Intussusception: quick review

(scroll to bottom for 10-second version)

DEMOGRAPHICS

--most common cause of intestinal obstruction in kids 3 months-6 years of age.

--male:female ratio is 4:1

--Seasonal variation with peaks after GI viral illness seasons.

PATHOPHYSIOLOGY
--In younger children, the ileum invaginates into the upper colon, bringing the mesentery with it (ileocolic).

--lead point is often lymphoid hyperplasia from viral gastroenteritis. 

--In older children, ileo-ileo intussusceptions are more common. 

--lead point causes include intestinal polyps, Meckel diverticulum, lymphosarcoma, or even HSP

--Constriction of the mesentery obstructs venous return, leading to bowel ischemia and bloody stools leading to the classic “currant jelly” stool, which is a late finding occurring in about 50% of cases. 

CLINICAL FEATURES

--Sudden colicky abdominal pain (child will stop, cry, draw up their legs, and then after a few minutes the child appears well). 

--As the condition progresses the time between episodes decreases.   
--Stool is generally guaiac positive even in the absence of gross blood. 
--A palpable sausage shaped mass can be found on the right side of the abdomen in about 2/3 of cases

DIAGNOSIS
--Diagnosis often made by history alone
--KUB may suggest a filling defect in the right lower quadrant of the abdomen or can be normal
--US can often show the classic target appearance of bowel within bowel (donut sign (transverse); sandwich sign (longitudinal)

TREATMENT
--Air contrast enema is preferred over barium enema because it enables better control over colonic pressure and in the case of perforation prevents barium spillage into the peritoneum.
--Children generally admitted for observation because of the 5-10% recurrence rate.  A second attempt at air reduction is usually successful, but if further recurrences occur surgical reduction may be necessary.  

10-SECOND RECAP:

--most common in kids 3 mo-6 yrs old; male:female 4:1

--ileocolic (younger), ileo-ileo (older), or wherever

--common lead points (lympoid hyperplasia from gastroenteritis, polyps, meckel's, cancer, HSP, etc.)

--bowel ischemia -> guaiac+ stool -> occasionally currant jelly stool

--history is key, palpable sausage in RLQ in 2/3, KUB maybe, ultrasound (donut/sandwich signs)

--air contrast enema = diagnostic + therapeutic; surgery if that doesn't work

Submitted by J. Grover.

Reference(s): Tintinalli's Emergency Medicine, picture 1, KUB, donut, sandwich