Intussusception in adults

What is intussusception?

Intussusception in children is the most common cause of bowel obstruction of that age. In contrast, its appearance in adults only accounts for ~5% of all cases of intussusception and 1-5% of patients with intestinal obstruction.^{1 2}

What causes intussusception in adults? (Aetiology)

• In intussusception, part of the gastrointestinal (GI) tract invaginates or telescopes into another neighbouring portion.

• This causes bowel obstruction and compression of the blood supply to the affected bowel, leading to bowel ischaemia.

• There is usually a 'lead point' which is the cause of the invagination.

• Cases in adults can be described as:³
  

  • Ileo-ileal (or entero-enteric - affecting only the small bowel).

  • Colo-colic (or colonic - affecting only the large bowel).

  • Ileo-colic (prolapse of the terminal ileum into the ascending colon).

  • Ileo-caecal (where the ileocaecal valve is the lead point of the intussusception). Almost all cases of ileo-caecal intussusception are due to an adenocarcinoma of the caecum involving the ileocaecal valve.⁴

• Ileo-ileal intussusceptions are more common than ileo-colic or colo-colic intussusceptions.⁴

• Unlike in children, where most cases of intussusception do not have any identifiable cause, in adults, a cause is identified in up to 90% of cases. These include the following:
  

  • Benign or malignant mass tumours in 54-69% (eg, primary neoplasms - eg, bowel carcinoma, lymphomas, polyps, or lipomas or metastatic deposits (rare) - eg, renal cell carcinoma).⁵ Small bowel intussusceptions are more likely to be caused by benign lesions (50-75% of cases) whereas some evidence suggests colonic intussusceptions are more likely to be malignant in origin (though other case series disagree).^{3 4}

  • Meckel's diverticulum.

  • Abnormal peristalsis (secondary to ulceration - for example, due to Yersinia infection).

  • Heterotopic pancreatic tissue.

  • Endometriosis.

  • Inflammatory bowel disease.

  • Adhesions.

  • Enterovirus infection has been reported as a cause.⁶

  • Another case report describes intussusception in the context of diabetic ketoacidosis - possibly by altering GI tract motility - and Vibrio parahaemolyticus gastroenteritis.⁷

Risk factors

• Cystic fibrosis.

• Roux-en-Y oesophagojejunostomy - eg, for obesity.⁸

• Meckel's diverticulum and other congenital abnormalities.

• Peutz-Jeghers syndrome.

• Familial polyposis coli.

Intussusception symptoms⁴

In adults, intussusception tends to present with nonspecific symptoms that can be very variable and intermittent, making diagnosis challenging. These are usually acute - lasting days to weeks - but in rare cases have been reported as lasting for years. It often causes symptoms of large or small bowel obstruction. Intussusception symptoms include:

• Abdominal pain, which can wax and wane and feel 'crampy' in nature.

• Nausea and vomiting. Vomiting may be bilious.

• Constipation and obstipation (being unable to pass flatus or stool)

• Bloating.

• Bloody diarrhoea, if intestinal ischaemia has occurred.

• Fever - although this may be a late sign that indicates intestinal necrosis, perforation, and/or sepsis.

Examination

Features on clinical examination can include:

• Abdominal distension.

• Abdominal tenderness and peritonism.

• A palpable abdominal mass.

• Decreased or absent bowel sounds.

• Intussusception is a (rare) cause of an acute abdomen.

Bowel obstruction is uncommon.

Investigations

• Abdominal CT scanning is the most effective and accurate diagnostic technique.^{4 9 10} CT scans may show a 'target lesion' in the distal ileum or ascending colon. It is common to see a target-shaped mass with the oedematous intussuscipiens, surrounding which is the intussusceptum (similar to ultrasonography).¹¹

• Abdominal ultrasound is less sensitive than CT in detecting adult intussusception, but can identify characteristic signs such as a 'doughnut' or 'bull's-eye' sign when the intussusception is seen transversely, or 'pseudo-kidney' or 'hayfork' sign in longitudinal section.³

• Plain abdominal X-rays are not usually helpful but may show a soft tissue mass ± signs of large and/or small bowel obstruction.

• A barium enema has been used for patients with colonic or ileo-colic intussusception, showing a 'cup-shaped' filling defect.

Treatment for intussusception in adults

• There is much debate as to the best management of intussusception in adults.

• Historically, surgical treatment was the mainstay of treatment for adult intussusception, due to the higher risk of pathology such as malignancies serving as the lead point.⁴

• However, with the widespread use of CT scanning, many cases of transient intussusception in adults have been observed that have caused few, if any, symptoms - especially in conditions that alter GI tract motility.¹²

• Intraoperative reduction before resection has also been attempted but the success rates are rather disappointing and there are concerns that this can lead to intraluminal seeding of malignant cells, perforation and increased risk of complications at the site of anastomoses, due to oedema of the bowel.¹³

• Reduction of the intussuscepted bowel is considered safe for benign lesions in order to limit the extent of resection or to avoid short bowel syndrome.²

• One recommendation is that all intussusceptions involving the large bowel should be resected, as there is an almost 60% risk of malignancy, whereas small bowel intussusceptions should be managed by reduction initially, as the risk of a neoplastic lesion is much less.^{3 13}

Complications

• GI haemorrhage - either from ileal ulcerations (eg, secondary to heterotopic gastric mucosa) or from mechanical trauma due to repeated intussusception.¹⁴

• Bowel obstruction.

• Bowel ischaemia.

• Bowel necrosis.

• Bowel perforation.

• Sepsis and septicaemia.

• Shock (septicaemic or haemorrhagic).