Intussusception
IncidenceIntussusception primarily affects infants and toddlers, although it can also occurprenatally or during the neonatal period. Intussusception rarely occurs in adults.The estimated incidence in the United States is about 1.5-4 cases per every 1,000live births. Males are affected more than females at a ratio of 3:2. Male predominanceis even greater in the 6-9 month age group.Incidence peaks during two seasons of the year: spring/summer and middle of winter. This seasonal variation correlates with times of increased number of cases of viral gastroenteritis and upper respiratory infection.
Etiology
Intussusception is most commonly idiopathic and no anatomic lead point can be identified. Several viral gastrointestinal pathogens (rotavirus, reovirus, echovirus) may cause hypertrophy of the Peyer’s patches of the terminal ileum which may potentiate bowel intussusception. Ileocolonic intussusception is the most common type of intussusception in children (Fig. 23.1).A recognizable, anatomic lesion acting as a lead point is only found in 2-12% of all pediatric cases. The most commonly encountered anatomic lead point is a Meckel’s
diverticulum. Other anatomic lead points include polyps, ectopic pancreatic or gastric rests, lymphoma, lymphosarcoma, enterogenic cyst, hamartomas (i.e., Peutz-
Jeghers syndrome), submucosal hematomas (i.e., Henoch-Schonlein purpura),inverted appendiceal stumps, and anastomotic suture lines. Children with cystic
fibrosis are at increased risk of intussusception possibly due to thickened inspissated stool.
Postoperative intussusception accounts for 1.5-6% of all pediatric cases of intussusception.Most of these patients develop small bowel intussusception following
operations that include retroperitoneal dissection as part of the procedure. Postoperative intussusception is the most common cause of intestinal obstruction
in the first postoperative week.
Pathology/Pathophysiology
The pathophysiology of the intussusception is that of bowel obstruction and progressive bowel ischemia. As the intussuseptum becomes invaginated within the
intussuscipiens, the bowel wall and mesentery of the intussuseptum is compressed causing venous and lymphatic occlusion, venous stasis, and edema. As the edema increases and venous outflow becomes obstructed, arterial inflow is compromised.
Inadequate perfusion leads eventually to ischemic bowel necrosis.
Clinical Presentation
Intussusception is primarily a disorder of infancy and occurs most commonly between 5–10 months of age. Two thirds of children with intussusception are less than 1 year of age at presentation. The principle signs and symptoms of intussusception
are
1. vomiting (85%),
2. abdominal pain (83%),
3. passage of blood or bloody mucous per rectum (53%),
4. a palpable abdominal mass, and
5. lethargye: The classic triad of pain, vomiting, and bloody mucous stools
(“red current jelly”) is present in only one third of infants with intussusception.
Diarrhea may be present in 10-20% of patients.
The abdominal pain of intussusception is frequently acute in onset, severe, and
intermittent. During episodes of pain the infant will often draw his/her knees up to the abdomen, scream inconsolably, and become pale and diaphoretic. Between pain
episodes, which may last only briefly, the child may be quiet and appear well. With time, the child may become more ill and appear lethargic with increasing abdominal
distention, vomiting, and progression to shock with cardiovascular collapse.Physical exam of the abdomen occasionally identifies a “sausage-shaped” mass at
the right upper quadrant or mid-abdomen. The right lower quadrant may feel empty and the cecum may not be palpable in the right iliac fossa (sign of Dance). Rectal
exam may reveal a palpable mass if the intussusception has passed far enough distally.Prolapse of the intussusceptum from the anus is a rare event (1-3%). Fever and leukocytosis are common findings. Tachycardia becomes more prominent as hypovolemia
ensues.The differential diagnosis includes intestinal colic, gastroenteritis, acute appendicitis,
incarcerated hernia, internal hernia, and volvulus
Diagnosis
If the diagnosis is suggested by history and physical exam, several radiographic studies can confirm the diagnosis. Early in the course of the illness, abdominal plain
x-ray may show a normal or nonspecific bowel gas pattern. Later, abdominal films will show a more obvious pattern of small bowel obstruction with a relative absence
of gas in the colon. In 25-60%, abdominal plain films demonstrate a right upper quadrant soft tissue density that displaces air-filled loops of bowel.
Ultrasonography of the abdomen is a reliable means to identify intussusception.
Two ultrasonographic signs of intussusception are:
1. the “doughnut” or “target” sign on transverse views, and
2. the “pseudokidney” sign on longitudinal views.
Barium or air contrast enema is the “gold-standard” diagnostic study for infants with suspected intussuception . It is both diagnostic and therapeutic in identifying and reducing intussusceptions
Treatment
Once a presumptive diagnosis of intussusception is made, the child should have
1. an intravenous line placed for rehydration,
2. a nasogastric tube placed for decompression, and
3. intravenous antibiotics started. A complete blood count, chemistry panel,and type and screen are obtained.
Hydrostatic barium enema or pneumatic enema is used to confirm the diagnosis and to reduce the intussusception. Hydrostatic reduction is contraindicated if the child has signs of peritonitis or gangrenous bowel. A surgeon should be present at the time of attempted reduction. In performing barium enema to reduce intussusception,
the barium column should be no higher than three feet above the patient.Each attempt should persist until reduction of the intussusception fails to progress
for a period of 3-5 minutes. A maximum of three attempts should be made. Successful complete reduction of the intussusception can be observed when the intussusceptum
passes through the ileocecal valve producing free flow of contrast into the distal ileum. For pneumatic reduction, air is delivered into the colon via a transanally
placed foley catheter. An initial pressure of 80 mmHg is raised to a maximum pressure of 120 mmHg. Reflux of air into the terminal ileum, seen flouroscopically,
signifies reduction of the intussusception.If the intussusception is successfully reduced, the child is admitted for overnight observation. Oral diet is resumed on the next morning. If the intussusception cannot
be completely reduced, operative intervention is indicated.
Surgery is indicated in children with:
1. clinical evidence of dead bowel,
2. peritonitis,
3. septicemia,
4. evidence of an anatomic/pathologic lead point,
5. failed enema reduction.
Surgical exploration for intussusception is performed through a right lower quadrant transverse incision. Retrograde pressure is applied by squeezing the intussusceptum within the intussucipiens in a proximal direction. No “pulling” attempts should be made at the ileal end. Following successful reduction, it is important to
assess bowel viability and search for anatomic lead points. Appendectomy is usually performed. Local or segmental resection is indicated if:
1. the intussusception cannot be reduced,
2. the segment of bowel appears infarcted or nonviable, or
3. a lead point is identified. Primary anastomosis can usually be performed with minimal morbidity.
Fever, probably related to cytokine release and/or bacterial translocation, commonly occurs following reduction of intussusception whether performed surgically
or nonoperatively and should be anticipated
Outcomes
Hydrostatic barium enema can successfully reduce intussusceptions in 50-75% of cases. Success with air insufflation for reduction is even better and may be as high
as 95%. The recurrence rate of intussusception after successful reduction (whether hydrostatic or surgical) is about 5-7%. Recurrence may be slightly lower with reduction using air insufflation. The mortality rate of intussusception is less than 1%.Mortality increases with delay in diagnosis, inadequate fluid resuscitation, perforation,and surgical complications.