A 57-Year-Old Woman With Bloody Diarrhea

Derik L. Davis, MD; Harvey Stern, MD; Helen T. Morehouse, MD


August 16, 2017

An intraluminal lead point may serve as a point of origin, precipitating the development of intussusception. These lesions may be benign or malignant. Adults with intraluminal lead points may follow a transient course, or they may experience relapsing and remitting obstruction. Children with lead points may present with a similar clinical picture. A high clinical suspicion is usually required to make the diagnosis, given the nonspecific nature of the symptoms.

The pathophysiology of cases without relation to a lead point is considered idiopathic, and in adults, it is typically transient. Most children ultimately demonstrate the idiopathic form of intussusception. Most cases of intussusception in adults that involve only the small bowel are also idiopathic. In contrast, intussusception of the large bowel in adults is frequently associated with lead points.

The most common causes of colocolic intussusception are lipomas, which are benign lesions. Adenomatous polyps are also benign causes of colocolic intussusception. Nearly 50% of colonic lesions responsible for intussusception in adults are malignant. Adenocarcinoma is the malignant neoplasm most frequently associated with colocolic intussusception. Other, less common causes of malignant lead points are lymphoma and metastasis.[1,3,5]

Children with intussusception usually present initially with vomiting, which is often bilious, and recurrent bouts of pain. Intussusception can occur at any age, but the incidence is highest between age 3 months and 6 years, with a peak between age 5 and 9 months. Diarrhea may also be present, and this symptom may lead the clinician astray. Upon physical examination, a sausage-shaped mass, often in the right upper quadrant, may be noted. The findings of the right upper quadrant mass and an "empty" right lower quadrant together constitute the classic "Dance sign." A "currant jelly" appearance of the stool and lethargy are late findings, but stool may be guaiac-positive early on. An early rectal examination may heighten suspicion and lead to a more timely diagnosis and therapy.

Adults with intussusception often experience nonspecific gastrointestinal symptoms. The most common symptoms are abdominal pain and nausea or vomiting. Fewer than 11% of patients have fever, constipation, diarrhea, or weight loss. Patients with the idiopathic form of intussusception may have transient symptoms, compared with those who have an underlying intraluminal lead point and may report intermittent and relapsing symptoms.

Physical examination is often nonlocalizing in adults. Only 7% of patients have a palpable mass. Less than 30% have guaiac-positive stools, but this presentation is more likely in patients with malignant colonic lesions. In contrast to the acute presentation of intussusception in children, adults frequently have a more atypical or chronic course. The nonspecific nature of symptoms often presents a confusing clinical picture that leads to an initial misdiagnosis. Adults presenting acutely are often thought to have bowel obstruction, with few patients having a preoperative diagnosis of intussusception.[1,5]

Contrast-enhanced CT is the most useful modality for intussusception in the adult. Multiple concentric rings representing the intussusception are seen as a target- or sausage-shaped mass: inner cylinder (canal and wall of intussusceptum), middle cylinder (low-attenuation mesenteric fat, with or without enhancing vessels), and outer cylinder (exiting intussusceptum and intussuscipiens). This bowel-within-bowel appearance on CT scan is pathognomonic for intussusception. A lead point can be identified in some cases, although this is a difficult task in many patients. A rim of contrast material surrounding the intussusceptum may also be seen, and it may help make the diagnosis in cases where mesenteric fat is not readily apparent within the mass. With the increasing use of CT in patients with gastrointestinal symptoms, the number of adults identified with unsuspected intussusception is likely to increase.[2,3,6]

Diagnostic studies other than CT are more often used in children when intussusception is suspected. Plain films, abdominal sonograms, and liquid-contrast or air-contrast enemas are the primary imaging modalities in pediatric patients. The contrast enema may be both diagnostic and therapeutic for children. In certain cases, ultrasonography is a good initial test, because it avoids ionizing radiation. Sensitivity is approximately 85%, although it probably varies significantly depending on sonographer experience with this condition. Plain films and sonography are frequently used in the workup of abdominal pain for adults, but they are less accurate than CT for detecting intussusception. The upper gastrointestinal series, flexible sigmoidoscopy, and colonoscopy all have a role in certain clinical situations.[1,7]


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