1. The Pediatric Abdomen: Intussusception
Mark Y. Wahba
X-ray rounds
October 9th, 2003

2. 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

3. 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
Infant May be comfortable and play normally between the paroxysms of pain, but if the intussusception is not reduced, the infant becomes progressively weaker and lethargic
It is common for these infants to have a history of severe intermittent abdominal pain every 20 to 30 minutes, with periods of relief lasting 10 to 20 minutes, during which they can appear calm and health
lethargy may be out of proportion to the abdominal signs

4. 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)
classic currant jelly stool is a late manifestation of the disease
pulse becomes weak and thready, the respirations become shallow and grunting, and the pain may be manifested only by moaning sounds

5. 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

6. Normal Abdomen
18 month old male

7. Gas Distribution: There are pockets of gas scattered in several areas of the abdomen. There is gas in the small bowel, colon, and rectum.
Bowel Dilatation: No excessively dilated bowel. The bowel walls are not smooth. Haustra and plicae are preserved.
Air-Fluid Levels: None.
Arrangement of Loops: Large loops are not present.
Impression: Within normal limits.

8. Case 1
2 month old female
All of these patients are vomiting with varying degrees of abdominal pain

10. Radiographic signs of Intussusception
target sign
crescent sign
absent liver edge sign (also called absence of the subhepatic angle)
bowel obstruction
But Normal abdominal radiographs do not rule out intussusception

11. plain abdominal films cannot be used to rule out intussusception
Keep in mind…
plain abdominal films cannot be used to rule out intussusception

12. 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

13. 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
Thus, it should be more generically called the intussusceptum protruding into a gas filled pocket sign, but this is too long and it is not nearly as catchy as the "crescent" sign.
superiorly if found in the ascending colon, right to left if found in the transverse colon, and inferiorly if found in the descending colon

14. Absent Liver Edge Sign Failure to see inferior edge of liver
Caused by mass in RUQ
Silhouetting of the liver edge

15. Bowel Obstruction gas distribution bowel dilation air-fluid levels
poor: not much gas over most of the abdomen
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
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
orderliness
does view resembles a bag of sausages (obstruction) or a bag of popcorn (ileus)?

16. Back to Case 1
2 month old female

18. 2 month old female

19. Case 2
3 year old female

21. There is a target sign in the right upper quadrant
In this case, the crescent sign truly is crescent shaped. Note that it again points in the direction of normal colon transit.

22. Case 3
3 yr old male

24. is a crescent sign in the right upper quadrant, which is definitely not crescent shaped. The intussuscepting lead point is pointing cephalad at the hepatic flexure. The colonic
air pocket is large in this case, so the classic crescent
shape is not seen. This is why it should more accurately be called the intussusceptum protruding into a gas filled pocket sign, but this is too long to say. Note again that the intusscepting lead point always points in the direction of normal colon transit

25. Case 4
21 month old male

27. Supine
There is a right upper quadrant mass and obliteration of the liver margin.

28. There possibly is a faint target sign in the right upper quadrant
Upright
There possibly is a faint target sign in the right upper quadrant

29. Case 5
8 month old male

31. This is an 8 month old male. supine
This is an 8 month old male. supine. The inferior liver margin is not visible. Now look carefully for a target sign. There is a target sign in the right upper quadrant.

32. There is also strong evidence for a bowel obstruction
There is also strong evidence for a bowel obstruction. There is an overall
paucity of gas which is poorly distributed. There is evidence of bowel dilation, especially on the upright view (right image). Note that most of the bowel is
smooth, resembling hoses. The smooth bowel wall appearance results when excessive bowel dilation results in the loss of haustration and plication. There
aren't many air fluid levels, but the degree of orderliness resembles a bag of sausages more so than a bag of popcorn. This type of bowel obstruction with a paucity of bowel gas in an infant or young child is frequenty associated with intussusception

33. Case 6
7 month old male

35. there is a mass appearance in the right upper quadrant of the supine view on the left. This might be a target sign. I’m not convinced
Bowel obstr:
1) gas distribution: paucity of gas in abdomen
2) bowel dilation: dilated, smooth loops, no plica circularis
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: looks like sausages, not popcorn

36. You think Intussusception, What next?
Alert surgery that you are sending someone for imaging to rule out intussusception
Get plain films
If Hx, Phy and plain films convincing:
Air/Contrast Enema
If Hx, Phy and plain films not completely convincing:
Ultrasound followed by Air/Contrast enema if necessary

37. 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 coil-spring appearance”

38. Ultrasonography a sensitive diagnostic tool
see a tubular mass in longitudinal views and a doughnut or target appearance in transverse images
in the diagnosis of intussusception
used in conjunction with hydrostatic or air reduction techniques but not here

39. Why Ultrasonography if Enema is diagnostic and therapeutic?
Fast (if operator available)
No radiation
Can rule in/out other pathology
eg. appendicitis

40. Summary Radiographic signs of Intussusception: target sign
crescent sign
absent liver edge sign (also called absence of the subhepatic angle)
bowel obstruction
May have a normal x-ray!

41. References
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
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

42. Extra slides
From various sources

43. 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

44. Pathopysiology
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

45. Clinical Presentation
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.

46. 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 % of attempted barium reductions. The perforation rate with air reduction ranges from %