The Pediatric Abdomen: Intussusception

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

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)

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

8. Case 1 2 month old female

10. Radiographic signs of Intussusception • target sign • crescent sign • absent liver edge sign (also called absence of the subhepatic angle) • bowel obstruction

11. 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

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 • 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

19. Case 2 3 year old female

22. Case 3 3 yr old male

25. Case 4 21 month old male

29. Case 5 8 month old male

33. Case 6 7 month old male

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

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 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

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 0.5-2.5% of attempted barium reductions. The perforation rate with air reduction ranges from 0.1-0.2%