From the Guidelines
Diagnosing intussusception involves a combination of clinical evaluation and imaging studies, with ultrasound being the most reliable diagnostic test, having high sensitivity and specificity, and can visualize the characteristic "target sign" or "pseudokidney sign" representing the telescoped bowel 1. The diagnosis should be suspected in any child presenting with sudden onset of severe, intermittent abdominal pain, vomiting, and sometimes bloody stools (often described as "currant jelly" stools). Physical examination may reveal a palpable abdominal mass and signs of intestinal obstruction. Some key points to consider in the diagnosis of intussusception include:
- Clinical presentation: Sudden onset of severe, intermittent abdominal pain, vomiting, and sometimes bloody stools.
- Physical examination: Palpable abdominal mass and signs of intestinal obstruction.
- Imaging studies: Ultrasound is the most reliable diagnostic test, with high sensitivity (97-100%) and specificity (88-100%) 1.
- Other diagnostic tests: Air or contrast enema can be both diagnostic and therapeutic, showing a filling defect or "coiled spring" appearance, while CT scan may be used in adults or complex cases, showing the pathognomonic "bowel-within-bowel" configuration.
- Laboratory tests: Not specific but may show leukocytosis or hematochezia.
- Plain abdominal radiographs: Limited diagnostic value but may show signs of intestinal obstruction. Early diagnosis is crucial as delayed treatment increases the risk of intestinal ischemia, necrosis, and perforation, leading to higher morbidity and mortality rates 1. It's worth noting that while other studies discuss the use of MR defecography in evaluating pelvic floor dysfunction, the most relevant and recent study for diagnosing intussusception is the one from 1, which provides the most up-to-date and accurate information on the topic.
From the Research
Diagnostic Methods for Intussusception
To diagnose intussusception, several methods can be employed, including:
- History taking: Symptoms such as vomiting, abdominal pain, and rectal bleeding can increase suspicion of intussusception 2, 3
- Physical examination: Findings like abdominal mass, abdominal tenderness, and guiac positive stool can be indicative of intussusception 2
- Imaging studies:
- Abdominal radiographs: Can show absence of stool in the ascending colon, but have low diagnostic test accuracy 2, 3
- Point-of-care ultrasound: Has the highest diagnostic test accuracy for ruling in or out intussusception 3
- Computed Tomography (CT) and Magnetic Resonance Imaging (MRI): Can be used for diagnosis, especially in adults, and may reveal lead point pathology 4
- Contrast enema: Can be used for diagnosis and treatment, especially in children 2, 5
Diagnostic Accuracy of Different Methods
The diagnostic accuracy of different methods varies:
- History and physical examination: Have low diagnostic test accuracy 3
- Abdominal radiographs: Have low diagnostic test accuracy, despite moderate discriminatory characteristics 3
- Point-of-care ultrasound: Has the highest diagnostic test accuracy, with a positive likelihood ratio of 19.7 and a negative likelihood ratio of 0.10 3
- Contrast enema: Can be used for diagnosis and treatment, but may have a false positive reduction rate, which can be decreased by using saline plus water-soluble contrast material and confirmation with a single direct abdominal radiograph 5
Special Considerations
In adults, intussusception is often associated with lead point pathology, which can be malignant, and diagnosis is typically made intraoperatively or by cross-sectional imaging 4. In children, idiopathic ileocolic intussusception is the most common form and is typically managed with nonoperative reduction via pneumatic and/or hydrostatic enemas 4.