A capsule endoscopy, often called a “pill camera,” is a non-invasive medical procedure used to capture detailed images of the small intestine, a section of the digestive tract difficult to reach with traditional endoscopes. Patients swallow this small, vitamin-sized device, which contains a miniature camera and light source. This allows physicians to visualize the small bowel lining to diagnose conditions like obscure bleeding, Crohn’s disease, or tumors. The intended method for removing the pill camera is through natural excretion, as the device is designed to travel the entire length of the gastrointestinal tract. After the camera has completed its diagnostic work, the body is expected to pass it without medical intervention.
The Expected Natural Passage
The transit of the pill camera through the digestive system is facilitated by the body’s natural muscular contractions, known as peristalsis. Once swallowed, the camera begins taking thousands of high-definition images, which are wirelessly transmitted to a data recorder worn on a belt around the patient’s waist. The device typically spends about eight hours traveling through the small intestine, the main area of diagnostic interest. For most people, the capsule will be excreted naturally within a few days following ingestion, often within 24 to 72 hours. The procedure is considered complete once the data recorder confirms the camera has finished transmitting or the patient observes the capsule’s passage.
Recognizing Capsule Retention
In a small percentage of cases, the natural passage fails, resulting in a complication known as capsule retention (CR). Retention is officially defined as the pill camera remaining in the digestive tract for a minimum of two weeks, necessitating targeted medical or surgical intervention. The overall frequency of this complication is low, occurring in approximately 2% of all patients undergoing the procedure.
Retention occurs when the capsule encounters an area of narrowing, or a stricture, within the small intestine. This narrowing can be caused by underlying conditions such as Crohn’s disease, previous gastrointestinal surgery, radiation enteritis, or small tumors. Patients with known strictures or those being evaluated for subacute small bowel obstruction face a significantly higher retention risk, sometimes as high as 10% to 20%.
While many cases of retention are initially asymptomatic, clinical symptoms arise if the retained capsule causes a partial or complete blockage. These symptoms usually indicate a small bowel obstruction and can include:
- Abdominal pain
- Cramping
- Persistent nausea
- Vomiting
- Abdominal distension
If the capsule is not passed within one or two weeks, a physician may use an abdominal X-ray to confirm its location and diagnose the retention.
Clinical Procedures for Active Removal
When a pill camera is retained, the decision for active removal is based on the patient’s symptoms and the capsule’s location. For a capsule retained in an accessible area of the upper gastrointestinal tract, such as the stomach or duodenum, a standard upper endoscopy can often be performed to retrieve the device. This minimally invasive approach uses a flexible tube inserted through the mouth to physically grasp and remove the capsule.
For retention deeper in the small intestine, a specialized procedure called double-balloon enteroscopy (DBE) is frequently used. DBE involves a long, flexible endoscope with two balloons that allow the physician to navigate the entire length of the small bowel, providing a safe and effective way to retrieve the retained capsule. This endoscopic technique has a high success rate and has substantially reduced the necessity of surgical intervention for removal.
Surgical removal is reserved for instances where the endoscopic approach fails or when the retention causes an acute complication, such as a complete bowel obstruction or perforation. In these situations, surgery is often necessary to treat the underlying cause of the stricture, such as resecting a diseased bowel segment, while simultaneously retrieving the camera.