Intussusception is an acute medical condition in which one section of the bowel telescopes inside another, strangling the blood supply. If left untreated for too long, it can lead to the death of that section of bowel. It is an emergency that can lead to a person's death in just two days. On the other hand, an enema may be all that is required to treat it.

The condition tends to occur in infants aged between 18 months and three years old, and is more common in boys.

Cause

Intussusception occurs when a piece of bowel (the intussusceptum) slides into the next part of the bowel (the intussuscipiens) and is drawn along by the contractions of the gut. The cause is not entirely clear. But it is obviously not due to some action or inaction on the part of the child's parents.

Telescoping of the end of the small bowel into the caecum (the start of the large bowel) is a common form of intussusception. It is thought that the enlargement of lymphoid tissue in the small bowel following a viral infection may predispose the drawing of the small bowel into the caecum. A 'lead point' for intussusception can also form through bruising of the intestinal wall in Henoch-Schonlein purpura (a bleeding disorder) or through obstruction of the bowel with secretions in cystic fibrosis.

This mechanism may have also occurred after the administration of an early rotavirus vaccine which was found to cause intussusception in approximately 1 in 7,000 children vaccinated. The vaccine has since been replaced by others that are not thought to cause intussusception.

Symptoms

As the condition is most common in infants, the presentation is different to that seen in an adult with a bowel problem. The main symptom is abdominal pain which manifests as bouts of screaming as the gut contracts around the site of intussusception. This is accompanied by paleness and drawing of the legs up towards the chest.

As the pain becomes more constant, it will cause nausea, with the child refusing feeds and vomiting. The vomit may contain bile, a green substance that enters the bowel above the part where intussusception occurs. The vomiting will cause dehydration, which is evident through signs such as a dry mouth, lethargy, fewer wet nappies and a sunken fontanelle¹.

Diarrhoea is not a feature of intussusception. Later, the child may pass mucus and blood in their stools, with the blood having a 'redcurrant jelly' appearance.

Management

Any child with symptoms like those described above should be seen by a doctor urgently. Diagnosis is based on a history of suggestive symptoms, examination, including a search for an abdominal lump and a rectal examination looking for blood, and investigations including routine blood tests, an abdominal X-ray and an abdominal ultrasound scan.

In most cases the condition is not immediately life-threatening and can be treated by passing an enema of air or water up through the bowel until the involved section unfolds. This is best left to the experts. However, if an enema fails to treat the problem, or if an enema cannot be used – this is the case if the child is more than two years old, the problem has been ongoing for more than 48 hours, or there are signs of bowel obstruction or rupture – then surgery is required. This involves squeezing the affected bowel out of itself or, if the bowel is stuck or has died off, removing the affected section and connecting the living bowel on either side. This can sometimes be done using keyhole surgery².

Management also involves rehydration of the child, which can include an intravenous drip and a nasogastric tube³.

Prognosis

Untreated, intussusception can lead to death within a matter of days. Enemas are more likely to be successful the earlier the child presents, with a delay increasing the chances of surgery and the need to remove a section of bowel. The outlook for children treated for intussusception is generally good, although the condition may recur in a small number.