Why constipation occurs?

This is supposed to be for medical students as an attempt to explain the mechanism of constipation in a simple way.

Constipation is diagnosed when the amount of bowel is small and the consistensy is hard or if no defecation occurs for 48 hours or more apart from the patient's habits.

Charcol test is negative in constipation if no black stool passes for 48 hours.

Mechanism of normal defecation:

1- Propulsion : from the caecum to the sigmoid part of the caecum.
2- Expulsion :the distended rectum initiates defecation and produces the urge to defecate. Then the intra-abdomina pressure is increased by straining with relaxation of the anal sphincter.

Causes of constipation:

• Insufficient fibers intake in diet.
• Dehydration.
• IBS.
• Laxatives over-use.
  
• Dehydration due to vomiting.Obstructed colon.
• Paralytic ileus.
• Weakened pelvic floor muscles by repeated pregnancies.
• Dyschezia: neglection of the urge to defecate.
• Anal sphincter dysfunction.
  

Mild constipation cases can be treated with a laxative. In some diseases the underlying disease must be treated and diet should be changed. In chronic constipation it may be more effective to perform a colonic cleanse.

Related links:
-What is a colon cleanse ?