Constipation is a common condition seen in all age groups. It is related to changing dietary habits all across the world. The ready availability of fast foods or fancy foods or processed food; which is ready to eat, easy to cook, very tasty but lacks fiber (western diet), maybe a major factor, especially in the young population.
Traditionally, constipation is defined as three or fewer bowel movements per week. Lumpy or hard stools are passed with much straining. Many people complain of a sense of incomplete evacuation and may even evacuate the stools manually.
Normally, the residual unabsorbed food enters the large intestine from the small intestine. It consists of food residue, water, electrolytes, bacteria, and gas. About 1 to 1.5 liters of water and electrolytes are absorbed leaving 100 to 200 ml of moisture content. In the slow-transit type of constipation in which the motility of the colon is delayed, more water is absorbed, leaving the stools hard.
Risk factors of chronic constipation
The risk factors are associated with an increased incidence of constipation.
Old age: With advancing age the incidence of constipation increases. The responsible factors are decreased appetite, reduced food consumption, reduced exercise, weakening of abdominal and pelvic wall muscles, and intake of pain killers.
Gender: Constipation is commoner in females due to the inhibitory effect of progesterone on the large intestine. It results in increased absorption of water and constipation.
Socio-economic status: in population-based surveys, constipation has been found to be more common in lower-income groups.
Diet: A low intake of fiber is associated with constipation. Increase fiber tends to retain more moisture and prevents constipation. Lack of fluid intake, especially in cold areas where people tend to take more tea/coffee which causes diuresis (increased urine production) may result in dehydration and constipation.
Causes of constipation
Drugs: constipation may be drug-induced as in the case of consumption of opioids, diuretics, antidepressants, antihistamines, antispasmodics, anticonvulsants, and aluminum antacids.
Diabetes: In long-standing diabetes, due to autonomic neuropathy, the gut motility (forward propulsion of food in the intestine) is reduced; allowing more time for water absorption in the large intestine. This results in constipation.
Hypercalcemia: constipation is commonly seen in hypercalcemia caused by hyperparathyroidism, sarcoidosis, and bone cancer.
Hypothyroidism: Constipation is the commonest complaint in these patients. There is infiltration of the intestine with myxedematous tissue. The transit time in the small intestine is increased.
Pregnancy: Due to a relaxing effect of high levels of progesterone on the large intestine, water is absorbed and constipation occurs. The other contributing factors for constipation in pregnancy include external compression of the rectum by the pregnant uterus causing a delay in the passage of stools, increased intake of calcium and iron supplements which directly cause constipation.
Spinal cord injury: In bed-ridden patients with spinal cord injury, the nerve supply to the lower large intestine and rectum is damaged. This results in failure of forwarding propulsion of stools and constipation.
Parkinsonism: This disease is associated with a deficiency of dopamine in the central nervous system. A defect in dopamine secretion in the nerve supply of the intestines may be responsible for constipation. It manifests with slow colonic transit of stools, diminished contractility of the rectal wall, weak abdominal wall muscular contractions required for passing stools, and abnormal contractions of anal sphincter mechanism; all contribute to constipation.
Multiple sclerosis: This is a degenerative disorder of the brain and spinal cord. When the lower spinal cord is involved, the nerve supply of the colon is affected. There is a reduction of colonic motor activity (peristalsis). They may have incontinence of stools.
Hirschsprung’s disease: Constipation in children occurs in this disease. This occurs because of the failure of the development of nerve supply of the terminal large intestine and rectum. Because of this, the affected intestine remains collapsed, without allowing the stools to pass. The constipation is severe and may be life-threatening.
Constipation may be functional or secondary to some diseases. A sudden change in bowel habit, any weight loss, or alternating constipation and diarrhea should raise alarm and call for a medical consult. The constipation is treated with lifestyle modifications and treatment of cause where feasible.
