The purpose of this case report is to emphasise the difficulty in making a preoperative clinical diagnosis of ileocolic intussusception unless there is a high index of suspicion, and to highlight the value of diagnostic radiology in reaching the diagnosis. Once diagnosed, treatment is straightforward and the prognosis depends upon the underlying pathology.
Adult intussusception is rare, with 95% of cases occurring in children. It is expected to be found in 1/30,000 of all hospital admissions, 1/1300 of all patients presenting with abdominal pain, and 1% of all cases operated for intestinal obstruction.1,4
It may be acute or chronic. The chronic intussusception may have lasted in some instances for a year before the diagnosis. The male to female ratio is 1:1–1.3.5
Intussusception in adults with a benign pathology presents at a younger age. Older age at presentation may point to underlying malignancy, with adenocarcinomas being the most common entity encountered.5,6
A demonstrable lead point which is a benign lesion in 25% and malignant in 75% is identified in 90% of adult cases, and the aetiology varies depending on its location. The common benign lesions are lipoma and adenomatous polyps, with adenocarcinoma and lymphoma being the most common malignancies.
Clinical presentation is usually non-specific which makes the clinical diagnosis difficult.2
The classical findings of abdominal pain, palpable sausage shaped mass and red current jelly stools seen in children are rare in adults.
Modern non-invasive and invasive imaging techniques can be very helpful in making the diagnosis of ileocolic intussusception preoperatively.1,7
Ultrasound and CT scans are the investigations of choice. Barium studies are obviously contraindicated if there is the possibility of bowel perforation or ischaemia. CT scan appearances are usually characteristic. Intussusception appears as a complex soft tissue mass, consisting of an outer and inner layer. A rim of the contrast medium is sometimes seen encircling the intussusceptum.2
The dense nature of the intussuscepted mass which is composed of oedematous bowel wall and mesentery within the lumen gives it a characteristic target sign or sausage shaped appearance.1,7
Ultrasonography has been used to evaluate suspected intussusception in both children and adults. It is easy to perform and less invasive than the other methods.8
The classic features of intussusception include the target and donut signs in the transverse view, and the pseudo kidney sign in the longitudinal view.9–11
The major limitation of ultrasound for evaluating an acute abdomen is the presence of air in the bowel, which leads to poor transmission and difficulties in image interpretation.
The optimal treatment of adult intussusception is not universally agreed upon. All authors agree that laparotomy is mandatory, in view of the likelihood of identifying a pathologic lesion.12
Most authors recommend resection without reduction whenever possible.5
A few authors have suggested a trial of intraoperative reduction of the intussusception13
; however this risks bowel perforation, especially when the bowel wall is ischaemic and can lead to intra- or extramural seedling or tumour embolisation if a carcinoma is present.
Most of the authorities agree that colonic lesions should not be reduced before resection because they most likely represent a primary adenocarcinoma, especially in patients over 60 years of age. It has also been reported that small bowel intussusception should be reduced only in patients in whom a benign diagnosis has been made preoperatively. In cases in which the bowel is inflamed, ischaemic, or friable, it is advisable not to attempt operative reduction but to proceed directly with resection.
- Ileocolic intussusception is rare but should be strongly suspected in patients with intermittent abdominal pain.
- Unlike children, in adults 75% of cases are due to a malignant tumour of the bowel.
- A preoperative diagnosis of intussusception can be made by ultrasound or CT scan.
- Primary resection without reduction should be performed, particularly in those patients >60 years of age, due to a higher risk of malignancy.
- Intraoperative reduction should only be performed if a benign preoperative diagnosis has been made or if the intussusception is so long that resection may lead to short gut syndrome.