Intussusception

A 24-month-old boy presents with intermittent severe abdominal pain and multiple episodes of vomiting over the past 8 hours. The pain is colicky, lasts for a few minutes, resolves spontaneously, and recurs in paroxysms, often every 15 to 30 minutes early in the illness. During painful episodes, the child draws his knees toward his chest and cries intensely. His mother reports passage of red, mucus-like stool resembling currant jelly. He had a viral illness approximately one week ago. On examination, the child is irritable. The abdomen is soft with mild distension, and a sausage-shaped mass is palpable in the right upper quadrant. Abdominal ultrasonography demonstrates a target sign. Diagnosis?

The diagnosis is ileocolic intussusception.

The combination of recurrent colicky abdominal pain, vomiting, knee-to-chest behavior, bloody mucus-containing stool, a palpable sausage-shaped abdominal mass, and a characteristic target sign on ultrasonography is highly characteristic of pediatric ileocolic intussusception.

1. Definition

Intussusception is the invagination of one segment of intestine into an adjacent segment, producing intestinal obstruction and potentially compromising mesenteric blood flow.

The invaginating segment is called the intussusceptum, and the receiving segment is called the intussuscipiens.

In children, the most common form is ileocolic intussusception.

Untreated intussusception may lead to:

1.      Intestinal obstruction

2.      Venous and lymphatic congestion

3.      Bowel wall edema

4.      Impaired arterial perfusion

5.      Ischemia and necrosis

6.      Perforation

2. Epidemiology and Etiology

1.      Intussusception occurs most commonly in infants and young children, particularly between approximately 3 months and 3 years of age, although it can occur outside this range.

2.      Most cases in young children are idiopathic.

3.      A recent viral illness may precede the episode.

4.      Postinfectious lymphoid hyperplasia, including enlargement of lymphoid tissue in the terminal ileum such as Peyer patches, has been proposed as a transient precipitating mechanism in some cases.

5.      A definite pathologic lead point is identified in a minority of pediatric cases.

Concern for a pathologic lead point increases particularly with:

1.      Older age

2.      Recurrent intussusception

3.      Atypical anatomic location

4.      Repeatedly irreducible intussusception

5.      Unusual imaging or clinical findings

A 24-month-old child with a typical ileocolic presentation does not automatically require an extensive search for a structural lead point.

2.1 Pathologic Lead Points

Potential structural lead points include:

1.      Meckel diverticulum

2.      Intestinal polyps

3.      Lymphoma

4.      Enteric duplication cysts

5.      Other intestinal masses or structural abnormalities

2.2 Associated Conditions

Certain disorders can predispose to intussusception without acting as a discrete structural lead point.

IgA vasculitis may predispose to intussusception through intestinal wall edema, hemorrhage, and altered bowel motility.

3. Pathophysiology

1.      A segment of bowel invaginates into the adjacent intestine.

2.      The associated mesentery is pulled into the intussusception.

3.      Compression of mesenteric veins and lymphatics causes venous congestion and bowel wall edema.

4.      Progressive edema worsens luminal obstruction and vascular compression.

5.      Continued vascular compromise may impair arterial blood flow and produce bowel ischemia and necrosis.

6.      Ischemic mucosal injury causes bleeding and mucus production.

7.      Blood mixed with mucus may produce the characteristic currant jelly stool.

8.      Untreated disease may progress to:

o    Bowel necrosis

o    Perforation

o    Peritonitis

o    Sepsis

o    Shock

4. Clinical Features

4.1 Typical Features

1.      Sudden intermittent colicky abdominal pain

2.      Pain occurs in recurrent paroxysms separated by relatively symptom-free intervals and may recur every 15 to 30 minutes early in the illness.

3.      During painful episodes, the child may:

o    Cry intensely

o    Draw the knees toward the chest

o    Become markedly distressed

4.      The child may appear relatively well between episodes early in the disease.

5.      Vomiting is common.

Vomiting may initially be nonbilious and may become bilious as intestinal obstruction progresses.

4.2 Gastrointestinal Bleeding

Bloody mucus-containing stool, classically described as currant jelly stool, results from ischemic mucosal injury and sloughing.

Currant jelly stool is an important finding but is usually a later manifestation and is not required for diagnosis.

Clinicians should not wait for currant jelly stool before investigating a child with a compatible presentation.

4.3 Abdominal Examination

A sausage-shaped abdominal mass may be palpable, classically in the right upper quadrant or epigastric region.

The abdomen may remain relatively soft between painful episodes early in the disease.

With progression to ischemia, necrosis, or perforation, findings may include:

1.      Persistent abdominal tenderness

2.      Guarding

3.      Rigidity

4.      Increasing abdominal distension

5.      Signs of peritonitis

Dance sign, referring to relative emptiness of the right lower quadrant, may be present but is not sufficiently sensitive or specific to establish the diagnosis.

4.4 Atypical Presentations

Some children, particularly infants, may present predominantly with:

1.      Lethargy

2.      Altered responsiveness

3.      Irritability

4.      Vomiting without prominent abdominal pain

The complete classic clinical picture occurs in only a minority of children, so absence of one or more traditional findings does not exclude intussusception.

5. Diagnosis

Diagnosis requires prompt clinical recognition and appropriate imaging.

5.1 Ultrasonography

Abdominal ultrasonography is the preferred initial imaging investigation in a clinically stable child with suspected ileocolic intussusception.

Typical ultrasonographic findings include:

1.      Target sign

2.      Donut sign on transverse imaging

3.      Pseudokidney sign on longitudinal imaging

Ultrasonography has high sensitivity and specificity for pediatric ileocolic intussusception and avoids ionizing radiation.

In this child, the characteristic clinical presentation together with the target sign on ultrasonography establishes the diagnosis in the appropriate clinical setting.

5.2 Abdominal Radiography

Plain abdominal radiography is not sufficiently sensitive to exclude intussusception and should not replace ultrasonography when ultrasound is readily available.

Abdominal radiography may be useful when there is concern for:

1.      Bowel obstruction

2.      Perforation

3.      Free intraperitoneal air

4.      An alternative abdominal diagnosis

A normal abdominal radiograph does not exclude intussusception.

5.3 Enema Reduction

Once ileocolic intussusception has been established by imaging, image-guided pneumatic or hydrostatic enema reduction is the preferred initial definitive treatment in an appropriate clinically stable child.

Although the enema also demonstrates the intussusception during the reduction procedure, ultrasonography is generally used to establish the diagnosis before therapeutic reduction.

6. Management

Intussusception is a time-sensitive pediatric abdominal emergency because prolonged vascular compromise may result in bowel ischemia, necrosis, and perforation.

6.1 Initial Management

Initial management includes:

1.      Keep the child nil per os

2.      Establish intravenous access

3.      Assess hydration and hemodynamic status

4.      Administer intravenous isotonic fluids when indicated

5.      Correct significant electrolyte abnormalities

6.      Provide appropriate analgesia

7.      Obtain early pediatric surgical and radiology consultation

Nasogastric decompression may be appropriate in children with:

1.      Significant abdominal distension

2.      Persistent vomiting

3.      Significant bowel obstruction

Routine prophylactic antibiotics are not required before radiologic reduction in every uncomplicated, clinically stable child.

Broad-spectrum antibiotics are appropriate when there is concern for:

1.      Bowel perforation

2.      Peritonitis

3.      Bowel necrosis or ischemia

4.      Sepsis

5.      Operative intervention

6.2 Nonoperative Reduction

Enema reduction is appropriate in a hemodynamically stable child without perforation or peritonitis.

Options include:

1.      Pneumatic air enema

2.      Hydrostatic liquid enema

Pneumatic air enema is widely used and has a high success rate.

Hydrostatic reduction using liquid under fluoroscopic or ultrasound guidance is also effective where appropriate expertise is available.

The choice between pneumatic and hydrostatic reduction depends partly on institutional expertise, available imaging guidance, and local practice.

6.3 Repeat Enema Reduction

If an initial enema reduction is incomplete or unsuccessful, repeat image-guided enema reduction may be appropriate in selected clinically stable children, provided there is no perforation, peritonitis, or other indication for immediate surgery.

6.4 Contraindications to Enema Reduction

Nonoperative enema reduction should not be attempted in a child with:

1.      Bowel perforation

2.      Generalized peritonitis

A child with severe hemodynamic instability or shock requires immediate resuscitation and urgent surgical assessment before definitive management.

6.5 Surgical Management

Surgical intervention is indicated when:

1.      Nonoperative reduction fails

2.      Perforation is present

3.      Peritonitis is present

4.      Nonviable or necrotic bowel is suspected or identified

5.      A pathologic lead point requiring operative treatment is identified

6.      Clinical circumstances make nonoperative reduction inappropriate

Surgery may involve manual reduction of the intussusception.

Bowel resection is required if the affected intestine is:

1.      Necrotic

2.      Perforated

3.      Otherwise nonviable

6.6 Observation and Disposition

After successful uncomplicated enema reduction, selected well-appearing children may be observed in the emergency department and subsequently discharged if they:

1.      Remain clinically stable

2.      Are asymptomatic or significantly improved

3.      Tolerate oral fluids

4.      Have no evidence of complications

5.      Have reliable caregivers and access to prompt return care

Routine hospital admission is not required for every child after successful uncomplicated reduction.

7. Complications

Potential complications include:

1.      Intestinal obstruction

2.      Bowel ischemia

3.      Bowel necrosis

4.      Perforation

5.      Peritonitis

6.      Sepsis

7.      Shock

8.      Recurrence

Recurrence occurs in approximately 6% to 9% of children after successful air enema reduction, although reported rates vary according to reduction technique and study population.

Early recurrence within the first 24 to 48 hours is less common than overall recurrence.

A recurrent episode can often be treated successfully with another image-guided enema reduction when the child remains clinically stable and has no contraindications.

8. Key Clinical Insight

A young child with recurrent paroxysmal colicky abdominal pain, knee-to-chest behavior, vomiting, bloody mucus-containing stool, a palpable sausage-shaped abdominal mass, and a target sign on ultrasonography has a highly characteristic presentation of ileocolic intussusception.

In this patient, the age, recurrent pain pattern, vomiting, currant jelly stool, right upper quadrant mass, recent viral illness, and characteristic ultrasonographic appearance strongly support ileocolic intussusception.

References

1.      Kelley-Quon LI, Arthur LG, Williams RF, et al. Management of intussusception in children: A systematic review. Journal of Pediatric Surgery. 2021;56(3):587-596. doi:10.1016/j.jpedsurg.2020.09.055.

2.      Alsabri M, Rath S, Elkarargy MA, et al. Accuracy of ultrasound for intussusception in pediatric emergency presentations: a systematic review and diagnostic meta-analysis. International Journal of Emergency Medicine. 2026;19(1):41. doi:10.1186/s12245-026-01134-z.

3.      Qafesha RM, Sharabati I, Kashbour M, et al. Pneumatic versus liquid enema reduction in the management of pediatric intussusception: an updated systematic review and meta-analysis. Annals of Medicine and Surgery. 2025;87(11):7549-7564. doi:10.1097/MS9.0000000000003754.