DESCRIPTION 
- The proximal bowel invaginates into the distal bowel, producing infarction and gangrene of the inner bowel:
- > 80% involve the ileocecal region.
- Often occurs with a pathologic lead point in children > 2 yr:
- Hypertrophied lymphoid patches may be present in infants.
- Children > 2 yr: 1/3 of patients have pathologic lead point.
- Children > 6 yr: Lymphoma is the most common lead point.
- Adults usually have a pathologic lead point.
- The most common cause of intestinal obstruction within the 1st 2 yr of life
- Epidemiology in US:
- Most frequently between 5 and 9 mo of age
- Incidence is 2.4 cases per 1,000 live births.
- Male > female predominance of 2:1
- Mortality < 1%
- Morbidity increases with delayed diagnosis.
ALERT
Patients, particularly those in the pediatric age group, with a picture of potential intestinal obstruction, especially with hematest-positive stool or altered mental status, need to have intussusception considered.
ETIOLOGY
- Most cases (85%) have no apparent underlying pathology.
- Predisposing conditions that create a lead point for invagination, esp. in older children and adults:
- Masses/tumors:
- Infection:
- Adenovirus or rotavirus infection
- Parasites
- Foreign body
- Henoch–Schönlein purpura
- Celiac disease and cystic fibrosis (small intestine intussusception)
[Outline]
SIGNS AND SYMPTOMS
History
- Classic triad (present in < 50% of patients):
- Recurrent painful episodes accompanied by pallor and drawing up of the legs; intermittent fits of sudden intense pain with screaming and flexion of legs:
- Occur in 5–20 min intervals
- Mental status changes:
- Irritability
- Lethargy or listlessness; child can be limp or have a rag doll appearance.
- May precede abdominal findings.
- Stool variable:
- Heme-positive (occult), bloody, or "currant jelly"
- Preceding illness several days or weeks prior to the onset of abdominal pain:
- Diarrhea
- Viral syndrome
- Henoch–Schönlein purpura
- Recurrent intussusception occurs in < 10% of patients.
Physical Exam
- Fever
- Abdomen distended and swollen:
- A "sausage" mass may be palpated in the right upper quadrant.
- May have absent cecum in right iliac fossa.
- Peristaltic wave may be present.
- Rectal exam may reveal bloody stool and palpable mass.
- Dependent on the time from onset to diagnosis; perforation with peritonitis and sepsis may be present.
ESSENTIAL WORKUP
- The diagnosis is suggested by the history and is proven radiographically.
- A heme-positive stool may aid in the diagnosis, particularly in the presence of lethargy or listlessness.
DIAGNOSIS TESTS & INTERPRETATION
Lab
- CBC
- Serum electrolytes, BUN
- Type and cross-match
Imaging
- Abdominal radiograph:
- Abnormal in 35–40% of patients
- Decreased bowel gas and fecal material in the right colon
- Abdominal mass
- Apex of intussusceptum outlined by gas
- Small bowel distention and air–fluid levels secondary to mechanical obstruction
- May aid in excluding intestinal perforation.
- Enema:
- Often both diagnostic and therapeutic. Reoccurrences do happen.
- 74% successful if intussusception present ≤24 hr
- 32% effective when present > 24 hr
- The more distal the intussusception, the lower is the ability to reduce it radiographically.
- Recurrent disease (up to 10%) has similar success to initial episode.
- Complications include bowel perforation, reduction of necrotic bowel, incomplete reduction with delay in surgery, and overlooking pathologic lead point.
- Hypovolemic shock reported following reduction secondary to endotoxins and cytokines.
- Barium:
- Traditional standard for diagnosis and treatment
- Characteristic coiled-spring appearance
- Air:
- Fluoroscopic guidance
- Avoids peritoneal contamination if perforation
- Increasingly used for diagnosis and treatment
- Contraindications:
- Peritonitis
- Perforation
- Unstable patients secondary to sepsis or shock
- US is highly accurate and may be useful as a screening technique; operator dependent:
- Typical appearance is a "donut" or "bull's eye" structure, with hyperechoic core surrounded by hypoechoic rim of homogeneous thickness.
Diagnostic Procedures/Surgery
If enema is unsuccessful in reducing, surgery is required on an emergent basis.
DIFFERENTIAL DIAGNOSIS
[Outline]
PRE-HOSPITAL
- IV access
- IV bolus of 20 mL/kg of 0.9% NS or lactated Ringer (LR) if evidence of hypovolemia, abdominal distention, peritonitis, sepsis
- Diagnosis rarely confirmed in pre-hospital setting
INITIAL STABILIZATION/THERAPY
- IV access and initiation of 0.9% NS or LR at 20 mL/kg bolus
- Nasogastric tube
ED TREATMENT/PROCEDURES
- Stabilize patient hemodynamically.
- Surgical consultation
- Abdominal radiograph film series
- Interventional radiography for reduction if no contraindications:
- Enemas are 75–80% successful at reduction, reflecting duration of condition.
- Recurrences may also be reduced radiographically.
- Antibiotics:
- Laparotomy:
- Indications:
- Enema is unsuccessful.
- Enema is contraindicated.
- Pathologic lead point
- Multiple recurrences
- Procedure:
- Gentle milking of the intussusceptum
- Resection of any nonviable bowel as well as any lead points that are identified
MEDICATION
First Line
- Ampicillin: 100–200 mg/kg/d q4h IV
- Clindamycin: 30–40 mg/kg/d q6h IV
- Gentamicin: 5–7.5 mg/kg/d q8h IV
- Ampicillin/sulbactam 100–200 mg/kg/d q6h IV
[Outline]
DISPOSITION
Admission Criteria
- Patients undergoing successful enema reduction should be observed for complications or recurrence.
- Patients undergoing surgery
Discharge Criteria
- May be considered after a very prolonged period of observation following successful enema reduction:
- Stable patient with normal mental status
- Symptomatic relief of abdominal pain during the postreduction period
- Parents have appropriate understanding to watch for potential reoccurrence, even after prolonged period observation
Issues for Referral
Surgeon should be aware of patients with potential diagnosis of intussusception.
Infants with intermittent abdominal pain, impaired mental status, and blood in stools should generally have intussusception considered.