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PEMdatabase.Org
Pediatric Abdominal Emergencies
Loren G. Yamamoto, MD, MPH, MBA, FAAP, FACEP
Pediatric abdominal emergencies are challenging diagnostic entities (1).
Whenever a correct diagnosis is made, a great deal of satisfaction results since significant
morbidity and mortality is avoided. Yet, these diagnostic entities are difficult, resulting
in frequent misdiagnoses and consequent morbidity and mortality. The purpose of this
essay is to familiarize the reader with these entities which include appendicitis,
intussusception, malrotation with midgut volvulus and Meckel's diverticulum. For all of
these conditions, an early diagnosis is associated with a substantially better outcome,
compared to a late diagnosis. Although there are other abdominal emergency conditions,
this essay will be limited to covering these four topics.
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Appendicitis
Appendicitis is the most common of the serious abdominal conditions. Without
quoting an actual incidence figure, it is only important to realize that children with
appendicitis will be encountered frequently, especially in an emergency department. This
makes appendicitis one of the most common serious pediatric conditions to be
encountered. Parent/patient expectations regarding appendicitis are unforgiving in that
since most lay perons have heard of appendicitis and have relatives or friends who have
had appendicitis, this should be a very easy diagnosis to make in the minds of most
parents/patients. Unfortunately, the diagnosis of appendicitis is difficulty. The
misdiagnosis rate is difficult to determine since no one likes to brag about their high
misdiagnosis rates in the literature. However, it may be as high as 50%, which means
that roughly 50% of the patients who have appendicitis, have seen a physician on a
previous encounter for which a different diagnosis (a misdiagnosis) was given. This is
probably because roughly 50% of the cases present in an atypical fashion. The more
atypical the clinical presentation is, the more likely it is, that a physician will misdiagnose
the case (1-6). Adding to the difficulty, is that patients frequently present very early in
their clinical course, when only mild and less specific symptoms may be present.
Infants and young children are especially difficult to evaluate since they can't
speak and their examination is difficult. Their chief complaint is often vomiting, which is
often attributed to gastroenteritis. It is almost impossible to perform an adequate
examination of the infant abdomen while they are supine on a gurney. It may be better to
have the parent carry the child (upright with the child's head on the parent's shoulder)
while the examiner wraps his/her hands around the infant's abdomen from behind. The
fingers can then be used to press on the abdomen in the RLQ and other areas. Infants are
usually content in this position and are easy to examine. Discomfort which occurs from
pressing on the abdomen is suspicious for appendicitis, especially if it occurs on the right
side. Older infants may still cry because of stranger anxiety, in which case, it is
sometimes useful to explain this maneuver to the other parent, who can do this for you
when you step out of the room. By utilizing the parent as an examiner, a more accurate
exam can be done. Another useful maneuver for infants and young children, is to have
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the parent bounce the child up and down (similar to an older child jumping). A happy
and interactive child suggests the absence of peritonitis, while fussiness with this
maneuver should raise the suspicion of peritonitis and appendicitis.
Classic symptoms of appendicitis include right lower quadrant pain/tenderness,
anorexia, peritoneal signs, fever, nausea, vomiting. Of these, the most important sign is
tenderness in the right lower quadrant. Such classic presentations are the minority of
presentations. Atypical features that increase the likelihood of a misdiagnosis include
abdominal pain in a different location, diarrhea, respiratory symptoms and abdominal
pain severity which is mild or minimal. A good appetite and the absence of fever are also
misleading (2-6). CBC and acute phase reactants (ESR and CRP) are not very useful in
establishing a diagnosis, nor in ruling it out (7-11). In fact, a normal ESR/CRP and/or the
absence of a leukocytosis contributes to the likelihood of a misdiagnosis. Pyuria found
on urinalysis is often present in appendicitis, but such cases are often misdiagnosed as a
urinary tract infection (12). Gynecologic diagnoses may be a misdiagnosis or they may
occur concurrently with appendicitis. Plain film abdominal radiographs are most often
non-diagnostic. The presence of a fecalith (appendicolith) may be helpful, but this is a
rare finding and occasionally, what appears to be a fecalith, may not be. The appearance
of fecaliths varies considerably (13) and they are difficult to distinguish from other
causes of calcification in the right lower quadrant. Rectal examination is most often nondiagnostic as well since it is unconfortable in children with and without appendicitis (1417).
If a patient presents with classic appendicitis, the diagnosis is not likely to be
missed. However, in many instances, the presentation will be atypical. Since clinical
evaluation, laboratory evaluation and plain film radiographs are often unreliable in
establishing or ruling out the possibility of appendicitis, clinicians must frequently
consider the use of advanced imaging modalities such as CT scanning and ultrasound.
The comparison between the two has been documented in numerous studies (18-32). To
summarize these basically, ultrasound is faster, less invasive and less accurate, compared
to CT scanning which is slower, results in radiation exposure, requires contrast, but it is
more accurate.
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Ultrasound is highly dependent on the interpreter of the study (i.e., the skill of the
ultrasonographer or radiologist). Most studies investigating its diagnostic accuracy have
originated from ultrasound supercenters utilizing ultrasound superspecialists. Such
expertise is not likely to exist in community general hospitals. Ultrasound is frequently
non-diagnostic in that the appendix is not visualized directly. The presence of absence of
free fluid in the abdomen may be helpful, but it is not definitive enough. The advantage
of ultrasound is that it is non-invasive and it does not expose the patient to radiation. In
females, ovarian pathology may be identified as an alternate diagnosis (but only if the
patient's bladder is full, required for transabdominal ultrasound). Vaginal probe
ultrasound use is generally not feasible in children.
CT scanning is more accurate. Most centers utilize GI contrast (either PO or
rectal) plus IV contrast. Contrast is not absolutely necessary, but it appears to add to the
diagnostic accuracy. Rectal contrast is faster, but it is messy and uncomfortable, making
some children fussy during the CT scan. PO contrast is slower since it is preferable for
the the contrast to travel down as far as possible (frequently 1 to 2 hours). Vomiting
patients can be given 1 to 1.5 mg/kg of Zofran (ondansetran) IV, to help them hold down
oral contrast, but this sometimes does not work.
Combining ultrasound with CT scan in a strategic fashion requires knowledge of
the expertise available in a specific institution. For example, if a highly skilled
ultrasonographer is available, it may be advantageous to start with ultrasound. However,
if a general adult radiologist is on call for ultrasonography, it may be preferable to go
straight to a CT scan. Parents/patients should also understand that if an ultrasound is
done first and it is non-diagnostic, they will still be charged for the ultrasound, plus the
subsequent CT scan.
Whetever advanced imaging modality is selected, 100% accuracy is not
guaranteed. A patient with a high clinical probability of appendicitis and an imaging
study negative for appendicitis should still be hospitalized. A second opinion to interpret
the CT scan can also be requested in some institutions (especially those that utilize
teleradiology). Some general hospitals may benefit by utilizing a pediatric radiology
group to interpret their CT scans by teleradiology.
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Surgical consultation has changed dramatically with the use of advanced imaging.
In the past, a patient suspected of having appendicitis would require a consultation with a
reluctant surgeon who frequently asked questions over the phone regarding the WBC,
temperature, location of pain, rebound, etc. Most of these surgical consultations were
negative and the accuracy of the surgeon was not perfect. With advanced imaging,
consulting a surgeon is now an efficient process consisting of a brief telephone
interchange. "Dr. Surgeon, I have a 7 year old with appendicitis confirmed on CT scan."
The surgeon replies, "I'll be there." The evolution of this consultation pattern is still
maturing. A patient who has a high clinical probability of appendicitis should probably
have an immediate surgical consultation, avoiding an advanced imaging study. However,
surgeons are loathe to operate on non-appendicitis case as well, since what appears to be
appendicitis clinically, may not be such. Thus, even in classic presentations of
appendicitis, the consulting surgeon will often order an imaging study to confirm this to
assist with the decision on whether to operate. The decison on when to consult a surgeon
should depend on the resources available at the institution. In an institution with only one
surgeon who was up all night the previous night, it would be preferable to consult this
extremely budy and tired individual, only after imaging confirmation of appendicitis. But
in an institution with surgical residents or many surgeons immediately available, it would
be preferable to consult a surgeon earlier.
A suggested algorithm follows: For a patient with a high clinical probability of
appendicitis: Go straight to a surgical consultation or advanced imaging study. For all
other patients with abdominal pain:
Consider starting with an optional abdominal series. If constipation is suspected,
administer an enema. If the enema treatment results in 100% resolution of the abdominal
pain, then the patient can be discharged with the abdominal pain instruction sheet. Such
patients should be able to jump up and down without any pain. However, if pain is still
present, then an assessment of the probability of appendicitis (or other serious condition)
should be considered and discussed with the parents. In a low risk patient, home
observation with specific instructions is acceptable, as long as this is acceptable to the
parents and their assessment skills are deemed to be satisfactory. If any party (clinician
or parents) are uncomfortable about the possibility of appendicitis, then advanced
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imaging is indicated. Optional laboratory studies can be ordered simultaneously (CBC,
lipase, ALT, UA, chemistry, etc.).
In my experience, I have seen patients with appendicitis who present with
epigastric pain, left sided pain and minimal pain while they jump up and down. Consider
advanced imaging for all causes of abdominal pain. There are more advanced imaging
studies being ordered than ever before. CT scans have proliferated to nearly every
hospital in the U.S.A. There are two sides of this argument. Some might consider this to
be an excessively liberal use of advanced imaging. Others would argue that by restricting
advanced imaging use, we are withholding technology from patients. Both arguments are
valid, leaving clinicians to make the decision.
Clinical Tips:
1. Have the patient cough, then jump up and down. For infants and young
children, have the parents bouce the child and observe them for discomfort.
2. Examine small children and infants from the back while the parent is carrying
them.
3. Vomiting in infants should be worrisome and not routinely assumed to be
gastroenteritis.
4. Utilize advanced imaging liberally.
5. Realize that appendicitis is common, so it is fairly likely that this patient will
have it.
6. Although pneumonia is a common cause of abdominal pain, the presence of
pneumonia does not rule out the possibility of appendicitis.
7. Provide all patients with a standardized information sheet on abdominal pain.
Clinical Pitfalls:
1. Never tell a patient that they DO NOT have appendicitis. This diagnosis is too
occult ever be sure about this. Instead, acknowledge the uncertainty honestly and
encourage them to return or call if their condition worsens.
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2. In patients with a high clinical probability of appendicitis, it may be preferable
to hospitalize patients with negative abdominal CT scans or ultrasounds (i.e., CT and
ultrasound are not 100% accurate).
References
1. Schnaufer L, Mahboubi S. Chapter 118-Abdominal Emergencies. In:
Fleisher GR, Ludwig S (eds). Textbook of Pediatric Emergency Medicine, 4th edition,
2000. Philadelphia: Lippincott Williams & Wilkins, pp. 1513-1538
2. Horwitz JR, Gursoy M, Jaksic T, Lally KP. Importance of diarrhea as a
presenting symptom of appendicitis in very young children. Am J Surg. 1997
Feb;173(2):80-82.
3. Reynolds SL. Missed appendicitis in a pediatric emergency department.
Pediatr Emerg Care 1993;9(1):1-3.
4. Rothrock SG, Skeoch G, Rush JJ, Johnson NE. Clinical features of
misdiagnosed appendicitis in children. Ann Emerg Med 1991;20(1):45-50.
5. Rappaport WD, et al. Factors Responsible for the High Perforation Rate Seed
in Early Childhood Appendicitis. Am Surg 1989;10(55):602.
6. Bender JD, et al. Childhood Appendicitis: Factors Associated with
Perforation. Pediatrics 1985;76(2):301.
7. Gronroos JM. Do Normal Leucocyte Count and C-Reactive Protein Value
Exclude Acute Appendicitis in Children? Acta Ped 2001;90:649.
8. Chung JL, et al. Diagnostic Value of C-Reactive Protein in Children With
Perforated Appendicitis. Eur J Ped 1996;155(7):529.
9. Lau WY, et al. Leucocyte Count and Neutrophil Percentage in Appendectomy
For Suspected Appendicitis. Aust N Z J Surg 1989;59:395.
10. Miskowiak, J., et al. The White Cell Count in Acute Appendicitis. Dan Med
Bull 1982;29(4):210.
11. Bower RJ, et al. Diagnostic Value of the White Blood Count and Neutrophil
Percentage in the Evaluation of Abdominal Pain in Children. Surg Gynecol Obstet
1981;152(4):424.
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12. Scott JH III, et al. Abnormal Urinalysis in Appendicitis. J Urol
1983;129(5):1015
13. Yamamoto LG, Goto CS. Appendicoliths. Radiology Cases In Pediatric
Emergency Medicine, 1999, Volume 6, Case 18. Available on CD-ROM and online at:
www.hawaii.edu/medicine/pediatrics/pemxray/v6c18.html
14. Brewster GS, et al. Medical Myth: A Digital Rectal Examination Should be
Performed on all Individuals with Possible Appendicitis. West J Med 2000;173:207.
15. Jesudason EC, et al. Rectal Examination in Paediatric Surgical Practice Br J
Surg 1999;86(2):376.
16. Scholer SJ, et al. Use of the Rectal Examination on Children with Acute
Abdominal Pain Clin Ped 1998;37:311.
17. Dickson AP, et al. Rectal Examination and Acute Appendicitis. Arch Dis
Child 1985;60(7):666.
18. Sivit CJ, Applegate KE, Stallion A, et al. Imaging evaluation of suspected
appendicitis in a pediatric population: effectiveness of sonography versus CT. Am J
Roentgenol. 2000;175(4):977-980.
19. Pena BM, Taylor GA, Fishman SJ, Mandl KD. Costs and effectiveness of
ultrasonography and limited computed tomography for diagnosing appendicitis in
children. Pediatrics 2000;106(4):672-676.
21. Garcia Pena BM, Mandl KD, Kraus SJ, et al. Ultrasonography and limited
computed tomography in the diagnosis and management of appendicitis in children.
JAMA 1999;282(11):1041-1046.
22. Rice HE, Arbesman M, Martin DJ, et al. Does early ultrasonography affect
management of pediatric appendicitis? A prospective analysis. J Pediatr Surg
1999;34(5):754-758. discussion 758-759.
23. Carrico CW, Fenton LZ, Taylor GA, et al. Impact of sonography on the
diagnosis and treatment of acute lower abdominal pain in children and young adults. Am
J Roentgenol 1999;172(2):513-516.
24. Ramachandran P, Sivit CJ, Newman KD, Schwartz MZ. Ultrasonography as
an adjunct in the diagnosis of acute appendicitis: a 4-year experience. J Pediatr Surg.
1996;31(1):164-167; discussion 167-169.
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25. Wong ML, Casey SO, Leonidas JC, et al. Sonographic diagnosis of acute
appendicitis in children. J Pediatr Surg 1994;29(10):1356-1360.
26. Sivit CJ, Newman KD, Boenning DA, et al. Appendicitis: usefulness of US
in diagnosis in a pediatric population. Radiology 1992;185(2):549-552.
27. Siegel MJ, Carel C, Surratt S. Ultrasonography of acute abdominal pain in
children. JAMA 1991;266(14):1987-1989.
28. Quillin SP, Siegel MJ, Coffin CM. Acute appendicitis in children: value of
sonography in detecting perforation. Am J Roentgenol 1992;159(6):1265-1268.
29. Lowe LH, Penney MW, Stein SM, et al. Unenhanced limited CT of the
abdomen in the diagnosis of appendicitis in children: comparison with sonography. Am
J Roentgenol 2001;176(1):31-35.
30. Sivit CJ, Applegate KE, Berlin SC, et al. Evaluation of suspected
appendicitis in children and young adults: helical CT. Radiology 2000;216(2):430-433.
31. Pena BM, Taylor GA, Lund DP, Mandl KD. Effect of computed
tomography on patient management and costs in children with suspected appendicitis.
Pediatrics 1999;104(3 Pt 1):440-446.
32. Balthazar EJ, Rofsky NM, Zucker R. Appendicitis: the impact of computed
tomography imaging on negative appendectomy and perforation rates. Am J
Gastroenterol 1998;93(5):768-771.
Intussusception
Intussusception is similar to appendicitis in that this is a condition that must be
diagnosed promptly. The consequence is bowel infarction and perforation.
Intussusception is most common in children under 2 years of age. However, from 2 to 7
years, it can still occur. After 7, it is unlikely to occur (1-5). There are two common and
classic presentations for intussusception: 1) Vomiting with crampy abdominal pain. 2)
Lethargic infant.
Most patients present with vomiting and crampy abdominal pain. The abdominal
manifests as severe crying episodes lasting 1 to 5 minutes separated by 3 to 30 minutes of
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normal behavior (sometimes quiet and drowsy behavior due to exhaustion) where they
have no pain. This cyclic pattern occurs as the peristaltic wave encounters the
intussception region. The vomitus does not have to be bilious since the obstruction is
usually in the ileocecal region.
The lethargic infant pattern is less common and it has been described in multiple
case reports, but unlike most case reports, this actually DOES occur. Most pediatric
emergency physicians will encounter this several times in their careers. Thus, if an infant
presents with lethargy and the diagnostic considerations include sepsis, hypoglycemia,
infant botulism, Guillaine Barre syndrome, etc., one should add intussusception to this
list of possibilities (6,7).
Atypical presentations include older children who have crampy intermittent
discomfort without vomiting, vomiting without the crampy abdominal pain, and very
early presentations of vomiting that resemble gastroenteritis.
Since vomiting is a common chief complaint, it may be difficult to identify the
occasional vomiting patient with intussusception. It is useful to ask parents if they think
that their child may be having abdominal pain. In most instances of gastroenteritis,
parents will respond that they do not think that their child is having abdominal pain.
However, in intussusception, pain is usually a prominent part of the chief complaint.
The classic triad of intussusception include vomiting, crampy abdominal pain, and
currant jelly stool. Currant jelly stool probably occurs less frequently now, since it
appears that the diagnosis is being made earlier. A sausage shaped abdominal mass is
also part of the classic presentation, and perhaps it should now become part of the classic
triad since currant jelly stool is uncommon. This sausage mass can best be palpated in
those who have very soft abdomens. In most infants and children with intussusception,
the abdomen is very soft once the painful cycle has passed, facilitating the palpation of
this mass, usually in the right side of the abdomen. In infants and children who have a lot
of muscle tone in their abdominal wall, palpation of the mass, may be very difficult.
Currant jelly stool has been alleged to be misleading term because most clinicians
don't know what it looks like and it does not occur commonly. Intussusception will more
often present with blood in the stool that does NOT resemble currant jelly. Although the
term, "currant jelly" has flair and it is easy to remember, it can distract a clinician from
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considering the possibility of intussusception if the blood in the stool does not resemble
currant jelly. Thus, whenever the term "currant jelly" is described in teaching clinicians
about intussusception, it should be pointed out that there are more cases of intussuception
that have blood in the stool which does NOT resemble currant jelly. In fact, there is not
"typical" appearance of the blood in intussusception. Classically, the "currant jelly"
appearance is gelatinous red, burgundy or maroon colored blood in the stool. The blood
may be mixed more homogenously with the stool resulting in a maroon stool or bloody
streaks in the stool. The stool may appear to be normal, but occult blood is detectable on
guaiac testing. If the stools are loose, it may have the appearance of dysentary (i.e.,
bloody diarrhea). Any type of blood in the stool should raise the possibility of
intussusception (8,9). What appears to be blood on gross inspection, should always be
guaiac'd, since children will frequently ingest red substances (fruit punch and gelatin are
common) which is the cause of the red appearance mimicking blood.
The intussusception usually originates in the ileocecal region (called ileocecal or
ileocolic intussusception). The terminal ileum intussuscepts into the cecum, then up the
ascending colon. If allowed to progress, it then proceeds to the left through the
transverse colon, then inferiorly down the descending colon. Occasionally,
intussusception may originate within the small bowel itself. Ileo-ileal intussusception is
uncommon, but when it occurs, it may be difficult to diagnose.
Patients with intussusception are frequently dehydrated, so IV fluids are usually
indicated. However, patients presenting early or those assessed as low risk initially, may
not immediately require an IV. Laboratory studies are not helpful in diagnosing
intussusception. Plain film radiographs of the abdomen can be diagnostic, but the
findings are frequently subtle. Radiographic signs indicating the presence of
intussusception include: the target sign, the crescent sign, the absence of the subhepatic
angle, and a bowel obstruction (10-12). All these signs cannot be described sufficiently
with words. Examples of these signs can be viewed using the online resources cited.
The target sign is a faint doughnut shaped mass in the right upper quadrant. The
reason for its radiographic appearance is difficult to understand. Suffice it to say that it is
subtle, you must specifically be looking for it, and its presence is almost diagnostic of
intussusception.
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The crescent sign occurs because the leading point of the intussusception
(intussusceptum) will often protrude into a gas filled pocket. When this occurs, a
crescent shape may result and this is highly indicative of intussusception. The shape of
the cresecent will always be in the direction such that the intussusceptum is pointing in
the direction of the colon (i.e., upward in the ascending colon, right to left in the
transverse colon, and downward in the descending colon). If the shape of the crescent is
going the wrong way, then this is not a true crescent sign. Sometimes, the pocket of gas
is large, so that if the intussusceptum protrudes into this, the shape will not be that of a
crescent. The "crescent sign" should be more accurately called the "intussusceptum
protruding into a gas filled pocket sign", but this is too long to say.
The absence of the subhepatic angle is present when a soft tissue mass is present
in the right upper quadrant obscuring the identification of the inferior liver margin.
When this occurs, look carefully for a target sign because it is frequently the target sign
itself that is obscuring the liver margin. Without the target sign, the absence of the
subhepatic angle is suspicious for intussusception, but the diagnostic probability
increases greatly when the target sign is present.
Intussusception may also present with a bowel obstruction picture on play film
radiographs. The mnemonic double AIM (A-A-I-I-M-M) can be used to remember the
causes of a bowel obstruction which include: adhesions, appendicitis, intussusception,
incarcerated inguinal hernia, malrotation/volvulus and Meckel's diverticulum.
Radiographic criteria for a pediatric bowel obstruction differ from the adult criteria.
Pediatric bowel obstructions will usually have a dominant radiographic appearance as a
paucity of gas or (not and) bowel dilation (13). The absence or paucity of bowel gas is
highly suggestive of a bowel obstruction. Bowel dilation (i.e., distention) criteria is not
based on the measured diameter of the bowel, but rather the smoothness of the bowel
walls, which indicates the loss of bowel haustration and plication, resulting in a picture
resembling sausages or hoses. Intussusception is a common cause of the paucity of gas
type of bowel obstruction in infants.
Some experts claim that plain film radiographs are almost always abnormal in
intussusception (4). However, this is usually determined after the fact. While plain film
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radiographs can be used to confirm or modify the likelihood of intussusception, normal
abdominal radiographs may not be sufficient to rule out intussusception.
If there intussusception is suspected, an advanced imaging study must be
performed to confirm its presence or to rule it out. A contrast enema is the most
definitive study available since a normal contrast enema will rule out the possibility of
intussusception. If the contrast enema identifies intussusception, then the pressure from
the contrast enema will usually be sufficient to reduce the intussusception, curing the
condition immediately.
Patients with a high clinical probability of intussusception should have a contrast
enema performed. However, a contrast enema is uncomfortable, it results in a higher xray radiation exposure and it has a modest complication rate. Thus, an alternative
imaging method may be considered for patients with a low or moderate clinical
probability of intussusception. CT scan and ultrasound are capable of diagnosing
intussusception. CT scanning is usually done when appendicitis is suspected, but
intussusception is found instead. Ultrasound is fairly accurate (14,15), but it is most
accurate when the study is being interpreted by a highly skilled ultrasonographer. If an
ultrasound is being considered, one must consider whether a normal ultrasound will
sufficiently rule out intussusception. In other words, if the radiologist tells me that the
ultrasound is normal, am I certain that intussusception is rule out. If significant
uncertainly still exists despite a normal ultrasound (i.e., intussusception is still possible),
then the ultrasound should not be ordered in the first place. If the ultrasound is positive
for intussusception, a contrast enema must be done to attempt reduction. If the
ultrasound is negative for intussusception, a contrast enema must still be done to rule it
out more definitively. Thus, an ultrasound should only be ordered if the clinical
probability of intussusception is low or moderate, and a highly skilled ultrasonographer is
available who can reliably rule out intussusception on ultrasound.
If a contrast enema is indicated, the options include enemas using air contrast,
barium or water soluble contrast (16,17). Most pediatric centers are favoring the use of
air contrast enemas. The reasons cited for this preference include a higher reduction
success rate and a lower risk of complications (18,19). Both of these claims are difficult
to substantiate (20). Air must be pumped in under pressure, while barium is hung from a
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bag, which presumably provides a steadier pressure gradient. If a bowel perforation
occurs during the contrast enema, air is less messy to remove compared to barium (18).
However, air flows in to the abdomen rapidly, which may cause respiratory failure
(necessitating immediate transabdominal needle decompression). Barium is less likely to
cause respiratory failure. A newer option which has been described in the literature is to
use saline or air to reduce the intussusception under ultrasound guidance (21,22). This is
not done in most U.S. centers; however, it is a trend that may gain popularity.
Another consideration is that the first goal of the contrast enema is to determine
whether intussusception is present. It is clearly easier to see using barium compared to
air. This doesn't appear to matter for highly skilled radiologists, but for non-radiologists
such as myself, it is much easier to see with barium. Textbooks covering the topic of
intussusception always show a picture of it using a barium contrast study, rather than an
air contrast study. That's because it is much easier to see with barium. After all these
considerations, the decision of which type of contast to use, should really be left to the
radiologist performing the procedure (16,23,24). If the radiologist is very familiar with
barium, and unfamiliar with air, then barium should be used and vice-versa. A
suboptimal study will result if the radiologist is forced to use a contrast material which
he/she is unfamiliar with.
The intussusception will usually be identified within the colon. However, with
ileo-ileal intussusception which has not yet crossed the ileocecal valve, contrast (air,
barium, etc.) must enter the terminal ileum to complete the study. In some instances, the
radiologist may have difficulty getting contrast past the ileocecal valve. In such
instances, ileo-ileal is not ruled out.
Is hospitalization required for all those with intussusception reduced with a
contrast enema? It is certainly reasonable to hospitalize these patients for observation or
extended bowel rest. Patients who have had symptoms for a prolonged period should be
hospitalized in most instances. If the duration of symptoms has been brief, and the child's
clinical condition has normalized following intussusception reduction and the parents are
reliable and they feel comfortable with discharge to home, then this is reasonable as well.
Clinical Tips
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1. For all patients who present with vomiting, ask parents about the presence of
abdominal pain.
2. Plain film signs of intussuception are subtle. Review the sample radiographs
in the online references to familiarize yourself with these findings.
3. A pediatric bowel obstruction has a different appearance than an adult bowel
obstruction. Most pediatric bowel obstructions are due to serious intestinal conditions
requiring immediate intervention.
4. For patients at low risk of intussusception, document that the patient does not
exhibit a crampy abdominal pain pattern on observation.
5. Although some experts suggest that air contrast enema is superior to barium
enema, this decision is best left to the radiologist performing the procedure.
Clinical Pitfalls
1. Bloody diarrhea is often due to bacterial dysentary such as shigella. However,
intussusception is a possible cause.
2. Currant jelly stools occur in the minority of cases. Any type of blood in the
stool may be due to intussusception.
3. Ordering an ultrasound for intussusception is a difficult decision and it should
depend on the diagnostic skill of the ultrasonographer. If the radiologist is unable to rule
out intussusception via ultrasound, then an ultrasound study should not be done in the
first place.
4. Intussusception cannot be totally ruled out unless contrast has entered the
terminal ileum.
5. Failure to recognize a bowel obstruction can have serious consequences since
many of the conditions causing a bowel obstruction must be corrected soon.
References
1. Schnaufer L, Mahboubi S. Chapter 118-Abdominal Emergencies. In:
Fleisher GR, Ludwig S (eds). Textbook of Pediatric Emergency Medicine, 4th edition,
2000. Philadelphia: Lippincott Williams & Wilkins, pp. 1513-1538.
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2. Kuppermann N, O'Dea T, Pinckney L, Hoecker C. Predictors of
intussusception in young children.
Arch Pediatr Adolesc Med 2000;154(3):250-255.
3. Luks FI, Yazbeck S, Perreault G, Desjardins JG. Changes in the presentation
of intussusception.
Am J Emerg Med 1992;10(6):574-576.
4. Eklof O, Hartelius H. Reliability of the abdominal plain film diagnosis in
pediatric patients with suspected intussusception. Pediatr Radiol 1980;9(4):199-206.
5. Stein M, Buchta R, Raszynski A, Nyhan WL. Intussusception. West J Med
1979;130(1):35-42.
6. Hickey RW, Sodhi SK, Johnson WR. Two children with lethargy and
intussusception.
Ann Emerg Med 1990;19(4):390-392.
7. Heldrich FJ. Lethargy as a presenting symptom in patients with
intussusception. Clin Pediatr (Phila). 1986 Jul;25(7):363-365.
8. Yamamoto LG, Morita SY, Boychuk RB, Inaba AS, Rosen LM, Yee LL,
Young LL. Stool Appearance in Intussusception: Assessing the Value of the Term
"Currant Jelly". Am J Emerg Med 1997;15(3)293-298.
9. Losek JD, Fiete RL. Intussusception and the diagnostic value of testing stool
for occult blood. Am J Emerg Med 1991;9(1):1-3.
10. Young LL, Yamamoto LG. The Stomach Flu? - The Target, Crescent, and
Absent Liver Edge Signs Radiology Cases In Pediatric Emergency Medicine, 1994,
Volume 1, Case 2. Available on CD-ROM and online at:
www.hawaii.edu/medicine/pediatrics/pemxray/v1c02.html
11. Yamamoto LG. Find the Intussusception Target and Crescent Signs.
Radiology Cases In Pediatric Emergency Medicine, 2002, Volume 7, Case 18. Available
on CD-ROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v7c18.html
12. Yamamoto LG. Lethargy and Vomiting Following Child Abuse. Radiology
Cases In Pediatric Emergency Medicine, 1996, Volume 5, Case 10. Available on CDROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v5c10.html
17
13. Chan-Nishina CC, Tim-Sing PML. Test Your Skill In Distinguishing
Obstruction From Ileus.
Radiology Cases In Pediatric Emergency Medicine, 1995, Volume 3, Case 18. Available
on CD-ROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v3c18.html
14. Harrington L, Connolly B, Hu X, et al. Ultrasonographic and clinical
predictors of intussusception. J Pediatr 1998;132(5):836-839.
15. Verschelden P, Filiatrault D, Garel L, et al. Intussusception in children:
reliability of US in diagnosis--a prospective study. Radiology 1992;184(3):741-744.
16. Calder FR, Tan S, Kitteringham L, Dykes EH. Patterns of management of
intussusception outside tertiary centres. J Pediatr Surg 2001;36(2):312-315.
17. del-Pozo G, Albillos JC, Tejedor D, et al. Intussusception in children: current
concepts in diagnosis and enema reduction. Radiographics 1999 Mar-Apr;19(2):299319.
18. Pediatr Radiol 1995;25(2):81-8 Perforation during attempted intussusception
reduction in children--a comparison of perforation with barium and air. Daneman A,
Alton DJ, Ein S, Wesson D, Superina R, Thorner P.
19. Lui KW, Wong HF, Cheung YC, et al. Air enema for diagnosis and
reduction of intussusception in children: clinical experience and fluoroscopy time
correlation. J Pediatr Surg 2001;36(3):479-481.
20. Maoate K, Beasley SW. Perforation during gas reduction of intussusception.
Pediatr Surg Int 1998 Dec;14(3):168-170.
21. Khong PL, Peh WC, Lam CH, et al. Ultrasound-guided hydrostatic reduction
of childhood intussusception: technique and demonstration. Radiographics
2000;20(5):E1.
22. Shehata S, El Kholi N, Sultan A, et al. Hydrostatic reduction of
intussusception: barium, air, or saline? Pediatr Surg Int 2000;16(5-6):380-382.
23. Poznanski AK. Why I still use barium for intussusception. Pediatr Radiol
1995;25(4):318.
24. Schmit P, Rohrschneider WK, Christmann D. Intestinal intussusception
survey about diagnostic and nonsurgical therapeutic procedures. Pediatr Radiol 1999
Oct;29(10):752-761.
18
Malrotation and Volvulus
In the normal abdomen, the small bowel is suspended by mesentary which
contains the vascular supply to the bowel. This mesentary has a broad attachment to the
abdominal wall. When considering the length of the small bowel and its multiple loops
and turns (similar to a bowl of spaghetti), it is truly remarkable that the bowel, or parts of
it, does not twist on itself (forming a volvulus) more often. The reason for this is the
broad mesentary attachment (1,2). Think of this as a broad fan or sheet of tissue
suspending the bowel, making it almost impossible for it to twist on itself. In a
malrotation, the mesentary is suspended by a stalk containing the vascular supply, rather
than a broad fan, which is susceptible to twisting. The term "malrotation" focuses
attention to its embryology which has no clinical importance to most of us. This term has
a tendency to misguide us on the true importance of its clinical consequence. Malrotation
should be renamed "Guts on a Stalk Syndrome" to emphasize the clinical importance this
abnormality.
Recall from the previous section in intussusception, that the causes of a bowel
obstruction include A-A-I-I-M-M. One of the M's stands for malrotation. In a
malrotation, i.e., Guts on a Stalk Syndrome (GOSS), a bowel obstruction can occur in
two ways. 1) The stalk can compress the duodenum (a phenomenon called Ladd's
bands). 2) The entire stalk can twist, which is known as midgut volvulus. The former
(Ladd's bands compression of the duodenum) condition is less serious in that it can easily
be corrected surgically and time is not a critical factor. However, a midgut volvulus is
potentially catastrophic. If the entire stalk twists, then ischemia to the ENTIRE small
bowel results. Failure to surgically correct this condition soon, will result in an infarction
of the entire small bowel, a condition which requires lifelong TPN (total parenteral
nutrition) for survival.
Roughly half of those born with malformation (GOSS), will manifest with an
acute bowel obstruction during the first few months of life. The remainder will often
present acutely with a bowel obstruction at any time in later life.
The term "volvulus" is used loosely, but more accurate terminology is preferable.
A midgut volvulus involves the entire small bowel twisted on its vascular stalk which
19
occurs in a malrotation. This is truly a serious condition. A sigmoid volvulus is a
condition that occurs sometimes in the elderly, in which the sigmoid colon is long and
loose, occasionally twisting and trapping a large amount of gas. This can frequently be
reduced with a rectal tube. A sigmoid volvulus usually does not result in a bowel
obstruction and it usually does not require an immediate surgical procedure. Vovulus of
the cecum (cecal volvulus) occurs occasionally, in which the cecum twists.
A patient with an acute bowel obstruction requires an immediate evaluation to
determine its cause. Symptoms and signs may include vomiting (often bilious),
dehydration, abdominal distention, abdominal pain, pallor, etc. Consultation with a
surgeon and/or pediatric radiologist will help to determine the next step in evaluation.
Plain film radiographs can usually identify a bowel obstruction, but the radiographic
findings are not always obvious (2,3). The radiographic appearance of a bowel
obstruction due to a midgut volvulus is variable. An upper GI series would appear to
show no passage of barium past the stomach. Careful identification of the duodenum will
demonstrate that the duodenal/jejunal junction (ligament of Trietz) is inferior to its
normal location (a subtle but reliable sign). Thin barium or water soluble contrast may be
able to diffuse into the midgut volvulus revealing a corkscrew appearance of the midgut
volvulus twist (4).
A barium enema will probably identify the cecum to be in the wrong position.
This is highly indicative of a malrotation, but it is possible for the cecum to be in the
correct position, despite a malrotation, so a barium enema is not perfect at identifying a
malrotation.
An ultrasound may be able to demonstrate the midgut volvulus. It may also be
able to see an abnormal anatomic location of the superior mesenteric axis that is often
(but not always) seen with a malrotation (5).
Some patients with malrotation have a phenomenon called intermittent volvulus
(2). If a midgut volvulus occurs, it starts with an initial twist. From the initial twist, it
could untwist or it could twist tighter. If the patient is lucky enough for it to
spontaneously untwist, the symptoms are likely to consist of brief bowel obstruction
symptoms followed by relief. Such episodes may recur periodically. A history
20
suggesting intermittent volvulus should prompt an imaging evaluation looking for an
asymptomatic malrotation, utilizing one of the imaging studies described above.
Clinical Tips:
1. The term "malrotation" should be more accurately called Guts on a Stalk
Syndrome.
2. A history suggesting an intermittent volvulus should prompt an imaging
evaluation looking for an occult malrotation.
Clinical Pitfalls:
1. Failure to recognize a pediatric bowel obstruction can be catastrophic if a
midgut volvulus is present.
2. Midgut volvulus is serious emergency requiring immediate diagnosis and
urgent surgical intervention.
3. The term "volvulus" by itself is an inadequate description of this clinical
condition.
1. Schnaufer L, Mahboubi S. Chapter 118-Abdominal Emergencies. In:
Fleisher GR, Ludwig S (eds). Textbook of Pediatric Emergency Medicine, 4th edition,
2000. Philadelphia: Lippincott Williams & Wilkins, pp. 1513-1538
2. Rosen LM, Yamamoto LG. Abdominal Pain and Vomiting in a 7-Year Old.
Radiology Cases In Pediatric Emergency Medicine, 1995, Volume 2, Case 8. Available
on CD-ROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v2c08.html
3. Chan-Nishina CC, Tim-Sing PML. Test Your Skill In Distinguishing
Obstruction From Ileus.
Radiology Cases In Pediatric Emergency Medicine, 1995, Volume 3, Case 18. Available
on CD-ROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v3c18.html
4. Yamamoto LG. Bilious vomiting in a 3-month old. Radiology Cases In
Pediatric Emergency Medicine, 1995, Volume 3, Case 17. Available on CD-ROM and
online at: www.hawaii.edu/medicine/pediatrics/pemxray/v3c17.html
21
5. Zerin JM, DiPietro MA. Superior mesenteric vascular anatomy at US in
patients with surgically proved malrotation of the midgut. Radiology 1992;183(3):693694.
Meckel's Diverticulum
Meckel's diverticulum is a special diverticulum located in the jejunum or ileum.
It has several distinct clinical consequences (1,2). It contains gastric mucosa, so it may
secret acid and cause a bleeding ulcer. In such instances, painless rectal bleeding may be
the presenting complaint. A "Meckel's scan" (nuclear medicine scintigraphy) can be
done to identify this condition. The radioisotope is taken up by gastric mucosa, so it will
typically image the stomach, but if a Meckel's diverticulum is present, the scan will
identify the stomach plus an ectopic source of acid secreting gastric mucosa. Barium
enema and upper GI series will often fail to identify the Meckel's diverticulum.
Meckel's diverticulum is a diverticulum (a tubular pouch), therefore, it may
become inflammed similar to the appendix resulting in Meckel's diverticulitis (3). The
clinical picture may be similar to acute appendicitis, but the pain may be in an atypical
location. This is another reason why abdominal pain in areas other than the right lower
quadrant could still be serious. In some instances, the appendicitis pain is located
elsewhere, and in rarer instances, it is a Meckel's diverticulitis causing the symptoms.
The Meckel's diverticulum may occasionally ulcerate and perforate which may present as
a bowel perforation without the preceding diveriticulitis symptoms. A CT scan or
ultrasound can sometimes identify this, but this can be a difficult diagnosis to establish
prior to surgery.
A Meckel's diverticulum may be attached to the abdominal wall and form a stalk
like connection, around which a volvulus can occur (4). A Meckel's diverticulum may
form a lead point for an intussusception (often ileo-ileal intussusception). In both such
presentations, the patient may present with symptoms of a bowel obstruction.
In summary, Meckel's diverticulum, presents with a diverse set of serious acute
surgical conditions. Many textbooks describe Meckel's diverticulum following the rule
22
of 2's: a) 2% of the population are born with a Meckel's. b) Only 2% of those with a
Meckel's manifest clinical problems. c) Usually located 2 feet proximal to the terminal
ileum and the diverticulum is usually 2 inches long. d) Symptoms commonly manifest at
age 2 years.
1. Goglia RP. Meckel's Diverticulum. In: Ashcraft KW, Holder TM (eds).
Pediatric Surgery, second edition. W.B. Saunders, Philadelphia, 1993, pp. 435-439.
2. Schnaufer L, Mahboubi S. Chapter 118-Abdominal Emergencies. In:
Fleisher GR, Ludwig S (eds). Textbook of Pediatric Emergency Medicine, 4th edition,
2000. Philadelphia: Lippincott Williams & Wilkins, pp. 1513-1538
3. Yamamoto LG. Periumbilical Abdominal Pain (Meckel's diverticulitis case).
Radiology Cases In Pediatric Emergency Medicine, 1996, Volume 4, Case 9. Available
on CD-ROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v4c09.html
4. Yamamoto LG. Bowel Obstruction With Intra-Intestinal Sand (A case of a
bowel obstruction and midgut volvulus due to a Meckel's diverticulum). Radiology
Cases In Pediatric Emergency Medicine, 1996, Volume 5, Case 19. Available on CDROM and online at: www.hawaii.edu/medicine/pediatrics/pemxray/v5c19.html