Transient or uncomplicated intussusception is known to occur in adults and children and can be considered physiological. Given the condition's transient nature, it is probably underdiagnosed. The main factors distinguishing transient from intussusceptions requiring surgical intervention are absent clinical symptoms, enteroenteric type, short length, and absent visible lead point ⁹.

A symptomatic intussusception, requiring further assessment or treatment, is discussed separately.

Epidemiology

Associations

Cannabinoids have been associated with single or multiple transient jejunal Intussusceptions ⁵.

Clinical presentation

Intussusceptions are often seen on CT imaging in patients with and without abdominal symptoms ^9,10. Asymptomatic patients are, unsurprisingly, more likely to have transient/uncomplicated intussusceptions not requiring surgical intervention ⁹.

Pathology

Aetiology

The exact aetiology of intussusceptions without a lead point is not clear ⁴.

Radiographic features

Ultrasound

The appearance of transient intussusceptions on ultrasound typically demonstrates bowel-within-bowel (+/- mesenteric fat and/or vessels) or a complex soft tissue mass ^4,10. A target sign may be present.

CT

CT features that favour transient intussusception over intussusception requiring surgery include:

• transitory (if multiple phases are acquired) ⁴

• jejunal location ^ref

• enteroenteric intussusception ⁹

• multiple ⁹ although are frequently solitary ⁷

• length <3.5 cm ^9,10, although two-thirds of transient intussusceptions are ≥3.6 cm ⁹

• absence of visible lead point ⁹

• small diameter (due to lack of lead point tumour) ^4,9

• absence of small bowel obstruction ^4,9,10

• absence of mural thickening/oedema and mesenteric vascular engorgement ¹⁰

Treatment and prognosis

• spontaneous resolution is the rule ⁴

• occasionally, laparoscopic reduction is required in patients with a clearly transient/uncomplicated intussusception

• cessation of any marijuana use ^ref

Differential diagnosis

Intussusception in adults has a strong association with bowel pathology:

• malignant or benign tumours

  • polyps

• diverticula

• abdominal adhesions

• coeliac disease

• Crohn disease

Practical points

• transient/uncomplicated enteroenteric intussusception can be secondary to increased bowel peristalsis due to downstream bowel obstruction (e.g. stricture, tumour) ¹⁰