This is a 3-month old female who is brought to the 
E.D. this evening for vomiting.  She began vomiting last 
night.  She vomited twice last night and 8 times today.  
Initially, the vomitus was yellow in color but the last 3 
episodes have been green.  There is no history of 
diarrhea.  She has a history of feeling warm, but her 
temperature was not measured at home.  She last 
passed a stool yesterday.  She is urinating less, only 
twice since this morning.  Her past history is significant 
for poor weight gain and an illness one month ago 
characterized by vomiting four times which resolved on 
its own.  She normally feeds a partially hydrolyzed 
formula because of "colic".
     Exam:  VS T37.5 (rectal), P168, R38, BP not 
obtained because of crying.  Wt 4.94 kg (25th 
percentile).  She is alert, crying, difficult to console.  
She arches her back at times and appears to be in 
pain.  Her color is slightly pale.  Anterior fontanelle soft 
and flat.  No tears when crying.  Her eyes appear to be 
somewhat sunken.  Oral mucosa sticky.  Neck supple 
(difficult to be certain).  Heart regular, tachycardic.  
Lungs clear.  Not coughing.  Abdomen firm, difficult to 
examine.  Bowel sounds are diminished but present.  
No detectable masses, but because of the firmness, 
this is inconclusive.  No hernias.  Rectal exam no stool.  
Residue is guaiac negative.  Color slightly pale and 
mottled.  Capillary refill time in the lower extremities is 
3-4 seconds.  Turgor good.
     Laboratory studies are drawn and an IV is begun.  
She is given a lactated Ringers solution fluid bolus and 
is continued on an IV infusion.  After the fluid bolus, she 
is no longer crying.  She is not fussy and her abdominal 
exam is now soft with active bowel sounds.  No masses 
are palpable.  Her color looks better.  She is sent to the 
imaging department for an abdominal series.

View abdominal series.

     Lab results:
Na 138, K 4.3, Cl 101, Bicarb 21
Glucose 95, BUN 11, Creat 0.5
CBC WBC 12.0, 3% bands, 47% segs, 40% lymphs,
     7% monos, Hgb 11.9, Hct 35.7, platelets 596,000

     The abdominal films show decreased intestinal gas 
with gastric and duodenal bulb distention.  This 
is felt to be consistent with a duodenal obstruction.

Questions
     Would you order a barium enema, an UGI series, or 
an ultrasound at this point?
     What would each of these studies be most effective 
in ruling out?
     Since your decision should be based on what you 
think the most likely diagnosis is, what is the most likely 
diagnosis at this point?

     Common causes of a bowel obstruction in this age 
group include pyloric stenosis, volvulus, and 
intussusception.  Other possibilities include constricting 
bands overlying bowel, intraluminal webs, intestinal 
stenosis, annular pancreas, etc.
     An ultrasound would be the best study to evaluate a 
possible pyloric stenosis.  An UGI series can also be 
performed to diagnose pyloric stenosis, but ultrasound 
involves no radiation, it does not require oral contrast, 
and it is more accurate than an UGI series in 
diagnosing pyloric stenosis.  Her clinical findings are not 
consistent with pyloric stenosis.  Her vomiting is not 
projectile in nature and it is not associated with feeding.  
Her vomitus is definitely bilious suggesting an 
obstruction below the pylorus.
     An intussusception would be most accurately 
visualized on a barium enema.  Ultrasound is capable 
of making the diagnosis most of the time.  However, if 
the ultrasound is negative, how certain can you be that 
intussusception has been ruled out.  In other words, 
what is its false negative rate.  Since ultrasound is 
highly operator and interpreter dependent, these factors 
must be discussed with the ultrasonographer on call in 
order to decide whether ultrasound is a plausible option 
to rule out intussusception.  In cases which have a high 
likelihood of intussusception, a barium enema would be 
better since the barium enema has the additional 
advantage of potentially reducing the intussusception 
most of the time.  This is not possible with ultrasound.  
Air contrast enema has also been used in the diagnosis 
and reduction of intussusception.  This option should be 
discussed with your radiologist.
     In our patient's case, a malrotation with volvulus is 
the most likely diagnosis.  The abdominal radiographs 
suggest a high obstruction just distal to the gastric 
outlet since there is a paucity of gas distal to the 
stomach.  Her history of colic and the previous vomiting 
episode raises the possibility of intermittent volvulus 
which is often a presentation for malrotation.  Although 
bilious emesis can occur with any type of bowel 
obstruction (including lower obstructions such as 
intussusception) and even an ileus, it is also suggestive 
of a high obstruction.  Radiographically, an ileus should 
have a good distribution of gas throughout the 
abdomen.  Our patient's abdominal radiographs are 
highly suggestive of an obstruction and not an ileus 
because of the poor gas distribution.
     An ultrasound of the abdomen is performed.  It is 
negative for pyloric stenosis and there are no findings to 
suggest an intussusception.  An upper GI series is 
ordered.  It initially shows no barium passing out of the 
stomach.  However a subsequent view following the 
administration of thin barium shows the following:

View upper GI series film.

     This pattern of contrast flow, sometimes referred to 
as a corkscrew (black arrow), shows thin barium flowing 
in a spiral fashion through a restricted bowel lumen.  
This indicates the presence of a midgut volvulus.  
Compare this to the diagram of a midgut volvulus.

View diagram of a midgut volvulus.

     You can see the tight strangulation of the upper 
small bowel volvulus forming a spiraling corkscrew 
pattern as seen in the UGI series.
     It may be difficult to radiographically demonstrate a 
volvulus in all instances.  Plain abdominal radiographs 
may range from gasless to normal.  A barium enema 
may be able to demonstrate the cecum in the wrong 
place suggesting a malrotation and a likely associated 
midgut volvulus.  An upper GI series may fail to 
demonstrate the volvulus itself, however, it will show a 
sudden obstruction in the bowel lumen where the 
barium fails to pass.  Using thin barium or soluble 
contrast may help to demonstrate the volvulus, 
however, it may be necessary to take the patient to 
surgery based on indirect radiographic findings alone.
     An UGI series may also demonstrate malrotation 
(with or without a volvulus) by demonstrating 
malpositioning of the duodenal-jejunal junction.  
Examine the UGI film again.

View UGI film.

     The black arrow points to the duodenal-jejunal 
junction.  The normal duodenum starts at the gastric 
outlet (duodenal bulb) and extends toward the right.  It 
then loops around downward and to the left, and then  
superiorly and to the left so that the duodenoal-jejunal 
junction is normally to the left of the spine at the same 
level as the duodenal bulb.  In this case, the 
duodenal-jejunal junction is clearly inferior to the 
duodenal bulb.  This indicates the presence of a 
malrotation.
     Case 8 in Volume 2 (Recurrent Abdominal Pain and 
Vomiting in a 7-Year Old) discusses the anatomy and 
the radiographic findings in malrotation and volvulus in 
more detail.  Refer to this case to clarify any questions 
you may have regarding malrotation and volvulus.

Can you answer the following questions?
     1.  Does a normal barium enema effectively rule out 
a midgut volvulus?
     2.  Does a normal barium enema effectively rule out 
a malrotation?
     3.  Why does a malrotation predispose one to a 
volvulus?
     4.  What are the radiographic findings seen in 
malrotation on UGI series and barium enema (in the 
absence of volvulus)?
     5.  Does a normal plain abdominal film (no air fluid 
levels, normal gas distribution, no distended bowel) rule 
out a volvulus?
     6.  Describe the difference between midgut volvulus, 
cecal volvulus, and sigmoid volvulus?
     7.  Which type of volvulus does malrotation 
predispose one to?
     
     Vomiting and abdominal pain are common reasons 
for children seeking emergency care.  To confidently 
rule out a volvulus and malrotation clinically and 
radiographically, one must be familiar with the 
topics above.  Refer to Case 8 in Volume 2 for a 
discussion on these topics.