Bowel intussusception is uncommon in adults,
representing only 5% of all intussusceptions and 1% of patients with bowel obstruction.
In contrast to children,
there is a demonstrable cause in 70-90% of the situations,
most commonly a neoplasm.
Malignant lesions are more frequent in the colon,
whereas benign tumors prevail in the small bowell.
They are classified according to their location within the gastrointestinal tract (gastric,
enteroenteric,
ileocolic,
ileocecal or colocolic),
the etiology (benign,
malignant or idiopathic) and the presence of a lead point.
Intraluminal lesions alter the normal peristaltic movements and act as lead points.
As a result the bowel wall invaginates into the lumen,
with the proximal segment referred to as the intussusceptum and the distal segment as the intussuscipiens.
The intussusceptum is propelled onwards by peristalsis,
with mesentery and vessels becoming involved,
and the process continues with more proximal areas following,
leading to intestinal obstruction.
As the pressure in the wall increases,
venous flow is first impeded,
followed by arterial supply.
Thus early diagnosis is required to prevent progression to infarction and perforation.
The clinical presentation is quiet nonspecific,
often leading to delayed diagnosis.
Symptoms are more commonly of long duration,
usually chronic colicky pain,
nausea and vomiting. An abdominal mass may be palpated in less than 50% of patients.
Presentation as an acute abdomen is rare.
The most important factor for establishing the diagnosis is awareness of the possibility of intussusception occurring in an adult patient with abdominal symptoms,
especially those with prior episodes of partial intestinal obstruction.
Imaging methods are central not only for the diagnosis,
but also to decide on the most appropriate management.
Nevertheless the growing use of computer tomography (CT) has led to an increased detection of transient intussusceptions with no underlying disease,
challenging the significance of asymptomatic intussusception detected with CT.
We review imaging findings of bowel intussusception in adults,
through examples from our institution.