Paediatrics: Intussusception

Intussusception

Intussusception typically affects infants between 6 and 18mths of age. The incidence is 1/500 children. The majority of intussusceptions occur in association with viral gastroenteritis.

•   Enlarged Peyer’s patch in the ileum acts as the lead point that then invaginates into the distal bowel.

•   Intussusceptions in older children and adults are more likely to be due to a pathological lead point, e.g. a polyp or Meckel’s diverticulum.

Intussusception causes a small bowel obstruction. The intussuscepted bowel becomes engorged, which causes rectal bleeding, and eventually gangrenous. Following this, perforation and peritonitis will occur. The most common site for an intussusception is ileocolic (Fig. 23.11) followed by ileo-ileal. Small bowel intussusception may occur as a post-operative complication in infants, typically following nephrectomy.

Presentation

The typical presentation of an intussusception in an infant is as follows:

•   Spasms of colic associated with pallor, screaming, and drawing-up legs.

•   The child falls asleep between episodes.

•   Later, as the intestinal obstruction progresses, bile-stained vomiting develops and rectal bleeding, (i.e. ‘red currant jelly stools’).

•   The child will appear ill, listless, and dehydrated.

•   In late cases circulatory shock or peritonitis will be present.

Assessment

·  In 30% of cases the intussusception will be palpable as a sausage-shaped abdominal mass.

•   Blood may be noted on rectal examination.

•   AXR: small bowel obstruction and occasionally a soft tissue mass will be visible.

•   US: confirms the diagnosis by showing a characteristic ‘target sign’.

Management

·  Resuscitation: often large volumes of IV fluid are required to restore perfusion.

·  Antibiotics.

•   Analgesia.

•   NGT passed if the infant is vomiting.

•   Radiological reduction: provided that there is no evidence of peritonitis, and facilities for immediate surgery are available, the treatment of choice is for an expert paediatric radiologist to reduce the intussusception pneumatically by rectal insufflation of air under fluoroscopic control. The risks of this procedure are incomplete reduction and perforation. The latter can be particularly dangerous as a tension pneumoperitoneum develops very rapidly.

•   Laparotomy: if pneumatic reduction fails, or is contraindicated because of concern about a gangrenous intussusception, laparotomy is necessary. The distal bowel is gently compressed to reduce the intussusception. If this is not successful then the intussusception is resected. There is a recurrence rate about 10% whether the intussusception is treated radiologically or by surgery. Further recurrence should raise the question of a pathological lead point.