Anal rectal and colonic stenosis

　　Congenital anomalies and inflammation are common causes of anal canal, rectal, and colonic stenosis, such as perianal abscess, perirectal abscess, extensive anal-rectal fistula, granulomatous colitis, ulcerative colitis, tuberculosis, schistosomiasis granuloma, venereal lymphogranuloma, actinomycosis, and others, which can all cause anal-rectal stenosis. Injury is also the most common cause, especially surgical trauma. Other causes include perineal accidental injury, delivery injury, burn injury, damage from corrosive drugs, suppository damage, radiation therapy, and tumors.

　　Patients with anal canal, rectal, and colonic stenosis may develop chronic constipation, and even fecal impaction. Long-term difficulty in defecation can lead to gradual expansion of the proximal rectum and sigmoid colon, resulting in secondary megacolon.

　　1, Constipation

　　Constipation refers to a decrease in defecation frequency, with fewer than 2 to 3 bowel movements within a week, or having a bowel movement once every 2 to 3 days, when the feces are less in quantity and dry and hard. This is called constipation, but a few people have a normal bowel movement pattern of once every 2 to 3 days, and their stool characteristics are normal. In this case, it should not be considered constipation; for the same person, if the bowel movement changes from once a day or every two days to once every two days or longer, it should be regarded as constipation.

　　2, Fecal impaction

　　Fecal impaction refers to the blockage of the rectum by dry fecal masses, causing severe constipation symptoms and perineal pain.

　　3, Secondary megacolon and rectosigmoiditis

　　Conditions such as congenital anal stenosis, postoperative scar stenosis, or extrarectal tumor compression can lead to poor defecation, fecal retention, and secondary colonic dilatation. A rectal examination can confirm the diagnosis. Idiopathic megacolon is related to improper defecation training, characterized by normal ganglion cells in the rectum and colon of children. It is manifested by no history of constipation in the neonatal period, symptoms appearing at 2 to 3 years of age, chronic constipation often accompanied by anal fecal pollution, and abdominal pain before defecation. The anal examination feels that in addition to rectal distension and feces, the sphincter muscles are in a tense state, and rectal and anal manometry has normal reflexes.

　　Patients with anal, rectal, and colonic stenosis often have a history of anal and rectal surgery, injury, or inflammation, or have used local injection therapy, corrosive suppositories, etc., and gradually appear symptoms such as difficulty in defecation mentioned above. Finger examination of the anal or anal canal may reveal narrowness, sometimes only the tip of the little finger can be inserted, sometimes a hard fibrous band or annular stenosis can be felt, and sometimes due to dry and hard stool, there may be linear fissures at the anal orifice. This condition should be distinguished from the defecation difficulty caused by anal spasm due to common anal fissure. There is pain during finger palpation, and it can only be examined and distinguished after local infiltration anesthesia. Visual examination of the anal area often shows feces or secretions. To clarify or exclude possible causes, or before considering repair surgery for stenosis, barium enema should be performed to observe for any changes in the rectum and colon. For annular smooth rectal stenosis, Frei test can be performed to distinguish from lymphogranuloma venereum. When suspected of having malignant tumors, rectoscopy or sigmoidoscopy should be performed, and histopathological examination should be done to confirm the diagnosis.

　　When there is injury or inflammation in the anal area, it is necessary to prevent anal stenosis. For example, during hemorrhoid surgery, when removing hemorrhoid nodules, a strip of normal skin and mucosa should be retained between the nodules. In addition, during anal fistula surgery, too much skin should not be excised. After surgery, maintain local cleanliness and hygiene to prevent various infections that may cause anal stenosis. Local warm saltwater sitz baths can be used to keep the area clean, and 5% to 10% silver nitrate solution can be applied to the bottom of the anal sinus once a day. Olive oil 30 to 60 mL can also be used for enema. Even minor injuries and localized inflammation can cause severe swelling and pain that is difficult to bear for patients. In terms of surgical manipulation, efforts should be made to minimize damage to the anal tissue and avoid rough handling, trying to minimize damage to the sphincter muscles; after surgery, maintain local cleanliness and hygiene to prevent various infections that may cause anal stenosis. Do not use rough, unclean toilet paper to wipe after each bowel movement; change clothes frequently to keep the anal area clean; use the hot water one-kangtang sitz bath pot for steaming to accelerate local blood circulation, alleviate pain, and promote recovery.

　　Patients with anal, rectal, and colonic stenosis should undergo laboratory and instrumental examinations, detailed as follows:

　　1. Laboratory Examination

　　(1) Blood: including routine blood tests, bleeding and coagulation time, erythrocyte sedimentation rate, plasma proteins, and van der Waals test. Erythrocyte sedimentation rate can increase in patients with anal, rectal, and colonic stenosis and widespread abscesses, as well as in cases of enteritis, rectitis, diverticulitis, and tuberculosis. The measurement of carcinoembryonic antigen (CEA) is an indicator for the effectiveness of surgery for cancer-induced rectal and anal stenosis and for monitoring recurrence;

　　(2) Fecal routine and culture: Rectal, colon, and perianal swab specimens should be examined within 1 hour; Molding feces can be examined within 1 hour for a small amount of fresh blood, usually from the rectum, sigmoid colon, and descending colon, bleeding from the cecum and upper gastrointestinal bleeding can also appear fresh blood, but upper gastrointestinal bleeding often manifests as black stools, and small amounts of bleeding in the stomach, small intestine, and colon manifest as occult blood in the stool;

　　(3) Fecal occult blood test: It is a simple method for detecting colon and rectal tumors and bleeding from other causes;

　　(4) Frie (Fie) test: It is a method for checking inguinal lymphogranuloma, a positive result indicates infection but does not indicate an active disease, but the rate of false positives is high;

　　(5) Cytology examination: It can distinguish between benign and malignant tumors, and can differentiate between rectal and colon cancer and diverticulitis.

　　Second, instrumental examination

　　(1) Motor conduction examination: The normal value of the motor latency at the distal end of the pudendal and perineal nerves is 1.9ms, the latency increases in patients with anal or urinary incontinence, the normal spinal cord motor latency of the external sphincter L is 5.5ms, and the rectal pubococcygeus muscle activity latency is 4.8ms and L is 3.7ms;

　　(2) Ultrasound examination: Rectal ultrasound imaging is relatively accurate, with high sensitivity, specificity, and predictive value, can determine the depth of rectal cancer infiltration in the intestinal wall and staging, and can detect high-lying tumors and bladder invasion and prostate invasion metastasis as well as local recurrence after surgery, but cannot clearly determine lymph node invasion and pelvic spread, distinguishing inflammation and cancer is difficult, and can guide the collection of biopsy tissue;

　　(3) Rectoscopy examination: See the mucosal color congestion, edema, and whether there are erosion, ulceration, polyps, tumor stenosis, and foreign bodies, and internal hemorrhoids, anal papillae, anal sinuses, and anal fistula orifices can be examined near the dentate line;

　　(4) Sigmoidoscopy examination: It is a simple and easy-to-implement method, more than 70% of rectal and colon cancers can be directly seen with this scope; Up to 39% of adenomas and other lesions can be found in routine sigmoidoscopy, 15% of adenomas have malignant changes, and diseases in the rectum and colon can be treated through sigmoidoscopy, improving the accuracy of diagnosis;

　　(5) Fiber colonoscopy examination: It can directly examine the rectum, colon, cecum, ileocecal valve, and terminal ileum, and can also perform biopsy, cancer cell examination, polypectomy, and cautery, which is beneficial for early diagnosis of colon diseases;

　　(6) X-ray examination: Chest X-ray examination determines the presence of pulmonary tuberculosis and tumor metastasis in the abdomen, determines the presence of colon stricture and obstruction. Barium enema examination can visualize the large intestine, especially the rectum and anal canal stenosis and mucosal arrangement, and whether there is destruction of polyps and tumors;

　　(7) CT scan examination: It is a sensitive method for checking anal canal and rectal cancer, capable of detecting cancer invasion in pre-sacral, pelvic lateral wall, pelvic organs, and lymph nodes, determining the size of the cancer, extension in the intestinal wall, around the rectum fat, uterus, and muscles, preoperative and postoperative scans can help in planning surgery and radiotherapy treatment plans;

　　(8) MRI examination: It can be used for preoperative examination of rectal cancer and postoperative recurrence examination, to determine the range of residual cancer after radiotherapy, and can also diagnose rectal and anal stenosis and their degree of lesion.

　　The etiology of anal, rectal, and colonic stenosis is relatively complex and can be caused by congenital malformations, inflammation, trauma, tumors, and surgical trauma. Therefore, it is necessary to eat light and easily digestible foods in the diet, eat more fresh vegetables and fruits appropriately, especially foods rich in fiber, avoid eating spicy and刺激性 foods, in order to maintain smooth defecation. Pay attention to keep the anal orifice clean to prevent local inflammation and infection.

　　Anal, rectal, and colonic stenosis can be caused by congenital malformations, inflammation, trauma, tumors, and surgical trauma. In addition to congenital malformations and injury, most colonic stenosis is a complication of colonic resection surgery, as well as complications of ulcerative colitis, granulomatous colitis, and other diseases. Below, the editor introduces the treatment methods for anal, rectal, and colonic stenosis.

　　1. Drug therapy

　　It includes using potassium permanganate warm water sitz bath or enema, internal administration of liquid paraffin, external use of suppositories, enema, etc. to ensure smooth defecation. When there are superficial cracks or ulcers, use 10% silver nitrate to rub or apply ointment externally.

　　2. Expansion method

　　For mild stenosis after surgery or injury, the expansion method can usually be used for treatment, using fingers or dilators for expansion, once a day or once or twice a week, gradually increasing the diameter of the dilator, and extending the interval between expansions. It also applies to annular rectal stenosis caused by syphilitic lymphogranuloma.

　　3. Surgical therapy

　　For severe stenosis and stenosis with hard scars for a long time, the expansion method can sometimes temporarily take effect, but it is easy to recur. The surgical method varies according to the condition of the lesion, the degree of stenosis, or the location of the stenosis.

　　The above introduces the treatment methods for anal, rectal, and colonic stenosis, and it is necessary to keep the local cleanliness and hygiene after surgery to prevent various infections from causing anal stenosis again.