Constipation is a common clinical complex symptom, not a disease. It mainly refers to reduced defecation frequency, reduced fecal volume, dry and hard feces, and labored defecation. The judgment of constipation must be made based on the characteristics of the stool, the person's usual defecation habits and whether there is any difficulty in defecation. If it lasts for more than 6 months, it is chronic constipation.

Constipation can be divided into two categories: organic and functional.

1. Organic

(1) Organic lesions of the intestine: Intestinal lumen stenosis or obstruction caused by tumors, inflammation or other reasons.

(2) Rectal and anal lesions: rectal prolapse, hemorrhoids, rectocele, puborectalis muscle hypertrophy, diastasis pubis, pelvic floor disease, etc.

(3) Endocrine or metabolic diseases: diabetes, hypothyroidism, parathyroid disease, etc.

(4) Systemic diseases: scleroderma, lupus erythematosus, etc.

(5) Nervous system diseases: central brain diseases, stroke, multiple sclerosis, spinal cord injury, peripheral neuropathy, etc.

(6) Intestinal smooth muscle or neurogenic lesions.

(7) Colonic neuromuscular disease, intestinal pseudo-obstruction, Hirschsprung disease, megarectum, etc.

(8) Neuropsychological disorders.

(9) Drug factors: Iron, opioids, antidepressants, anti-Parkinson’s drugs, calcium channel blockers, diuretics and antihistamines, etc.

2. Functional

The cause of functional constipation is not yet clear, and its occurrence is related to a variety of factors, including:

(1) Little food intake or Food lacking in fiber or water content reduces colon movement stimulation.

(2) Normal defecation habits are interfered with by work stress, fast pace of life, changes in work nature and time, mental factors, etc.

(3) Colon motility disorder, common in irritable bowel syndrome, is caused by spasm of the colon and sigmoid colon. In addition to constipation, there is also abdominal pain or bloating. Some patients may present with constipation and diarrhea. alternately.

(4) Insufficient abdominal and pelvic muscle tension, insufficient defecation driving force, and difficulty in expelling feces from the body.

(5) Abuse of laxatives can lead to drug dependence and constipation.

(6) The elderly are frail, inactive, have difficulty defecation due to intestinal spasm, or due to a long colon.

3. Classification

Constipation is mainly divided into two categories according to its pathogenesis: slow transit type and outlet obstruction type.

(1) Slow transit constipation is caused by weakened intestinal contraction movement, which slows down the movement of feces from the cecum to the rectum, or by uncoordinated movement of the left colon. It is most common in young women and occurs around puberty. It is characterized by decreased defecation frequency (less than once per week), less urge to defecate, and hard feces, making defecation difficult; there is no feces or hard feces is palpable during anorectal digital examination. The external anal sphincter's anal contraction and forced defecation functions are normal; the total gastrointestinal or colonic transit time is prolonged; there is a lack of evidence of outlet obstruction, such as normal balloon expulsion test and anorectal manometry. Increasing dietary fiber intake and osmotic laxatives are ineffective. Constipation caused by diabetes, scleroderma and drug-induced constipation are mostly slow-transmission types.

(2) Outlet obstruction constipation is a disorder of fecal discharge due to muscle incoordination in the abdomen, anus, rectum and pelvic floor. It is particularly common in older patients, many of whom have failed to respond to conventional medical treatments. The outlet obstruction type may have the following symptoms: labored defecation, incomplete or falling feeling, small defecation volume, or lack of intention to defecate; there is a lot of muddy feces in the rectum during digital anorectal examination, and the external anal sphincter may show signs of abnormality during defecation. Paradoxical contraction; total gastrointestinal or colonic transit time is normal, and most markers can be retained in the rectum; anorectal manometry shows paradoxical contraction of the external anal sphincter during forced defecation or abnormal sensory threshold of the rectal wall, etc. Many patients with outlet obstruction constipation also have slow transit constipation.