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Questions, Comments? Email Sujit Iyer at ssiyer@seton.org March 27, 2013 Volume 1

Welcome to the First Edition of the DCMC ED, Radiology Case of the MonthThese cases have been removed of identifying information. These cases are intended for peer review and educational purposes only.

In conjunction with our pediatric radiology specialists from ARA we hope you enjoy the first edition of the pediatric radiology case of the month.

These cases are meant to highlight important chief complaints, cases and radiology findings that we all encounter every day. If you enjoy these reviews we invite you all to look for

invitations for Pediatric Emergency Department Radiology conferences to be held at Dell Children’s in conjunction with the Pediatric Emergency Medicine Fellowship. If you have any questions or feedback regarding the Case of the Month format, feel free to email Sujit Iyer at ssiyer@seton.org

Abdominal Radiographs in ChildrenDo you have a systematic approach to evaluating the pediatric abdominal radiograph? Differentiating a mechanical obstruction in children versus an adynamic ileus can be challenging and radiograph interpretation should always be done in context with the clinical picture. Having a stepwise approach to looking at a pediatric radiograph can help. Here is an

example checklist of things to look for. See the final page for some tips and tricks on looking at pediatric abdominal radiographs

1. Look at fixed anatomy first (i.e. bones, lungs)

2. Gas distribution

3. Bowel dilatation ( do you know small from large bowel)

4. Air fluid levels

5. Arrangement of loops in the supine view

Remember that in pediatrics most cases are variable and you should have a high index of suspicion when the XR findings are unclear or the patient continues to get worse despite your initial diagnosis of gastroenteritis.

Does this look normal to you?

DCMC Emergency Department - Radiology Case of the Month

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Case One

Case One - Be wary of the vomiting child (without diarrhea, and not getting better)11 month old presents day one to the ED with complaints of 4-5 episodes of vomiting and possible diarrhea. Receives IVF, looks better after Zofran and is tolerating liquids prior to discharge. Child returns to the ED 24 hours later with complaint of continued vomiting. Radiograph in the ED is shown. After IVF, child still appears dehydrated and not tolerating liquids well so is admitted for IVF hydration.

Official read of abdominal radiograph above: mildly distended small bowel loops-increased relative to the prior study, measuring up to 2.2 cm in diameter. There are air-fluid levels without definitive free air. The findings could be seen with ileus, gastroenteritis, early obstruction (which can be seen with variable causes) - image/workup further as clinically indicated

Case Conclusion: While admitted, child has repeated episodes of vomiting and now appears to be in pain. Vomiting turns bilious. Abdomen appears to be increasingly distended and eventually child appears to be guarding with worry for early peritoneal signs. CT of the abdomen is done and is shown on the next page with the final diagnosis.

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Case One Conclusion

Case One Conclusion and Key PointsCT shows an intraluminal mass with findings consistent with ileocolic intussusception causing the patient’s high grade small bowel obstruction. Mild enhancement of peritoneal fluid is seen in the right paracolic gutter, consistent with the clinical findings of peritonitis. Due to the long standing symptoms and peritoneal exam, the patient was not a candidate for air contrast enema and taken to the operating room. Patient’s intussusception was easily reduced with general anesthesia and no need for resection of bowel.

Intussusception in ChidrenIntussusception if the most common cause of intestinal obstruction in infants between 6 and 36 months of age. The vast majority (75%) are idiopathic and may be triggered by a preceding viral infection. Children outside of the normal age range may be suspected to have a pathological lead point. The classic presentation is a child with intermittent, severe, crampy abdominal pain, sometimes with vomiting and grossly bloody stools. In a minority of cases children can present with altered mental status from the third spacing and dehydration that can occur after prolonged obstruction. These children can be more intravascularly dry than you appreciate due to bowel wall edema and obstruction.

Radiology Pearls: In one small retrospective study, air in the cecum on more than one view in a child with LOW clinical suspicion for intussusception can help exclude instussusception. However in a study aimed at creating a clinical decision tree for intussusception, more than 20% of patients with intussusception had negative plain films. Our recommendation is that plain radiograph should never be used alone to rule out intussusception in if there is significant clinical suspicion of the disease. Ultrasound is the method of choice to diagnose and rule out intussusception in the hands of an experienced ultrasonographer. Classic ultrasound images include a bull’s eye or coiled spring appearance. Plain radiograph findings suspicious for intussusception include a target and crescent sign and lack of air in the cecum. These findings can often be quite subtle (see last page)

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SummaryKey Points• Develop a checklist for how you read pediatric abdominal radiographs, and understand their limitations and utility with true

emergencies.

• A child between the ages of 6 to 36 moths with worsening vomiting and colicky pain should raise the concern of intussusception. Ultrasound is the imaging modality of choice to rule in/out this illness at DCMC.

•Early diagnosis of intussusception is key to successful reduction with air contrast enema

•Diagnostic momentum - Take pause in your initial diagnostic consideration if the child is failing to improve as expected. Review your differential and make sure you did not have

premature closure to considering other illnesses. Be wary of the child with vomiting and no diarrhea.

Pediatric Abdominal Radiographs• Gas distribution - a paucity of gas or gasless abdomen is suspicious for pathology but not specific. In obstruction you should see a preference for air proximal to the obstruction versus an ileus where this is no preference. See first picture with mostly small bowel loops

• Bowel dilatation - In children with obstruction you usually see dilated bowel with smooth walls (loss of plicae and haustration). The bowel can resemble sausages or hoses (see first picture). Short segments of dilation adjacent to areas of inflammation are called sentinel loops and may raise the suspicion of pathology depending on the location (i.e. RLQ sentinel loop, ? appy) *** - Tricks of the trade: If infant/toddler is not yet toilet trained loop of bowel should be no wider than L3 (from pedicle to pedicle)

• Air Fluid Levels - In obstruction, there is characteristically more air fluid levels than an ileus and they may be more dilated. One can see short air fluid levels in both limbs of what look like hairpin loops of intestine. See picture 2

• Arrangement of loops - Most helpful on the supine view. Obstruction can have dilated loops in a stepladder fashion (“bag of sausages”). Ileus usually shows more disorderly scattered loops (“bag of popcorn”)

Radiographs on the left:

• Picture 1 - Small bowel dilated loops, more bag of sausage than popcorn. Small bowel obstruction from an incarcerated hernia in a 17 day old

•Picture 2 - Although distributed gas, is limited to just a few bowel segments. Smooth bowel walls, hard to tell if small or large bowel. Multiple air fluid levels on left. In a 9 day old this is obstruction until proven otherwise. Dx: Hirschsprung’s disease

• Picture 3 and 4 - Can you see the subtle target sign in the RUQ in Picture 3? The crescent sign is also subtle and signifies the intussusceptum protruding into a large gas filled pocket. DX: Intussusception.

Special Thanks: To Gael Lonergan and the pediatric radiology department of ARA for their support in teaching us all on how to better read and make decisions regarding pediatric imaging. To the staff at DCMC ED who spend tireless hours to take the time to teach and train the next generations while working in a busy emergency department.Sources:

1.Dell Children’s Medical Center Pediatric Radiology Teaching Folder,

2.University of Hawaii Pediatric Emergency Medicine XRAY Teaching Cases

3. uptodate.com

4. Accuracy of plain radiographs to exclude the diagnosis of intussusception. Pediatr Emerg Care. 2012. Roskind CG, et al.

5. Risk stratification of children being evaluated for intussusception. Pediatrics. 2011. Weihmiller SN, et al.