Intussusception

Intussusception is the telescoping of one segment of intestine into another adjacent distal ("downstream") segment of the intestine. It comes from the Latin "intus", within + "suscipere", to receive = to receive within).

Intussusception is the most common cause of intestinal obstruction in children between 3 months and five years of age. It is extremely rare in children under 3 months of age or in older children and adults.

During intussusception, a segment of bowel (intussusceptum) telescopes into a more distal segment (intussuscipiens), and drags the associated mesentery, vessels, and nerves with it. This results in compression of the veins, followed by swelling of the region leading to obstruction and a subsequent decrease in blood flow to the affected part of the intestine. Most cases affect the ileocolic region of the intestine (where the small intestine meets the large intestine).

The compression of blood vessels in the involved intestine reduces the supply of blood to the affected intestine. If the blood supply is greatly reduced, the involved intestine may swell, causing an obstruction, or even die (become gangrenous) and bleed. It also may rupture and lead to abdominal infection and shock.

Signs and symptoms of intussusception include:

• paroxysms (about every 10-20 minutes) of colicky abdominal pain (>80%) ± crying.
• the child may appear well between paroxysms initially.
• early vomiting - rapidly becoming bile-stained.
• neurological symptoms such as lethargy, hypotonia or sudden alterations of consciousness can occur.
• palpable 'sausage-shaped' mass (often in the right upper quadrant).
• absence of bowel in the right lower quadrant (Dance's sign).
• dehydration, pallor, shock.
• irritability, sweating.
• later, mucous and bloody 'red currant stools'.
• late pyrexia.

It is usually of sudden onset, and may be more insidious in the older child.

The causes of intussusception may vary depending on its type.

Non-pathological lead point (>90%) known as primary intussusception:

• Viral 50% - rotavirus, adenovirus and human herpesvirus 6 (HHV6).
• Amoebomata, shigella, yersinia.
• Peyer's patch hypertrophy.

Pathological lead point (<10%) known as secondary intussusception:

• Meckel's diverticulum (75%).
• Polyps and Peutz-Jeghers syndrome (16%).
• Henoch-Schönlein purpura (3%).
• Lymphoma and other tumours (3%).
• Reduplication - a process by which the bowel wall is duplicated (2%).
• Cystic fibrosis.
• An inflamed appendix.
• Ascariasis.
• Nephrotic syndrome.
• Foreign body.
• Postoperative - rarely, postoperative intussusception following operative treatment of an intussusception has been reported.
• Hyperperistalsis.
• Exclusive breast-feeding.
• Weight above average.
• Rotavirus vaccine.
• Abdominal tuberculosis.

Adult causes of intussusception include:

• Cases in adults can be described as:
• Ileo-ileal (or entero-enteric - affecting only the small bowel)
• Colo-colic (affecting only the large bowel)
• Ileo-colic (small bowel is pushed into the large bowel)
• Ileo-caecal (small bowel is pushed into the caecum)
• 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 neoplasms - e.g., bowel carcinoma, lymphomas, polyps, or lipomas or metastatic deposits (rare) - e.g., renal cell carcinoma).
• Meckel's diverticulum.
• Abnormal peristalsis (secondary to ulceration).
• Heterotopic pancreatic tissue.
• Endometriosis.
• Inflammatory bowel disease.
• Adhesions.
• Association with enterovirus infection.
• Association with diabetic ketoacidosis - possibly by altering GI tract motility

Your child's physician will obtain a medical history and perform a physical examination to make a diagnosis of intussusception. Imaging studies are also done to examine the abdominal organs.

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. Barium has been gold standard (crescent sign, filling defect) but air and water-soluble double-contrast now available; each has pros and cons - the choice is left to the individual radiologist.

Abdominal ultrasonography

May show a 'doughnut' or 'bull's-eye' sign when the intussusception is seen transversely, or 'pseudo-kidney' or 'hayfork' sign in longitudinal section.

CT is the most effective and accurate diagnostic technique

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). CT scanning is probably the imaging modality of choice.

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 is not recommended, as there is risk of perforation.

U&Es

May reflect dehydration.

TBC

May show neutrophilia.

Treatment of intussusception typically happens as a medical emergency.

• Any child with possible intussusception or other serious cause of abdominal pain should be referred urgently to hospital for further assessment.
• Early diagnosis reduces the need for open surgery.
• Resuscitation - 'drip and suck' - nasogastric tube and IV fluids.

Radiological:

• Reduction (three tries for three minutes each) if there is no sign of peritonitis, perforation or shock.
• Air enema <120 mm Hg of pressure or barium enema.
• The choice of enema is usually left to the radiologist (many now favour air enema).

Laparotomy (reduction/resection) - indications:

• Peritonitis
• Perforation
• Prolonged history (>24 hours)
• High likelihood of pathological lead point
• Failed enema
• Hospital admission is usually required but outpatient management may on occasions be an acceptable alternative.

The accepted methods of management in adults include:

• Many cases of transient intussusception in adults have been observed - especially in conditions that alter GI tract motility.

• 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 site of anastomoses, due to oedema of the bowel.

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

• 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.

There are no guidelines for preventing intussusception because the cause is unknown.

Talk to your doctor about avoiding vaccines that may cause a recurrence.

Complications associated with intussusception, which rarely occur when the diagnosis is prompt, include the following:

• Perforation during nonoperative reduction
• Wound infection
• Internal hernias and adhesions causing intestinal obstruction
• Sepsis from undetected peritonitis (major complication from a missed diagnosis)
• Intestinal hemorrhage
• Necrosis and bowel perforation
• Recurrence