String sign in Crohn’s disease can indicate intestinal narrowing. People with other conditions, such as ulcerative colitis, may also have a string sign.

Crohn’s disease (CD) is a type of inflammatory bowel disease (IBD). It affects the digestive tract and causes several symptoms and signs that can develop over time.

A gastrointestinal (GI) string sign is where a part of the bowel appears string-like on medical scans. It may indicate a person has CD or other conditions. Another name for a string sign is the string sign of Kantor, which takes its name from the gastroenterologist who first described it.

This article discusses what gastrointestinal string signs mean, what other conditions can cause string signs, and GI string sign symptoms. It also outlines signs of Crohn’s disease.

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A GI string sign on a medical scan can indicate the presence of CD or other GI conditions.

Conditions such as CD can cause repeated inflammation or other effects on parts of the upper GI tract. This inflammation can lead to severe narrowing of a loop of the bowel. This section of the bowel may look like a length of frayed cotton string on some medical scans.

Healthcare teams may use several types of scans to investigate the GI area. A fluoroscopic upper GI series is a type of X-ray examination. Healthcare professionals use it to examine organs in the upper GI tract, such as the esophagus (food pipe), stomach, and duodenum (the first part of the small intestine).

During an upper GI series, a person drinks a liquid containing barium, a water-soluble contrast material. These substances appear on X-rays, allowing healthcare professionals to view the upper GI tract.

Healthcare professionals may also use CT scans to examine the upper GI tract. A CT scan uses X-rays and computer technology to create an image of the digestive tract. During a CT scan, specialists give a person a solution to drink. They also inject a special dye called a contrast medium.

Both of these substances make the structures, such as GI strings, inside a person’s body easier to see during the procedure. Healthcare professionals also use CT scans to diagnose CD and CD complications.

Idiopathic IBD can cause GI string signs. Idiopathic IBD is a group of conditions that mainly includes CD and ulcerative colitis (UC).

UC is a chronic condition. People with UC have immune systems that cause inflammation and ulcers on the inner lining of their large intestine. Both UC and CD cause long-term inflammation of the digestive tract.

Pyloric stenosis in infants can also cause string sign. The condition refers to when a person has a narrowing in the opening from their stomach into their small intestine.

Other conditions that can cause GI string sign include intestinal tuberculosis, an infectious bacterial disease that mainly affects the lungs. Another possible cause is carcinoma or neoplasm, a type of cancer that starts in the tissue lining the skin, organs, or internal passageways.

String signs are an indication of a persistently narrowed part of the intestine. Several effects of Crohn’s disease or other conditions can cause this narrowing, such as:

  • inflammation
  • stricture, narrowing of a part of the intestines due to scar tissue
  • inflammatory edema, or swelling due to trapped fluid
  • abdominal spasms
  • fibrosis, thickening or growing of scar tissues in the intestines

Not everyone with Crohn’s disease will have a string sign or experience the issues and conditions that can lead to one.

CD signs or symptoms may vary depending on where and how severe the inflammation is. The most common symptoms and signs of Crohn’s disease include:

  • abdominal pains or cramps
  • diarrhea
  • weight loss
  • blood in stool

Other signs and symptoms include:

  • anemia, having low levels of healthy red blood cells
  • eye pain and redness
  • fatigue
  • fever
  • joint soreness or pain
  • loss of appetite or nausea
  • skin changes, such as red or discolored and tender bumps under the skin

The string sign of Crohn’s disease (CD) is an indication observable on medical scans by healthcare professionals.

CD and other conditions may cause part of the intestines to narrow. Healthcare professionals may see this narrowing on medical scans of the upper gastrointestinal tract. The narrowing looks similar to a frayed piece of string, which is why it is known as a string sign.

String signs may have symptoms due to the condition that causes them.

IBD resources

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