Prevalence of constipation is reported to be 20%. In the U.S.A, $800 million are spent yearly on laxatives. Constipation in the U.S.A account for 20,000 hospitaliza- tions and 2.5 million out-patient consultations per year.
Definitions: Stool frequency 2 or less per week, straining, hard stools and a feel- ing of incomplete evacuation are all features used by the Rome consensus criteria to define constipation.
Constipation secondary to other conditions: such as (a) primary bowel dis- orders: cancer, benign stricture, anal fissure etc., (b) metabolic: hypercalcaemia, hypothyroidism and diabetes, (c ) neurological : parkinsonism, spinal cord lesions and (d) last but not the least are medications too numerous to list.
Slow transit constipation: These patients have long history. They have slower than normal propagation of stool from ascending to distal colon also known as colonic inertia. Another sub-group have uncoordinated contractions in the descend- ing colon impeding the progression of faeces to rectum. Either nuclear medicine or radiological marker studies could be used to determine colonic transit time and these studies are available locally.
Pelvic floor dysfunction: These patients complain of prolonged and excessive straining. Not uncommonly pressure is required on the perineum or from the vagi- na to aid defaecation. These patients have difficulty emptying faeces from the rectum adequately . A plain xray of the abdomen may demonstrate excessive rectal faecal loading. Referral to a bowel surgeon for anorectal manometry, balloon explu- sion test and or barium defaecography should be considered.
Constipation predominant irritable bowel syndrome: These patients com- plain of pain and bloating in addition to constipation. Colonic transit times are either normal or slightly reduced.
Combination of pelvic floor dysfunction and slow transit constipation: is also encountered.
Clinical evaluation: It is clear from the above discussion that careful history is important to get an idea as to the cause of patient’s constipation. Preliminary in- vestigations should include , FBC, electrolytes, renal function, TSH, calcium, blood glucose and a plain xray of the abdomen. Patient 50 yrs of age or older with brief history of constipation or recent exacerbation should prompt consideration for colonoscopy.
Treatment of constipation: Once primary bowel disorders, systemic diseases as discussed above have been excluded and patient’s medication issues have been ad- dressed, one has to then embark on managing patient’s constipation.
Education: Patients should be encouraged to respond to the natural urge to def- aecation following meals and in the mornings when bowel activity is maximal.
Dietary changes and fibre: Psyllium, legumes and wheat bran are effective with wheat bran being the most effective. Recommended daily intake is between 20-30 gms. Some of these fibre could cause significant wind and bloating. Some authorities believe that fibre could aggravate some patients with slow transit con- stipation. I find sterculia (normafibe) causes least bloating and wind formation. It is important to start fibre at a low dose e.g., one teaspoon daily after food. Water intake needs to be encouraged for fibre to be effective.
Stool softner: Coloxyl allows water to penetrate stool by lowering surface ten- sion.
Osmotic laxatives: Sorbitol is less expensive than lactulose but they are both effective . These agents take 24-48 hours to exert their effect. Polyethylene glycol (movicol) is also effective and safe and mainly used for moderate to severe consti- pation. No good data is available as to the safety and effectiveness of Epsom salt but should be used with caution in patients with renal impairment.
Stimulant laxatives: e.g., senna, bisacodyl, cascara ,castor oil are used when simplier measures fail and I tend to avoid using these agents.
Treatment of constipation associated with neurogenic conditions: e.g.,in dementia, strokes ,wheel chair bound. These are often severe and may require surgical referral for disimpaction under anaethesia followed by travad/fleet enema and then regular polyethylene glycol (movicol) / sorbitol with or with out twice weekly enema to ensure alternate day bowel actions.
Biofeedback for pelvic floor dysfunction: The aim of biofeedback is to train the patient to relax the pelvic floor while straining to achieve defaecation. Success rate is around 75% among adults . This facility is not widely available. Some ex- perts prefer to use suppositories to liquefy stool to overcome obstructed defaeca- tion.
Miscellaneous adjuncts: Maxolon may be helpful in mild to moderate constipa- tion as a prokinetic agent as is tagaserod (zelmac). Misoprotol (cytotec), originally introduced for the treatment of peptic ulcer disease and largely shunned by the gastroenterology community for its side effects of diarrhoea and cramps, now finds use for the treatment of moderate to severe constipation at a dose of 200 microgms 4 times a day. Colchicine has also been found to be effective for the treatment of constipation at a dose of 500 microgms