Makindo Medical Notes.com

Masses in the bowel or lumen act as an irritant and provoke abnormal peristaltic movement, which may lead to the telescoping of one bowel segment over the adjacent segment

About

• From the Latin intus (within) and suscipere (to receive).
• Invagination of a proximal piece of bowel into a distal segment

Epidemiology

• Intussusception in adults is rare.
• It is estimated to account for only 5% of all intussusceptions
• It causes only 1% of all bowel obstructions

Aetiology

• Can be due to a polyp or tumour or Meckel's at the apex
• There is telescoping of bowel within itself
• Can lead to oedema, vascular insufficiency
• Gut necrosis and peritonitis and death

Causes

• A polyp or tumour or GIST
• Small-bowel intussusceptions usually secondary to benign lesions
• Scar-like tissue in the intestine (adhesions)
• Weight-loss surgery (gastric bypass) or other surgery on the intestinal tract
• Inflammation due to diseases such as Crohn's disease

Site

• 52% were found in the small intestine (39% enteroenteric, 13% ileocolic)
• 38% in the large intestine (17% ileocecal, 17% colocolic, 4% appendiceal).

Clinical

• Malaise, pyrexial, Colicky abdominal pain that comes and goes.
• Nausea and vomiting may also occur.
• May be holding knees drawn up to chest
• Melaena, weight loss, fever, and constipation
• Symptoms are usually of long duration (several weeks to several months)
• Patient may occasionally present with an acute abdomen

Investigation

• FBC: raised WCC. U&Es: dehydration.
• Abdominal X-ray: may be dilated gas-filled proximal bowel, paucity of gas distally, multiple fluid levels (but may be normal in the early stages).
• Ultrasound: may identify doughnut or target sign or mass
• CT: Intussusception appears as a sausage-shaped mass when the CT beam is parallel to its longitudinal axis but as a target like mass when the beam is perpendicular to the longitudinal axis
• Bowel enema - barium has been gold standard (crescent sign, filling defect) but air and water-soluble double-contrast now available. Urgent Air-contrast enema is needed which causes reduction and relieves the problem. X-rays may be normal in 30%.

Management

• Most intussusceptions in adults are associated with either acute intestinal obstruction or partial and recurring obstruction.
• A correct and timely diagnosis is not only necessary to avoid the complications of bowel infarction and perforation secondary to high-grade obstruction but also to resect the underlying lesion that serves as a lead point.
• Exploratory laparotomy and entire bowel inspected from the ligament of Treitz to the terminal ileum
• This is particularly important because an underlying malignancy may first present as an intussusception.
• Prognosis is generally favourable depending on the aetiology of disease
• Acute Abdomen: Resuscitation: nasogastric tube and IV fluids. Air enema is usually tried several times if there is no sign of peritonitis, perforation or shock. If not successful then laparotomy is performed with operative reduction. Careful observation post-op as can recur

References

• Intussusception (Adults)