What are the characteristics of intussusception in adults?

Surgical Management of Adult Intussusception

Adult intussusception usually requires surgical resection due to the high likelihood of pathological lead points, with 92-94% of cases having an underlying lesion, often malignant in colonic cases. 1, 2

Characteristics of Adult Intussusception

Adult intussusception differs significantly from pediatric cases in several key ways:

• Etiology: Unlike pediatric cases which are typically idiopathic, adult intussusception is associated with a pathological lead point in 92-94% of cases 2, 3
• Frequency: Represents only 1% of all bowel obstructions, 5% of all intussusceptions, and 0.003%-0.02% of all hospital admissions 4
• Presentation: Most commonly presents with intestinal obstruction (71% of cases) 2
• Distribution: Occurs more frequently in the small intestine (76.9%) than colon (15.4%) or ileocecal valve (7.7%) 3

Diagnostic Approach

Diagnosis is often challenging due to variable and non-specific symptoms:

• CT scan: Most accurate diagnostic tool with 90% accuracy 2
• Ultrasonography: 78.5% diagnostic accuracy 2
• Colonoscopy: 100% accuracy for ileocolic and colonic intussusception 2

Treatment Strategy

Small Bowel Intussusception

• Lead point risk factors: Age >60 years (RR 2.2), history of malignancy (RR 3.7), and mass on CT (RR 2.9) significantly increase likelihood of pathological lead point 5
• Approach: Reduction before resection may be attempted if:
  • Underlying etiology is suspected to be benign
  • Resection without reduction would require extensive bowel removal 2
  • No evidence of strangulation or perforation 3

Colonic Intussusception

• Approach: En-bloc resection without reduction is recommended due to:
  • High malignancy rate (43-70% of cases) 1, 3, 4
  • Risk of perforation and spillage of malignant cells 3

Retrograde Intussusception

• Typically does not have a lead point 5
• May be managed more conservatively

Outcomes and Prognosis

• Surgical mortality is low when properly managed 3
• Recurrence is uncommon after appropriate surgical management
• Hydrostatic reduction, which is commonly used in pediatric cases, is not typically effective in adults due to the high prevalence of pathological lead points 6

Common Pitfalls to Avoid

• Delayed diagnosis: Intussusception in adults presents with variable symptoms and can be easily missed; maintain high index of suspicion
• Inappropriate reduction: Attempting reduction in colonic intussusception risks perforation and tumor seeding
• Overlooking incidental findings: Transient, asymptomatic intussusceptions found on imaging may be observed without intervention 6
• Assuming idiopathic cause: Unlike in children, adult intussusception is rarely idiopathic and underlying pathology should always be suspected

The answer to the multiple-choice question is (b) - adult intussusception usually requires resection due to the high likelihood of pathological lead points, particularly in colonic cases where malignancy is common.