Volume 3, Case 17
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaiʻi John A. Burns School of Medicine
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:
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.