- Clinical science
Intussusception occurs when a proximal part of the bowel invaginates into a distal part, leading to a mechanical obstruction and bowel ischemia. Infants aged 3–12 months are most commonly affected, usually with no identifiable underlying cause. Some patients may have an intraperitoneal anomaly or abnormality which initiates the process of intussuception (pathological lead point). The patient is typically chubby and healthy-looking, and presents with acute cyclical abdominal pain, knees drawn to the chest, and vomiting (initially nonbilious). Pallor, lethargy, and altered mental status may be present. A late-onset symptom is “currant jelly" stool (stool with blood and mucus) passed from the ischemic bowel. A classic sign is a palpable right upper quadrant (RUQ) mass on abdominal examination, seen as a target or pseudokidney sign on abdominal ultrasound. Contrast enema, i.e., pneumatic insufflation or hydrostatic enema with normal saline or barium, is the best confirmatory diagnostic test, and often has therapeutic effects. Intussusception is considered a surgical emergency, as it may lead to bowel necrosis and perforation if left untreated. Open surgery is indicated when non-operative measures fail, a pathological lead point is suspected, or bowel perforation is present. If treated before complications arise, patients generally have an excellent prognosis.
- Sex: ♂ > ♀ (3:2)
- Peak incidence: 3–12 months; otherwise commonly occurs in children 5 months to 6 years of age
- One of the most common causes of bowel obstruction in childhood
Epidemiological data refers to the US, unless otherwise specified.
- Mostly idiopathic (usually in children 3 months to 5 years of age)
- Pathological lead points: more likely the underlying cause in patients with recurrent episodes of intussusception; more common in children < 3 months or > 5 years of age
- Ileocecal invagination (most common; accounts for 85–90% of cases)
- Ileoileal invagination
- Ileocolic invagination
- Colosigmoidal invagination
- Appendicocecal invagination (very rare)
- Imbalance in the bowel wall (idiopathic or via a pathological lead point) → a portion of intestinal bowel (intussusceptum) invaginates or “telescopes” into the distal adjacent bowel loop; (intussuscipiens) → impaired lymphatic drainage and increasing pressure in intussusceptum bowel wall → venous impairment → mesenteric vessels are congested → ischemia of intussusceptum bowel wal; l → bowel mucosa sloughs off (most sensitive to bowel ischemia since it is the furthest from the arterial supply) → transmural necrosis and perforation with prolonged ischemia
- The dysfunctional passage leads to a mechanical bowel obstruction → vomiting
- Child typically looks healthy
Acute cyclical colicky abdominal pain (sudden screaming or crying spells), often with legs drawn up, with asymptomatic intervals
- Acute attacks occur approx. every 15–30 min.
- Vomiting (initially nonbilious)
- Lethargy , pallor, and other symptoms of shock or altered mental status may be present.
- Abdominal tenderness, palpable sausage-shaped mass in the RUQ , and an “emptiness” or retraction in the right lower quadrant (Dance sign) during palpation
- High-pitched bowel sounds on auscultation
- "Currant jelly stool" (usually a late sign): may be noticed in passed stool or during digital rectal examination
Less than 15% of patients with intussusception present with the classic triad of abdominal pain, a palpable sausage-shaped abdominal mass, and blood per rectum!
- If clinical suspicion is high : perform enema .
- If the diagnosis is unclear at presentation or ultrasound or abdominal x-ray) to confirm the diagnosis. are suspected : perform radiographic imaging (
Abdominal ultrasound (best initial test): often sufficient to confirm diagnosis
- Target sign; (transverse view): The invaginated portion of bowel appears as rings on a target in transverse view on ultrasound.
- Pseudokidney sign (longitudinal view): the lead point of the invagination in the distal loop of bowel resembles a kidney. This “pseudokidney” is made up of longitudinal layers of bowel wall.
- Possible pendulous peristalsis
- Rule out other causes of an acute abdomen
- Contrast or pneumatic enema using ultrasound or fluoroscopy (best confirmatory test); : interruption of contrast or air at site of invagination
- Abdominal x-ray
- Inhomogeneous distribution of gas with absence of air at the site of invagination (usually right upper and lower quadrants) may be visible
- In cases of advanced stage intussusception, other features of will be detected
- Laboratory tests: leukocytosis (suggests peritonitis)
|Differential diagnosis of lower gastrointestinal bleeding in children|
|First month of life (neonate)|| || |
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|1 month to 1 year (infant)|| || |
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|1 year to 2 years|| || |
|> 2 years|| || |
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Intussusception, alongside incarcerated hernia, is one of the most common causes of bowel obstruction in children! It is the most common cause of bowel obstruction in the first two years of life!
The differential diagnoses listed here are not exhaustive.
- Initial steps: nasogastric decompression and fluid resuscitation
Nonsurgical management (performed under continuous ultrasound or fluoroscopic guidance)
- Air (pneumatic) enema: treatment of choice
- Hydrostatic reduction: normal saline (or water-soluble contrast enema)
- Observe for 24 hours post-reduction, as there is a small risk of perforation and recurrence is common during this period
- Open or laparoscopic method
Urgent intervention is necessary for intussusception to prevent potentially life-threatening complications!
The prognosis of intussusception depends on how quickly it is treated. Most cases may be treated successfully with conservative pneumatic insufflation (air enema) or hydrostatic reduction. The absence of ischemia or necrotic bowel is associated with a good prognosis.
- Success rates for reduction: 80–90%
- Rate of relapse in patients with non-surgical reduction: ∼ 10–15%