Gastric Dilatation in a 2-Week Old
Radiology Cases in Pediatric Emergency Medicine
Volume 5, Case 17
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
This is a 3-week old male with a history of vomiting
for three days. He vomits only after being fed. It
resembles partially digested formula without blood or
bile. He feeds well, but vomits 1-2 hours following
feeding. The emesis is forceful. His mother describes
the emesis as being able to project about 30 cm, rather
than just dribbling down his mouth. He has already
vomited 5 times today. He has also had two loose
stools (no mucus, no blood, not foul). There is no
history of irritability, fever, or ill contacts. His birth
history is unremarkable.
Exam: VS T36.5 (rectal), P 140, R 37, BP 91/48.
Weight 3.4 kg (birth weight 3.1 kg). Alert, active, looks
around, focuses on mother. Anterior fontanelle flat.
Sutures not splayed. Eyes normal. TM's normal. Oral
mucosa moist without erythema. Neck supple. Heart
regular without murmurs. Lungs clear. Abdomen soft,
flat, bowel sounds active, no masses, no hernias.
There is no palpable olive. Testes normal, descended.
Hips, good range of motion without clicks or
dislocatability. No CVA tenderness noticeable.
Extremities, good tone and pulses. Color, perfusion,
An abdominal series is obtained.
View abdominal series.
The view on the left is a supine view. The view on
the right is an upright view. The supine view shows a
dilated stomach, though not necessarily dilated with
gas. The inferior margin of the stomach can be seen
because it pushes the small bowel inferiorly. The
upright view shows a moderate sized gastric air bubble.
The gastric dilatation is not as clearly visible here.
However, note that the small bowel does not seem to
rise upward. It appears to be pushed inferiorly even
though the patient is upright. This is probably because
a dilated fluid-filled stomach is pushing it inferiorly.
Although gaseous distention of the stomach is
commonly seen in crying infants or infants who swallow
a lot of air, this is usually accompanied by lots of gas
seen in the small bowel as well. In this case, the
stomach is prominent, while the small bowel gas pattern
is minimal, suggesting the presence of some type of
gastric outlet obstruction. These plain films, in
conjunction with the patient's history are highly
suggestive of pyloric stenosis.
An ultrasound study is ordered to confirm the
presence of pyloric stenosis.
View pyloric ultrasound.
US-1 shows the measurements of the pylorus. The
pyloric length measures 21.6 mm (line #1). The pyloric
wall thickness measures 4.6 mm (line #2). The pyloric
diameter measures 9.3 mm (line #3). Exceeding the
measurements of 16 mm, 4 mm, and 14 mm,
respectively is indicative of pyloric stenosis.
US-2 shows another view of the pylorus. The
pyloric length measures 21.4 mm in this view. The
black arrow points to a prominent indentation of the
pylorus into the stomach. This finding is also indicative
of hypertrophic pyloric stenosis.
Hypertrophic pyloric stenosis occurs in roughly 1 in
every 500 to 1000 live births. It is more common in
male infants. The etiology is unclear. There is a
moderate hereditary predisposition in children of
Although pyloric stenosis is felt to be congenital,
nearly all affected infants do not have symptoms as a
newborn. Vomiting usually begins at about three weeks
of age, but ranges from 1 week to 5 months. Initially,
infants may vomit 1 to 2 times per day. As the
obstruction worsens, vomiting becomes more forceful
and more frequent. The vomitus is non-billious. It may
occasionally contain blood due to capillary rupture
secondary to the forceful vomiting.
Gastric peristalsis can often be seen as an
impressive wave passing from left to right. These
infants are typically very hungry. While feeding,
palpation of the abdomen may reveal an olive shaped
mass in the right upper quadrant. Palpation of an olive
is pathognomonic for pyloric stenosis. It should be
noted that palpation of an olive is very difficult. It is
most accurately identified by highly experienced
Initially, there may be modest dehydration with
hyponatremia, hypokalemia, and a metabolic alkalosis.
An Addisonian crisis in infant males with undiagnosed
congenital adrenal hyperplasia (21-hydroxylase
deficiency) may also present with vomiting; however,
Addisonian crisis infants have HYPERkalemia and
usually are acidotic.
If appropriate treatment for pyloric stenosis is not
implemented, the dehydration will worsen and
continued weight loss with failure to thrive will occur.
Hypoglycemia may also occur.
In the past, upper GI barium contrast radiographs
were most commonly used to confirm the diagnosis of
pyloric stenosis. The contrast study would identify an
elongated and thin pyloric canal. The thickness of the
pyloric wall could not be assessed with barium contrast.
Ultrasound is currently the most frequently used
study to identify pyloric stenosis. There is no radiation
exposure and it keeps the stomach empty to reduce the
risk of regurgitation and aspiration during anesthesia
induction if surgery is required. Examining the length of
the pylorus, the thickness of the pyloric wall, the
diameter of the pylorus, and the shape of the pylorus
are all helpful signs in establishing the diagnosis of
Plain films of the abdomen are often obtained before
an ultrasound is ordered. The finding of a dilated
stomach (fluid or air filled) associated with not much
gas in the small intestine, is highly suggestive of pyloric
stenosis if the clinical history is consistent. However,
ultrasound should still be used to confirm pyloric
Surgical intervention (pyloromyotomy) is the most
efficient means to relieve the pyloric stenosis.
However, medical management, including fluid
resuscitation and correction of metabolic abnormalities,
is often required prior to surgical intervention.
Benson CD. Infantile Hypertrophic Pyloric Stenosis.
In: Welch KJ, Randolph JG, Ravitch MM, etal (eds).
Pediatric Surgery, fourth edition. Year Book Medical
Publishers, Inc., Chicago, 1986, pp. 811-815.
Dudgeon DL. Lesions of the Stomach. In: Ashcraft
KW, Holder TM. Pediatric Surgery, second edition.
W.B. Saunders Company, Philadelphia, 1993,
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