What Is Distal Intestinal Obstruction Syndrome?

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Distal intestinal obstruction syndrome (DIOS) is a complication that arises in people who have cystic fibrosis (CF). It presents as a complete or partial blockage of the bowel in the upper intestinal tract. Symptoms of DIOS can include vomiting, abdominal cramps, and a feeling of fullness that occurs alongside diarrhea.

This article discusses the symptoms, causes, and treatment options available for someone with DIOS.

Woman experiencing abdominal pain.

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Distal Intestinal Obstruction Syndrome Symptoms

When DIOS develops, a person’s bowel movements become blocked, resulting in various symptoms, including:

  • Abdominal pain and cramping
  • Stomach ache
  • Bloating
  • Vomiting a green or yellow fluid due to bringing up bile from the stomach
  • A mass that can be felt or touched in the abdomen
  • Inability to pass stools or gas
  • Feelings of fullness
  • Diarrhea

The symptoms that present when someone has DIOS are often mild and can be mistaken for appendicitis.

Prevalence of DIOS In People With CF

Roughly 10% to 15% of people with CF will develop DIOS at some point in their lifetimes.


In CF, thick mucus builds up within the body and can lead to blockages in organs. The organs that are mainly affected are the lungs, pancreas, and intestines.

When that mucus builds up in the digestive tract, it slows down the digestive process. Stool can end up stuck within the intestines behind the area where the mucus has gathered. Together, the mucus and the stool that cannot make their way through the body properly cause a blockage.

Other research suggests that more factors are at play when DIOS develops, such as a lack of proper digestive enzymes meant to break down food properly. The ability to move stool through the intestines may also be compromised in people with DIOS.


It is fairly easy to diagnose DIOS in people with CF because they are already known to be at risk for it, and the symptoms are specific to an intestinal blockage.

To diagnose the condition, healthcare providers will take a note of all the symptoms a person is experiencing and perform an X-ray of the abdomen to identify where the mass is located.

Can DIOS Be Predicted in CF?

While everyone with CF is at risk of developing DIOS, there are two specific risk factors associated with the complication:

  • Genetic predisposition
  • Pancreatic insufficiency (when the pancreas doesn’t create enough of digestive enzymes)


The main goal of treatment is to rid the intestines of the blockage to restore proper bowel movement. There are several ways this can be done:

  • Osmotic laxatives: Osmotic laxatives work to soften the stool by drawing fluid from the body into the large bowel.
  • Stimulant laxatives: Stimulant laxatives increase how quickly stool or food moves through the intestines, improving motility within the intestines. They work by encouraging the muscles of the bowel to contract more frequently.
  • Mucolytics: Mucolytics are designed to break down the overabundance of mucus within the intestines.

Other medications can be used to either increase the pancreatic enzymes that may be lacking in the system to help improve digestion or improve the motility of the digestive tract so that food and stool are passed more effectively.

If none of the aforementioned medications work, surgery may be required. Types of surgery that can be used for DIOS include:

  • Surgical decompression: This surgery is done by decompressing the blockage so it can move freely through the intestines.
  • Caecostomy: Caecostomy is a type of surgery that involves using the pouch found at the opening of the large intestine to form a bridge that can be opened to help drain the blockage.
  • Right hemicolectomy: This surgery is done by removing the right portion of the colon. Afterward, the small intestine is attached to what is left of the colon.
  • Small bowel resection: In this surgery, part of the small bowel is removed.

Surgery Risks and DIOS

Surgery is typically reserved for the most stubborn cases of DIOS because they carry significant risks, such as bleeding, infection, and delayed healing. These factors increase the risk that someone could die during surgery.


DIOS is a complication of cystic fibrosis that occurs when CF-related mucus builds up in the intestines and blocks stool from passing through properly. When a blockage occurs, symptoms such as vomiting, abdominal pain, and difficulty passing stool can develop.

DIOS can cause larger problems if left untreated, but it can be effectively treated early on through various medical interventions such as laxatives and digestive enzymes. Surgery may be required in rare and more severe cases, but it is typically reserved as a last-resort treatment option.  

A Word From Verywell

If you have cystic fibrosis and begin experiencing any signs of DIOS, it’s best to meet with your healthcare provider as soon as you can. DIOS is easily dealt with in the majority of cases. Prompt treatment can remedy the situation and negate the need for more invasive interventions such as surgery.

Frequently Asked Questions

  • What does DIOS feel like?

    A person experiencing DIOS will begin to feel mild symptoms such as stomach aches or pain. These pains can be lower in the abdomen. Painful cramps can also develop, and you may be able to feel a mass within your abdomen.

  • Can you prevent DIOS from happening?

    While it is difficult to stop the initial mucus build-up in CF that leads to DIOS, you can do some things to help lower your risk of total blockage. First, you will want to ensure that you take pancreatic enzyme supplements. You will also want to stay as hydrated as possible so that there is enough water in the bowel to move stool through freely.

  • What is the main form of treatment for DIOS?

    Typically, cases of DIOS are mild and can be treated easily. When that is the case, laxatives are the first-choice treatment followed by other medications designed to reduce the amount of mucus build-up within the intestines and help improve the motility of the digestive system.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cystic Fibrosis Canada. Distal intestinal obstruction syndrome (DIOS).

  2. Mavilia M. Distal intestinal obstructive syndrome (DIOS): a gastrointestinal complication of cystic fibrosis in adults. Clin J Gastroenterol. 2019;12(6):571-573. doi:10.1007/s12328-019-00979-7

  3. Lavie M, Manovitz T, Vilozni D, et al. Long-term follow-up of distal intestinal obstruction syndrome in cystic fibrosis. World J Gastroenterol. 2015;21(1):318-325. doi:10.3748/wjg.v21.i1.318

  4. Sandy NS, Massabki LHP, Gonçalves AC, et al. Distal intestinal obstruction syndrome: a diagnostic and therapeutic challenge in cystic fibrosis. J Pediatr. 2020;96(6):732-740. doi:10.1016/j.jped.2019.08.009

  5. Green J, Carroll W, Gilchrist FJ. Interventions for treating distal intestinal obstruction syndrome (DIOS) in cystic fibrosis. Cochrane Database Syst Rev. 2018;8(8):CD012798. doi:10.1002/14651858.CD012798.pub2

By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.