Intussusception is a medical condition where one segment of the intestine slides or “telescopes” into an adjacent part, similar to how parts of a collapsible telescope fit together. This phenomenon can block the passage of food and fluids, and it also compromises the blood supply to the affected intestinal segment. While this condition is more commonly observed in children, it presents as a distinctly different and serious concern in adults. In adults, intussusception is a rare occurrence, yet its presence often signals an underlying issue that requires prompt medical evaluation.
Understanding Adult Intussusception
Intussusception occurs when a segment of the intestine (the intussusceptum) slides into an adjacent segment (the intussuscipiens). This telescoping can occur in various parts of the gastrointestinal tract, including the small and large bowel. It is rare in adults, accounting for about 1% of all intestinal obstructions and 5% of all intussusception cases.
A key distinction between adult and pediatric intussusception lies in their underlying causes. In children, the cause is often unknown, or idiopathic. In adults, nearly 90% of cases are linked to an identifiable pathological “lead point.” This lead point is typically a mass or lesion within the intestinal wall that the bowel’s muscular contractions pull into the adjacent segment.
These lead points can include benign growths such as polyps, lipomas, or inflammatory lesions, as well as malignant tumors like carcinomas or lymphomas. Malignancy is a more frequent cause in colonic intussusception, while small bowel intussusceptions are more often associated with benign lesions. Other potential causes include adhesions from previous abdominal surgery or conditions that alter intestinal motility.
Recognizing the Signs
Recognizing the signs of adult intussusception can be challenging because symptoms are often non-specific and may mimic other gastrointestinal disorders. The variability and intermittent nature of these symptoms can delay diagnosis, which contributes to the seriousness of the condition. While symptoms can be acute, appearing suddenly, they may also be subacute or chronic, persisting for weeks or even months.
The most common symptom reported is abdominal pain, which often presents as crampy and can wax and wane. Patients may also experience nausea and vomiting. Changes in bowel habits are also frequent, including constipation, diarrhea, or a combination of both. In some instances, patients might notice bloating or, less commonly, bloody stool, which can indicate compromised blood flow to the bowel.
Unlike in pediatric cases where a classic triad of symptoms, including “currant jelly” stool, is often observed, this specific presentation is rare in adults. The non-distinct nature of adult symptoms underscores the importance of not disregarding persistent or worsening gastrointestinal complaints, especially when they are recurrent or accompanied by other signs of discomfort.
Immediate Medical Attention and Diagnosis
Immediate medical attention is crucial for suspected intussusception in adults due to the high risk of severe complications. Delays in diagnosis can lead to life-threatening outcomes. A high level of clinical suspicion is necessary, particularly given the non-specific nature of the symptoms.
The diagnostic process relies heavily on imaging studies to visualize the telescoped bowel segment and identify any underlying lead point. Computed tomography (CT) scans of the abdomen and pelvis are considered the most effective and accurate method for diagnosing adult intussusception. A CT scan can clearly show the characteristic “bowel-within-bowel” or “target” appearance, which indicates intussusception.
Beyond confirming the presence of intussusception, CT imaging provides crucial information about the location, the specific intestinal segments involved, and the extent of the telescoping. It is also highly effective in identifying the lead point, such as a tumor or polyp, and can reveal signs of complications like bowel obstruction, inflammation, or compromised blood supply. While ultrasound may also be used, CT is superior for a comprehensive assessment.
Treatment and Potential Outcomes
Treatment for adult intussusception almost always requires surgical intervention. This approach differs from pediatric cases, where non-surgical reduction methods, such as enemas, are often successful. The primary reason for surgical management in adults is the high likelihood of an underlying pathological lead point, particularly a malignancy, which necessitates its removal.
During surgery, the goals include reducing the intussusception, removing the identified lead point, and resecting any part of the bowel that has been damaged due to lack of blood flow. For small bowel intussusceptions, if the bowel appears healthy and a benign lead point is suspected, surgeons may attempt to gently reduce the telescoping before resection. However, for colonic intussusceptions, direct resection without attempted reduction is often preferred due to the significantly higher risk of malignancy and the concern of potentially spreading malignant cells.
If adult intussusception is left untreated, it can lead to severe and life-threatening complications. The telescoping action can cause complete bowel obstruction, preventing the passage of intestinal contents. Prolonged compression of blood vessels can result in bowel ischemia, where the affected tissue does not receive enough oxygen.
This can progress to necrosis, which significantly increases the risk of intestinal perforation. A perforation can lead to peritonitis and subsequently cause sepsis and septic shock. With timely diagnosis and appropriate surgical management, the prognosis for adults with intussusception is generally favorable, but the condition itself remains a serious medical emergency.