreting acid → ulcer →
bleeding
Intestinal obstruction—25%; most
common complication in adults;
includes volvulus and intussusception
Inflammation ( ± perforations)—20%
```
59
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What are the signs/
symptoms?
P292
```
Lower GI bleeding, abdominal pain, SBO
60
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the most common
complication of Meckel’s
diverticulum in adults?
P292
```
Intestinal obstruction
61
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
In what percentage of cases
is heterotopic tissue found
in the diverticulum?
P292
```
>50%
62
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What heterotopic tissue type
is most often found?
P292
```
Gastric mucosa (60%), but duodenal,
pancreatic, and colonic mucosa are also
found
63
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the “rule of 2s”?
P292
```
2% of patients are symptomatic
Found ≈2 feet from the ileocecal valve
Found in 2% of the population
Most symptoms occur before age 2 years
Ectopic tissue found in 1 of 2 patients
Most diverticula are ≈2 inches long
2 to 1 male:female ratio
```
64
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the role of
incidental Meckel’s
diverticulectomy (surgical
removal upon finding
asymptomatic diverticulum)?
P292
```
Most experts would remove in children
| very controversial in adults
65
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is a Meckel’s scan?
P293
Scan for ectopic gastric mucosa in
Meckel’s diverticulum; uses technetium
pertechnetate IV, which is preferentially
taken up by gastric mucosa
66
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the treatment of a
Meckel’s diverticulum that
is causing bleeding and
obstruction?
P293
```
Surgical resection, with small bowel
resection as the actual ulcer is usually
on the mesenteric wall opposite the
diverticulum!
67
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the name of the
hernia associated with
incarcerated Meckel’s
diverticulum?
P293
```
Littre’s hernia (Think alphabetically:
| Littre’s, then Meckel’s)
68
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
In patients with guaiacpositive
stools and a negative upper- and lower-
GI workup, what must be ruled out?
P293
```
Small bowel tumor; evaluate with
| enteroclysis (small bowel contrast study)
69
```
SMALL BOWEL
MECKEL’S DIVERTICULUM
What is the most common
cause of small bowel
bleeding?
P293
```
Small bowel angiodysplasia
