Logical treatment for constipation and its complications
Developing a shared model of the interaction of the factors may involve consideration of many of the factors above which should be clear from a full history, examination, and perhaps abdominal radiograph. If features of Hirschsprung’s disease are present then suction rectal biopsy for acetylcholinesterase positive nerve excess should be requested.
Evacuation of retained faeces in the large rectum is best carried out by softening the mass sufficiently with docusate sodium (Dioctyl paediatric syrup, Medo) then using sodium picosulphate elixir (Laxoberal, Windsor or less acceptably Picolax, Ferring) as a single dose provided the faecal mass is of a size which could be physically passed through the pelvic outlet and anus. If there is doubt about this then a more prolonged course of docusate sodium with its detergent like activity may permit the picosulphate treatment later. If picosulphate is ineffective even after repeating an adequate dose further success may be achieved by using a polyethylene glycol solution such as Golytely (Seward) or Klean-Prep (Norgine) (although high fluid volumes are required and, if nasogastric tubes are the only effective method of administration, it would be kinder to use alternative means). If these oral methods are ineffective or impossible to administer the use of microenemas or phosphate enemas can be considered provided the child understands and can cooperate with them or can be given sufficient sedation to avoid the stress.
If the enema procedure is impossible, ineffective, or if the faecal mass is persistently too large to pass despite a lengthy course of docusate sodium, or if there are signs of acute impaction, an evacuation under a general anaesthetic should be performed. An extra benefit that can be gained from the manual evacuation under general anaesthetic is that the opportunity to perform a vigorous anal dilatation can be taken. This will weaken any increase in the activity of the internal anal sphincter (secondary to the prolonged faecal retention leading to rectal smooth muscle hypertrophy) seen on anorectal manometry. Once the rectum is clear from the accumulation of old stools, steps must be taken to avoid a new build up.
Maintenance treatment involves using both bulk laxatives such as lactulose or methyl-cellulose tablets (Celevac, Boehringer Ingelheim) as well as regular stimulant laxatives such as senna (Senokot, Reckitt and Coleman). Regular senna given once a day or alternative days is helpful in stimulating an episode of defaecation approximately 24 hours later. With a sufficient dose the reluctant child may not be able to prevent the stools from being passed and the older child may have a more complete defaecation at a convenient time for spending a period in the lavatory. Once the senna regularity is achieved it is vital that the medication is continued for long enough to avoid a relapse. In my study currently in progress, stopping active laxatives too soon is the commonest cause for relapse.
The length of time my patients have spent regularly taking stimulant laxatives. This is in agreement with traditional teaching that children with chronic constipation rarely require less than a year on stimulant laxatives.
If periods of reaccumulation occur then it is essential to repeat the evacuation procedure. It may be helpful in children who frequently relapse to have a boost in the laxatives by having regular weekend sodium picosulphate provided they are warned of the loose stools in advance of important social activities.
Frequent relapsers may benefit from an anal dilatation or partial internal anal sphincterotomy when there is evidence of internal anal over-activity. The table show some data from 230 children with severe protracted constipation treated in my clinic treated over a four year period.
Data from 230 children seen over a four year period:
|No anal dilatation||47 (20)|
|Rapid response to anal dilatation||32(14)|
|Slow response to anal dilatation||58 (25)|
|Rapid response to sphincterotomy||7 (3)|
|Slow response to sphincterotomy||6 (3)|
|Needed anal dilatation after sphincterotomy||12 (5)|
|Still on laxatives after four years||28 (13)|
|Failed to attend to complete regimen||40(17)|
It should be stressed that parallel psychological help is vital for approximately half the children presenting with protracted constipation. In children with hugely dilated megarectums other abnormalities of the myenteric plexus other than Hirschsprung’s disease may be involved and this is an area of developing interest. Only by clear understanding of the abnormalities of the myenteric nerve plexi will the children with apparently untreatable constipation be clearly separated from those in whom the treatment regimen has been subtly sabotaged either as part of a Munchausen by proxy syndrome or where the family dynamics have become so dependent on the child’s bowel problem that resolution of this appears too hazardous to the family members.
These two extremes facing the paediatrician demonstrate how important it is to have a correct appreciation of the factors involved in the condition as well as access to specialised teams embracing specialised paediatrics, psychiatry/psychology, surgery/histopathology, and nurse specialists when the constipation becomes complicated.