Distal intestinal obstruction syndrome
Distal intestinal obstruction syndrome (DIOS) is one the of many abdominal manifestations of cystic fibrosis. In older children or young adults with cystic fibrosis, the distal small bowel may become obstructed with a mucofaeculent material in the distal ileum and right colon.
DIOS occurs in 10-15% of patients with CF - but the incidence is said to have decreased with the administration of microsphere pancreatic enzymes 2. Precipitating factors include 5:
- poor compliance with pancreatic enzyme
- change of diet
Prevalence is highest in the 2nd and 3rd decades of life 2
DIOS is said to be the most common GIT complication in CF patients following lung transplantation, especially if patients have had a diagnosis of meconium ileus in infancy 4.
Clinical manifestations of DIOS include 3:
- abdominal pain: recurrent bouts of colicky abdominal pain
- palpable caecal masses that may pass spontaneously
- abdominal distention and flatulence are common
Clinical findings may mimic those of appendicitis or partial intestinal obstruction due to stricture or adhesions from previous bowel surgery.
Despite the common distension of the appendix by inspissated secretions, the reported prevalence of acute appendicitis in CF patients is lower than that in the general population.
Pathologic mechanisms for this syndrome include inspissated intestinal secretions and pancreatic insufficiency, undigested food residue, disordered intestinal motility, faecal stasis and dehydration.
- features of small bowel obstruction
- bubbly soft tissue mass in the right lower quadrant
- may help to find the level of obstruction
- aids in treatment/reduction of obstruction
- typically seen to affect the right colon
- colonic wall thickening
- mural striation
- mesenteric soft-tissue infiltration
- increased pericolonic fat
- intussusception may be a complication
- the appendix is routinely distended (>6 mm) in the absence of appendicitis resulting from mucoid impaction, and therefore the diagnosis of appendicitis should not be made unless secondary signs are present
Treatment and prognosis
Surgery is usually not required. Treatment options include:
- water-soluble (e.g. Gastrografin) contrast enemas, result in an osmotic influx of water into the lumen of the bowel 5
- intestinal lavage is reserved for recurrent but not complete obstruction - the aim is to wash out the accumulated secretions
- colonoscopy is rarely necessary
Small bowel obstruction from other causes including:
- 1. Robertson MB, Choe KA, Joseph PM. Review of the abdominal manifestations of cystic fibrosis in the adult patient. Radiographics. 26 (3): 679-90. doi:10.1148/rg.263055101 - Pubmed citation
- 2. Fields TM, Michel SJ, Butler CL et-al. Abdominal manifestations of cystic fibrosis in older children and adults. AJR Am J Roentgenol. 2006;187 (5): 1199-203. doi:10.2214/AJR.05.0327 - Pubmed citation
- 3. Agrons GA, Corse WR, Markowitz RI et-al. Gastrointestinal manifestations of cystic fibrosis: radiologic-pathologic correlation. Radiographics. 1996;16 (4): 871-93. Radiographics (abstract) - Pubmed citation
- 4. Morton JR, Ansari N, Glanville AR et-al. Distal intestinal obstruction syndrome (DIOS) in patients with cystic fibrosis after lung transplantation. J. Gastrointest. Surg. 2009;13 (8): 1448-53. doi:10.1007/s11605-009-0924-5 - Pubmed citation
- 5. Klingensmith ME, Chen LE, Glasgow SC et-al. The Washington manual of surgery. Lippincott Williams & Wilkins. (2007) ISBN:0781774470. Read it at Google Books - Find it at Amazon
- 6. Orenstein DM, Stern RC. Treatment of the hospitalized cystic fibrosis patient. Informa Healthcare. (1997) ISBN:0824795008. Read it at Google Books - Find it at Amazon