What are the causes of intussusception in infants?

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Last updated: February 25, 2026 • View editorial policy

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Causes of Intussusception in Infants

Idiopathic vs. Pathological Lead Points

In infants aged 5-9 months (the peak incidence period), intussusception is predominantly idiopathic with no identifiable anatomical cause, whereas pathological lead points become increasingly important outside this typical age range. 1, 2

Age-Specific Etiology

Typical Age Range (3 months to 5 years, peak 5-9 months)

  • 75-90% of cases are idiopathic with no identifiable structural abnormality serving as a lead point 1, 2
  • The idiopathic form likely results from lymphoid hyperplasia in the terminal ileum, often following viral illness or in association with rotavirus infection 2
  • Intussusception is uncommon in the first 3 months of life, and when it occurs in this age group, a pathological lead point should be strongly suspected 1, 3

Neonates and Young Infants (<3 months)

  • Neonatal intussusception is rare and typically associated with pathological lead points rather than being idiopathic 1, 3
  • When intussusception occurs in full-term newborns, it presents a diagnostic challenge due to atypical presentation and high mortality if diagnosis is delayed 3

Older Infants and Children (>2 years)

  • 86-93% of cases have an underlying pathological lesion serving as a lead point 1
  • The presence of a pathological lead point is significantly more likely in older children compared to the typical infant age group 4

Specific Pathological Lead Points

Most Common Lead Points Overall

  • Meckel's diverticulum is the most common identifiable lead point across all age groups 5, 2, 4
  • Intestinal duplication cysts are the second most common structural cause 5, 4
  • Benign polyps (including those associated with Peutz-Jeghers syndrome) are frequent, particularly in older children 4

Age-Specific Lead Point Distribution

In infants <2 years old:

  • Meckel's diverticulum and intestinal duplication cysts account for 81% of pathological lead points 4
  • These congenital anomalies are the predominant structural causes in this younger age group 4

In children >2 years old:

  • Intestinal polyps, Meckel's diverticulum, and Peutz-Jeghers syndrome account for 72% of pathological lead points 4
  • Peutz-Jeghers syndrome becomes a more prominent consideration in this older age group 4

Other Pathological Lead Points

  • Lymphoma and other neoplasms (more common in adults but can occur in older children) 2, 6
  • Mucosal lesions, intramural masses, or extrinsic structures can all serve as lead points 6
  • Pathological lead points are not limited to infants and occur with variable frequency (0.3-20% in different series) 6

Clinical Implications

Diagnostic Considerations

  • Only 12% of pathological lead points are detected on initial ultrasound, highlighting the limitation of imaging in identifying the underlying cause 4
  • When a lead point is suspected based on age (<3 months or >2 years), recurrent episodes, or atypical presentation, additional imaging or endoscopy may be warranted 4
  • Technetium-99m pertechnetate scans have 50% sensitivity for detecting Meckel's diverticulum when performed 4

Surgical Planning

  • Complex/compound intussusception is the most common type when a pathological lead point is present, followed by small intestinal and ileocolic types 4
  • Nearly all cases with pathological lead points require surgical intervention rather than pneumatic or hydrostatic reduction 4
  • Surgical exploration allows for definitive diagnosis through histopathological examination and treatment of the underlying lesion 4

Important Caveats

  • Recurrent intussusception should raise suspicion for a pathological lead point, even in the typical age range where idiopathic cases predominate 5
  • The classic triad of abdominal pain, vomiting, and bloody stools is often absent; lethargy and irritability may be the primary presenting signs 2
  • Previous history of intussusception places infants at higher risk for repeat episodes, regardless of whether a lead point was identified 7

References

1
Guideline

Intussusception Diagnosis and Clinical Features

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

2
Research

Intussusception.

American family physician, 1996

3
Research

A rare case report of a neonatal idiopathic intussusception in a full-term newborn.

International journal of surgery case reports, 2020

7
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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