Intussusception

Question 1

What is intussusception?

Answer 1

= Invagination of proximal into distal bowel

Question 2

Where is intussusception most common?

Answer 2

• commonest occurrence is ileum moving into the colon through the ileo-caecal valve

Question 3

Peak incidence (and why) and age bracket of intussusception

Answer 3

• Can occur 3m to 3y
• Peak incidence at 5-7 months
  
  • Due to change in immune system and antigenic exposure

Question 4

Explain how idiopathic intussusception occurs.

Answer 4

• Most likely due to change in immune system and antigenic exposure -> inflamed Peyer’s patches in terminal ileum -> gut tries to push that along -> small to large bowel intussusception

Question 5

What are some causes of pathological intussusception.

Answer 5

Less commonly due to a pathological lead point:
• Meckel’s diverticulum
• Polyp (look for circumoral freckling – Peutz- Jegher’s syndrome)
• Vascular malformation
• Duplication cyst

Question 6

Which is more common in paeds: idiopathic or pathological intussusception?

Answer 6

Idiopathic

Question 7

Symptoms of intussusception

Answer 7

• Crampy episodic abdominal pain
  
  • 3-4 minutes between waves of severe pain (waves of small bowel obstruction)
  • Episodes typically 2-3 times/hour
• Sympathomimetic response - pallor while crying, sweating
• Vomiting and fever
  
  • Faeculant vomiting is very late sign, uncommon

• Pallor and lethargy
• Bowel motions
○ blood and/or mucus
○ classic red currant jelly stool is a late sign
○ Diarrhoeais quite common and can lead to a misdiagnosis of gastroenteritis

Question 8

How can intussusception lead to perforation?

Answer 8

Venous obstruction→oedema→obstruction→ischaemia→perforation→peritonitis

Question 9

What is a classic behavioural sign of intussusception?

Answer 9

🐝Children tend to pull legs up towards buttocks to relieve pressure on abdominal wall

Question 10

What will the intussusception feel like on examination?

Answer 10

Abdominal mass- sausage shaped mass RUQ or crossing midline in epigastrium or behind umbilicus, palpable in about two thirds of children.

Question 11

What Ix are done for intussusception, and which is the most relevant?

Answer 11

1. AXR
   • Exclude perforation or bowel obstruction
   • A normal AXR does not exclude intussusception
2. US (Dx Ix of choice, but not needed if high suspicion)
3. Air enema (initial if high suspicious)

Question 12

What are classical signs of intussusception on AXR?

Answer 12

1. Target sign - 2 concentric circular radiolucent lines usually in the right upper quadrant
2. Crescent sign - a crescent shaped lucency usually in the left upper quadrant with a soft tissue mass

Question 13

What risks are there when doing an air enema?

Answer 13

• Bowel perforation

- Bacteraemia

Question 14

Mx of intussusception

Answer 14

• General
  
  • Supportive: analgesia, IV fluids
  • Correct electrolyte abnormalities
  • Nil orally, NGT if bowel obstruction/perforation on AXR/for decompression
• Simple (= <48h, no peritonitis, stable child)
  
  • Air enema reduction successful in 80-90%, repeat in 6h if doesn’t work
• Complicated (=>48h, peritonitis and/or septicaemia)
  
  • Laparotomy (10-15%)

Question 15

Complications of intusussception

Answer 15

• Recurrence - majority occur within 24 hours
• Dehydration
• Bowel obstruction
• Bowel ischaemia→necrosis→perforation