Constipation is a common problem in children and accounts for almost 20 % of the referrals to the Paediatric surgical clinics. Functional constipation (i.e. no organic cause or pathology is found) is the most common type of constipation and accounts for more than 85% cases, that means that most of the cases can be managed by a proper bowel management program (most of the time it lingers on because of inadequate/inappropriate management). The remaining 10-15% cases involve some organic pathology and Hirschsprung disease is most common and important cause and requires some form of intervention. Other causes may be Congenital anomalies, Neurological (e.g. spina bifida etc.), Endocrine (e.g. Hypothyroidism etc.), Drugs (e.g. Anticonvulsants etc.) etc. and are managed accordingly.
Before understanding and labelling a patient of constipation we should understand the normal stool patterns of infants and children which is highly variable. It may range from 3-6 times/day at 1-month age to 1/ day after 6 months. So, the definition of constipation is also variable. As per the ROME III criteria functional constipation is defined as presence of two or more of the following in absence of any organic pathology and the duration should be at least one month.
Before going to the management we should understand the whole cycle of events that lead to functional constipation and how we can break the chain to manage it. The first event in functional constipation is a painful passage of hard stools which leads to voluntary withholding of stools by the child who wants to avoid unpleasant defecation. This can be caused by a number of factors and can range from change in routine like timing of defecation or diet, stressful events, inter-current illness, non-availability of toilets (travel etc.), child’s postponing defecation because he or she is too busy (morning school, playing, watching TV), and forceful toilet training (e.g.too early or too vigorous). All these events give rise to large, hard stool and passage of such stool leads to stretching of the pain sensitive anal canal, and that frightens the child. As a result of which the child is fearful of passing stools and avoids defecation by all of means. They avoid defecation by contracting their external anal sphincter and gluteal musclesto withhold stool. With holding of stools leads to stools present in the rectum for a longer duration, with resultant absorption of fluids and formation of much harder stools. This leads to build up of stools in rectum and this makes it larger. As the cycle is repeated, successively greater amounts of larger and harder stools are built up in the rectum and passed with even greater pain accompanied by severe “stool withholding manoeuvres”or retentive posture which parents erroneously think it as an attempt to defecate. They feel that the child is trying hard (straining) in an attempt to pass stool when the child is actually trying his best to stop it.
In response to the urge, they refuse to sit on the toilet, rather rise on their toes, hold their legs and buttocks stiffly and often rock back and forth, holding on to a furniture, scream, turn red until a bowel movement finally takes place (because the rectum is fully loaded and trying to push out the stools due to the peristalsis or the movement of the colon – also known as the defecation reflex), which is increasingly painful. With time, such retentive behaviour becomes an automatic reaction. Eventually, liquid stool from the proximal colon may collect around the hard retained stool and pass per rectum involuntarily (faecal incontinence). Sometimes this faecal incontinence is mistaken as diarrhoea. Eventually, with more and more stasis, the rectum becomes dilated and redundant, and the sensitivity of the defecation reflex and the effectiveness of peristaltic contractions of rectal muscles decrease. This is the stage when it becomes more difficult to have a normal defecation due to impaction of the stools in the rectum. Additionally,the urinary bladder is located anteriorly and inferiorly to the rectum and sigmoid colon. Distention from a stool-filled sigmoid colon and rectum can cause bladder compression, which can lead to bladder outlet obstruction. This outlet obstruction from a compressed, distorted bladder has been shown to lead to voiding dysfunction, impaired bladder emptying and urinary tract infection.
It involves taking a careful history (which includes bowel diary, type of stools, birth history – delay in passing meconium, “ Red flags” like fever, vomiting, bloody diarrhoea, failure to thrive) and a thorough physical examination (including digital rectal examination, presence of abnormal physical findings like lack of lumbo-sacral curve, sacral agenesis, flat buttock, anteriorly displaced anus, tight and empty rectum, gush of liquid stool and air on withdrawal of finger, absent anal wink and cremasteric reflex). The most important features in the history, which help to distinguish Hirschsprung disease from functional constipation, are onset in first month of life and delayed passage of meconium beyond 48 hours and the most important examination finding is empty rectum on digital rectal examination. In a classic case of functional constipation (where history and physical findings are normal), no investigation is required to make the diagnosis. There is no need to do barium enema in all cases of constipation to rule out Hirschsprung disease. If the clinical suspicion of Hirschsprung disease is strong (based on history of delayed passage of meconium and empty rectum on digital rectal examination and or other “red flags” are present) then only one may consider getting barium enema X-ray done. This is a special X-ray in which dye is injected through the anal opening with the help of a tube and X-rays are taken at intervals of time.
In Hirschsprung disease there isa reversal of recto-sigmoid ratio (i.e. sigmoid becomes more dilated than rectum) and presence of transition zone. However, for confirmation of Hirschsprung disease -Absence of ganglion cells on rectal biopsy is mandatory before any intervention to be done. There are also other tests to rule out other rarer causes like a slow transit colon but details are beyond the scope of this write up.
Most children with functional constipation get benefited from a precise, well-organized treatment plan, which broadly includes cleaning of stool from the colon and rectum, prevention of further stool retention and promotion of regular bowel habits. This is known as BOWEL MANAGEMENT PROGRAM. This includes the following steps: (a) determine whether faecal impaction is present or not, and treat the impaction if present by Dis-impaction, (b) maintenance treatment with oral laxative, dietary modification, toilet training, and (c) close follow up and medication adjustment accordingly.
First step in the management of constipation is to decide whether the child has faecal impaction or not. This can be accomplished by abdominal examination (hard stool mass may be palpable in the lower abdomen), by digital rectal examination (rectum is usually loaded with hard stools) – but a painful procedure, or by abdominal X-ray (more important in older children who do not allow for a proper digital rectal examination). If there is stool impaction (most of the children with functional constipation do have), then the first step in the management is dis-impaction i.e. clearing or removal of stool load from the colon and rectum. This can be achieved by oral or by rectal route (Rectum is evacuated manually and so it is a painful procedure). Oral route is better as it is simple and non-invasive. A Polyethylene glycol (PEG) solutionis given orally (1-1.5g/kg/day for 3-6 days) or by Ryle’s tube (a stomach tube inserted through the nose at 25mL/kg/hour) until clear fluid is excreted through anus. Only in very severe cases where dis-impaction is not successful by the oral route then rectal evacuation with enemas is required.
To prevent re-accumulation of the stools in the rectum, maintenance therapy in the form of dietary modification, toilet training (promotion of healthy bowel habits) and laxatives needs to be started immediately after dis-impaction or in the first case if no impacted stools are present.
Dietary modification: The diet of most children with functional constipation lacks fibre. Many of them are predominantly on milk with very little complementary food. The children with functional constipation should be encouraged to take more fluids. A balanced diet that includes whole grains, fruits and vegetables is advised and to avoid constipating foods like Fast foods containing refined products – which has become the staple diet in the urban population (maida containing products like bread, cakes, packaged food etc.). The recommended daily fibre intake is age (in years) + 5 in g/day.
Toilet training (Promotion of Healthy bowel habits): It is the most important part as it takes time and the earlier it is inculcated, the better is the outcome of the management. It goes a long way in the management of constipation. It should be started after 2 to 3 years of age. Too early and vigorous toilet training may be detrimental for the child. The child is encouraged to sit on the toilet for 5 to 10 minutes, 3 to 4 times a day 15-20 minutes after major meals for initial months. The gastro-colic reflex, which is stronger in early childhood, comes into play shortly after a meal, so helps in promoting bowel movement.
Children and parents are encouraged to maintain a daily record (stool diary) of bowel movements, faecal soiling, pain or discomfort, consistency of stool and the laxative dose. This helps to monitor compliance and to make appropriate adjustment in the treatment program. Parents are instructed to follow a reward system. Children should be rewarded for not soiling and for regular sitting on the toilet. This acts as a positive reinforcement for the child.
Exercise – children should be encouraged for physical activity like outdoor sports or a scheduled exercise plan should be formulated. This goes a long way in promoting all round health and also prevents constipation.
A close and regular follow-up is a key to the success of treatment of functional constipation. Initial follow-up should be done frequently till regular bowel movements have been achieved, after that can be it can be charted according to the compliance of the patient/parents. On each visit, by reviewing stool records and repeating abdominal and (if required) rectal examination, progress should be assessed. If necessary, dosage adjustment is to be made. Once regular bowel habit is established, the laxative dosage is decreased gradually before stopping, however the other aspects of the management i.e. High Fibre Diet, exercise, behaviour modification etc. should be continued so as to prevent recurrence.
Case – a 15 year old girl was referred with h/o constipation for 10 years and was taking laxatives off and on since the age of 4 years. The child was referred for ruling out an organic component. The child was fully examined and also investigated, however no organic cause was found. On digital rectal examination, the rectum was loaded. X-ray abdomen revealed a loaded colon (Fig 1). She was started on bowel management program and stool dis-impaction done and repeat X-ray emptying of colon, however with some stool present rectum (Fig 2), so she was continued on dis-impaction therapy for some more time. Once dis-impacted, she was started on maintenance therapyand is now on regular follow up and has regular bowel movements.
