Once the diagnosis of chronic intestinal pseudo-obstruction (CIP) is established, the underlying etiology should be determined. It is recommended that all patients undergo laboratory testing to identify secondary causes of CIP.
Full thickness biopsy is rarely needed and should be considered in patients with severe dysmotility of unknown etiology who undergo surgery, in patients with poor outcomes after surgery, or in patients with a permanent catheter for enteral or parenteral nutrition.
You cannot not eat or drink anything for at least 4 hours before the test and should inform the doctor if you regularly take anticoagulants or non-steroidal anti-inflammatory drugs (such as aspirin, ibuprofen, or naproxen). These medications must be discontinued for some time before the procedure to reduce the risk of bleeding complications.
About the test:
The procedure used to obtain the biopsy depends on which section of the intestine is being tested.
It can be obtained by endoscopy if the doctor is getting the biopsy from the first part of the intestine (the duodenum). After giving you a sedative and other medication, the doctor inserts the tube into your mouth, down your throat, and into your esophagus—the long, hollow passageway that connects your throat to your stomach. When the tube reaches your stomach, the doctor uses the camera to find the duodenum—the entryway into your small intestine—and inserts the tube there. Your doctor inserts a tiny surgical instrument through the tube and into your small intestine. Your doctor will then take tissue samples from two or three areas of your small intestine.
However, most biopsies for CIP are obtained from the jejunum (the second portion of the intestine) and are usually obtained during placement of a J-tube or during another surgery that involves the small intestines (i.e. ostomy) while you are under anesthesia. This area is extremely difficult to access by endoscopy or colonoscopy.
Biopsy specimens are sent to a pathology laboratory and examined under a microscope for changes that indicate a bacterial or parasitic infection or another abnormality. The findings from a full-thickness intestinal biopsy may help differentiate between myopathic, neuropathic, or other disorders as the cause of CIP.
This test usually results in a definitive diagnosis. Results may take a few days to weeks to come back. Your doctor will recommend an appropriate course of treatment, depending on the specific results.
Source: The Johns Hopkins Consumer Guide to Medical Tests. http://www.healthcommunities.com/digestive-system-tests/small-bowel-biopsy-small-intestine.shtml