Distal intestinal obstruction syndrome (DIOS) involves obstruction of the distal part of the small

intestines The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...

by thickened intestinal content and occurs in about 20% of mainly adult individuals with

cystic fibrosis Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. O ...

. DIOS was previously known as

meconium ileus Meconium is the earliest stool of a mammalian infant resulting from defecation. Unlike later feces, meconium is composed of materials ingested during the time the infant spends in the uterus: intestinal epithelial cells, lanugo, mucus, amniotic ...

equivalent, a name which highlights its similarity to the intestinal obstruction seen in newborn infants with cystic fibrosis. DIOS tends to occur in older individuals with

pancreatic insufficiency Exocrine pancreatic insufficiency (EPI) is the inability to properly digest food due to a lack of digestive enzymes made by the pancreas. EPI is found in humans afflicted with cystic fibrosis and Shwachman–Diamond syndrome, and is common in ...

. Individuals with DIOS may be predisposed to bowel obstruction, though it is a separate entity than true

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

Signs and symptoms

Signs and symptoms of DIOS include a sudden onset of crampy

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

, and a palpable mass (often in the right lower quadrant) in the abdomen. The characteristic abdominal pain is typically located in the center or right lower quadrant of the abdomen.

X-rays An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...

of the abdomen may reveal stool in the colon and air-fluid levels in the

small intestine The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the p ...

Diagnosis

A complete history and physical examination can be suggestive, especially if a palpable mass in the right lower quadrant of the abdomen is present (though this can be present in the absence of DIOS).

Ultrasound Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hea ...

and computed tomography (CT) imaging of the abdomen can confirm the diagnosis by demonstrating dilated loops of intestine with material in the intestinal lumen with bubbles. Air-fluid levels may be seen in those affected by DIOS.

Classification

DIOS is sometimes classified by the degree of obstruction as incomplete or complete DIOS.

Differential diagnosis

Additional diagnoses which may present with similar symptoms to DIOS include severe

appendicitis Appendicitis is inflammation of the appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. However, approximately 40% of people do not have these typical symptoms. Severe complications of a rup ...

, and intussusception.

Management

Differentiation of DIOS from constipation is generally performed by unit specializing in the treatment of cystic fibrosis. Adequate hydration and an aggressive regimen of laxatives are essential for treatment and prevention of DIOS.

Osmotic laxative Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...

s such as

polyethylene glycol Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular we ...

are preferred. Individuals prone to DIOS tend to be at risk for repeated episodes and often require maintenance therapy with pancreatic enzyme replacement, hydration and laxatives (if the symptoms are also mild). Oral contrast instillation into the colon/ileum under radiological control has been found to reduce the need for surgical intervention.

References

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External links

* http://www.cfmedicine.com/htmldocs/CFText/dios.htm * http://www.rbht.nhs.uk/healthprofessionals/clinical-departments/cystic-fibrosis/clinical-guidelines/nutritional-and-gastrointestinal-care/constipation-and-distal-intestinal-obstructive-syndrome/ Gastrointestinal tract disorders Cystic fibrosis Syndromes affecting the gastrointestinal tract