In practice, the differential diagnosis of mild incomplete DIOS versus severe constipation may not always be possible to make clinically. Although an abdominal X-ray may help to clarify this by showing faecal accumulation predominantly in the right flank in DIOS, imaging may not be required as initial management of these conditions is similar ^1,2.

However if there is concern that there may be complete intestinal obstruction - especially in children who have had previous abdominal surgery - eg a history of severe or worsening abdominal pain and / or vomiting – especially bilious - a plain abdominal x-ray (AXR) should be requested early. Dilated bowel loops +/- Intestinal fluid levels may support a diagnosis of complete DIOS with obstruction, or adhesional obstruction.

DIOS incidence varies widely (paediatric lifetime prevalence of ~8%) but it mostly affects those with pancreatic insufficiency. The pathophysiology is not fully understood, but there may be multiple contributory factors including:

• Severe CF genotype
• Pancreatic insufficiency
• Inadequate salt intake
• Dehydration
• Poorly controlled fat malabsorption
• History of meconium ileus as neonate or DIOS Post organ transplantation ²

ESPGHAN Working Group Definition of DIOS in CF ³

Incomplete DIOS - Mild / Severe

DIOS is associated with relatively acute onset of symptoms (days rather than weeks) .Thick faecal material accumulates in the terminal ileum leading to partial obstruction in incomplete DIOS. Symptoms may be mild or severe and include mild to moderate intermittent, peri-umbilical and/or right lower quadrant abdominal pain with nausea. There may be a palpable mass in the RIF. Children who have had previous surgery (particularly a laparotomy in the neonatal period for meconium ileus) may have complications related to intraperitoneal adhesions – close monitoring for developing signs of complete obstruction is required.

Management of  Mild / Severe Incomplete DIOS

Management is step-wise and will depend on severity of symptoms and response to treatment Stages 1-3.

If there is any concern that complete bowel obstruction has occurred a plain abdominal x-ray (AXR) is required. 

Complete / Obstructed DIOS

Complete/ Obstructed DIOS is characterised by abdominal distension, worsening abdominal pain (often colicky), frequent or worsening vomiting –often bilious - and bowel loop dilatation +/- fluid levels on AXR. Complete DIOS is rare in children, but a surgical opinion should be sought early and AXR requested if this is suspected or there is doubt about the differential diagnosis eg complex / complicated case due to previous abdominal surgery. In particular, signs of intestinal ischaemia should prompt immediate surgical referral. These include tachycardia, pyrexia, abdominal tenderness on palpation or percussion, and raised inflammatory markers.

Constipation may occur over a period of time (weeks rather than days) and present with a history of generalized abdominal pain and infrequent, hard stools. Clinical examination may reveal faecal masses which are generally felt in the left iliac fossa. Vomiting is rare and non-bilious. 

Mild constipation can be managed with regular laxatives. If constipation is prolonged or severe the GGC Paediatric Disimpaction protocol may be required. There should be frequent review of the patient’s progress at home and re-assessment with AXR if signs of complete obstruction become evident. 

GGC Paediatric Disimpaction Protocol

Paediatric Movicol- 

• 1-5 yrs 2 sachets on day 1, then 4 sachets for 2 days, then 6 sachets for 2 days and 8 sachets daily thereafter.
• 5-12 yrs 4 sachets on day 1, then increase by 2 sachets daily until max of 12 sachets daily.
• >12 yrs see adult regime(BNF)

If disimpaction not achieved by 2 weeks, add a stimulant laxative eg Senna. If Movicol is not tolerated, use Lactulose and Senna for disimpaction

Further Management

Following treatment for DIOS or Severe Constipation, Movicol Paediatric should be prescribed for ongoing home use:

Child 1–11 months
0.5–1 sachet daily.

Child 1 year
1 sachet daily, adjust dose to produce regular soft stools; maximum 4 sachets per day.

Child 2–5 years
1 sachet daily, adjust dose to produce regular soft stools; maximum 4 sachets per day.

Child 6–11 years
2 sachets daily, adjust dose to produce regular soft stools; maximum 4 sachets per day.

• The CF dietitian should be informed of any cases of constipation, DIOS or adhesional obstruction requiring hospital admission.
• A dietary assessment should be conducted and a review of pancreatic enzyme replacement therapy (PERT) initiated if there is evidence of under or over dosing of PERT.
• Avoidance of dehydration is important to prevent future episodes occurring. Advice to maintain adequate fluid intake should also be given.

Oral regular paracetamol - doses as per BNFC 

For severe pain consider IV paracetamol for  24-48 hours- doses as per BNFC.  

Avoid/stop all opioid analgesia

GASTROGRAFIN BNFC 2020

Distal intestinal obstruction syndrome in children with cystic fibrosis

By mouth

Child 1–23 months 
15–30 mL for 1 dose.

Child (body-weight 15–25 kg)
50 mL for 1 dose.

Child (body-weight 26 kg and above)
100 mL for 1 dose.

Directions for administration

Intravenous prehydration is essential in neonates and infants. Fluid intake should be encouraged for 3 hours after administration.

By mouth

• for child bodyweight under 25 kg, dilute Gastrografin® with 3 times its volume of water or fruit juice; 
• for child bodyweight over 25 kg, dilute Gastrografin® with twice its volume of water or fruit juice.

KLEAN PREP – BNFC 2020

Distal intestinal obstruction syndrome

By mouth, or by nasogastric tube, or by gastrostomy tube

Child 1–17 years

10 mL/kilogram/hour for 30 minutes, then increased to 20 mL/kilogram/hour for 30 minutes, then increased if tolerated to 25 mL/kilogram/hour, max. 100 mL/kg (or 4 litres) over 4 hours, repeat 4 hour treatment if necessary.

Directions for administration

1 sachet should be reconstituted with 1 litre of water.

Flavouring such as clear fruit cordials may be added if required.

After reconstitution the solution should be kept in a refrigerator and discarded if unused after 24 hours.

N-ACETYLCYSTEINE 

Oral N-acetylcysteine – Disulphide bond breaker.  

The 200mg/ml injection can be given orally and should be mixed with water, orange juice, blackcurrant juice or cola to a concentration of 50mg/ml. 
Alternatively, 200mg sachets or 600mg tablets are available. 
For larger doses consider the use of the IV preparation for oral administration to reduce the burden of volume

• 1 month – 6 months: 0.4 g
• 6-12 months: 1 g
• 12-18 months: 1.6 g
• 18m – 2 year: 2 g
• 2-6 years: 3 g
• 6-12 year: 4 g
• >12 year:  6 g