Constipation

ConstipationIt is the passage of hard stools.

Constipation is delay and decrease in frequency of stools often associated with difficulty in defecation. When there is no passage of stool or flatus, it is called absolute constipation.

 

Constipation is a symptom and, like all symp- toms, it is difficult to define. It is a common symptom for one in twenty-five of over 1000 people interviewed at their work considered themselves to be constipated. It is interesting, however, to analyse what these people meant by the term. About half of them had fewer than five bowel actions a week, a small proportion described their stools as hard but had a bowel action on most days and over a third had a daily bowel action with a stool of normal consis- tency.

 

Constipation is a common gastrointestinal problem, which causes many expenses for the community with an estimated prevalence of 1% to 80%, worldwide, where the condition is characterized by a wide geographical variation. It is noteworthy that the varieties of definitions have led to a wide range of prevalence.

Pathogenesis

Dietary residue after extensive absorption in the small intestine passes across the ileocecal valve. About 800 ml of this residue which is of little nutritive value is daily converted in colon to solid fecal material by absorption of sodium, chloride and along with it water. The solid fecal matter is finally transported to the rectum and excreted.The defecation reflex is initiated by acute distension of the rectum.The supraspinal centres stimulate sigmoid and rectal contractions and increase the pressure within the rectum.

The rectosigmoidal angle relaxes permitting the evacuation of feces. This is aided by increasing the intra-abdominal pressure by glottal closure, descent of the diaphragm and contraction of the abdominal muscles.

Defecation can be voluntarily prevented by forceful contraction of the voluntary muscles of the pelvic diaphragm and external anal sphincter. When this is abused, chronic rectal distension results with reduced afferent signals, loss of motor tone and chronic constipation.

The abnormal action of the bowel in constipation may occur in the following ways.

v Defecation may occur with insufficient frequency.

v Defecation may occur daily but insufficient quantity of stool is passed.

v Defecation may occur daily but feces are hard and dry due to increased absorption of fluid as a result of prolonged contact of the luminal contents with colonic mucosa. Sometimes ingested materials like calcium carbonate or barium may lead to hard, rocklike stool.

In patients with slow-transit constipation refractory to medical therapy, colonic manometry can identify underlying neuropathy that may warrant colectomy . Hydrogen breath testing may also be useful in patients with chronic constipation suffering from severe gas and bloating to assess for co-existing SIBO or dietary carbohydrate intolerances.

Causes Constipation

o   Acute:

1. Acute intestinal obstruction: Volvulus, intussusception, hernia, diverticulitis, etc.

2. Acute abdominal conditions: Acute appendicitis, salpingitis, colic, perforation of peptic ulcer, etc.

3. General conditions: Septicemia

o   Chronic:

 

1. Faulty habit and dietary: Abuse of laxatives, avoidance of public toilet, insufficient dietary roughage, suppression of defecatory urges, lack of exercise and prolonged travel.

2. Painful and conditions: Piles, fissure in ano, etc..

3. Organic obstruction: Carcinoma colon, diverticulosis, strictures, etc.

4. Adynamic bowel: Scleroderma, Hirschsprung's disease, myopathies, myotonia.

5. Metabolic: Hypothyroidism, hypokalemia, hypercalcemia, porphyria, lead poisoning. dehydration, etc.

6. Drugs: Anticholinergic drugs, bismuth, aluminium, morphine, codeine, tricyclic antidepressants.

7. Functional: Psychosis, Proctalgia fugax, depression, neurotic disorder.

8. Extrinsic neurological disorders: Spinal cord disorders, sacral nerve disorders, pudendal nerve damage, Parkinson's disease, chronic intrinsic neuromuscular disease of colon, diabetic neuropathy.

Complications of Constipation