Intussusception
Updates to Article Attributes
Intussusception occurs when one segment of bowel is pulled into itself (or a neighbouring loop of bowel) by peristalsis.
It is an important cause of an acute abdomen in children and merits timely ultrasound examination and reduction to preclude significant sequelae including bowel necrosis.
Intussusception may also occur in the adult population where it is usually usually caused by a focal lesion acting as a lead point.
Epidemiology
The vast majority of intussusceptions occur intussusceptions occur in children (95%), usually after the first three months of life 13.
In children, no lead point can usually be identified (90%) and this most frequently thought to relate toenlarged lymphoid tissue following an infection. This potentially explains the relative rarity of this entity in the first three months of life, when passive immunity is still paramount.
In infants or adults, a lead point is more frequently identified (up to 90% of the time in adults, usually malignant in the large bowel and benign in the small bowel13). Lead points are numerous and include 9,11,13:
- gastrointestinal malignancy (most common cause in adults, accounting for 65% of cases 13)
- colorectal carcinoma (most common)
- metastases, e.g. malignant melanoma, breast cancer, lung cancer
- small bowel lymphoma/Burkitt lymphoma
- benign neoplasms
- gastrointestinal stromal tumour (GIST)
- intestinal polyps
- intestinal lipoma
- polypoid haemangioma
- congenital
- inflammatory
- trauma
- mural haematoma
Clinical presentation
While the classic triad of intermittent abdominal pain, vomiting and right upper quadrant mass, plus occult or gross blood on rectal examination has great positive predictive value for intussusception in children1, these findings are seen in less than 20% of intussusception cases2. Approximately 15% (range 13-22%) of patients with intussusception do not even present with abdominal pain3,4.
Pathology
A proximal part of bowel is pulled into the distal lumen and peristalsed forwards as it it were a bolus of food. The prolapsing part of the bowel is described as the intussusceptum while the distal segment of bowel receiving the intussusceptum is described as the intussuscipiens. As the mesentery is incorporated into the intussusception, venous return is compromised resulting in oedema and further restriction to blood flow. Eventually arterial supply to the bowel is interrupted and ischaemia and necrosis ensues.
Radiographic features
Intussusception can occur essentially anywhere, although in children there is a strong predilection for predilection for the ileocolic region:
- ileocolic: most common (75-95%), presumably due to the abundance of lymphoid tissue related to the terminal ileum and the anatomy of the ileocaecal region
- ileoileocolic: second most common
- ileoileal and colocolic: uncommon
In adults no such distribution is present as in the vast majority of cases a lead point lesion is present, and thus the location will depend on the location of that lesion.
Gastric intussusception is rare, but documented 13.
Abdominal plain film
Abdominal x-rays may demonstrate an elongated soft tissue mass (typically in the right upper quadrant in children) with a bowel obstruction proximal to it.
Ultrasound
Ultrasonography has a false-negative rate approaching zero and is a reliable screening tool for children at low risk for intussusception 5-9. Children with classic findings of intussusception, however, need to be investigated with contrast enema, which is both diagnostic (the gold standard in the diagnosis of intussusception) and therapeutic.
Ultrasound signs include:
- target sign (also known as the doughnut sign)
- pseudokidney sign
- crescent in a doughnut sign
Fluoroscopy - contrast enema
A contrast enema remains the gold standard, demonstrating the intussusception as an occluding mass prolapsing into the lumen, giving the "coiled spring” appearance (barium in lumen of the intussusceptum and in the intraluminal space)
The main contra-indication for an enema is a perforation.
CT
CT has become the modality of choice for assessment of acute abdomen in adults, and thus most frequently images intussusception. In addition short length transient intussusception is a frequent incidental finding.
The appearance of intussusception on CT is characteristic and depends on the imaging plane and where along the bowel images are obtained.
Best know is the so-called bowel-within-bowel configuration, in which the layers of the bowel are duplicated forming duplicated forming concentric rings (CT equivalent of the ultrasonographic target sign) when imaged at right angles to lumen, and a soft tissue sausage when imaged longitudinally13.
At the proximal end of the intussusception intussusception there will be two concentric enhancing / hyperdense rings, formed by the inner bowel and the folded edge of the outer bowel. As one images further along the intussusception the the mesentery (fat and vessels) will form a crescent of tissue around the compressed inner most lumen, surrounded by the two layers of the outer enveloping bowel. Even further distally the lead point (if present) will be visualised 13.
Treatment and prognosis
In children, intussusceptions can be treated without recourse to surgery in most cases. Using a water soluble medium or air, retrograde pressure can be exerted to reduce the intussusception. If symptoms have been protracted, rectal blood is present, there are signs of peritonitis or enema reduction is unsuccessful then surgical intervention is usually required. With no surgical treatment there can be recurrence rates of up to 30%.
In adults a laparotomy is usually required, especially as in most cases a lead point requiring treatment is present.
Differential diagnosis
On imaging the appearances on ultrasound and CT are characteristic. The main differential is that oftransient intussusception, which is an incidental finding requiring no requiring no treatment or follow-up.
Other conditions to be considered in adults include:
- intestinal lipoma (without intussusception)
- gallstone ileus (cholesterol stones can have a layered appearance with fat density)
-<p><strong>Intussusception</strong> occurs when one segment of bowel is pulled into itself (or a neighbouring loop of bowel) by peristalsis. </p><p>It is an important cause of an <a href="/articles/acute-abdomen">acute abdomen</a> in children and merits timely ultrasound examination and reduction to preclude significant sequelae including bowel necrosis.</p><p>Intussusception may also occur in the adult population where it is usually caused by a focal lesion acting as a lead point. </p><h4>Epidemiology</h4><p>The vast majority of intussusceptions occur in children (95%), usually after the first three months of life <sup>13</sup>.</p><p>In children, no lead point can usually be identified (90%) and this most frequently thought to relate to enlarged lymphoid tissue following an infection. This potentially explains the relative rarity of this entity in the first three months of life, when passive immunity is still paramount. </p><p>In infants or adults, a lead point is more frequently identified (up to 90% of the time in adults, usually malignant in the large bowel and benign in the small bowel <sup>13</sup>). Lead points are numerous and include <sup>9,11,13</sup>:</p><ul>- +<p><strong>Intussusception</strong> occurs when one segment of bowel is pulled into itself (or a neighbouring loop of bowel) by peristalsis. </p><p>It is an important cause of an <a href="/articles/acute-abdomen">acute abdomen</a> in children and merits timely ultrasound examination and reduction to preclude significant sequelae including bowel necrosis.</p><p>Intussusception may also occur in the adult population where it is usually caused by a focal lesion acting as a lead point. </p><h4>Epidemiology</h4><p>The vast majority of intussusceptions occur in children (95%), usually after the first three months of life <sup>13</sup>.</p><p>In children, no lead point can usually be identified (90%) and this most frequently thought to relate to enlarged lymphoid tissue following an infection. This potentially explains the relative rarity of this entity in the first three months of life, when passive immunity is still paramount. </p><p>In infants or adults, a lead point is more frequently identified (up to 90% of the time in adults, usually malignant in the large bowel and benign in the small bowel <sup>13</sup>). Lead points are numerous and include <sup>9,11,13</sup>:</p><ul>
-</ul><h4>Clinical presentation</h4><p>While the classic triad of intermittent abdominal pain, vomiting and right upper quadrant mass, plus occult or gross blood on rectal examination has great positive predictive value for intussusception in children <sup>1</sup>, these findings are seen in less than 20% of intussusception cases <sup>2</sup>. Approximately 15% (range 13-22%) of patients with intussusception do not even present with abdominal pain <sup>3,4</sup>.</p><h4>Pathology</h4><p>A proximal part of bowel is pulled into the distal lumen and peristalsed forwards as it it were a bolus of food. The prolapsing part of the bowel is described as the <strong>intussusceptum</strong> while the distal segment of bowel receiving the intussusceptum is described as the <strong>intussuscipiens. </strong>As the mesentery is incorporated into the intussusception, venous return is compromised resulting in oedema and further restriction to blood flow. Eventually arterial supply to the bowel is interrupted and ischaemia and necrosis ensues.</p><h4>Radiographic features</h4><p>Intussusception can occur essentially anywhere, although in children there is a strong predilection for the ileocolic region:</p><ul>- +</ul><h4>Clinical presentation</h4><p>While the classic triad of intermittent abdominal pain, vomiting and right upper quadrant mass, plus occult or gross blood on rectal examination has great positive predictive value for intussusception in children <sup>1</sup>, these findings are seen in less than 20% of intussusception cases <sup>2</sup>. Approximately 15% (range 13-22%) of patients with intussusception do not even present with abdominal pain <sup>3,4</sup>.</p><h4>Pathology</h4><p>A proximal part of bowel is pulled into the distal lumen and peristalsed forwards as it it were a bolus of food. The prolapsing part of the bowel is described as the <strong>intussusceptum</strong> while the distal segment of bowel receiving the intussusceptum is described as the <strong>intussuscipiens. </strong>As the mesentery is incorporated into the intussusception, venous return is compromised resulting in oedema and further restriction to blood flow. Eventually arterial supply to the bowel is interrupted and ischaemia and necrosis ensues.</p><h4>Radiographic features</h4><p>Intussusception can occur essentially anywhere, although in children there is a strong predilection for the ileocolic region:</p><ul>
-</ul><h5>Fluoroscopy - contrast enema</h5><p>A contrast enema remains the gold standard, demonstrating the intussusception as an occluding mass prolapsing into the lumen, giving the "coiled spring” appearance (barium in lumen of the intussusceptum and in the intraluminal space)</p><p>The main contra-indication for an enema is a perforation.</p><h5>CT</h5><p>CT has become the modality of choice for assessment of acute abdomen in adults, and thus most frequently images intussusception. In addition short length <a href="/articles/transient-intussusception">transient intussusception</a> is a frequent incidental finding. </p><p>The appearance of intussusception on CT is characteristic and depends on the imaging plane and where along the bowel images are obtained. </p><p>Best know is the so-called bowel-within-bowel configuration, in which the layers of the bowel are duplicated forming concentric rings (CT equivalent of the ultrasonographic <a href="/articles/target-sign-of-intussusception">target sign</a>) when imaged at right angles to lumen, and a soft tissue sausage when imaged longitudinally <sup>13</sup>. </p><p>At the proximal end of the intussusception there will be two concentric enhancing / hyperdense rings, formed by the inner bowel and the folded edge of the outer bowel. As one images further along the intussusception the mesentery (fat and vessels) will form a crescent of tissue around the compressed inner most lumen, surrounded by the two layers of the outer enveloping bowel. Even further distally the lead point (if present) will be visualised <sup>13</sup>.</p><h4>Treatment and prognosis</h4><p>In children, intussusceptions can be treated without recourse to surgery in most cases. Using a water soluble medium or air, retrograde pressure can be exerted to reduce the intussusception. If symptoms have been protracted, rectal blood is present, there are signs of peritonitis or enema reduction is unsuccessful then surgical intervention is usually required. With no surgical treatment there can be recurrence rates of up to 30%.</p><p>In adults a laparotomy is usually required, especially as in most cases a lead point requiring treatment is present. </p><h4>Differential diagnosis</h4><p>On imaging the appearances on ultrasound and CT are characteristic. The main differential is that of <a href="/articles/transient-intussusception">transient intussusception</a>, which is an incidental finding requiring no treatment or follow-up. </p><p>Other conditions to be considered in adults include:</p><ul>- +</ul><h5>Fluoroscopy - contrast enema</h5><p>A contrast enema remains the gold standard, demonstrating the intussusception as an occluding mass prolapsing into the lumen, giving the "coiled spring” appearance (barium in lumen of the intussusceptum and in the intraluminal space)</p><p>The main contra-indication for an enema is a perforation.</p><h5>CT</h5><p>CT has become the modality of choice for assessment of acute abdomen in adults, and thus most frequently images intussusception. In addition short length <a href="/articles/transient-intussusception">transient intussusception</a> is a frequent incidental finding. </p><p>The appearance of intussusception on CT is characteristic and depends on the imaging plane and where along the bowel images are obtained. </p><p>Best know is the so-called bowel-within-bowel configuration, in which the layers of the bowel are duplicated forming concentric rings (CT equivalent of the ultrasonographic <a href="/articles/target-sign-of-intussusception">target sign</a>) when imaged at right angles to lumen, and a soft tissue sausage when imaged longitudinally <sup>13</sup>. </p><p>At the proximal end of the intussusception there will be two concentric enhancing / hyperdense rings, formed by the inner bowel and the folded edge of the outer bowel. As one images further along the intussusception the mesentery (fat and vessels) will form a crescent of tissue around the compressed inner most lumen, surrounded by the two layers of the outer enveloping bowel. Even further distally the lead point (if present) will be visualised <sup>13</sup>.</p><h4>Treatment and prognosis</h4><p>In children, intussusceptions can be treated without recourse to surgery in most cases. Using a water soluble medium or air, retrograde pressure can be exerted to reduce the intussusception. If symptoms have been protracted, rectal blood is present, there are signs of peritonitis or enema reduction is unsuccessful then surgical intervention is usually required. With no surgical treatment there can be recurrence rates of up to 30%.</p><p>In adults a laparotomy is usually required, especially as in most cases a lead point requiring treatment is present. </p><h4>Differential diagnosis</h4><p>On imaging the appearances on ultrasound and CT are characteristic. The main differential is that of <a href="/articles/transient-intussusception">transient intussusception</a>, which is an incidental finding requiring no treatment or follow-up. </p><p>Other conditions to be considered in adults include:</p><ul>
Unable to process the form. Check for errors and try again.