Overview of the disease
A non-inflammatory, benign, reversible hyperpigmentation of the colon lumen manifested by darkening of the colon, abdominal distension, abdominal pain, constipation, etc. Mainly associated with the long-term use of anthraquinone laxatives, other causes include chronic constipation, long-term inflammatory bowel disease, etc. Removal of the causative factors, supplemented with medication, diet, behavioral therapies
Definition
Colonic melanosis is a benign, non-inflammatory, reversible disease characterized by pigmentation of the colonic mucosa.
Endoscopically, it is characterized by florid, reticular, granular tan or black pigmentation of the intestinal mucosa in an intermittent or continuous pattern.
Causes
Causes
The cause of colonic melanosis has not been fully elucidated, and the pathogenesis is still unclear. Currently, relevant studies believe that it is related to the following factors.
Anthraquinone laxatives
Long-term oral use of anthraquinone laxatives is the main cause of colorectal melanosis, and common drugs include senna, laxative, Ma Ren Pills, Sanshuang Tablets, Niu Huang Xieyi Tablets, Aloe vera and so on.
Anthraquinone laxatives induce the destruction of the intestinal mucosal barrier, which leads to apoptosis of colonic epithelial cells, which are phagocytosed by macrophages and then deposited in the lamina propria of the colon to form brown pigment.
In addition, anthraquinone laxatives may cause a decrease in the expression of aquaporin (AQP8), which reduces water absorption, resulting in colonic melanosis.
Chronic constipation
If the patient suffers from chronic constipation, the fecal matter accumulates in the intestines for a long period of time, and the intestinal mucosa absorbs the pigment particles synthesized by the bacteria, leading to colomelanosis.
Inflammatory bowel disease
Inflammatory bowel disease patients’ intestinal contents are prone to pigmentation under the action of enzymes, which induces patients to develop colomelanosis.
Others
Metal elements, minerals, apoptosis of colon epithelial cells, and chronic diarrhea may also be contributing factors to colonic melanosis.
Symptoms
Main Symptoms
Colonic melanosis
Colonoscopy shows diffuse black, brown, or dark gray pigmentation of varying degrees on the surface of the colonic mucosa at different ranges.
The entire colonic mucosa shows leopard pattern, snake skin or grid granular changes, the vascular texture is blurred or even disappears, and the endoscopic field of view is dark.
Abdominal distension, abdominal pain
Some patients have weakened intestinal peristalsis and may experience abdominal distension and abdominal pain.
Constipation, Difficulty in defecation
Patients may have difficulty in defecation, constipation, in addition, some patients may also have diarrhea due to the use of laxatives.
Complications
Bowel obstruction
Patients with colorectal melioidosis who are not treated in time may experience a situation where the contents of the intestines do not function properly and pass through the intestines smoothly.
Common symptoms include abdominal pain, vomiting, and bloating.
Consultation
Department of Medicine
Gastroenterology
When patients experience symptoms such as difficulty in defecation, constipation, abdominal pain and bloating, they can visit the Department of Gastroenterology.
Anorectal Medicine
Patients with the above symptoms may also consult the Department of Anorectal Medicine.
Preparation for medical treatment
Preparation for the consultation: registration, preparation of documents, common problems
Tips for medical treatment
Do not abuse drugs or drink alcohol before the medical examination to avoid interfering with the diagnosis and treatment of the disease.
List of medical preparation
Symptom list
Pay particular attention to the time of onset of symptoms, special manifestations, etc.
Is there any bloating or abdominal pain? When did it start?
Do you have difficulty in passing stools? How often do you have bowel movements?
Is there diarrhea?
What aggravates or relieves these symptoms?
Medical History Checklist
Any constipation, inflammatory bowel disease, chronic diarrhea?
Any recent use of laxatives?
Checklist
Test results from the last 6 months to bring with you to the doctor’s office
Laboratory tests: routine stool test.
Colonoscopy.
Pathologic examination.
Medication list
Medication used in the last 3 months, if available in boxes or packages, may be brought to the doctor’s office
Anthraquinone laxatives: senna, laxative, hemp pills, Sanhuang tablets, etc.
Diagnosis
Diagnosis based on
medical history
History of chronic constipation.
Regular use of anthraquinone laxatives.
History of inflammatory bowel disease.
Clinical manifestations
Symptoms
Difficulty in defecation, constipation, abdominal pain, bloating, and diarrhea.
Laboratory tests
Stool routine examination
Stool examination is performed to determine whether the patient has red and white blood cells, fecal occult blood, which can exclude whether there is infection in the intestinal tract and gastrointestinal bleeding.
Colonoscopy
Purpose: To view the condition of the patient’s colonic mucosa.
Significance: The presence of mottled, reticulated, granular brown or black pigmentation in the intestinal mucosa in an intermittent or continuous distribution can be diagnosed as colonic melanosis.
Precautions: Prepare the intestinal tract before the examination, take a slag-free diet three days in advance (e.g., porridge, milk, noodles and other foods with less crude fiber content), and drink laxatives such as polyethylene glycol electrolyte bulk 4 to 6 hours before the examination as required.
Pathologic examination
The diagnosis of colonic melanosis can be confirmed by obtaining diseased tissue from the intestinal mucosa for cytologic examination, which shows a large number of macrophages containing lipofuscin in the lamina propria of the mucosa.
Grading
Grading is based on the degree of melanin deposition in the colonic mucosa, which can be categorized as follows:
Degree I: the colonic mucosa is light dark brown, similar to leopard skin, and asymmetric milky white spots are seen, and the mucosal vascular texture is faintly visible.
Degree II: the colonic mucosa is dark black-brown, with lines of milky white mucosa, mucosal blood vessels are not easy to see, and the demarcation between the diseased and normal intestinal segments is clearer.
Degree III: the colonic mucosa is dark black brown, there are tiny creamy white lines or spots of mucosa between the dark brown mucosa, and the vascular texture disappears.
Differential diagnosis
Brown Bowel Syndrome
Similarities: brown bowel syndrome and colonic melanosis both show tan pigmentation of the bowel.
Differences:
Brown Bowel Syndrome is most often caused by steatorrhea or vitamin E deficiency in adults, giving the colon a tan appearance with no pigmentation of the colonic mucosa.
In colonic melioidosis, the mucosal lamina propria has a large number of lipofuscin-containing macrophages, resulting in hyperpigmentation of the colonic mucosal layer.
Ulcerative colitis
Similarities: Both ulcerative colitis and colonic melioidosis have symptoms such as diarrhea and abdominal pain.
Differences:
Ulcerative colitis is related to the environment, genetics, intestinal microecology, etc. In the active stage, there may be infiltration of neutrophils, eosinophils, etc., which can be seen as mucosal erosion and ulceration.
Colonic melanosis is generally caused by long-term chronic constipation, the use of anthraquinone laxatives, etc., and the intestinal mucosa appears to have florid, reticulated, granular brown or black pigmentation.
Colorectal cancer
Similarities: both colorectal cancer and colonic black change disease may have symptoms such as constipation, diarrhea, and abdominal pain.
Differences:
Colorectal cancer is a space-occupying lesion, which can be detected by endoscopy and imaging tests that reveal a mass in the patient’s intestines.
Colonic melanosis is a lesion of the intestinal mucosa, and the diagnosis can be confirmed directly by the pigmentation of the intestinal mucosa under colonoscopy.
Treatment
The purpose of treatment: to relieve the patient’s symptoms, remove the causative factors, and reduce the occurrence of complications.
Treatment principle: Colonic melanosis generally needs to remove the cause of the disease, improve diet, exercise, as well as drug symptomatic treatment.
General treatment
Discontinuation of anthraquinone laxatives
Indications: For patients whose long-term use of anthraquinone laxatives leads to colonic melanosis.
Common medications: Senna, Sanhuang tablets, Niuhuang detoxification tablets, Laxative, Ma Ren Pills, etc.
Dietary modification
Indications: For patients with long-term constipation.
Eat more fiber-rich vegetables and fruits, such as celery, broccoli, dragon fruit, bananas and so on.
Eat more coarse grains rich in dietary fiber, such as sweet potato, corn, yam, etc., which can replace part of the main food.
Exercise therapy
Indications: Suitable for patients with long-term constipation.
More physical exercise, such as running, jumping rope, swimming, etc., to increase peristalsis.
Medication
Gastrointestinal stimulants
Indications: Applicable to patients with constipation symptoms, which can be treated by using gastrointestinal stimulants.
Common drugs that promote gastrointestinal power to promote defecation include Cisapride, Itopride and so on.
Common adverse reactions are diarrhea, abdominal pain, nausea and so on.
Cautions: usually need to be taken before meals.
Probiotics
Indications: suitable for patients with constipation in the presence of intestinal flora imbalance.
Common probiotic drugs include Lactobacillus, Bifidobacterium, Bacillus licheniformis and so on.
Common adverse reactions include gastrointestinal flatulence and diarrhea.
Precautions: Be careful to use warm boiled water to avoid destroying the probiotic drug activity.
Volumetric, osmotic laxatives
Indications: for patients with chronic constipation.
Common drugs are methylcellulose, polyethylene glycol electrolyte bulk, lactulose and so on.
Common adverse reactions include abdominal pain, diarrhea, electrolyte disorders.
Precautions: Abdominal distension may occur when taking the drug initially, which usually disappears with continued treatment.
Prognosis
Cure
After removing the causative factors, mucosal pigmentation may subside or even disappear.
Daily
Daily Management
Dietary management
Eat more vegetables and fruits, such as broccoli, cauliflower, celery, dragon fruit, watermelon, etc., to consume enough dietary fiber and vitamins, which will help normal bowel movement.
Ensure the body has sufficient water intake of about 1.5 to 2L per day, which can soften the feces and help defecation.
It is recommended that you can mix coarse and fine grains in your daily life, and common coarse grains include sweet potatoes, corn, yams, potatoes, etc., which are conducive to intestinal peristalsis and relieve constipation.
Supplement more protein-rich foods, such as lean meat, fish, eggs and milk, to enhance nutrition.
Life management
Avoid long-term use of anthraquinone laxatives, such as senna and tricholoma tablets.
Ensure sleep time in daily life.
Develop good defecation habits, defecate at a fixed time every day, and the defecation time should not be too long.
It is recommended to strengthen outdoor physical exercise in daily life, such as walking, brisk walking, etc., to maintain good health and enhance the resistance of the body.
Psychological management
Patients with colorectal melioidosis may have bad moods such as irritability and anxiety, so it is necessary to strengthen communication with patients and encourage them to maintain an optimistic state of mind.
Follow-up
Regular follow-ups will help the doctor assess the patient’s condition and prevent complications.
Patients with colorectal melioidosis should have their doctor determine when to have a follow-up colonoscopy according to their condition.
Prevention
Avoid prolonged use of anthraquinone laxatives for constipation.
Patients with chronic constipation and inflammatory bowel disease should be treated promptly.
Develop good defecation habits, do not defecate for too long.
Actively exercise in daily life, such as walking, brisk walking, etc., to improve their immunity.
Eat more fruits and vegetables in daily life, and eat less spicy, stimulating and greasy food to prevent constipation.