Summary

In yet another series of write-ups, Dr. YK Amdekar touches upon a very commonly encountered problem in paediatric practice-constipation. While revisiting the basics of evaluation and treatment he also,

• points out the red flags that demand further investigations
• different laxatives for the management of primary constipation

Begin by taking the quiz to test your knowledge!

 

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Back to basics – understanding constipation

Constipation- gut in slow motion, constant anticipation without culmination is constipation

Change in bowel pattern resulting in infrequent passage of stools, often hard and at times accompanied with painful defecation and maybe stool smeared with blood. Frequency of passing stools varies in normal individuals from 2-3 times a day to once in two days. It is the change in frequency and/or consistency that is considered. Individual passing stools 3 times a day, suddenly passes one stool a day is a change that needs to be noted. Infant on exclusive breastfeeding may pass a stool once in few days and as there is no change in frequency, and this should not be considered as constipation. In fact, such an infant passes soft stool at the end of a few days, has no discomfort, and grows well.

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Physiology of bowel movements

After food is digested and absorbed by small intestines, it is passed on to the large intestine. Colon and rectum function together to provide absorption of water, electrolytes and short chain fatty acids, dehydration of faecal matter and storage. Ultimately they help in elimination in a socially appropriate manner.

If stool matter remains in colon and rectum for a longer time, it becomes more hard and difficult to expel. Continence is maintained by coordinated function of the pelvic floor, rectum and anal sphincters. Evacuation occurs through relaxation of the pelvic floor. Rectum acts to store as well as expel stool matter, both actions require cortical sensory awareness acting in conjunction with intramural and spinal reflexes that ensure timely defecation.

Anal sphincters act individually and in unison in response to rectal distension and sensation of rectal filling. There has to be an adequate amount of stool matter for rectal distension enough to feel the sensation of filling. Reflex relaxation of internal sphincter has an additional sensory function that allows rectal stool matter to move into the upper anal canal. Voluntary control of external sphincter allows deferring evacuation till opportunity exists.

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Prerequisites for normal bowel movements

Consumption of adequate amount of food is necessary to form the volume of stool enough to distend rectum so that the sensation of rectal filling is perceived by the cortex. There has to be enough insoluble fibre in the diet to form the bulk of soft stool matter so that it moves smoothly through colon and rectum and is expelled without difficulty. Bowel movements depend upon normal intestinal muscle function leading to peristalsis.

Once rectal filling results in the urge to pass stools, intact nervous system acts through reflex action to relax the internal sphincter and pelvic floor muscles and move the stool matter into the upper anal canal, possible with good anorectal tone. Finally intact voluntary control of external anal sphincter is necessary to defer evacuation to the right moment. Thus, multiple factors contribute to normal bowel movements and disturbance of any of these factors may result in constipation.

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Types of constipation

1. Primary constipation that is due to an intrinsic problem in colon and anorectum related to abnormal function of normally innervated and structurally intact muscle. This may result from dyssynergia between external sphincter and puborectalis muscle. In such a case, there is incomplete emptying of the rectum in spite of soft stools.
2. Functional constipation is a result of gut-brain interaction. It is contributed by altered motility, visceral hypersensitivity, altered mucosal and immune functions and change in the intestinal microbiota, It could be worsened by stress.
3. Habitual constipation is a type of primary constipation and is known as constipation of modern civilisation. It is due to improper eating habits (inadequate intake of fiber and water), poor physical exercise and defecation without squatting (use of toilet seat) resulting in an anorectal angle that is not conducive for smooth expulsion. Irregular bowel habits due to rush in the morning to go to school and holding back stools through school period adds to habitual constipation.
4. Secondary constipation is due to structural defects (Hirschprung disease), chronic systemic illness (inflammatory bowel disease, intestinal TB, chronic diverticulitis), neurological (spinal or cortical disorders), hormonal (hypothyroidism, hyperparathyroidism), metabolic disorders (hypercalcemia, cystic fibrosis), lead poisoning and also side effect of few commonly used medications (calcium and iron supplements, anti-spasmodic like dicyclomine, pain relievers such as NSAIDs, propranolol etc.).

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Harmful effects of effects of persistent constipation

Constipation in children must be successfully treated without delay because persistent constipation results in loss of rectal tone and perpetuates worsening constipation. Urinary tract infection often results from constipation due to pressure over the lower urinary tract by distended rectum.

Besides, such harmful effects, constipation also causes significant discomfort due to bloating of abdomen and pain and appetite may be disturbed leading to undernutrition. Straining at stools leads to hernia and at times rectal prolapse. Thus, constipation in children must be viewed as potential permanent harm and must be addressed promptly.

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Management of constipation

Causes of secondary constipation should be ruled out clinically and in case of suspicion should be investigated as these problems can be treated effectively with appropriate intervention.

Immediate short-term aim in the management of primary constipation is to ensure bowel movement every day to avoid permanent damage, for which drugs may be necessary. However, drugs must be used sparingly. Balanced diet with adequate fiber and intake of water, lifestyle changes with proper toilet habits and physical exercise, and behavioural modification with coping with stress form the mainstay of long-term management.

Fibre is a natural bulk laxative that works by increasing the bulk of stools. Prunes have lots of insoluble fiber and also have sorbitol that is laxative. Besides, it also has soluble fiber that is fermented in the colon to produce short chain fatty acids that add bulk to stools. Prunes also stimulate beneficial gut bacteria. Apple, pear, kiwi, figs, citrus fruits, spinach and greens, sweet potato, beans, peas, lentils, flaxseeds, whole grain and oats are some of the food items that are very useful. It is important to avoid fried food, chips, cookies, lots of dairy products and red meat.

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Prevention of of constipation

Exclusive breast feeding for the first 6 months followed by complimentary feeds consisting of suitably modified family food, continuing breast feeds for at least the first year of life promotes ideal bowel movements. Good eating habits with consumption of vegetables and fruits, adequate water intake, physical exercise with outdoor activities and ideal toilet habits help in the prevention of constipation. Once such habits are established in early childhood, they are sustained over subsequent years.

In summary, constipation is a common problem in children and is often ignored in the initial stages till it becomes troublesome. Ideal habits promote good bowel movements. Secondary constipation must be suspected clinically and treated accordingly while primary constipation is managed by diet and lifestyle modifications with stool softeners or osmotic laxatives as per the need. Long term use of drugs must be avoided.

Stay tuned for the next part in the series, where Dr. Amdekar explains clinical applications with the help of case studies.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.