Ileo-ileal intussusceptions in a child complainting of abdomnial pain

Clinical History

A 6 year-old child came to the Emergency Department complaining of abdominal pain that had started one month previously. Clinically, he had abdominal distention without vomiting and hyporexia. Abdominal examination revealed a soft and non-tender abdomen with no palpable masses. Laboratory tests were unhelpful.

Imaging Findings

Plain abdominal radiography ruled out bowel obstruction (Fig. 1). Therefore, an abdominal US was performed. It showed two incompressible intraabdominal bowel masses. One in the lower right quadrant that showed a doughnut sign (Fig. 2) and another in the mesogastrium that showed a crescent-in-doughnut sign with an adenopathy within the mesentery, which was dragged into the intussusception (Fig. 3).

Discussion

Intussusception is defined as the invagination of a segment of the bowel into the adjacent bowel segment. It is one of the most common causes of abdominal pain in children and is the most common cause of acute bowel obstruction in this group of patients (94% of all cases). [1-2]
Typically intussusceptions occur in children between six months and two years of age with 40% of all cases among three and nine months of age. [1, 3]
There are several types of intussusceptions: ileocaecal, ileocolic, ileoileocolic and ileoileal.
The ileocaecal type is the most frequent, especially in infants under 2 years of age. It has a male-female predominance of 2:1 [1-2]. Transient ileoileal intussusceptions in paediatric patients are uncommon. It is important to differentiate small bowel intussusceptions from ileocaecal ones because treatment changes: while for the former is usually conservative for the latter is therapeutical enema [4].
The cause of intussusception can be identified only in 5% of children, being the most frequents a Meckel diverticulum, tumours or a duplication cyst [1, 3]
Intussusception symptoms are nonspecific, including vomiting, abdominal pain, irritable crying. A palpable abdominal mass has been reported in less than 60% of cases [1-2]
Radiological studies are very important for the prompt and accurate diagnosis. Nowadays ultrasound (US) is the first imaging technique to rule out intussusception in the paediatric population, this technique allows not only a rapid, non-ionising and real-time evaluation but also helps to make alternative diagnosis, and characterize its possible causes [1, 5]. The US features of intussusception are well described, they include an incompressible intraabdominal bowel mass, a doughnut or target-like sign (an even, thickened hypoechoic outer and a central hyperechoic core), a crescent-in-doughnut sign (an even, outer hypoechoic rim with a central hyperechoic crescent), or a multiple-concentric-rings sign (a mass with multiple alternating hypoechoic and hyperechoic concentric rings). [1-2]
The key to differenciate ileoileal from ileocolic intussusceptions is its diameter and length. Several studies have demonstrated that ileoileal intussusceptions are shorter and smaller in diameter than the ileocolic ones. Wiersma F. et al found in a series of cases that "the mean diameter of ileoileal intussusceptions was 1.5 cm and the mean length was 2.5 cm, compared with 3.7 cm and 8.2 cm, respectively, for ileocolic intussusception". [6, 7]

Differential Diagnosis List

Final Diagnosis

Ileoileal intussusception

URL:	https://www.eurorad.org/case/10092
DOI:	10.1594/EURORAD/CASE.10092
ISSN:	1563-4086