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Chapter 39 • Weight Loss/Gain (Unintentional)
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469
References and Readings
American Congress of and Gynecologists: Obstetricians ACOG an-
nounces new Pap smear guidelines, 2014. Retrieved from www.
pdfshares.net/pdf/acog-pap-smear-guidelines-2014.html.
Austin J, Marks D: Hormonal regulators of appetite, Int J Pediatr
Endocrinol 2009:141753, 2009.
Flegal KM, Carroll MD, Ogden CL, et al: Prevalence and trends in
obesity among US adults, 1999-2008, JAMA 303:235, 2010.
Healthallrefer.com: Symptoms guide: Weight gain—unintentional.
Retrieved from health.allrefer.com/health/weight-gain-uninten-
tional-info.html.
Kmetova A, Kralikova E, Stepankova L, et al: Factors associated
with weight changes in successful quitters participating in a
smoking cessation program, Addict Behav 39:239, 2014.
Maciosek MV, Cofeld AB, Edwards NM, et al: Priorities among
effective clinical preventive services: Results of a systematic review and analysis, Am J Prev Med 31:52, 2006.
Metalidis C, Knockaert DC, Bobbaers H, et al: Involuntary weight
loss: Does a negative baseline evaluation provide adequate reassurance? Eur J Intern Med 19:345, 2008.
Reife CM: Involuntary weight loss, Med Clin North Am 79:299,
1995.
Scholler I, Nittur S: Understanding failure to thrive, Paediatr Child
Health 22:438, 2012.
US Department of Health and Human Services, US Department of
Agriculture: Dietary guidelines for Americans, 2010. Retrieved
from www.health.gov/dietaryguidelines/2010.asp.
PART III Diagnostic Imaging
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n x-ray is a stream of high energy photons pro-
A
duced by an x-ray tube used for their penetrating
power in radiography. The short wavelength produced
by this light energy is unique in that it penetrates
opaque objects. Releasing the beam onto a photosensitive surface causes a photochemical reaction, which
results in an image on the x-ray lm in conventional
systems or on an image receptor in digital systems. For
ease of reference, the term “image” will be used
throughout the chapter. The density of the material
determines the penetration of the light energy. The image is a result of the amount of x-rays being absorbed
by the density of the tissue/organ as it passes to the
receptor. Two terms are used to describe this absorption. The rst is radiolucent, which means there is no
interference with the ow of the x-ray particles. The
result is a black or very dark image. The second term
is radiopaque; in this instance, something lies between
the beam and the cassette that causes the beam to absorb or disperse, thereby not allowing the beam to
reach the cassette and making the image appear white.
Decreasing density (black)
Radiolucent Radiopaque
Increasing density (white)
→
Gradations of gray result from variations in density of the tissue or organ. There are four basic roentgen densities, and all images include one or more of
these densities (Table III-1). A chest image demon-
strates all four densities: from the black of the air in
the lung tissue to the full white density of the rib
bones. Structures will merge together unless the
boundaries between two adjacent structures have
differing densities. The densities of the objects result
in the shadows on the image.
The radiograph image is a two-dimensional shadow
picture of a three-dimensional object. Because the image is two-dimensional, it is important that the clinician think three-dimensionally when viewing the image. This thinking requires knowledge of the normal
anatomy of the area being x-rayed and transference of
this knowledge to the shadows on the image.
Chapters 40 and 41 address specic x-rays commonly used for diagnosis.
Table III-1
DENSITY DESCRIPTION EXAMPLES
Gas (air) Black, radiolucent Lung tissue, trachea,
Fat Gray, less
Water Whitish, slightly
Metal All white, radi-
From Kersten L: Comprehensive respiratory nursing, Philadelphia,
1989, Saunders.
Image Densities
Soft tissue around
radiolucent
Heart, blood vessels,
radiopaque
Calcium of ribs,
opaque
bronchi, gas in
stomach or intestine
muscle
muscle, diaphragm
vertebrae, scapulae,
clavicles, other
bones, prostheses,
contrast media
470
CHAPTER
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40
he abdominal x-ray is used primarily for acute con-
T
ditions and has a more limited use than the chest xray. Often the abdominal x-ray may require additional
imaging and the use of contrast radiographic substances
to make structures more visible. Generally abdominal
images are taken to help in diagnosing pain, vomiting,
and lack of or abnormal bowel sounds. They are also
useful in nding stones in the kidneys, ureter, bladder,
and gallbladder; ingested foreign objects; and air distribution. Frequently a chest image is done at the same
time. Every female patient should be asked if she is pregnant before an image is taken.
Abdominal X-Ray
DIAGNOSTIC REASONING: VIEWING
THE ABDOMINAL IMAGE
What are the rst steps in reviewing the image?
Key Questions (to self)
l
Does the image being examined belong to the correct
patient?
l
Do I have all views of the area being examined?
l
Is the image correctly displayed on the view box or
screen?
l
Is the image of good quality?
l
Do I know the anatomy of the abdomen?
Image and Patient Identification
As with the chest x-ray, it is important to determine that the
image being viewed is from the patient being evaluated.
Pertinent information about the patient should be found
on the image in the upper corner and veried.
Views
Flat Plate or Anteroposterior View
For an anteroposterior (AP) view, the patient lies in a
supine position on the x-ray table. A cassette is placed
beneath the patient, with the x-ray machine above the
patient. The beam passes from front to back. The patient is asked to exhale and the x-ray is taken. Because
of the size of the cassette, a second image may be
needed while the patient is in this position to see the
entire abdomen from diaphragm to groin.
Left Lateral Decubitus View
In a left lateral decubitus image, the x-ray machine
moves to a position where the beam is horizontal to the
patient and the left chest is closest to the image. This
view is obtained when an obstruction or perforation
may have occurred, resulting in free air in the abdomen.
Erect View
For an erect view, an x-ray of the abdomen is taken as
the patient is standing. A standing erect x-ray is used to
assess for free air; however, this is seen only when an
excessive amount of air is present.
Chest X-Ray
A chest x-ray may be ordered to rule out free air collection beneath the diaphragm, a pneumonia that may be
causing abdominal symptoms, a pleural effusion, or a
subphrenic abscess.
Kidneys, Ureter, Bladder
The term kidneys, ureter, bladder (KUB) is often used
to indicate a at plate of the abdomen. A KUB x-ray is
done to look for stones or abnormalities.
Image Box Placement
The image, if an x-ray lm, is placed on the lighted
view box with the patient’s left side facing the reader’s
right side. The image is labeled with an R or L on the
bottom. Digital imaging is common where the x-ray
image is viewed on a computer screen.
Image Quality
The amount of x-ray beamed through the patient
affects the details seen on the image. If too few beams
were delivered, the image will be underexposed and
appear lighter than normal. If too many beams were
471
472
Splenic
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Chapter 40 • Abdominal X-Ray
delivered, the image will be overexposed and appear
darker than normal. An underexposed abdominal image
is not usually a problem. However, an overexposed image (darker than normal) requires a high density spotlight looking for any free air. If the spine is visible, most
other structures should be seen.
Reviewing Anatomy
Reviewing the normal anatomy of the structures of the
abdomen is helpful when learning how to interpret an
abdominal image. Superimposing the anatomy onto the
image will help to correlate the normal structures to the
shadows. The abdomen, unlike the chest image, is more
difcult to read because of soft tissue organs. A review
of the principles of radiology will help explain this. Radiodense objects, like bone and calcium, are easy to see
(white). Radiolucent objects, such as air and fat, are also
easy to see (dark). Structures of intermediate density are
more difcult to see because they appear gray (such as
solid organs of the abdomen) and gray densities next to
each other are invisible. Organs that have varying densities next to each other (such as the liver border next to
fat) assists in identication. Careful viewing and knowledge of anatomy is important (Figure 40-1).
What approach should be used when viewing the image?
Key Questions (to self)
l
What is my initial impression?
l
Am I using a systematic examination technique?
Initial Impression
When beginning to view the image, it is helpful to ask
why you ordered the image, what you expect to see
based on the history and physical examination, and if
you see it. Initially, view the gas pattern and look for any
extraluminal air, soft tissue masses, or calcications.
Systematic Examination
Systematic examination of the image after an initial overview is mandatory. All parts of the abdominal anatomy
are evaluated at 2 to 4 feet from the image, concentrating
on one part of the image at a time to observe any abnormalities. A suggested systematic examination follows.
DIAGNOSTIC REASONING: SYSTEMATIC
EXAMINATION
How do I assess the AP view?
Bones
Identify the lower rib cage, lumbar spine, sacrum, pelvis, and hip joints. In each instance, look for fracture,
cortical density, and joint and disc space.
Bladder
The inferior aspect of the bladder projects 5 to 10 mm
above the symphysis pubis. If the bladder is full, it will
appear as a soft tissue density in the pelvis (Figure 40-2).
Liver
Gallbladder
Ascending
colon
Small
intestine
Cecum
Appendix
FIGURE 40-1 Normal abdominal anatomy. (From Seidel HM, Ball
JW, Dains JE, et al: Mosby’s guide to physical examination, ed. 8,
St. Louis, 2015, Mosby.)
Spleen
Stomach
Transverse
colon
Descending
colon
Sigmoid
colon
Bladder
flexure
Hepatic
flexure
Transverse
colon
Descending
colon
Ascending
colon
Bladder
FIGURE 40-2 Supine abdominal radiograph showing colon, bladder,
and flexures. (Modified from Johns Hopkins University, Piccini J,
Nilsson K: The Osler medical handbook, ed. 2, Philadelphia, 2006,
Saunders.)
Chapter 40 • Abdominal X-Ray
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473
Uterus
The uterus sits on top of the bladder, possibly indenting
the bladder, and is often not seen on plain x-ray.
Liver
Observe for homogeneous density in the right upper
abdominal quadrant. The lower border of the liver is
found in the right ank near the right costal margin.
The adjacent fat provides the contrast showing the
liver edge (Figure 40-3).
Spleen
The spleen is found in the left upper quadrant between
the diaphragm and fundus of the stomach. It is the size
of the adult st and is usually not seen. Because the
spleen must be very enlarged to be seen, ultrasound
may be more benecial (see Figure 40-3).
Psoas Muscle
The psoas muscle shadows are visible as diverging
lines on both sides of the spine starting from the rst
lumbar vertebra towards the pelvis (see Figure 40-3).
Kidneys
The kidneys are retroperitoneal organs that are visualized on the x-ray because of the presence of perirenal
fat. Visualization may be obscured by bowel loops.
The left kidney is higher than the right. The shadow
should appear smooth with the superior pole closest
to the midline. Kidneys are located on either side of
the lower thoracic and upper lumbar spine between
the upper border of the eleventh thoracic vertebra and
the lower border of the third lumbar vertebra (see
Figure 40-3).
Stomach
The stomach can be identied in its location above the
transverse colon by the bandlike shadows of the gastric
rugae in the supine view and by the gas uid level beneath the left hemidiaphragm in the erect view. When
supine, air in the stomach will rise anteriorly and uid
will pool posteriorly (Figure 40-4).
Colon
The colon often has a bubbly appearance representing a
mixture of gas and fecal material. It lies on the periphery
of the abdomen and may be lled with air or feces. The
colon begins at the hepatic exure and goes to the rectum.
Fecal matter in the bowel gives a “mottled” appearance.
This is seen as a mixture of grey densities representing a
gas-liquid-solid mixture (Figure 40-5). A mechanical ob-
struction causes the large bowel to become dilated more
than 6 cm. The dilated colon is above the obstruction and
no air in the colon appears below the point of obstruction
FIGURE 40-3 Supine abdominal radiograph showing kidneys,
spleen, liver, and psoas muscle. (Modified from Johns Hopkins
University, Piccini J, Nilsson K: The Osler medical handbook, ed.
2, Philadelphia, 2006, Saunders.)
Spleen
Liver
Left kidney
Right
kidney
Psoas
muscles
Spleen
Right
kidney
Gas in
stomach
Left
kidney
Right psoas
muscle
Left psoas
muscle
Tip of
liver
FIGURE 40-4 Normal gas in the stomach. (From Mettler F:
Essentials of radiology, ed. 2, Philadelphia, 2005, Elsevier.)
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Chapter 40 • Abdominal X-Ray
FIGURE 40-5 Constipation. (From Walsh T, Caraceni A, Fains-
inger R, et al: Palliative medicine, Philadelphia, 2009, Elsevier.)
A
FIGURE 40-6 Mechanical large bowel obstruction. (From Herring
W: Learning radiology: Recognizing the basics, St. Louis, 2007,
Elsevier.)
BB
FIGURE 40-7 (A) Supine view of the abdomen showing mechanical small bowel obstruction (black arrows) and no air in
the rectum (white arrow). (B) Erect view of the abdomen showing small bowel obstruction. (From Herring W: Learning
radiology: Recognizing the basics, St. Louis, 2007, Elsevier.)
Chapter 40 • Abdominal X-Ray
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475
(Figure 40-6). A paralytic ileus (postsurgery) shows a
bowel that is dilated but has gas throughout the small and
large intestine with no delineation.
Small Bowel
The small bowel lies in the center of the abdomen
within the “frame” of the large bowel; often little
small bowel is seen on the image. The normal small
bowel diameter should not exceed 3 cm. A small bowel
obstruction presents as multiple dilated loops in
the central abdomen with no air in the large bowel
(Figure 40-7).
Calcifications
Whiteness of calcications is caused by the absorption
of the x-rays. Calcications seen in the pancreas, kidney (Figure 40-8), gallbladder, and aorta are abnormal.
Occasionally one may see a calcication in the area
of the appendix called an appendicolith. In women,
broids may become calcied and visible.
Gas Patterns/Extraluminal Air
Air is naturally swallowed and can be seen in the stomach. When a patient is in the supine position, the gas
will rise to the anterior portion of the stomach. Gas in
the small bowel is located in the left midabdomen and
the lower central abdomen. Gas in the colon often has
a bubbly appearance representing a mixture of gas and
fecal material. Gas within the peritoneal cavity outside
the sealed gastrointestinal (GI) tract is abnormal and is
termed pneumoperitoneum (Figure 40-9).
Artifacts
Artifacts may be immediately obvious. Piercing of the
umbilicus is very popular, especially in young women;
genital piercing is not infrequent. Metallic objects are
obvious. There may be clips or materials from previous
surgeries.
If the patient has abdominal pain, what other x-ray
should I consider?
Key Question (to self)
l
What are the indications for ordering other x-rays?
Upright Abdominal X-Ray and Standing
Chest X-Ray
If an obstruction or ileus is suspected, an upright
abdominal x-ray and a standing chest x-ray are
ordered. The upright abdominal x-ray provides a
view of the air/uid levels within the bowel to
differentiate between an obstruction and an ileus.
Additionally, if free air in the abdomen is a concern,
the standing image will demonstrate free air underneath the hemidiaphragm, which is unable to be seen
on the plain abdominal x-ray. A standing chest image
should be viewed using the procedure outlined in
FIGURE 40-8 Nephrocalcinosis. (From Mettler F: Essentials of
radiology, ed. 2, Philadelphia, 2005, Saunders.)
FIGURE 40-9 Pneumoperitoneum. (From Mettler F: Essentials of
radiology, ed. 2, Philadelphia, 2005, Saunders.)
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Chapter 40 • Abdominal X-Ray
Chapter 40. When looking for free air in the abdomen,
pay particular attention to the area under the right
diaphragm. Extraluminal free air appears as a crescent
of radiolucent gas between the diaphragm and the
liver, and usually indicates a perforated viscus (see
Figure 40-9).
Left Lateral X-ray
If the patient is too ill to stand, a left lateral x-ray will
be useful in nding free air in the abdomen. In the left
lateral decubitus image, the patient is lying on the left
side for 10 to 15 minutes and a horizontal beam is
used. In this image, small amounts of free air can be
seen over the lateral aspect of the right lobe of the
liver. Often the free air is seen as a dark shadow between the white of the abdominal wall and the liver
(Figure 40-10).
Additional Causes of Abdominal Pain
Abdominal pain may also be caused by chest pathology mimicking abdominal pain, such as pleurisy, pneumonia, and pleural effusion (Evidence-Based Practice
box). A chest x-ray should be ordered.
What other imaging studies should I consider?
Key Questions (to self)
l
What other common imaging studies are available
for the abdomen?
l
What imaging studies would give me the best infor-
mation for a particular patient concern?
Upper Gastrointestinal Series
For an upper GI series, the patient drinks a barium
solution that passes through the digestive tract and
lls and coats the esophagus, stomach, and rst part of
the small intestine, making them more visible with the
x-ray. A uoroscope is held over the body part being
examined and transmits continuous images to a video
monitor. This test is used to diagnose hiatal hernia,
reux, narrowing of upper GI tract, and esophageal
conditions.
Small Bowel Series
For a small bowel series, the barium ingested for
the upper GI series is allowed to pass through the
stomach into the small bowel and images are taken.
This test is used to detect tumors and malabsorption
syndrome.
FIGURE 40-10 Left lateral free air. (From Adam A, Dixon A:
Grainger & Allison’s diagnostic radiology, ed. 5, Philadelphia,
2008, Churchill Livingstone.)
EVIDENCE-BASED PRACTICE
Undifferentiated Abdominal Pain?
Thirty-eight studies on the use of abdominal x-rays in undifferentiated abdominal pain were reviewed. The studies were
evaluated for the diagnostic value and outcome of the use
of the abdominal x-ray. In one study, 75% of cases had
normal x-rays. In the 25% of cases with abnormal x-ray findings, over half of the abnormalities were unrelated to the final
Data from Smith J, Hall E: The use of plain abdominal x-rays in the emergency department. Emerg Med J 26:160, 2009.
Lower Gastrointestinal Series
In a lower GI series, barium enemas are used to
examine the large intestine and the rectum. For this
test, barium or an iodine-containing liquid is introduced gradually into the colon through a tube inserted
Should Abdominal X-Rays Be Obtained in Patients With
diagnosis. As the radiation exposure of an abdominal x-ray is
35 times that of a chest x-ray, the authors concluded that
plain abdominal x-ray should not be used routinely in patients
with undifferentiated abdominal pain, unless there is clinical
suspicion of bowel obstruction.
Chapter 40 • Abdominal X-Ray
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477
into the rectum. As the barium passes through the
lower intestines, it lls the colon. As in the upper
GI series, a uoroscope transmits continuous images
to the video monitor. A lower GI series is used to diagnose colon polyps, tumors, diverticular disease,
narrowing or obstructions, ulcerative colitis, or Crohn
disease.
Colonoscopy
In a colonoscopy, a colonoscope is inserted into the
rectum and advanced through the large intestine
and part of the small bowel. The scope has a brotic
light and camera projecting images onto a monitor.
Polyps can be identied, biopsied, and/or entirely
removed. Colonoscopy is used to evaluate intestinal
bleeding, inammatory bowel disease, colorectal
polyps, or cancer.
Sigmoidoscopy
In a sigmoidoscopy, a exible sigmoidoscope is
passed through the rectum to view the last 2 feet of
the colon. The scope transmits images of the inside
of the rectum and colon. Biopsies may be taken of
polyps or suspicious tissue on the intestinal wall. This
test is useful for viewing inammatory conditions in
the rectum and lower colon, polyps, bleeding, and
ulcerations.
Computed Tomography
Computed tomography (CT), or computed axial tomography, provides a cross-sectional slice of the area
examined (see Chapter 41). A CT is useful for diagnosing sigmoid diverticulitis, appendicitis, bowel obstruction, and extracolonic causes of abdominal pain.
Endoscopy
A exible beroptic tube called an endoscope is
equipped with a camera at the end. The camera is connected to either an eyepiece for direct viewing or a video
screen that displays the images on a monitor. The endoscope is inserted into the mouth and threaded down the
esophagus to the stomach and small intestine. Endoscopy is useful for diagnosing gastric bleeding, hiatal
hernia, and swallowing difculties; for removing stuck
objects such as food; and for obtaining biopsy samples.
Ultrasound
Ultrasound is a noninvasive examination that uses
high-frequency sound waves to produce images. The
ultrasound images are captured in real time. They can
show the size, structure, and movement of the body’s
internal organs, as well as blood owing through
blood vessels and pathological lesions. It is useful for
evaluating the size of the spleen, gallstones, aortic
aneurysm, kidney stones, and abdominal masses.
DIFFERENTIAL DIAGNOSIS OF
WHAT TO LOOK AT NORMAL FINDING ABNORMAL FINDING SUGGESTED CAUSE
Visible spine Image of good quality Spine not visible Poor quality image
Metallic objects History of piercing Present without history Foreign object ingested
Gastric air bubble Present on the right Not visible Image placement error, label
Liver Right upper quadrant Enlarged Many causes: CHF, alcohol
Spleen Left upper quadrant, usually not
Kidneys Left higher than right, three
Small bowel Central portion of image, loops
Large bowel Periphery of image, slight air in
Fluid
Free air Normally not seen Free air in abdomen Rupture of hollow viscus
The Abdominal Image
seen
vertebrae in size
normally 2-3 cm, little air
rectum
In erect image, present in stomach,
two to three levels in small
bowel, never in large bowel
error
Must be very enlarged to be
visualized
Enlarged, calcifications Renal calculi, hydrosis
Dilated .3 cm, multiple
distended loops
Dilated .5 cm, multiple
dilated loops
Mottled appearance
Fluid present in small bowel Small bowel obstruction
abuse, hepatitis
Many causes: infectious,
anemia, trauma, cancers
Constipation, ileus, small
bowel obstruction
Large bowel obstruction
Constipation
Continued
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Chapter 40 • Abdominal X-Ray
DIFFERENTIAL DIAGNOSIS OF
The Abdominal Image—cont’d
WHAT TO LOOK AT NORMAL FINDING ABNORMAL FINDING SUGGESTED CAUSE
Diaphragm Right higher than left; right at
level of sixth rib
Bladder Usually not visible Visible when full Full bladder, bladder stone
Uterus Sits on top of bladder, usually
not visible
Aorta Usually not visible Calcifications in abdominal aorta Abdominal aortic aneurysm
CHF, Congestive heart failure.
References and Readings
Adam A, Dixon A (eds.): Grainger & Allison’s diagnostic radiology,
ed. 5, Philadelphia, 2008, Churchill Livingstone, Elsevier.
Brickel I, Kelly B: Abdominal x-rays made easy: Normal radio-
graphs, Student BMJ 10:103, 2002.
Clayton K: Pediatric abdominal imaging, Pediatr Rev 31:12, 2010.
Herring W: Learning radiology: Recognizing the basics, St. Louis,
2007, Mosby.
Elevated Collapsed lobe or multi-
segmental collapse; pleural
Radiolucent line present that
follows the curvature of the
diaphragm
Flattened diaphragm Emphysema, asthma, tension
Elevation on left Perforated ulcer, or gas
Bilateral elevation Pregnancy, obesity, peritoneal
Visible with uterine fibroids Possible fibroids
Mettler F: Essentials of radiology, ed. 2, Philadelphia, 2005,
Saunders.
Musson R, Bickle I, Vijay R: Gas patterns on plain abdominal radio-
graphs: A pictorial review, Postgrad Med J 87:274, 2011.
Novelline RA: Squire’s fundamentals of radiology, ed. 6, Cambridge,
2004, Harvard University Press.
Walsh T, Caraceni A, Fainsinger R, et al: Palliative medicine,
Philadelphia, 2009, Saunders.
effusion
Free air present
pneumothorax
distention of stomach
fluid
Ultrasound often used for
diagnosis of size
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