| disease | Constipation |
| alias | Constipation |
Constipation refers to a decrease in bowel movements and/or difficulty passing dry, hard stools. Generally, the absence of bowel movements for more than two days suggests constipation. However, bowel habits can vary significantly among healthy individuals. For example, a survey of a group of healthy people showed that about 60% had one bowel movement per day, 30% had several per day, and 10% had one every few days. Therefore, determining whether constipation is present must be based on an individual's usual bowel habits and whether they experience difficulty during defecation.
bubble_chart Etiology
The process of defecation can be roughly divided into two steps: ① The propulsion of feces into the rectum: Under normal circumstances, the intestines undergo 3 to 4 mass peristalsis movements per day, rapidly moving feces into the rectum, expanding and stimulating the rectal mucosa, triggering the defecation reflex; ② The emptying of the rectum: When the rectum is filled with feces, the urge to defecate occurs. The act of defecation is regulated by the cerebral cortex and the lower centers in the lumbosacral spinal cord, involving rectal contraction, relaxation of the anal sphincter, and contraction of the abdominal and diaphragmatic muscles to expel feces through the anus. Mass peristalsis is often triggered by the gastrocolic reflex, so defecation usually occurs after eating.
There are many factors that can cause constipation by affecting the defecation process, including insufficient food intake, overly refined food lacking residue, pyloric or intestinal obstruction, low colonic tension, excessive and irregular spasmodic contractions of the sigmoid colon, as well as weakened contraction of the abdominal muscles, diaphragm, levator ani muscle, and/or intestinal smooth muscles.
Constipation can be classified based on the course or onset of the disease into acute and chronic constipation; based on the presence or absence of organic lesions into organic or functional constipation; and based on the site of fecal retention into colonic and rectal constipation. Colonic constipation refers to the excessively slow movement of food residue in the colon, while rectal constipation refers to feces that have already reached the rectum but remain there for too long without being expelled, also known as dyschezia. Additionally, it can be classified by disease cause. Below, we will mainly discuss organic and functional constipation.
(I) Organic Constipation1. Rectal and anal lesions: Proctitis, hemorrhoids, anal fissure, perianal abscesses and ulcers, tumor-induced cicatricial stenosis, etc.
2. Colonic lesions: Benign and malignant tumors, intestinal obstruction, intestinal strangulation, colonic diverticulitis, specific (such as intestinal tuberculosis, amebic colitis) and non-specific inflammations (Crohn's disease, ulcerative colitis), intestinal adhesions, etc.
3. Muscle weakness: Weakness of the intestinal smooth muscles, levator ani muscle, diaphragm, or abdominal wall muscles; aging, chronic pulmonary emphysema, severe malnutrition, multiple pregnancies, general debilitation, intestinal paralysis, etc., can lead to difficulty in defecation due to weakened muscle strength.
4. Endocrine and metabolic diseases: Hyperparathyroidism can cause relaxation and reduced tension of intestinal muscles; hypothyroidism and anterior pituitary hypofunction can weaken intestinal motility; diabetes insipidus with dehydration, diabetes complicated by neuropathy, scleroderma, etc., can all lead to constipation.
5. Medications and chemicals: Morphine and opium preparations; anticholinergic drugs, ganglionic blockers, and antidepressants; bismuth subcarbonate, diphenoxylate, and aluminum hydroxide, etc., can all cause constipation.
6. Neurological diseases: Paraplegia, multiple radiculitis, etc., affecting the nerves controlling the intestines, congenital megacolon, etc., can result in constipation.
(II) Functional Constipation
1. Simple constipation
(1) Insufficient food intake or overly refined food lacking fiber, reducing stimulation of colonic movement.
(2) Disruption of defecation habits due to psychological factors, changes in daily routines, long-distance travel, etc., leading to delayed defecation.
(3) Abuse of strong laxatives, which reduces intestinal sensitivity and creates dependence on laxatives.
2. Irritable bowel syndrome: Constipation is one of the main manifestations of this syndrome, caused by motility disorders of the gastrointestinal smooth muscles.
bubble_chart Pathological Changes
Defecation is a complex physiological movement process involving multiple systems and influenced by various factors. Pathological changes in the digestive tract itself can cause constipation, and disorders in other systems can also lead to constipation by affecting the structure and function of the digestive tract.
Once the contents of the small intestine reach the colon, they become a culture medium for the colonic flora, allowing the flora to proliferate extensively, accounting for up to half of the solid matter in the colon. Together with other components, they form feces, which move slowly toward the distal end at a speed of approximately 5 cm per hour.
The structure and function of the colon directly affect colonic motility and are thus closely related to constipation. Diseases that affect the structure of colonic smooth muscle can cause constipation and may be associated with the formation of certain megacolon conditions. Such diseases often lead to a reduction in the number of smooth muscle cells, replaced by fibrosis, thinning the colonic wall and reducing motility. Numerous factors influence colonic function, including colonic peristalsis patterns, changes in intraluminal pressure, the nervous system, hormones, and regulatory peptides.
In recent years, the importance of the enteric nervous system has gained attention and is referred to as the "gut brain." In addition to the well-known congenital megacolon, some authors have reported cases of idiopathic megacolon, megarectum, and even constipation patients without the appearance of megacolon, whose resected colonic specimens show significant abnormalities in the myenteric plexus.
The absorptive function of the colonic mucosa and the volume of the colon are also closely related to constipation. Absorption directly affects the consistency of intestinal contents, and colonic lumen volume can influence the movement of feces.
Normally, solid feces are stored in the sigmoid colon or even the descending colon. When the sigmoid colon or more proximal colon contracts, feces are propelled into the rectum, triggering the defecation reflex.
Among constipation patients, the lack of bowel movement sensation is one of the most common complaints. Some of these patients experience this due to an excessively large rectal ampulla, which prevents them from sensing the stimulation from normal stool volume. However, a larger proportion of patients suffer from gradually reduced rectal sensory function caused by long-term neglect of the urge to defecate.
Internal sphincter relaxation dysfunction is one of the causes of outlet obstruction, with congenital megacolon being its typical representative, characterized by tonic contraction of the distal rectum and the inability of the internal sphincter to reflexively relax. In cases of internal sphincter dysfunction caused by other reasons, such as anal fissure patients, the resting pressure of the internal sphincter is elevated, but the anorectal inhibitory reflex remains present.
If the striated muscles of the pelvic floor and the external sphincter fail to relax during defecation, the anorectal angle cannot widen, and the pelvic floor outlet cannot open, which is one of the common causes of outlet obstructive constipation. The disease cause of this condition remains unclear to this day.
Additionally, certain diseases or conditions that significantly affect the increase in intra-abdominal pressure can also lead to a reduction in defecation force, thereby impairing normal bowel movements.
bubble_chart Clinical Manifestations
Constipation is not an independent disease in itself, but rather a group of symptoms that can manifest in the digestive tract due to various diseases. Therefore, the clinical manifestations of patients with constipation symptoms can be understood from the following three aspects.
(1) Corresponding manifestations of the primary disease causing constipation: For example, large intestine cancer may present with mucus-bloody stools and masses; chronic intussusception may involve abdominal pain and lumps; anal fissure may cause painful defecation and bright red bloody stools; spinal tumors may exhibit neurological localization signs; hypothyroidism may present with cold intolerance and mucous edema, etc.
(2) Manifestations of defecation disorders:
1. Naturally infrequent bowel movements, fewer than three times per week, with small stool volume and gradually worsening prolonged intervals between natural bowel movements.
2. Difficulty in defecation. This can be divided into two scenarios. One is dry and hard stools, resembling foxtail millet in shape, making them difficult to pass; the other scenario is stools that are not dry or hard but still difficult to pass. Some patients feel a sense of obstruction above the anus, which intensifies with increased straining during defecation, forcing the patient to exert excessive effort, even moaning loudly in extreme discomfort. Some female patients experience a sensation of stool pushing forward, feeling that the stool does not descend toward the anus but instead pushes toward the vagina; experienced individuals can insert a finger into the vagina and apply pressure to the posterior wall to facilitate easier passage of the stool. Some patients feel fullness in the rectum, pain in the sacrococcygeal region, and incomplete defecation, which can be alleviated by inserting a finger, paper roll, or soap bar into the anus. These symptoms are collectively referred to as outlet obstruction syndrome. Among these patients, the majority (90.0%) have normal rectal-type urges to defecate, with frequent urges and prolonged defecation time, averaging 23±16 minutes, with the longest reaching up to 2 hours per defecation.
(3) Associated symptoms. Apart from the characteristic manifestations of the aforementioned primary diseases, common associated symptoms in patients without obvious abnormalities in routine examinations include abdominal distension and fullness, abdominal pain, thirst, nausea, and perineal distending pain. Most patients experience mood dysphoria, and some may also have a bitter taste in the mouth, headache, rashes, etc. A few patients exhibit neurotic tendencies, with some even having suicidal inclinations.
From the perspective of Chinese medicine, the author believes that chronic constipation syndromes mainly include three patterns: insufficiency of body fluids, depression and stagnation of qi movement, and dual deficiency of the spleen and kidney.
(1) pattern of fluid and humor insufficiency: Often caused by postpartum blood loss, excessive sweating or urination, or repeated damage to yin, indulgence in alcohol, excessive consumption of spicy and hot foods leading to intestinal dryness-heat, or exposure to wind-heat-dryness-fire pathogens, or cold-damage disease Rebing damaging fluids, or constitutional yang exuberance, insufficient water intake, blood deficiency, and yin deficiency, all of which can lead to insufficient body fluids in the intestines, resulting in the loss of lubrication and smooth passage of stools, forming the syndrome of body fluids insufficiency constipation. The characteristics of this syndrome are difficult and sluggish defecation, stools forming lumps, often dark brown or black in color, foul-smelling and small in volume, occurring every 3-5 days, accompanied by fetid mouth odor, lip sores, dry tongue and mouth, dizziness and headache, scanty and dark urine, irritability, vexing heat in the chest, palms, and soles, palpitations and insomnia, emaciation and anemia, poor appetite, abdominal distension and fullness, a red tongue with scant moisture, and a fine and rapid pulse, etc. The so-called yin deficiency, blood deficiency, fluid exhaustion, and yang constipation constipation described by predecessors ultimately lead to depletion of fluids and humors, causing stool stagnation due to insufficient body fluids, and thus can all be categorized under the pattern of fluid and humor insufficiency.
(2) pattern of qi activity stagnation: Often caused by emotional distress, grief, worry, neglect of regular bowel movements, prolonged inactivity or bed rest, insufficient food intake, leading to depression and stagnation of qi movement, inability to disperse and reach, impaired conduction, and retention of waste. Patients with hemorrhoids or anal fissures who habitually withhold bowel movements, leading to abnormal descending and movement, are also common causes of this syndrome. The characteristic of this syndrome is "internal stagnation of qi preventing the movement of matter." Although the stools are not dry or hard, they are difficult to pass, and despite feeling abdominal distension and fullness and rectal heaviness, there may be no stool or incomplete evacuation after squatting, or a persistent feeling of heaviness after defecation. Associated symptoms include chest and hypochondriac stuffiness and fullness, reduced food intake, heaviness of the head and mental fog, fatigue and bodily heaviness, abdominal distension and fullness with borborygmi, excessive flatulence, belching, a thin and greasy tongue coating, and a wiry and large pulse, etc. Impaired lung purification, stomach disharmony, liver failing to act freely, and spleen failing to transform and transport can all lead to depression and stagnation of qi movement. Dampness obstructing the middle energizer or wind affecting the large intestine can also impair dispersion and conduction, leading to delayed defecation and constipation. The so-called qi constipation, wind constipation, and dampness constipation described by predecessors mostly belong to this syndrome.
(3) Spleen-Kidney Dual Deficiency pattern: Mostly caused by prolonged use of purgatives, bitter-cold drugs damaging the spleen, excessive sexual activity leading to essence depletion and kidney deficiency, resulting in spleen deficiency with weakened qi and impaired transmission and propulsion. Kidney deficiency leads to essence exhaustion, failing to transform body fluids and warm-moisten the intestines, causing stools that should be expelled to remain. Its characteristics include stool retention in the intestines without the urge to defecate, or straining with lack of strength despite the urge, making defecation extremely difficult, accompanied by sweating and shortness of breath during bowel movements, and extreme fatigue afterward. Associated symptoms include dizziness, tinnitus, panting, palpitations, soreness in the lower back and back pain, abdominal distension and fullness with a preference for warmth, clear and copious urine, anorexia with reduced food intake, long-term reliance on laxatives for bowel movements, and failure to defecate for several days without laxatives. Other signs include a pale tongue with thick greasy coating and a weak pulse.
bubble_chart Auxiliary Examination
(1) Physical Examination:
1. A comprehensive and systematic physical examination must be conducted in accordance with diagnostic requirements. Constipation should not be treated carelessly as a minor issue, leading to the oversight of significant conditions such as fistula disease. At the same time, diagnosing constipation should not be regarded as overly challenging, prompting the excessive use of complex examination methods while neglecting routine checks, which may delay the detection of otherwise easily identifiable conditions. However, for most chronic constipation patients, due to the prolonged course of the disease and numerous past examinations, abdominal signs are often not very obvious.
2. Anorectal Examination:
⑴ Inspection: Check for anal fissure, fistula openings, hemorrhoidal prolapse, perianal inflammation, blood traces, etc. Ask the patient to perform a defecation maneuver; in cases of perineal descent, the pelvic floor will visibly protrude downward with the anus as the center. Then instruct the patient to contract the anus; those with severe nerve damage to the pelvic floor will exhibit weakened or absent contraction ability.
⑵ Digital Rectal Examination: Avoid roughness. Adequately lubricate the examining finger and the patient’s anus to ensure a painless examination and minimize interference with the physiological state of the anorectal canal. A normal anal canal can accommodate one finger with moderate tension. When the patient performs a defecation maneuver, the external sphincter and pelvic floor muscles should relax noticeably. Increased anal canal tension may indicate nearby irritative sexually transmitted disease lesions. If the anal canal cannot accommodate one finger, organic stenosis is present, often due to low-lying tumors, post-surgical scarring, or improper sclerotherapy. Some patients may have hardened fecal masses palpable in the rectal ampulla. A large amount of retained feces in the rectum without the urge to defecate suggests rectal inertia. Patients with rectocele may exhibit a sac-like weak area above the sphincter and below the pubic symphysis during defecation. Those with rectal intussusception may have a lax rectal wall, with a sensation of accumulated mucus during digital examination, and occasionally, the intussuscepted bowel wall may be palpable. Patients with pelvic floor dyssynergia syndrome will show no relaxation of the pelvic floor muscles, puborectalis muscle, or external sphincter during defecation; severe cases may present with a markedly hypertrophic, thickened, rigid, and less mobile anorectal ring, increased anal canal tension, and significant pain. Using the examining index finger to press various directions of the rectal ampulla can assess pelvic floor sensory function (i.e., rectal sensation), providing a rough estimate of sensory impairment severity.
⑶ Anoscopy: Internal hemorrhoids and low-lying rectal masses can be visualized. If rectal mucosa shows edema, erosion, or other changes not easily explained by general inflammation, consider the possibility of rectal intussusception. Unexplained blood traces, especially old blood, should raise suspicion of proximal tumors.
(2) Auxiliary Examinations:
1. Stool Examination: The examiner should visually inspect the patient’s stool, roughly estimate its weight, and observe its physical characteristics. Dry, hard, or pellet-like stools may indicate irritable bowel syndrome. Routine stool and occult blood tests should also be performed.
2. Blood Tests: Focus on endocrine and metabolic factors that may cause constipation. In recent years, the relationship between gastrointestinal hormones and constipation has garnered attention. International scholars have conducted some research, but conclusions remain unclear, and domestic studies in this area are still limited.
3. Barium Enema: One of the primary methods for diagnosing organic sexually transmitted diseases of the colon. It can reveal redundant colon or colonic dilation. If the rectosigmoid width exceeds 6.5 cm at the pelvic inlet on lateral films, it is considered abnormal.
4. Endoscopy: The main purpose is to rule out tumor sexually transmitted diseases. Long-term enema users, especially those using soapy water, may exhibit colonic mucosal edema and obscured vascular patterns. Chronic users of anthraquinone laxatives may show mucosal melanosis, ranging from light brown to black.
5. Colonic Transit Function Test: This involves ingesting radiopaque markers and taking timed abdominal X-rays to track the markers’ progress through the colon. It is a method to assess the speed and obstruction sites of colonic content movement.
6. Anorectal manometry: Using a pressure measurement device to examine the functional status of the internal and external sphincters, pelvic floor, and rectum, as well as their coordination, is of significant importance in determining whether constipation is related to functional abnormalities in these structures.
7. Pelvic Floor Electromyography (EMG): This electrophysiological technique is used to assess the functional status of the pelvic floor muscles, puborectalis muscle, external sphincter, and other striated muscles, as well as the functional state of their innervating nerves. Due to the high technical demands on the examiner and the difficulty in interpreting results, this method is currently only employed to observe whether abnormal discharges occur in the pelvic floor striated muscles during simulated defecation. When needle electrodes are used, the invasive nature of the procedure may trigger protective reflexes, leading to false positives. This is especially true when multiple needle electrodes are used simultaneously, as inexperienced examiners often misinterpret the results. Caution is advised.
8. Defecography: After injecting barium into the rectum and colon (orally administered barium may also be used to observe the small intestine), the patient sits on an X-ray-transparent commode. Multiple X-rays or video recordings are taken during defecation to observe imaging changes in the anal canal and rectum. The examiner should personally review the images and integrate clinical data with other test results for a comprehensive assessment, rather than relying solely on imaging findings for diagnosis.
9. Histological Examination: If congenital megacolon is suspected, a biopsy should be performed. In the past, samples were typically taken 2–3 cm above the dentate line, but some now recommend sampling 1–1.5 cm above the dentate line, as higher sampling may miss "ultrashort-segment megacolon" or fistula disease.
Diagnosing constipation is not difficult based on reduced bowel movements and dry, hard stools that are difficult to pass. However, to determine the cause of constipation, in addition to carefully inquiring about medical history, symptoms, and conducting a comprehensive physical examination, the following tests are also required.
(1) Stool examination: Carefully observe the shape, size, consistency, and presence of pus, blood, or mucus in the stool. Routine stool tests and occult blood tests are standard procedures.
(2) Digital rectal examination: Helps detect rectal cancer, hemorrhoids, stenosis, hard fecal blockages, external compression, or anal sphincter spasms or relaxation.
(3) Endoscopic examinations such as proctoscopy, sigmoidoscopy, and colonoscopy: Allow direct observation of the intestinal mucosa for lesions and enable biopsy to determine the nature of the pathology.
(4) Gastrointestinal X-ray examination: Barium meal studies provide reference value for understanding gastrointestinal motility. Normally, barium reaches the splenic flexure of the colon within 12–18 hours and should be completely expelled from the colon within 24–72 hours. In constipation, emptying may be delayed. Barium enema, especially low-tension double-contrast colonography, may help identify the disease cause of constipation.
(5) Special tests: Swallowing a certain number of X-ray-opaque tube fragments as markers and taking timed abdominal X-rays can reveal the speed and distribution of the markers in the gastrointestinal tract, distinguishing between rectal constipation and colonic constipation. Defecography is a combined dynamic and static examination of defecation, aiding in the diagnosis of functional constipation. Other tests include direct or colonic manometry, anorectal electromyography, and transanal balloon dilation tests.
bubble_chart Treatment Measures
Emphasize treatment based on the medical record after a clear diagnosis. Treatment without a clear diagnosis is a blind symptomatic approach, risking the omission of important conditions like fistula disease, delaying treatment, and even leading to incorrect therapy.
Some have proposed the goals for treating chronic constipation as: ① restoring normal bowel movement frequency and stool consistency; ② relieving discomfort caused by constipation; ③ maintaining regular bowel movements without artificial assistance; and ④ addressing the underlying conditions that may cause constipation symptoms. Achieving these goals is not easy and requires doctors to be familiar with the physiology of defecation, deeply understand the disease causes and pathophysiology of the patient's constipation, correctly apply various treatment methods, and ensure the patient's active cooperation. However, the key remains an accurate diagnosis.
(1) Treatment of the primary disease: For identified primary conditions, after a clear diagnosis, appropriate measures should be taken for active treatment. For example, anal fissures can be treated with local anesthesia and anal dilation or lateral internal sphincterotomy; colon tumors may require radical or palliative resection; if constipation is drug-induced, the medication should be discontinued or replaced with a non-constipating alternative; for constipation caused by psychiatric or endocrine-metabolic disorders, corresponding treatments should be administered to promptly eliminate the impact of the primary disease on intestinal function.
(2) General treatment: For cases where the primary disease is difficult to correct temporarily or no obvious primary factors have been identified, the following general measures are beneficial for most constipation patients.
1. Correct poor dietary habits: Increase intake of high-fiber foods and develop a habit of drinking more water. Dietary fiber softens stools, increases stool volume, and stimulates colonic motility, speeding up colonic transit. Regularly consuming small amounts of wheat bran is an effective and inexpensive therapy for constipation patients, though this method is not suitable for those with organic intestinal strictures. Daily water intake should reach 3,000 ml, and excessive tea or coffee-containing beverages should be avoided to prevent excessive diuresis. With these treatments, constipation caused by dietary and lifestyle changes can often be quickly relieved.
2. Correct poor defecation habits: Ignoring the urge to defecate is common among female constipation patients, with statistics showing rates as high as 33%. This is often due to busy morning routines, rushing to work, or workplace constraints forcing patients to suppress the urge. Frequently ignoring the urge disrupts normal defecation reflexes, leading to constipation. Reading on the toilet is another poor habit, hindering the continuity of the defecation reflex. For those unaccustomed to sitting toilets, squatting may be more beneficial, as it increases the anorectal angle, facilitating stool passage. For those habitually relying on laxatives, their use should be stopped immediately, and normal defecation habits should be restored under medical guidance.
3. Develop healthy lifestyle habits: Maintain a regular daily routine, engage in physical activity, and stay optimistic, as these can also help improve digestive function.
(3) Drug treatment: Many medications can be used to treat constipation, but most are unsuitable for chronic constipation or long-term use. Currently, laxative abuse is widespread, leading to iatrogenic constipation, so clinical caution is advised. Common laxatives fall into the following categories.
1. Stimulant laxatives: These work by stimulating the colonic mucosa, myenteric plexus, and smooth muscles to increase intestinal motility and mucus secretion. Examples include Rhubarb Rhizoma, senna leaves, phenolphthalein, and castor oil.
Rhubarb Rhizoma and Senna Leaf contain anthraquinones, which are hydrolyzed by colonic bacteria into active ingredients and act only on the colon or distal ileum. Rhubarb Rhizoma, when taken orally, produces slightly soft stools within 6–8 hours; Senna Leaf induces diarrhea 8–10 hours after ingestion. If taken in large doses, it may cause abdominal pain and pelvic congestion due to excessive irritation, hence it is contraindicated during menstruation and pregnancy. Anthraquinones can cause "melanosis coli," where melanin deposits in the colonic mucosa, often occurring after 4–13 months of use and disappearing within 3–6 months after discontinuation, generally without causing long-term lesions. Phenolphthalein, when taken orally, forms soluble sodium salts upon encountering alkaline intestinal fluids, mildly irritating the colon and producing soft stools within 4–8 hours. Part of it is excreted via bile and reabsorbed in the intestines, forming an enterohepatic circulation, so a single dose can maintain its effect for 3–4 days. Castor Oil, when taken orally, is hydrolyzed in the small intestine, releasing sodium ricinoleate, which stimulates active secretion in the small intestine, reduces sugar absorption, and promotes intestinal motility, resulting in loose stools within 3–5 hours after ingestion.
Stimulant laxatives can cause severe colicky pain, and long-term use may lead to water-electrolyte imbalances and acid-base disturbances. When used regularly for many years, they can induce "laxative colon," which is often misdiagnosed as intractable constipation, leading to the administration of more laxatives or even inappropriate treatments.
2. Mechanical Laxatives: These work by increasing fecal volume or altering fecal composition to enhance colonic propulsion. They can be further classified into the following categories:
⑴ Saline Laxatives: Examples include magnesium sulfate and sodium sulfate. Since they are poorly absorbed after oral administration, they increase osmotic pressure in the intestinal lumen, preventing water absorption and causing intestinal contents to expand, thereby stimulating peristalsis. Their effects are rapid, occurring within 0.5–3 hours after oral intake or 5–15 minutes after rectal administration. They are suitable for acute constipation, and enemas are often used for fecal impaction. However, they should not be used long-term. Severe diarrhea may lead to dehydration.
⑵ Bulk-Forming Laxatives: These contain fiber, which absorbs water to form a soft gel, facilitating stool passage and stimulating peristalsis. Effects occur within 1 to several days after ingestion. They have no systemic effects and can be used long-term, especially in cases of low-fiber diets, pregnancy, or when discontinuing stimulant laxatives. Examples include wheat bran, corn bran, konjac starch, agar, methylcellulose, and Plantain Seed preparations. Adequate water intake is essential when using these agents. Caution is advised in patients with intestinal strictures due to the risk of obstruction.
⑶ Stool Softeners: These are surfactants that facilitate the mixing of fat and water in stool and increase intestinal secretion, such as sodium (calcium) docusate. They are not absorbed but may enhance the absorption of other substances, potentially contributing to the hepatotoxicity of laxatives. Suitable only for short-term use (1–2 weeks) and not recommended for chronic constipation.
⑷ Lubricant Laxatives: Examples include mineral oil. Indigestible and unabsorbed in the intestines, they coat stool to ease passage while inhibiting colonic water absorption, thus lubricating the bowel and softening stool. Effects occur within 6–8 hours after oral intake. Long-term use may impair the absorption of fat-soluble vitamins. Should not be used with surfactants to avoid increased mineral oil absorption. This agent may also leak from anal fistulas, causing cutaneous pruritus. Suitable only for short-term use and not for chronic constipation.
⑸ Osmotic Laxatives: By increasing intraluminal osmotic pressure, they stimulate peristalsis. Glycerin, when administered rectally, induces defecation within minutes due to its hyperosmotic effect on the rectal wall, combined with lubrication. Lactulose is metabolized by colonic bacteria into low-molecular-weight acids, lowering colonic pH and increasing motility.
⑹ Other Laxatives: Previously used laxatives such as calomel, aloes, lobedleaf pharbitis seed, croton fruit, and sulfur are no longer in use.
When managing constipation, it is essential to understand the effects of these laxatives and use them appropriately. Generally, bulk-forming laxatives are preferred for chronic constipation, with stimulant laxatives reserved for necessity. Acute constipation may be treated with small doses of saline laxatives, stimulant laxatives, or lubricant laxatives, but not for more than one week. If constipation persists beyond a week, further evaluation is needed. Patients who have long abused stimulant laxatives must gradually discontinue them while adding bulk-forming laxatives. The author has managed many cases of long-term laxative abuse by switching to bran preparations with increased water intake, gradually restoring regular bowel movements. Intermittent use of mild laxatives may aid in a smooth transition.
Many patients, whether self-medicating or following medical advice, take laxatives continuously for extended periods. However, after a single dose empties the colon, it takes 3–4 days for the colon to refill. Thus, continuous use is inappropriate. Most oral laxatives take 6–8 hours to take effect, so the optimal dosing time is bedtime, allowing for defecation the next morning or after breakfast, which aligns better with physiological rhythms.
(4) Enema: The main indications are preoperative bowel preparation, fecal impaction, and acute constipation. Warm saline is more suitable as it causes less irritation to the intestines. Soapy water should be avoided due to its excessive irritation to the colonic mucosa. Additionally, frequent enemas can lead to dependency, which should be noted.
(5) Surgical treatment: The main indications for surgical treatment are constipation caused by organic or functional sexually transmitted diseases of the colon, rectum, and anal canal.
1. Colonic obstruction: Since conventional diagnostic methods can easily identify such lesions, corresponding treatment measures can be promptly taken to restore colonic patency and relieve constipation symptoms.
2. Rectal-anal outlet obstruction:
⑴ Anal stenosis, anal fissure, and hemorrhoids can be treated with appropriate surgical interventions, with care taken to protect anal canal tissues to avoid postoperative stenosis.
⑵ Rectal intussusception.
⑶ Rectocele: This is very common in women, but only some patients experience constipation symptoms, and there is no clear correlation between the depth of the rectocele and the severity of defecation difficulty. This suggests that identifying a rectocele does not necessarily reveal the true disease cause of constipation. According to the author’s research, rectocele is merely one manifestation of pelvic floor relaxation, and many patients with slow-transit constipation also exhibit significant rectocele. Only after repeated and thorough examinations—excluding factors such as slow intestinal transit, dysfunction of the internal and external sphincters, pelvic floor muscle abnormalities, rectal intussusception, and laxative abuse—followed by 1–3 months of strict conservative treatment, can it be determined whether rectocele is the primary cause of outlet obstruction symptoms. If conservative treatment fails to alleviate symptoms, rectocele repair surgery may then achieve the desired outcome. Rushing into surgical treatment based solely on certain diagnostic findings is unlikely to yield reliable long-term results.
(4) Spastic pelvic floor syndrome and puborectalis syndrome: Both are syndromes caused by the inability of the pelvic floor muscles (striated muscles) to relax during defecation, or even contracting instead, thereby obstructing the pelvic floor outlet and leading to difficulty in defecation. Many issues regarding the disease cause, diagnosis, and treatment of these two syndromes remain to be further explored. Previously, it was believed that the main difference between the two syndromes was the hypertrophy of the puborectalis muscle in the latter, leading to partial resection or transection of the puborectalis muscle as a treatment for such conditions for a period of time. However, the long-term outcomes were unsatisfactory. Currently, biofeedback therapy is more commonly favored to train patients to relax their pelvic floor muscles during defecation. Persistent long-term training has yielded better therapeutic results. After studying the above two syndromes, the author suggests that the etiology of such diseases may be related to underlying congenital abnormalities. The two syndromes may represent different stages of the same disease. Their common clinical feature is the reflexive relaxation dysfunction of the pelvic floor striated muscles during defecation, leading to overall abnormal contraction of the pelvic floor muscles and external sphincter, while showing no significant abnormalities during rest or pelvic floor contraction. Therefore, it is proposed to uniformly rename them as "unrelaxed pelvic floor syndrome." To date, no pathological changes have been anatomically, physiologically, or histologically confirmed to occur solely in the puborectalis muscle in the latter syndrome. The author conducted synchronous electromyography measurements of the puborectalis, pubococcygeus, and external sphincter muscles in multiple patients, all confirming synchronous abnormal discharges. Thus, the term "puborectalis syndrome" is deemed inappropriate and should be abandoned. Isolated resection or transection of the puborectalis muscle cannot alter the pathophysiological mechanism causing overall abnormal contraction of the pelvic floor and external sphincter muscles. Moreover, the damage caused by surgery may affect the treatment of such patients, with younger patients experiencing relief from constipation symptoms. The author believes that biofeedback therapy should be the first-line treatment for such patients, combined with other measures to alleviate defecation difficulties, such as a high-fiber diet, to restore normal defecation reflexes as much as possible. The following criteria may be considered as surgical indications: ① Digital rectal examination reveals significant hypertrophy of the pelvic floor muscles leading to anal canal stenosis, with posterior rectal pouch-like protrusion; ② Anorectal manometry shows an anal canal functional length exceeding 5–6 cm, while the internal sphincter functions normally; ③ Pelvic floor electromyography detects pathological polyphasic waves in the pelvic floor striated muscles exceeding the upper normal limit, with confirmed abnormal discharges during simulated defecation; ④ Intestinal transit function tests show significant decompensation in expulsion function, i.e., markers retained in the rectal ampulla; ⑤ Long-term (at least 3 months) strict conservative treatment proves ineffective, and the patient experiences extreme distress. Since partial posterior muscle resection can shorten the anal canal length and reduce defecation resistance, it may serve as a palliative therapy for the late stage [third stage] of this syndrome, provided the procedure is well-designed and meticulously performed. The extent of striated muscle resection should ensure a postoperative anal canal functional length of no less than 3 cm.
3. Visceral Neuropathy:
(1) Congenital Megacolon: For patients with short-segment congenital megacolon, forceful anal dilation or anorectal smooth muscle resection can be employed. Literature reports indicate that this method yields good therapeutic outcomes and simultaneously serves both diagnostic and therapeutic purposes. Key surgical points: Posterior to the anal canal, a strip of internal sphincter and rectal smooth muscle approximately 1 cm wide and 6–10 cm long is excised submucosally upward, followed by suturing the wound.
(2) Idiopathic Megacolon: Its clinical and radiographic manifestations resemble those of "short-segment megacolon." The disease cause may be acquired, but congenital factors cannot be ruled out. Clinical features include extremely long intervals between bowel movements, the passage of large amounts of dry, hard stools accompanied by pain during defecation, though the patient's general condition is usually good. Routine examination reveals palpable fecal masses in the abdomen and large amounts of dry, hard stool in the rectum. Water-soluble contrast enema shows significant rectal dilation. Two key points differentiate it from short-segment megacolon: ① The anorectal inhibitory reflex is present (note: due to rectal dilation, the balloon used to distend the rectum must be large enough to contact the intestinal wall to avoid false negatives); ② No abnormalities in the myenteric plexus are observed, and intestinal transit studies show marker retention in the rectum. Treatment primarily involves enemas and maintaining rectal emptiness, with oral magnesium sulfate administered as needed. For cases unresponsive to conservative treatment, partial internal sphincter resection, anorectal smooth muscle resection, or even Duhamel's procedure may be performed.
(3) Colonic Inertia: Also known as idiopathic slow-transit constipation, its surgical treatment remains a challenging issue. Colonic inertia refers to a normal-appearing colon with significantly prolonged whole-gut transit time. Although many authors report favorable outcomes with colectomy for this type of constipation, surgeons are generally reluctant to remove a morphologically normal colon. Reports suggest significant visceral nerve abnormalities in such patients, but due to the difficulty in preoperatively determining the extent of these abnormalities, the appropriate length of bowel resection remains uncertain. According to foreign authors' experience, resection of the affected colonic segment can correct constipation. For example, if colonic inertia occurs in the left colon, left hemicolectomy can relieve constipation; if it involves the entire colon, total colectomy with ileorectal anastomosis is required.
(6) Chinese Medicine Treatment: Chinese medicine has long emphasized a holistic approach to treating constipation, targeting the disease cause, adjusting diet, lifestyle, and emotions, and adhering to the principles of "preserving stomach qi and body fluids" while using medications judiciously. It opposes the misuse of purgatives, which can deplete qi and fluids. Zhang Zhongjing repeatedly stressed in the "Treatise on Cold Damage Diseases" that not all cases of yangming disease with constipation warrant cold purgation. If intestinal body fluids are depleted, even hard stools should not be treated with purgation but rather with external guidance or moistening purgation. He cautioned, "In yangming disease with spontaneous sweating, if sweating is induced and urination is free, this indicates internal exhaustion of body fluids; even if stools are hard, purgation should not be used." Yet, many practitioners treat constipation superficially, prescribing Chengqi Decoction for purgation without understanding that "Chengqi is primarily for expelling pathogens, not solely for removing fecal impaction." Purgation is only appropriate when harmful substances such as pathogenic heat, retained food, static blood, phlegm-fluid retention, or food/drug poisoning are present, allowing the expulsion of pathogens. Chronic constipation results from depleted body fluids, stagnant qi movement, and spleen-kidney deficiency, making purgation entirely unnecessary.
1. Adjusting diet and daily routine is the fundamental treatment for constipation. Chinese medicine places great emphasis on dietary therapy for constipation, advocating that once the symptoms of constipation are relieved, one should rely on "grains, meat, fruits, and vegetables for health preservation." Commonly used foods include black sesame, walnut kernel, hemp fruit, Platycladi Seed, pine nut kernel, Bush Cherry Seed, Bitter Apricot Seed, root juice of earth melon, sunflower seeds, Donkey-hide Gelatin, honey, milk, cow butter, sheep butter, etc. These foods are smooth in nature, rich in nutrients, and particularly suitable for constipation in the elderly, postpartum women, children, and patients. The vast majority of habitual constipation cases can return to normal bowel movements by improving diet and daily routines, increasing physical activity, and correcting reliance on laxatives. Only a very few patients require medication for treatment.
2. The greatest characteristic of Chinese medicine in treating chronic constipation is dialectical medication, opposing the simplistic approach of purging upon seeing constipation, thus achieving flexibility and appropriateness without leaving any sequelae. Common treatments include:
⑴ **Replenishing humor to promote defecation**: This method involves nourishing yin and blood to replenish humor and facilitate bowel movements. *Yizong Bidu* states: "In the elderly, dryness of body fluids, postpartum blood loss in women, excessive sweating, or diuresis, as well as unrecovered qi and blood after illness, can all lead to constipation. The method should focus on tonifying and nourishing qi and blood, allowing body fluids to regenerate and naturally restore bowel movements." It further notes: "Misusing purgatives like nitre and rhubarb for such constipation often leads to dire consequences, while Croton Fruit and lobedleaf pharbitis seed are even more harmful. Instead, Eight Precious Ingredients Decoction should be used, supplemented with cultivated purple perilla fruit, red tangerine exocarp, bitter apricot seed, and desertliving cistanche, with an increased dosage of Chinese angelica." The author primarily uses **Four Ingredients Decoction** supplemented with desertliving cistanche, fleeceflower, and donkey-hide gelatin as the main formula. For **yin deficiency**, add glossy privet fruit, songaria cynomorium herb, and asparagus root; for **blood deficiency**, add black sesame and mulberry fruit; for **intestinal dryness and depleted fluids**, add hemp fruit, platycladi seed, and honey; for **qi stagnation**, add submature bitter orange and magnolia bark; for **blood deficiency with heat**, add sanguisorba root, Japanese pagodatree pod, and skullcap root. Numerous cases treated this way have yielded satisfactory results.
⑵ **Regulating qi to relieve constipation**: This method involves smoothing qi flow, dispersing stagnation, ascending lucidity and descending turbidity, opening the upper orifices, and unblocking the lower orifices—akin to "lifting the pot and removing the lid." It is suitable for constipation caused by **depression and stagnation of qi movement**. Earlier practitioners often used **Six Milling Decoction** (areca seed, aquilaria, aucklandia root, lindera, submature bitter orange, rhubarb rhizome) as the main formula. However, rhubarb rhizome in this formula may injure body fluids, worsening constipation. Therefore, *Taiping Huimin Heji Jufang* recommends **Perilla Fruit Qi-Descending Decoction** (cultivated purple perilla fruit, pineilia, peucedanum, magnolia bark, red tangerine exocarp, Chinese angelica, liquorice root, cassia bark, or aquilaria) as the primary formula, optionally supplemented with radish seed, trichosanthes fruit, submature bitter orange, and bitter apricot seed.
⑶ **Strengthening the spleen and tonifying the kidneys**: This method focuses on **tonifying and replenishing the spleen and kidney**, addressing the root cause to relieve constipation. The kidneys govern the **five kinds of fluids**, while the spleen governs the distribution of essence. The kidneys, located below, dominate qi transformation, while the spleen, situated centrally, manages transportation. When body fluids are abundant and qi transformation functions smoothly, bowel movements remain regular. If the spleen fails in distribution and transformation, or the kidneys lack warmth and moisture, severe constipation ensues. Thus, **strengthening the spleen and tonifying the kidneys** is a fundamental approach for treating stubborn constipation. For **spleen deficiency with insufficient middle qi**, leading to **qi deficiency constipation** where the large intestine lacks propulsion, **Middle-Tonifying Qi-Replenishing Decoction** can be modified by adding the tail of Chinese angelica, desertliving cistanche, and Chinese clematis root. For **kidney yin deficiency with depleted fluids**, **Six-Ingredient Rehmannia Decoction** can be supplemented with ophiopogon tuber, achyranthes root, desertliving cistanche, and black sesame. For **kidney yang deficiency with impaired qi transformation**, **Fluid-Replenishing Decoction** can be combined with **Pineilia and Sulfur Pill**. The author often uses a self-formulated **Intestine-Moving Constipation-Relieving Decoction** to treat stubborn constipation. The formula includes: - Desertliving cistanche (15g), - Achyranthes root (10g), - Prepared rehmannia root (15g), - Chinese angelica (15g), - White atractylodes rhizome (15g), - Chinese clematis root (10g). This formula simultaneously tonifies the spleen and kidneys without excessive dryness or coldness, enhancing intestinal propulsion and facilitating bowel movements—hence its name. It is particularly effective for constipation caused by **dual spleen-kidney deficiency** in the elderly, chronic illness, postpartum conditions, or prolonged laxative use. For cases with **mixed deficiency and excess**, where abdominal distension and severe constipation are present, add radish seed and magnolia bark (10g each). For **spleen-kidney yang deficiency** with cold abdomen and constipation, add leek seed and common fenugreek seed (10g each).
In recent years, **Hu Bohu** has achieved notable results using **Cistanche Constipation-Relieving Oral Liquid** to treat constipation, demonstrating confirmed efficacy for **chronic deficiency-type constipation** and **habitual constipation**. After administration, well-formed soft stools are passed. Its laxative effect primarily works by **enriching yin, tonifying the kidneys, and moistening the intestines to relieve constipation**.
