Transcript The Pediatric Abdomen

The Pediatric Abdomen:
Intussusception
Mark Y. Wahba
X-ray rounds
October 9th, 2003
Intussusception
• most common cause of intestinal obstruction
between 3 mo and 6 yr of age
• 60% per cent of patients are younger than 1
yr
• 80% of the cases occur before 24 mo
• rare in neonates
• incidence 1-4/1,000 live births
• male:female ratio is 4:1
Clinical Presentation
• “sudden onset, in a previously well child, of severe
paroxysmal colicky pain that recurs at frequent
intervals and is accompanied by straining efforts with
legs and knees flexed and loud cries”
• Vomiting in most cases and is usually more frequent
early
• In the later phase, the vomitus becomes bile stained
• Stools of normal appearance may occur during the
first few hours of symptoms
• then fecal excretions are small or more often do not
occur, and little or no flatus is passed
Clinical Presentation
• Blood generally is passed in the first 12 hr but
at times not for 1-2 days and infrequently not
at all
• 60% of infants pass a stool containing red
blood and mucus, the currant jelly stool
• Some patients have only irritability and
alternating or progressive lethargy
• Eventually a shock-like state may develop,
with an elevation of body temperature to as
high as 41°C (106°F)
Clinical Presentation
• palpation usually reveals a slightly tender
sausage-shaped mass
• often in the right upper quadrant
• about 30% of patients do not have a palpable
mass
• presence of bloody mucus on the finger after
DRE supports the diagnosis
• abdominal distention and tenderness develop
as intestinal obstruction becomes more acute
Normal Abdomen
18 month old male
Case 1
2 month old female
Radiographic signs of
Intussusception
1. target sign
2. crescent sign
3. absent liver edge sign (also called
absence of the subhepatic angle)
4. bowel obstruction
Keep in mind…
plain abdominal films cannot be
used to rule out intussusception
Target sign
• a mass in the right upper quadrant
• sometimes does not have a target
appearance
• may just resemble a solid mass
• “pseudokidney” sign because it may
have the shape of an oval mass in the
RUQ
Crescent Sign
• caused by the intussuscepting lead
point protruding into a gas filled pocket
• if the pocket is large, it may not be
crescent shaped
• direction of the crescent always points
in the direction of normal colon transit
Absent Liver Edge Sign
• Failure to see inferior edge of liver
• Caused by mass in RUQ
• Silhouetting of the liver edge
Bowel Obstruction
1. gas distribution
•
poor: not much gas over most of the abdomen
2. bowel dilation
•
not a measured diameter of the bowel, but rather the loss of plications
such that a smooth hose-like or sausage-like appearance results
3. air-fluid levels
•
classic candy cane (or upside down J) appearance where the level in one
half of the loop is different from the level in the other half of the loop
4. orderliness
•
does view resembles a bag of sausages (obstruction) or a bag of
popcorn (ileus)?
Back to Case 1
2 month old female
Case 2
3 year old female
Case 3
3 yr old male
Case 4
21 month old male
Case 5
8 month old male
Case 6
7 month old male
You think Intussusception,
What next?
1. Alert surgery that you are sending someone
for imaging to rule out intussusception
2. Get plain films
3. If Hx, Phy and plain films convincing:
•
Air/Contrast Enema
4. If Hx, Phy and plain films not completely
convincing:
•
Ultrasound followed by Air/Contrast enema if
necessary
Air/Contrast Enema
• diagnostic and
therapeutic
• shows a filling defect in
the head of contrast
where its advance is
obstructed by the
intussusceptum
• “contrast material
between the
intussusceptum and the
intussuscipiens is
responsible for the coilspring appearance”
Ultrasonography
• a sensitive
diagnostic tool
• see a tubular mass
in longitudinal views
and a doughnut or
target appearance in
transverse images
Why Ultrasonography if Enema is
diagnostic and therapeutic?
• Fast (if operator available)
• No radiation
• Can rule in/out other pathology
– eg. appendicitis
Summary
• Radiographic signs of Intussusception:
1.target sign
2.crescent sign
3.absent liver edge sign (also called
absence of the subhepatic angle)
4.bowel obstruction
• May have a normal x-ray!
References
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Find the Intussusception Target and Crescent Signs Radiology Cases
in Pediatric Emergency Medicine Volume 7, Case 18 Loren G.
Yamamoto, MD, MPH University of Hawaii John A. Burns School of
Medicine
http://www.hawaii.edu/medicine/pediatrics/pemxray/v7c18.html
Behrman: Nelson Textbook of Pediatrics, 16th ed., 2000 W. B.
Saunders Company
Index of suspicion. Case 2. Diagnosis: intussusception, Muhammad
Waseem MD, Orlando Perales MD, Pediatrics in Review, Volume 22 •
Number 4 • April 2001
James D'Agostino MD, COMMON ABDOMINAL EMERGENCIES IN
CHILDREN Emergency Medicine Clinics of North America Volume 20 •
Number 1 • February 2002 W. B. Saunders Company
Dr. M. Hodsman
Peter the radiiology resident and unknown Radiologist at Alberta
Children’s Hospital
Extra slides
From various sources
Intussusception
• cause of most intussusceptions is unknown
• seasonal incidence has peaks in spring and
autumn
• correlation with adenovirus infections has
been noted
• postulated that swollen Peyer’s patches in the
ileum may stimulate intestinal peristalsis in an
attempt to extrude the mass, thus causing an
intussusception
Pathopysiology
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Intussusceptions are most often ileocolic and ileoileocolic, less commonly
cecocolic, and rarely exclusively ileal
Very rarely, the appendix forms the apex of an intussusception
The upper portion of bowel, the intussusceptum, invaginates into the lower, the
intussuscipiens, dragging its mesentery along with it into the enveloping loop.
Constriction of the mesentery obstructs venous return; engorgement of the
intussusceptum follows, with edema, and bleeding from the mucosa leads to a
bloody stool, sometimes containing mucus
The apex of the intussusception may extend into the transverse, descending, or
sigmoid colon--even to and through the anus in neglected cases. This
presentation must be distinguished from rectal prolapse
Most intussusceptions do not strangulate the bowel within the first 24 hr but may
later eventuate in intestinal gangrene and shock
Clinical Presentation
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Intussusception should be considered strongly in the presence of a
distinctive triad of factors: vomiting without diarrhea; colicky, intermittent
abdominal pain; and heme-positive stool. It is important to remember
that only 20% of infants who have ileocolic intussusception have this
typical triad.
A definite anatomic lead point can be recognized in up to 10% of cases.
Lead points are more common in neonates, older children, and adults
than in infants between 5 and 24 months of age. The typical lead points
include Meckel diverticulum, intestinal polyps, intestinal duplications,
appendix, and neoplastic lesions. Lead points also occur more
frequently in patients who have certain conditions, such as cystic
fibrosis, Henoch-Schönlein purpura, Peutz-Jeghers syndrome, and
hemolytic-uremic syndrome.
Some children who have this condition become very still, listless, and
pale and appear to be in shock due to the visceral pain. Lethargy may
be the only presenting sign of intussusception in up to 10% of cases.
The mechanism causing lethargy is unknown, although it is possible
that endorphins or intestinal hormones resulting from the
gastrointestinal insult are responsible.
Treatment
• Reduction of an acute intussusception is an emergency
procedure and performed immediately after diagnosis in
preparation for possible surgery
• In patients with prolonged intussusception with signs of
shock, peritoneal irritation, intestinal perforation, or
pneumatosis intestinalis, hydrostatic reduction should not
be attempted
• success rate of hydrostatic reduction under fluoroscopic or
ultrasonic guidance is approximately 50% if symptoms are
present longer than 48 hr and 75-80% if reduction is done
within the first 48 hr
• Bowel perforations occur in 0.5-2.5% of attempted barium
reductions. The perforation rate with air reduction ranges
from 0.1-0.2%