✅ Model Answer:
• Coiled-spring sign – contrast trapped between the intussusceptum and intussuscipiens.
• Filling defect in the colon (usually right colon/transverse colon).
• Meniscus sign – concave filling defect at the leading edge.
• Obstruction – contrast does not pass beyond the intussusception.
• Diagnosis: Ileocolic intussusception.

✅ Model Answer:
• Coiled-spring sign: A classic radiographic appearance on barium enema in intussusception.
• Mechanism: The intussusceptum (telescoped segment) invaginates into the intussuscipiens (receiving segment). Barium is trapped in the narrow space between the two layers of bowel, creating a coiled, spiral appearance.
• Appearance: A helical or spiral pattern of contrast outlining the intussusception.
• Significance: It is pathognomonic for intussusception on barium enema.
• It indicates that the intussusception is present and the bowel layers are edematous, trapping the contrast.

✅ Model Answer:
• Classic triad (present in ~40-50% of cases):
1. Intermittent, severe, cramping abdominal pain – often paroxysmal, causing the child to draw up knees and cry.
2. Vomiting – initially non-bilious, may become bilious as obstruction progresses.
3. Passage of currant jelly stool – blood and mucus mixed with stool (due to venous congestion and mucosal sloughing).
• Other features:
- Palpable sausage-shaped mass in the right upper quadrant.
- Lethargy disproportionate to abdominal findings.
- Young child (peak age 5-36 months).

✅ Model Answer:
• Pathophysiology: One segment of bowel (intussusceptum) telescopes into an adjacent segment (intussuscipiens), causing bowel obstruction and vascular compromise.
• Venous congestion → edema → ischemia → necrosis → perforation (if untreated).
• Lead points – abnormal structures that serve as a focal point for the intussusception:
- Idiopathic (most common in 6-36 months): No identifiable lead point (likely due to lymphoid hyperplasia).
- Pathologic lead points (5-10%): Meckel diverticulum, intestinal polyp, lymphoma, duplication cyst, Henoch-Schönlein purpura, cystic fibrosis, post-surgical.
- In older children (>3 years): Higher likelihood of a pathologic lead point.

✅ Model Answer:
• Ultrasound is the first-line imaging modality for diagnosing intussusception.
• Findings on ultrasound:
- Target sign (doughnut sign): On transverse view – concentric hyperechoic and hypoechoic rings representing the edematous bowel layers.
- Pseudokidney sign: On longitudinal view – resembles a kidney with a central echogenic core (mesentery) and hypoechoic rim (edematous bowel).
- Absence of blood flow: On Doppler – indicates ischemia.
• Advantages: No radiation, high sensitivity (>95%), and can identify lead points.
• Barium enema/air enema: Both diagnostic and therapeutic (reduction).

✅ Model Answer:
• Air enema (pneumatic reduction) is the preferred method for reducing intussusception.
• Success rate: 80-95% (when performed within 24 hours of symptoms).
• Procedure: Air is insufflated into the colon under fluoroscopic guidance. The pressure pushes the intussusception back into normal position.
• Contraindications:
- Peritonitis or signs of perforation.
- Shock or hemodynamic instability.
- >24-48 hours of symptoms (increased risk of bowel ischemia).
- Bowel obstruction with free air or pneumoperitoneum.
• Alternative: Hydrostatic reduction with saline or barium (less commonly used now).

✅ Model Answer:
• Radiographic criteria for success:
1. Free flow of air into the small bowel (visualized on fluoroscopy).
2. Disappearance of the filling defect – the intussusception is no longer visible.
3. Air fills the terminal ileum – indicates complete reduction.
• Clinical criteria:
- Improvement in the child's condition – less pain, less irritability.
- Passage of stool or flatus.
- Resolution of abdominal mass.
• If unsuccessful: Consider repeat attempt (max 2-3 attempts) or proceed to surgery.

✅ Model Answer:
• Absolute indications:
1. Peritonitis – signs of perforation or peritoneal irritation.
2. Free air on abdominal X-ray – indicates perforation.
3. Hemodynamic instability – shock, sepsis.
4. Pneumoperitoneum – free intraperitoneal air.
• Relative indications:
1. Failed air enema reduction – after 2-3 attempts.
2. Recurrent intussusception – may indicate a lead point.
3. Suspected pathologic lead point – Meckel diverticulum, polyp, lymphoma (especially in older children).
4. Strangulated bowel – signs of bowel necrosis (sepsis, severe acidosis).
• Procedure: Laparotomy with manual reduction (± resection if necrotic).

✅ Model Answer:
• Observation: Admit for 24-48 hours of observation.
• Hydration: IV fluids until the child tolerates oral intake.
• Feeding: Start with clear liquids, then advance as tolerated.
• Monitor for recurrence: Up to 10% recurrence (most within 72 hours). Watch for recurrence of pain, vomiting, or currant jelly stool.
• Pain management: As needed.
• Discharge: When tolerating oral diet, pain-free, and no recurrence.
• Follow-up: If recurrence occurs, consider repeating air enema or evaluating for a lead point.

✅ Model Answer:
• Recurrence rate: 5-10% after successful air enema reduction.
• Most recurrences occur within 72 hours after reduction.
• Risk factors for recurrence:
- Presence of a pathologic lead point (Meckel, polyp).
- Older age (>3 years).
- History of recurrent intussusception.
- Delayed reduction (>48 hours).
• If recurrence occurs:
- Consider repeating air enema (if no contraindications).
- Evaluate for lead point (ultrasound, CT, or laparoscopy).
- Surgery may be indicated for recurrent cases.

✅ Model Answer:
• This is a failed reduction – requires surgical intervention.
• Next step: Laparotomy with manual reduction.
• Procedure:
1. Manual reduction – gently milk the intussusception back.
2. If the bowel is viable and reducible → perform reduction only.
3. If the bowel is non-viable (necrotic, perforated) → perform resection and anastomosis.
4. Inspect for a lead point (Meckel diverticulum, polyp, duplication cyst) and remove it if found.
5. Post-operatively: IV fluids, antibiotics (if resection), and monitor for complications.

✅ Model Answer:
• This is a complicated intussusception with bowel ischemia or perforation.
• Diagnosis: Peritonitis, sepsis, or bowel necrosis.
• Management:
1. Emergent surgery – laparotomy.
2. IV fluids and antibiotics (covering Gram-negative and anaerobic organisms).
3. Resection of non-viable bowel with primary anastomosis (or stoma if unstable).
4. Post-operative ICU care.
5. Monitor for complications: anastomotic leak, wound infection, sepsis.