Intussusception

Intro & Epi - Telescoping Trouble

• Definition: Invagination (telescoping) of a proximal bowel segment (intussusceptum) into an adjacent distal segment (intussuscipiens).
• Peak Age: 6-36 months.
• Epidemiology:
  • Male predominance (M:F ~3:2).
  • ⭐ > The most common cause of intestinal obstruction in infants and toddlers aged 6-36 months.
• Risk Factors:
  • Idiopathic (~90%): Frequently follows viral infections (e.g., adenovirus, rotavirus), leading to hypertrophied Peyer's patches acting as a lead point.
  • Pathological Lead Point (PLP) (common if <3mo, >3yr, or recurrent):
    • Meckel's diverticulum (most common PLP).
    • Polyps, lymphoma.
    • HSP (submucosal edema).
    • Cystic fibrosis (thick stool).

Pathophys & Types - Bowel's Inside Job

• Mechanism: Peristalsis pulls proximal bowel (intussusceptum) into distal bowel (intussuscipiens).
• Progression: Results in bowel wall edema → venous congestion → arterial compromise → ischemia → necrosis → perforation.
• Lead Points:
  • Idiopathic: Most common (~90% in infants, 3mo-3yr), often due to hypertrophied Peyer's patches (post-viral).
  • Pathological Lead Point (PLP): Commoner in older children/adults (Meckel's diverticulum, polyp, tumor, HSP).
• Common Types:
  • Ileocolic (most frequent)
  • Ileo-ileal
  • Colo-colic

⭐ The most common type of intussusception is ileocolic.

Clinical Picture - Red Currant Crisis

• Classic triad: Intermittent colicky abdominal pain, vomiting, red currant jelly stool (<30% cases).
• Pain: Sudden, severe, paroxysmal; child draws legs up.
• Vomiting: Initially non-bilious, later bilious.
• Stool: Red currant jelly (late; ischemia/sloughing + mucus). Blood on PR.
• Other signs:
  • Lethargy, pallor.
  • Sausage-shaped mass (RUQ/epigastrium).
  • Dance's sign (empty RLQ).
• 📌 Sausage Dance for Red Currants: Sausage mass, Dance's sign, Red currant jelly stool.

⭐ The classic triad of colicky abdominal pain, vomiting, and red currant jelly stool is present in less than 30% of patients.

Imaging & Diagnosis - Spotting the Sausage

• Ultrasound (USG): Gold standard.
  • Transverse: Target/Donut sign.
  • Longitudinal: Pseudokidney/Hayfork sign.
  • High sensitivity & specificity.
• Abdominal X-ray (AXR):
  • May show obstruction signs (dilated loops, air-fluid levels), RLQ mass, ↓RLQ gas.
  • Often normal. Rules out perforation (free air).
• Contrast Enema (Air/Barium/Water-soluble):
  • Diagnostic & therapeutic.
  • Shows 'crescent sign'/'meniscus sign'.
  • ⚠️ Contraindicated: peritonitis, perforation.

⭐ Ultrasound is the imaging modality of choice for diagnosing intussusception, showing a characteristic 'target sign'./n

Management - Unfolding the Fix

Initial: IV fluids, NG tube decompression, antibiotics (if sepsis/perforation).

• Non-operative Reduction (Enema):
  • Pneumatic (air) or hydrostatic (saline/contrast) under fluoroscopic/USG guidance.
  • Contraindications: Peritonitis, perforation, shock, prolonged symptoms (>48h debated).
  • Max 3 attempts; max pressure (air) 80-120 mmHg.
• Surgical Management:
  • Indications: Enema failure/contraindications, Pathological Lead Point (PLP), ischemia/perforation.
  • Options: Manual reduction (Milking maneuver), resection & anastomosis if non-viable/irreducible PLP. Laparoscopic or open.
• Recurrence: ~5-10% post-enema; ↓ post-surgery.

⭐ Non-operative reduction with pneumatic or hydrostatic enema is the first-line treatment for stable patients, with success rates of 70-90%.

High‑Yield Points - ⚡ Biggest Takeaways

• Most common intestinal obstruction in infants 6-36 months.
• Classic triad: intermittent colicky pain, sausage-shaped mass, red currant jelly stools.
• Lead point (e.g., Meckel's diverticulum, lymphoma) more likely in older children.
• Ultrasound is diagnostic: target sign or doughnut sign.
• Therapeutic enema (air/contrast) is first-line treatment if no perforation.
• Surgery if enema fails or signs of ischemia/perforation.
• Ileocolic is the most common site.