Intussusception

Intussusception is the invagination of a segment of intestine into an adjacent section of intestine, potentially causing bowel obstruction and/or intestinal ischemia. Intussusception occurs primarily in infants and young children and is most commonly idiopathic. Children with intussusception usually have sudden colicky abdominal pain, intermittent vomiting, and have their knees drawn toward their chest. Some children have a palpable mass in the RUQ and/or blood in their stool. Ultrasound is the preferred diagnostic modality. In children with no evidence of bowel ischemia, intussusception is typically reduced by a radiologist using a hydrostatic or pneumatic enema. Intussusception in adults is rare and is typically caused by a pathological abnormality of the bowel (e.g., a neoplasm) that acts as a lead point. Symptoms are usually nonspecific but often include features of bowel obstruction. CT abdomen is the diagnostic modality of choice and surgical reduction is usually required. Complications in children and adults include intestinal ischemia, peritonitis, and recurrence.

• Children: most commonly affected (95% of all intussusceptions) ^[1]
  • Primarily seen in children between 3 months to 5 years of age ^[2]
  • Peak incidence: 4–18 months of age ^[3][4]
  • Incidence decreases after 2 years of age. ^[4][5]
  • ♂ > ♀
• Adults: rarely affected ^[3][4]
  • Mean age 50 years ^[4]
  • Incidence is the same in men and women.

In children, intussusception is one of the most common causes of bowel obstruction and acute abdomen. ^[3]

Epidemiological data refers to the US, unless otherwise specified.

Idiopathic ^[4]

• No identified pathological lead point
• Approx. 90% of all pediatric intussusceptions; rare in adults ^[6]
• Most common in children 3–12 months of age ^[7]
• Enlarged Peyer patches due to a viral illness (e.g., adenovirus infection) or immunization (e.g., rotavirus) are thought to act as a temporary lead point. ^[4]

Pathological lead point ^[4]

See “Pathophysiology” for the definition and mechanism of action of pathological lead points.

• Adults
  • Most common cause: neoplasms (∼ 65%)
  • Less common causes include:
    • Infections
    • Postoperative adhesions
    • Crohn granulomas
    • Congenital abnormalities (e.g., Meckel diverticulum)
• Children (uncommon)
  • Most common cause: Meckel diverticulum ^[6]
  • Less common causes include:
    • Intestinal polyps and other benign tumors
    • Hematoma, hemangioma
    • Lymphoma
  • Associated conditions include:
    • IgA vasculitis with bowel wall thickening
    • Cystic fibrosis

In children, a pathological lead point is more likely in full-term neonates, children > 5 years of age, and those with recurrent intussusception. ^[7]

• Development of a lead point: an intestinal lesion or abnormality of the intestinal wall that enables the proximal bowel to be pulled by peristalsis into the distal bowel
• Peristalsis moves the lead point distally → invagination or so-called “telescoping” of a portion of intestinal bowel (intussusceptum) into the distal adjacent bowel loop (intussuscipiens)
• Invaginated bowel leads to mechanical bowel obstruction → vomiting
• Impaired lymphatic drainage and increasing pressure in intussusceptum bowel wall → venous impairment → congestion of mesenteric vessels → ischemia of intussusceptum bowel wall → sloughing of bowel mucosa (most sensitive to bowel ischemia since it is the furthest from the arterial supply) → transmural necrosis and perforation with prolonged ischemia

Intussusception is classified by the portion and location of the bowel that has been invaginated. ^[4]

• Ileocolic (most common): terminal ileum invaginates through the ileocecal valve into the colon
• Enteroenteric: e.g., ileoileal, jejunojejunal, jejunoileal
• Colocolic: e.g., colosigmoidal, appendicocecal (rare)

The following signs and symptoms apply to children. See “Intussusception in adults” for the presentation in adults. ^[3][4]

Symptoms

• Abdominal pain
  • Acute cyclical colicky pain with asymptomatic intervals
  • Knees drawn toward the chest
• Vomiting (may be bilious in patients with bowel obstruction)
• Blood and/or bloody mucus in stool (so-called “currant jelly stool”) ^[4]
• Restlessness, irritability, and/or lethargy

Physical examination

• Abdominal tenderness
• Palpable abdominal mass; may be sausage-shaped
  • Typically in RUQ or epigastrium
  • Dance sign: RLQ is visibly empty (i.e., appears to have a scaphoid depression). ^[9]
• Abnormal bowel sounds: high pitched (early obstruction) or absent (late obstruction)

The classic triad of abdominal pain, palpable abdominal mass, and bloody stool is present in < 15% of children with intussusception. ^[4]

Approach ^[3][4][10]

See “Diagnostic workup of acute abdominal pain” for a general approach.

• Confirm the diagnosis with imaging.
  • Ultrasound abdomen: preferred in children
  • CT abdomen: preferred in adults
• Obtain laboratory studies to identify secondary complications.
• If the diagnosis remains uncertain, consider consulting radiology for an image-guided enema.

Ultrasound abdomen ^[3][4][10]

• Indication: suspected intussusception in children
• Findings
  • Target sign (transverse view): Invaginated bowel-in-bowel appears as concentric rings.
  • Pseudokidney sign (longitudinal view): Invaginated bowel looks like kidney.

Abdominal ultrasound is the preferred imaging modality in children because it has high sensitivity and specificity, minimizes radiation exposure, and facilitates immediate ultrasound-guided reduction.

CT abdomen ^[3][4][10]

• Indication: suspected intussusception in adults
• Findings
  • Target sign
  • Evidence of pathological lead point (e.g., intestinal mass)
  • Evidence of bowel ischemia

Image-guided enema ^[4][10]

• Indication: diagnostic uncertainty and/or planned reduction
• Techniques: fluoroscopic barium enema, ultrasound-guided hydrostatic enema
• Advantage: may also reduce the intussusception
• Contraindication: suspected bowel perforation

Additional studies ^[3]

• X-ray abdomen
  • Not recommended as the initial examination for suspected intussusception because diagnostic accuracy is low.
  • If performed as part of the workup for acute abdomen, distended bowel loops may be seen. ^[10]
• Colonoscopy: may identify the lead point; increased risk of perforation if there is bowel ischemia ^[4]

Differential diagnoses of lower gastrointestinal bleeding in children

Other differential diagnoses

• Acute appendicitis
• Incarcerated inguinal hernia
• Gastroenteritis
• See also “Differential diagnosis of abdominal pain.”
• See also “Differential diagnosis of bowel obstruction.”

The differential diagnoses listed here are not exhaustive.

Intussusception in children is typically initially managed with image-guided reduction. In adults, surgical treatment is usually necessary; see “Intussusception in adults” for details.

Initial management of intussusception ^[3][4]

• ABCDE assessment
• IV fluid resuscitation
• Consider NG tube placement for decompression (see also “Nonoperative management of mechanical bowel obstruction”).
• Empiric antibiotic therapy for intra-abdominal infections if intestinal ischemia or perforation is suspected
• Acute pain management and/or procedural sedation
• Surgical and/or radiology consultation

Urgent intervention is necessary to prevent potentially life-threatening complications, e.g., bowel ischemia.

Guided reduction ^[3][4][11]

• Indication: intussusception in clinically stable children
• Contraindications: suspected intestinal ischemia or perforation
• Technique
  • Fluoroscopy-guided pneumatic reduction
    • Air is injected rectally while the bowel is observed with continuous fluoroscopy.
    • Most commonly performed technique ^[10]
    • Disadvantage: radiation exposure
  • Ultrasound-guided hydrostatic reduction
    • Normal saline or water-soluble contrast is injected rectally while the bowel is observed with continuous ultrasound.
    • Avoids radiation exposure, but may not be available at all facilities
• Success rates: Reduction is achieved in ∼ 80% of patients; recurrence occurs in up to 16%. ^[10]

Image-guided reduction is contraindicated in patients with suspected gangrenous and/or perforated bowel.

Surgery ^[3][4]

• Indications
  • Signs of bowel perforation or intestinal ischemia
  • Pathological lead point on imaging
  • Unsuccessful conservative management
  • Most intussusceptions in adults; see “Intussusception in adults” for details.
• Technique
  • Open laparotomy with Hutchinson maneuver (manual proximal bowel compression to reduce the intussusception) ^[12]
  • Laparoscopic reduction
  • Possible bowel resection (e.g., for bowel ischemia, malignant pathological lead point)

Disposition ^[3][11]

• Consider discharge home if the child is stable, asymptomatic, and tolerating oral fluids 4 hours after successful reduction.
• Hospital admission is recommended for children with any of the following:
  • Persistent symptoms or unsuccessful reduction
  • Prior abdominal surgery
  • Neuromuscular disease
  • Prematurity
  • Recurrent intussusception

• ABCDE assessment
• IV fluid resuscitation
• Consider NG tube placement.
• Empiric antibiotic therapy for intra-abdominal infections if intestinal perforation or ischemia is suspected
• Acute pain management
• Obtain imaging.
  • Abdominal ultrasound in children
  • CT abdomen in adults
• Radiology consult for nonoperative reduction in children
• Surgical consultation

Intussusception is uncommon in adults and the clinical presentation is often nonspecific. ^[3][4]

• Clinical features
  • Cramping abdominal pain
  • Symptoms of bowel obstruction
  • Constipation, vomiting
  • Nonspecific physical findings (e.g., abdominal distention)
• Diagnostics
  • CT abdomen is the recommended initial study.
  • See also “Diagnosis of intussusception.”
• Differential diagnosis
  • See “Differential diagnosis of abdominal pain.”
  • See “Differential diagnosis of bowel obstruction.”
• Management
  • For initial management steps, see “Initial management of intussusception.”
  • Consult surgery, particularly for patients with:
    • Signs of bowel obstruction, perforation, or ischemia
    • Ileocolic or colocolic intussusceptions ^[4]
    • Pathological lead point on imaging
• Disposition: hospital admission

Surgical reduction and/or bowel resection is typically required to treat intussusception in adults.

• Bowel obstruction
• Intestinal ischemia
• Gastrointestinal perforation

We list the most important complications. The selection is not exhaustive.