Intussusception

Question 1

Pathophysiology

Answer 1

One segment of bowel invaginates into another
May ‘telescope’ on itself (non-pathological lead point) or may be a pathological lead point (eg enlarged lymphatics following a viral infection; polyp; lymphoma; complication of HSP)
Mesentery become compressed
Bowel wall distends and obstructs the lumen
Peristalsis is disrupted
Lymphatic and venous occlusion => ischaemia
75% ileocaecal

Question 2

Clinical Presentation

Answer 2

2/3 patients <1year, peak age 5-10 months
Sudden onset
Episodic screaming, drawing knees up pallor and colicky pain, may appeal well between episodes
Early vomiting
Redcurrent jelly stool
Shock, dehydration
Palpable, sausage-shaped mass

Question 3

Investigations

Answer 3

Abdominal US - 'doughnut sign'
Abdominal XRay - dilated gas-filled bowel proximally, paucity of gas distally
Bowel enema(?)
FBC, U+E

Question 4

Management

Answer 4

ABC + resus
Gas insufflation (or barium enema)
If this fails (3 attempts) or there is evidence of peritonitis then a laparotomy is required