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, 
turgor good.
     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 
affected parents.
     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 
pyloric stenosis.
     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, 
pp. 289-293.

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Web Page Author:
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine