Abdominal Radiographic Diagnosis in the Newborn, by Dr. George Taylor.
Today, we will be discussing an approach to abdominal radiographic diagnosis in the newborn,
using a very simple algorithm that was taught to me by Dr. Rita Teele, a very important
mentor of mine.
And it uses the mnemonic bones, stones, gas, and mass, to organize our visual approach.
Let's begin with bones.
Are all of the expected bony structures present, and are they normal?
Here is a newborn with an abnormal abdominal exam, and a normal pelvis for comparison.
And we notice that there is widening of the pubic symphysis in this baby compared to the
normal radiograph on the right, because the baby on the left has a bladder exstrophy.
Here is another baby with abdominal distension who has a non-specific pattern of distended
bowel.
But in this situation, the bony findings give us a clue as to the diagnosis.
We see multiple segmentation abnormalities of the spine.
And looking at the pelvis, we see an absence of the sacrum in a baby who has the VACTERL
anomaly and sacral agenesis.
Next, we will be looking at stones, or any abnormal calcification.
We look for size, distribution, and location of the calcifications, and the pattern.
Here, we have a newborn with an abnormal prenatal MRI, in which we see a collection of amorphous
calcifications in the right flank, and spinal curvature.
An ultrasound shows us a calcified mass that is anteriorly displacing a normal kidney and
is separate from the adrenal.
This baby has an extra-adrenal neuroblastoma.
Another baby with a large left-sided abdominal mass, where the radiograph shows a pattern
of amorphous calcifications in the right flank.
An ultrasound shows a mass with mixed cystic and solid components.
A CT was performed, showing displacement of the right kidney inferolaterally by a large
cystic and solid mass in the retroperitoneum.
At biopsy, it was shown to be a retroperitoneal teratoma.
This baby has abdominal distension with multiple dilated loops of bowel.
And we notice a pattern of eggshell calcifications in the peritoneum.
This baby has calcified peritoneum related to meconium peritonitis, or prenatal rupture
of the bowel.
Another baby with bilious vomiting shows us a pattern of eggshell calcifications in the
upper abdomen.
But when we focus on the pelvis, we see a large cluster of abnormal calcifications in
the right hemiscrotum, due to meconium peritonitis that has extended down into the right hemiscrotum
by a patent processus vaginalis.
Now, this baby, presenting with bilious vomiting, has a very distended upper abdominal loop.
But in the right flank, we notice a collection of calcifications that looks like collapsed
bowel.
This is a baby who has ischemic bowel.
And when ischemic bowel persists for several weeks, it can become calcified and have this
appearance.
Next, let's look at the gas.
And this means both looking at bowel gas and extraluminal gas.
When we evaluate the bowel, we need to see if there is focal or diffuse distension of
the bowel.
Is there abnormal distribution or location or bowel?
Are the patterns associated with a high or a low intestinal obstruction?
Is there pneumatosis?
Or is there too little gas present?
Extraluminal gas means both the presence of pneumoperitoneum, as well as portal venous
gas.
Here, we have a six-week-old with bilious vomiting, where the bowel gas pattern looks
pretty normal, except for distension of the stomach and mild distention of duodenum.
An upper GI series is performed, showing malrotation of the bowel with a corkscrew appearance of
the jejunum, consistent with malrotation and volvulus.
This is a baby who is very sick and has a fixed loop of bowel.
And what that means is a dilated focal loop of bowel that is unchanging over several hours
to days.
This represents a focal ileus, and often seen with ischemic bowel in babies with necrotizing
enterocolitis.
Along those lines, we have a baby with abdominal distention, a premature baby.
And we see a mottled appearance of the bowel.
Now, many times normal feces can have this appearance, but when we see little bubbles
of gas in the periphery of the bowel, it increases the likelihood that this represents pneumatosis
intestinalis.
And here, a pathologic specimen shows us bubbles of gas in the submucosa and serosa related
to pneumatosis intestinalis.
Another baby, who has very distended distal bowel.
And here, the findings are quite subtle.
When I'm looking for pneumoperitoneum or pneumatosis, I use a high contrast setting on our PACS
system.
And here, the finding is much more obvious.
Baby has portal venous gas in the setting of necrotizing enterocolitis.
This newborn presents with temperature instability, and the x-ray on the left side was performed
when the baby was relatively stable.
The x-ray on the right side shows us a smaller heart and pulmonary edema, because the baby
is in shock.
Now, the reason for the shock is located below the diaphragm.
Here, we see a continuous line of gas in the baby with necrotizing enterocolitis and perforation
of the bowel.
This finding is confirmed by a decubitus view of the abdomen, showing the large amount of
pneumoperitoneum.
This two-month-old ex-premie with vomiting shows us that we need to evaluate locations
of gas that may not be in the abdomen.
Here, we see a collection of gas that appears to be above the diaphragm.
Now, this baby has a hiatal hernia, but the hiatal hernia contains some unusual contents.
Not only is there a herniation of the fundus of the stomach, there is also herniation of
the transverse colon.
We have two infants with bilious vomiting.
And now, we start looking at the patterns that are associated with high versus low intestinal
obstruction.
These two babies have a gasless distal abdomen, and a markedly distended irregular contour
of the stomach, with a dilated duodenal bubble.
This is the classic appearance of a duodenal atresia.
We've seen this baby before, with a loop of calcified bowel in the right flank, and a
gasless distal abdomen with focal dilatation of one proximal loop of bowel.
By giving positive contrast, we see that there is marked dilatation of the jejunum related
to a child with jejunal atresia and a focal ischemic loop of bowel in the right flank.
Here is a baby that presents with abdominal distension and failure to pass meconium for
36 hours.
And we see a very distended loop of bowel that appears to be colon, with a mottled appearance
of the feces within.
And if this is colon, then our differential diagnosis going from the most distal cause
of obstruction includes an imperforate anus or Hirschsprung's disease, colonic atresia
or stenosis.
But if it does not represent the colon, it could represent very dilated distal small
bowel as a result of ileal atresia or stenosis, or meconium ileus, or multiple atresias.
So in this situation, we did a water soluble enema showing that, in fact, this very distended
loop of bowel was not colon.
In fact, it was dilated distal small bowel.
We see that the caliber of the colon is very small throughout.
Baby has a microcolon.
And we have reflux of contrast into the distal ileum that contains multiple filling defects.
This is the result of meconium ileus.
So the key teaching point here is that it is very difficult in the newborn to tell the
difference between a distended colon and a very distended small bowel.
Here, we have two ex-premies with abdominal distention that is quite intermittent.
And we see a collection of gas in the left-- in the right hemiscrotum-- sorry, left hemiscrotum
on this child and contrast containing cecum and appendix in the right hemiscrotum in a
baby with inguinal hernia.
These can obstruct and may cause a pattern of distal small bowel obstruction.
Here, we have a baby with a clinical diagnosis of imperforate anus.
We see that there are segmentation abnormalities in the sacrum.
And we notice that there is gas in the proximal urethra.
A prone cross-table lateral view of the abdomen shows a distended rectum and distal colon
and gas in the bladder.
This confirms a diagnosis of a recto-urethral fistula.
Now, let's shift our attention to an evaluation of masses.
And this, to us, means both the presence of a mass and/or organomegaly.
We need to see the location of the mass-- and it's based on the vector of displacement
of other normal structures-- the size of the mass, and the presence of calcification or
fat.
Here, we have an eight-week-old boy with fever, failure to thrive, a left upper quadrant mass,
and an unusually shaped skull.
The radiograph shows us a very dilated, very enlarged spleen that is confirmed by an ultrasound,
and the plain film radiographs showing a very dense-appearing set of bones with abnormal
ends to the bones and no distinction between the cortex and the medullary cavity, in this
baby with osteopetrosis and splenomegaly related to extramedularry hematopoiesis.
Here, we have a newborn with a cough and an incidental finding of a left paraspinal mass
that is subtle on the chest x-ray but much more obvious on the plain film, in a baby
with neuroblastoma.
Finally, we have a newborn with marked abdominal distention and respiratory distress, where
the abdomen is gasless except for a small amount of gas in a centrally-placed stomach.
There is hypoplasia of the lungs with elevation of hemidiaphragms.
An ultrasound shows us marked enlargement of both kidneys with multiple tiny cysts throughout,
consistent with a diagnosis of an autosomal recessive polycystic kidney disease.
So in summary, we have a pattern approach that we can use for the evaluation of the
newborn abdomen using the mnemonic bones, stones, gas, mass.
Thank you.
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