Intussusception in Adults

Intussusception in children is the commonest cause of bowel obstruction of that age - see separate article Intussusception in Children. 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

• In intussusception part of the gastrointestinal (GI) tract invaginates or telescopes into another neighbouring portion.
• There is usually a "lead point" which is the cause of the invagination.
• Cases in adults can be described as entero-enteric (affecting the small bowel only); colo-colic (affecting the large bowel only); ileo-colic or ileo-caecal. Ileo-ileal intussusceptions are more common than ileo-colic intussusceptions.
• A cause is identified in up to 90% of cases and includes the following:
  • Malignancy in 54-69% (primary neoplasms¹, e.g. bowel carcinoma, lymphomas, polyps, or lipomas or metastatic deposits (rare), e.g. renal cell carcinoma³)
  • Meckel's diverticulum in 2%⁴
  • Abnormal peristalsis (secondary to ulceration)
  • Heterotopic pancreatic tissue
  • Endometriosis
  • Inflammatory bowel disease
  • Adhesions
  • Association with enterovirus infection⁵
  • Association with diabetic ketoacidosis - possibly by altering GI tract motility⁶

• Cystic fibrosis
• Roux-en-Y oesophagojejunostomy, e.g. for obesity⁷
• Meckel's diverticulum
• Peutz-Jeghers' syndrome
• Familial polyposis coli

• Typically with non-specific abdominal pain which is recurrent
• Nausea and vomiting in 20%
• Change in bowel habit

Examination

• Abdominal distension
• Palpable mass
• Decreased or absent bowel sounds
• Can present with an acute abdomen
• Bowel obstruction is uncommon

• Plain abdominal X-rays are not usually helpful but may show a soft tissue mass ± bowel obstruction.
• Barium enema - useful in colonic or ileo-colic intussusception with "cup-shaped" filling defect.⁸
• Abdominal ultrasonography - may show a "doughnut" or "bull's eye" sign when the intussusception is seen transversely, or "pseudokidney" or "hayfork" sign in longitudinal section.
• CT scans may show a "target lesion" in distal ileum or ascending colon^9,10 - there may be invaginated vasculature visible, and intramural air indicates bowel vascular compromise.⁴ It is common to see a target-shaped mass with the oedematous intussuscipiens, surrounding which is the intussusceptum (similar to ultrasonography).¹ CT scanning is probably the imaging modality of choice.^11,12
• Colonoscopy may visualise the intussusception and can be used to reduce the intussusception - but this depends on the site of the problem, and it appears to be better at detecting a neoplastic mass as the lead point; biopsy not recommended, as risk of perforation.⁸

• There is much debate as to the best management of intussusception in adults.
• Many cases of transient intussusception in adults have been observed - especially in conditions that alter GI tract motility.
• It has been argued that surgery with primary resection of the intussusception should be performed in all, as there is a high risk of a malignant cause.⁴
• Intra-operative 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 anastomoses site due to oedema of the bowel.⁸
• 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.⁸

• GI haemorrhage - either from ileal ulcerations (e.g. secondary to heterotopic gastric mucosa) or from mechanical trauma due to repeated intussusception.¹³
• Bowel obstruction ± perforation.
• Septicaemia.
• Shock (septicaemic or haemorrhagic).