Intussusception

Question 1

Define intussusception.

Answer 1

Intussusception describes the invagination of one portion of bowel into the lumen of the adjacent bowel, most commonly around the ileo-caecal region.

Question 2

What is the classic triad of intussusception?

Answer 2

1. colicky abdominal pain
2. redcurrant jelly stool
3. and a palpable abdominal mass

Question 3

How common is inussusception?

Answer 3

• Intussusception usually affects infants between 6-18 months old
• Boys> girls: 2:2-3:1

Question 4

What are the risk factors for intussusception?

Answer 4

• male sex
• age 6-12 months
• recent viral illness
• first gen rotavirus vaccine (tetravalent rhesus-human reassortant rotavirus vaccine [RRV-TV])

Question 5

Why is intussusception clinically important?

Answer 5

It results in venous obstruction and bowel-wall oedema that can progress to bowel necrosis, perforation, and, rarely, death

Question 6

What are the presenting features of intussusception?

Answer 6

• abdominal colic pain - lasts between 1-3 minutes with normal episodes in between (during paroxysm the infant will characteristically draw their knees up and turn pale)
• vomiting
• PR blood- ‘red-currant jelly’ is a late sign
• lethary/irritability in between waves of pain

Question 7

What are the findings on examination in inussusception?

Answer 7

• sausage-shaped mass in the right upper quadrant
• PR examination may show blood on gloved finger

Question 8

What is the investigation of choice for intussusception? What are the results?

Answer 8

Abdominal ultrasound - shows a target like mass. Colour Doppler can show if bowel is ischaemic.

Air contrast enema - can also diagnose itussusception

Results: Target sign (variants include bull’s eye sign, doughnut sign, crescent-in-doughnut sign, and multiple concentric ring sign); pseudokidney sign; sandwich sign; abnormal Doppler flow

Question 9

What is the most common anatomic location for intussusception to occur?

Answer 9

Ileocolonic intussusception (prolapse of the terminal ileum into the proximal colon) is the most common anatomical location for intussusception to occur, followed by ileoileal and colocolonic

Question 10

What is the management of intussusception?

Answer 10

Refer to surgeons

1. fluid resuscitation
2. +/- WS antibiotics (clindamycin + gentamycin)
3. +/- NG tube insertion if repeated vomiting
4. radiological air reduction (air enema/barium enema/US guided saline enema)
5. if that fails then surgery (bowel resection)

Question 11

When is surgery rather than air reduction indicated in intussusception?

Answer 11

• unsuccessful air reduction
• perforation,
• peritonitis,
• Henoch-Schönlein purpura.

Question 12

What are the predisposing factors for intussusception? What are the lead points in older children/adults?

Answer 12

• Young children: hyperplasia of Peyer’s patches and lymphoid tissue from viral infection e.g. gastroenteritis. Appendicitis. These may act as the lead point.
• Older children and adults: pathological lead point include luminal polyps, malignant tumours (including lymphoma), and benign mass lesions (e.g., lipomata, Meckel’s diverticulum, Henoch-Schonlein purpura[haematoma of bowel wall], and enteric duplication cysts, cystic fibrosis [hypertrophied mucosal glands])

Question 13

Summarise the pathophysiology of intussusception.

Answer 13

• One portion of the bowel telescopes into the portion distal to it
• The mesentery is dragged along with it and causes venous obstruction
• This causes oedema and mucosal bleeding
• Arterial obstruction can also occur causing necrosis

Question 14

What is the risk of recurrence in intussusception?

Answer 14

10%

Surgical reduction: 2-5%

Question 15

What is seen on this abdominal x-ray showing intussusception? Why is AXR indicated?

Answer 15

1. A mass and paucity of bowel gas in the right upper quadrant (ileo-colic likely)
2. Loss of clarity of the liver edge.
3. Dilated loops of small bowel proximal to the intussusception
4. Paucity of gas within the deflated large bowel distal to the obstruction

Essential to look for free air if the patient has signs of peritonitis and may have perforated.

Question 16

What are the late complications of intusussception?

Answer 16

• bowel wall gangrene
• adhesions and infection
• bowel perforation

Question 17

What is the recurrence rate in intuseusception?

Answer 17

10%