[Skip to content]

Royal Brompton & Harefield NHS Foundation Trust
For healthcare professionals
Search our Site

Clinical guidelines

Care of adults with cystic fibrosis (2013)

7. Nutritional and gastrointestinal care

7.9 Constipation and distal intestinal obstructive syndrome  


It is thought that constipation and distal intestinal obstructive syndrome is more common in cystic fibrosis patients receiving sub optimal or excessively high doses of pancreatic enzyme therapy or when a rapid increase in enzyme dose occurs, however the incidence of distal intestinal obstructive syndrome varies widely and the pathophysiology is not fully understood.  


Although DIOS is not fully understood there are often multiple contributory factors including:

  • Dehydration

  • Rapid increase in enzyme use

  • Viscid intestinal secretions

  • Altered gut motility and pH

  • Poor compliance with enzyme therapy


Viscid muco-faeculent material accumulates in the terminal ileum / caecum leading to partial obstruction with pain usually in the lower quadrant, abdominal fullness and a palpable mass in the right iliac fossa. Patients often report having their bowels open as usual, or sometimes having diarrhoea (from over flow).


Differential diagnosis

  • Constipation

  • Appendicitis

  • Intussusception

  • Biliary tract or gall bladder disease

  • Acute pancreatitis

  • Urinary tract infection

  • GI cancer



  • A plain abdominal x-ray (AXR) is usually all that is necessary to diagnose DIOS or constipation. However if there if still doubt over the cause of abdominal pain, the following may be helpful:

    • WBC, amylase, liver function tests.

    • Urinalysis

    • Stool culture, stool microscopy for fat droplets, 3-day faecal fat.

    • AXR - dilated small bowel loops with “bubbly” ileocaecal mass, classic feature but not commonly seen.

    • Abdominal ultrasound.

    • Barium /gastrografin enema - by specialist radiologist can diagnose and help treatment at same time.

    • After the acute episode, consider faecal fat study.



1. Chronic

  • Check dose / compliance / timing of enzyme supplements.

  • Diet – ensure adequate dietary roughage.

  • Ensure adequate fluid intake.

  • Laxatives may help e.g. lactulose 5-20 mls bd or movicol.

  • If ongoing malabsorption is documented consider:-

    • Acid reduction with ranitidine or omeprazole 


2. Acute

Gastrografin (oral) - 100 mls in 200 to 400 ml water or juice

  • Patient must be well hydrated before, during and 3 hours post gastrografin, as it is highly osmotic. The suggested fluids above are the minimum.

  • Repeat at 24 hours if no response.


Rectal Gastrografin – 100 mls twice daily are also effective


Intestinal lavage with Kleen Prep a balanced electrolyte solution which can be administered either orally or via a nasogastric tube at a rate of 0.75 – 1 l/h to a total volume of 4-7 litres

  • The aim is to take solution until clear fluid is passed PR.

  • NG tube is usually required as volume is so large but occasionally some patients will prefer to drink it (more palatable if cool).


Colonoscopy with installation of gastrograffin

Colonoscopy is performed under sedation and gastrograffin 500 mls and 50% solution is instilled to the lumen at the site of obstruction.  This is performed when other treatments have failed and in consultation with Dr Westaby. (NB: this prevents the need for laparotomy in most patients)


7.9.1    Constipation

Simple constipation should not be confused with DIOS related to fat malabsorption.  It is important to recognise that increasing doses of pancreatic enzymes which may prevent DIOS can be counterproductive in constipation.


  • Ensure adequate fluid intake.

  • Lactulose 5-20 mls twice daily or Movicol may be used.

  • Ensure dietary review re fibre intake.

  • Chronic constipation refractory to the above measures should raise suspicions in older adults and referral to Dr Westaby and Dr Steele is recommended for CT +/- colonoscopy (note higher incidence of GI cancers in CF adults).