Transcript Common Surgical Problems of the Stomach and Small Intestine

Common Surgical Problems
of the Stomach and Small
Intestine
Tara Wofford
Links to Helpful Online
Tutorials
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An Approach to Abdominal Plain Films:
http://www.learningradiology.com/lectures/gilect
ures/plainabdomenflashpage.htm
Abnormal Bowel Gas Patterns:
http://www.learningradiology.com/notes/ginotes/
pictorialbowelgas.htm
Recognizing SBO, LBO, and Paralytic Ileus:
http://www.learningradiology.com/medstudents/r
ecognizingseries/recogobstructflashpage.htm
Objectives
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To become familiar with abdominal
anatomy on a radiograph and CT image.
To be able to identify the radiologic signs
of pathology of the stomach and small
intestine.
To be able to evaluate the presence of
common surgical problems in these
organs.
Anatomy of the Stomach
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The stomach has
four parts (cardia,
fundus, body, and
pylorus) and two
crurvatures.
The gastric mucosa
forms longitudinal
folds called rugae.
The stomach is
bordered anteriorly
by the diaphram, left
lobe of the liver and
ant. abd wall.
Posteriorly it is
bordered by the
omental bursa and
pancreas
Barium X-Rays
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A barium swallow, also
called an upper GI series,
is an examination of the
esophagus and stomach
using barium to coat the
walls of the upper
digestive tract so that it
may be examined under
x-ray.
Barium swallows are used
to identify any
abnormalities such as
tumors, ulcers, hernias,
pouches, strictures, and
swallowing difficulties.
High-Resolution CT scan of
stomach
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Optimal luminal
distension with
barium, water, or gas
is key for evaluating
the gastric wall.
Water-soluble oral
contrast is used
when perforation is
suspected.
Common Surgical Pathology
of the Stomach
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Peptic Ulcers
Tumors - Adenocarcinoma, Lymphoma
Hiatal Hernia
Peptic Ulcers
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Causes: H. Pylori infection,
hyperparathyroidism,
steroid tx, uremia, stress,
burns (curling), cerebral
disease (cushing).
Duodenal ulcers are also
present in 5-42% of cases.
The ratio of DU:GU is 3:1.
Most common location of
benign ulcers is the lesser
curvature area of body and
antrum.
Almost all lesions < 1cm
are benign.
Radiologic Findings
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Ulcer crater: barium collection
on dependent surface
penetrates beyond anticipated
wall.
Hampton’s line: 1mm thin
straight line at neck of ulcer,
represents undermined
mucosa.
Ulcer collar: smooth, thick,
lucent band at neck of ulcer,
represents thicked wall.
Ulcer mound: tissue mass
surrounding ulcer.
Adenocarcinoma of the
Stomach
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24,000 new cases
diagnosed each year.
M:F ratio is 2:1
Risk factors: H. Pylori
infection,
adenomatous polyps,
chronic atrophic
gastritis, pernicious
anemia and partial
gastrectomy.
Radiologic Findings
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Conventional CT is not sensitive
in early phases compared to
HRCT.
Early cases may appear as focal
wall thickening with mucosal
enhancement during the early
arteriovenous contrast phase.
Advanced cases appear as
thickened, abnormally enhancing
gastric wall, in localized or
circumferential pattern,or as a
polypoid mass. Ulceration may
be apparent as well.
Gastric Lymphoma
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The stomach is the most
common site for GI
lymphoma and is more
commonly part of a
generalized disease.
80% of cases are NonHodgkins.
Perforation is a major
complication occuring in
9-47% of patients
Radiologic Findings which
differentiate Lymphoma from
Adenoarcinoma
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Gastric wall thickness
is much greater in
lymphoma, with a
mean of 4cm.
Adenopathy is more
pronounced and
lymph nodes larger.
Mural thickening is
more homogenous.
Hiatal Hernia
Caused by a weakness or
tear in the
phrenoesophageal
membrane.
There are two types:
 Sliding hernia, in which the
gastroesophageal junction
is displaced above the
diaphram (includes 99% of
cases).
 Paraesophageal hernia, in
which there is stomach
herniating into chest but the
GE junction is not effected.
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Radiologic Findings
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Extension of multiple gastric
folds above the diaphram.
Bulbous area of distal
esophagus containing
contrast.
“Schatzki’s Ring” - a filling
defect that marks the position
of esophagogastric junction
and defines the presence of
sliding hernia
Anatomy of Small Intestine
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Includes duodenum,
jejunum, and ileum.
The mucosal wall is
characterized by circular
folds (plicae circulares).
The duodenum has a cshaped course around the
pancreas and is partially
retroperitoneal.
Most of the jejunum lies in
the LUQ and ileum mostly
in RLQ.
Assessing the Abdominal
Radiograph
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Gas pattern: stomachalways a small amount,
small int. will have 2-3 gas
filled loops (< 2.5cm in
diameter), and rectumusually has a small
amount.
Air-fluid levels: stomachalways present, small int.
may have 2-3 levels,
usually never in rectum.
Also look for soft-tissue
masses and calcifications.
Small vs Large Intestine
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Small intestine: located
centrally, has circular folds
that extend across the lumen,
and has a maximum diameter
of 2-2.5 cm.
Large Intestine: located
peripherally and has haustral
markings that do not cross the
lumen
Abdominal Anatomy on CT
Identify Stomach, small and large intestine, liver, spleen, and
descending aorta.
Vascular Supply to the Small
Intestine
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The duodenum is
supplied by both the
celiac trunk (proximal to
bile duct) and the SMA
(distal to the entry of the
bile duct).
The jejunum and ileum
are supplied by the SMA
via 15-18 branches which
form arterial arcades that
give rise to the vasa
recta.
Common Surgical Problems of
the Small Intestine
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Small Bowel Obstruction
Crohn’s Disease
Acute Mesenteric Ischemia
Intussusception
Gall-Stone Ileus
Tumors - Adenocarcinoma, Lymphoma
Pneumoperitoneum
Superior Mesenteric Artery Syndrome
Small Bowel Obstruction
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Pathophysiology: bowel proximal to obstruction
dilates with swallowed air and secretions and
there is hyperparastalsis. Ischemia can occur
from vascular compromise of effected loops.
Most common etiologies: adhesions from prior
surgery, hernia, intussesception, gallstone ileus,
volvulus, and tumors.
Clinical symptoms: abdominal pain, distention,
N/V/D, hyperactive bowel sounds.
Surgery is indicated with s/s of ischemia,
peritonitis, or when refractory to conservative tx.
Radiographic Findings
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Proximal loops dilated >2.5-3cm
Multiple air-fluid levels
Absence or small amount of gas in colon.
Associated CT Findings
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Dilated, fluid filled loops of small bowel proximal to
obstruction and collapse of distal bowel.
Signs of ischemia include thickening of bowel wall,
stranding of adjacent to small bowel mesesentary or
pneumatosis intestinalis.
Crohn’s Disease
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Characterized by non-caseating
granulomas with transmural
inflammation, which can effect
any part of the GI tract.
Clinically patients frequently
have recurrent diarrhea, occult
blood loss, anemia, abd pain,
and low-grade fever.
Small intestine is involved 80%
of the time, particularly the
terminal ileum.
Radiographic findings
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Skip lesions - separated by
normal areas of bowel.
Squaring of folds, indicating
lymphedema.
Apthous ulcers - small nodular
filling defects which appear as a
mound of edema with central
ulceration.
String-sign - marked narrowing of
terminal ileum usually from edema,
spasm and fibrosis. Proximal
dilatation is common.
Associated CT Findings
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Bowel wall thickening
with skip lesions.
Proliferation of
mesenteric fat and
lymphadenopathy.
Inflammatory
stranding.
Ddx in Crohn’s Dz
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Ulcerative Colitis - the entire colon is frequently
involved with the terminal ileum spared.
Diverticulitis - diverticula are present, mucosa is
intact, and terminial ileum less involved.
TB - cecum is more effected than terminal ilem.
Lymphoma - tumor masses are visualized.
Acute Mesenteric Ischemia
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Defined as interruption of blood
supply to small or large intestine.
(Associated with 70-90% mortality overall)
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Causes: embolism (SMA most common),
arterial thrombus, venous thrombus,
and diffuse mesenteric
vasoconstriction due to low cardiac
output.
Common clinical symptoms: severe
abd pain out of proportion to exam,
usually poorly localized, N/V/D, and
GI bleeding.
Surgical options: thrombectomy/
embolectomy, arterial bypass, and
resection of necrotic bowel.
Radiographic Findings
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Pneumoperitoneum
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Pneumatosis
X-ray is abnormal in 20-60%.
Thumbprinting - (nonspecific)
indicates wall edema and
hemhorrage in the this
setting.
Pneumatosis, portal vein gas,
pneumoperitoneum indicates infarcted bowel.
Possible CT Findings
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Bowel wall thickening
indicating edema or
hemorrhage.
Lack of enhancement in
wall indicated infarction.
Pneumatosis, portal vein
gas, pneumoperitoneum.
Intraluminal thrombus in
involved vessel.
Intussusception
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Most common cause of
bowel obstruction in kids but
much less common in adults.
In adults there is usually an
associated cause such as a
mass, polyp, or adhesions.
There are three types:
enteroenteric, ileocolic, and
colocolic.
CT characteristics include a
target-shaped mass
enveloped with a thick outter
rim of soft tissue
representing edematous
bowel wall.
Gallstone Ileus
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Occurs when a gallstone
erodes into GI tract and
causes obstruction.
Dilated loops of small
intestine are seen, with
air in the biliary tree and
gallbladder.
The stone is usually
located in the terminal
ileum but can be
anywhere along small
intestine.
Adenocarcinoma of the Small
Intestine
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Most often this lesion arises in
the proximal jejunum.
Risk factors: hx of Crohn’s,
sprue, Peutz-Jeghers, and
duodenal/jejunal bypass surg,
among others.
Common types are infiltrative
(bowel obstruction) and
ulcerative (bleeding).
On CT the tumor appears as
eccentric focal mass or
circumferential bowel wall
thickening in a short segment.
Lymphoma of the Small
Intestine
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Occurs most often in the
ileum where there is more
lymph tissue.
Risk factors:
immunocompromised or
suppressed state, celiac
sprue, and CLL.
Small intestine is the
second most common site
in the GI tract for
lymphoma.
CT Findings
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The typical patterns are
aneurysmal, constrictive, nodular,
and ulcerative.
There is frequently asymmetric
wall thickening (>2cm),
aneurysmal dilatation, polyploidal
mass, abdominal
lymphadenopathy.
Tissue density in the thickened
bowel is relatively homogenous.
Pneumoperitoneum
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Defined as free air in abdominal cavity.
Causes:
disruption of a hollow viscus from trauma,
iatrogenic perforation, or GI tract disease.
Extension from chest.
Via female GU tract.
Through peritoneal surface via a procedure.
Intraperitoneal source, such as abscess rupture
or gas-forming microbes.
Key Radiologic findings
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“Rigler’s sign” or double-wall
sign, which appears as air on
both sides of bowel wall (usually
indicating > 1000 ml of free air).
RUQ is the best place to look for
small air collections. These
appear as lucency over liver.
With a larger gas collection the
patient may have abdominal
distension and lack a gastric airfluid level.
Superior Mesenteric Artery
Syndrome
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Compression of the
third (transverse)
portion of duodenum
against the aorta by
the SMA.
This results in
chronic or intermittent
acute complete or
partial obstruction.
Quiz Time!!
42 y.o. woman presents with abd pain,
distension, and nausea. What is the most likely
problem?
A. Mesenteric Ischemia
B. Small Bowel Lymphoma
C. Small Bowel Obstruction
42 y.o. woman presents with abd pain,
distension, and nausea. What is the most likely
problem?
C. Small Bowel Obstruction
65 y.o. man c/o rapid onset of diffuse abd pain
combined with vomiting, diarrhea, and blood in
the stool. What is the likely problem?
A. Perforated Gastric Ulcer
B. Acute Mesenteric Ischemia
C. Small Bowel Obstruction.
65 y.o. man c/o rapid onset of diffuse abd pain
combined with vomiting, diarrhea, and blood in
the stool. What is the likely problem?
B. Acute Mesenteric Ischemia
32 y.o. woman with recurrent moderate
epigastric pain, hematemesis, and anorexia.
What is the likely problem?
A. Gastric Ulcer
B. Gastric Adenocarcinoma
C. Gastric Lymphoma
32 y.o. woman with recurrent moderate
epigastric pain, hematemesis, and anorexia.
What is the likely problem?
A. Gastric Ulcer
42 y.o. man with recurrent crampy abd pain
combined with weight loss, diarrhea, and fever.
What is the likely cause?
A. Small Bowel obstruction
B. Acute Mesenteric Ischemia
C. Crohn’s disease
42 y.o. man with recurrent crampy abd pain
combined with weight loss, diarrhea, and fever.
What is the likely cause?
C. Crohn’s disease
References
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Haaga, Lanzieri, and Gilkeson. CT and MR
Imaging of the Whole Body. 4th ed. Mosby
2003.
Strang and Dogra. Body CT Secrets. Mosby
Elsevier 2007.
Moore and Dalley. Clinically Oriented Anatomy.
4th ed. Lippincott Williams and Wilkins1999.
www.meddean.luc.edu/Lumen/Meded/Radio/cur
riculum/GI/GI_atlas_list1.htm
rad.usuhs.mil/medpix/medpix_home.html
www.learningradiology.com
www.brighamrad.harvard.edu/education/online/t
cd/tcd.html