Juvenile polyps

　　1. Etiology

　　Juvenile polyps account for 85% as solitary, 14% as two or three concurrent, and more than 90% occur in the rectum or sigmoid colon. Most are located within 3 to 4 cm to 7 to 8 cm from the anal opening in the rectum, and a few can also occur in the right half of the colon. The possible causes may be on the basis of allergy, due to the injury caused by hard stools, chronic inflammation, with the intestinal mucosa showing chronic inflammation and localized granuloma proliferation at the beginning. Gradually, it increases to form a polyp with a diameter of about 1 cm, mostly spherical, with a smooth surface or nodular red appearance. With the traction of intestinal peristalsis, the base of the polyp gradually forms a mucosal pedicle, which becomes thinner with the growth of the mass until the blood supply is insufficient or the pedicle twists, leading to erosion, necrosis, and shedding of the polyp and spontaneous healing (often requiring more than 1 year).

　　2, Pathogenesis

　　The gross morphology of juvenile polyps is mostly pedunculated, with only a very small number of polyps being sessile. The pedicles are mostly thin and elongated, without muscular components. The size of the polyps is mostly 1-3 cm, with a few less than 1 cm. The head of the polyp is mostly spherical, smooth or nodular, and may also have lobular phenomena, usually red, often accompanied by erosion or superficial ulcers, tissue is friable and prone to bleeding. Histologically, polyps are mucosal lesions, including dilated mucin-filled convoluted cysts and inflammatory cells in the raised lamina propria. The glands contain well-differentiated mucous cells, with明显 widened stroma, containing abundant connective tissue, with a large number of blood vessels and inflammatory cells, and sometimes a small amount of smooth muscle cells. Occasionally, foreign giant cell reactions can be found due to the rupture of the dilated glands into the stroma. Most pathologists believe that juvenile polyps are hamartomas, due to the cystic formation of part of the glands and the retention of a large amount of mucin, they are also called retention polyps. It is generally believed that they do not belong to tumor polyps and do not undergo malignancy. However, recent reports have shown that adenomatous changes may appear in some areas of juvenile polyps. These adenomatous components and epithelial proliferation may cause malignancy. The polyps are often damaged, stimulated, inflamed, and have small amounts of bleeding due to the injury, stimulation, and inflammation of the stool. The pathological sections show hyperplasia of mucosal epithelial cells and fibrous tissue, as well as chronic inflammatory infiltration.

　　About 1/3 of patients may have anemia, and occasionally there may be massive hematochezia, rectal prolapse. Large pedunculated polyps may occasionally cause intussusception, and some may also cause diarrhea. The disease seriously affects the health of patients and must be treated promptly.

　　Painless chronic rectal and colonic polyps are the main symptoms of juvenile polyps. Hematochezia occurs at the end of defecation, usually with a streak of bright red blood on the surface of the stool, not mixed with the stool, in small amounts. In a few cases, a few drops of fresh blood may drip from the anus after defecation. Massive bleeding due to polyp shedding is rare. When there is secondary infection on the surface of the polyp, in addition to hematochezia, there is also a small amount of mucus. Sometimes, a streak of indentation can be seen on the bloodstain in the stool, caused by the compression of the polyp on the stool. Children usually have no pain or urgency of defecation during defecation. Polyps with low position or long pedicles can be pushed out of the anus during defecation, and a red fleshy ball can be seen at the anus. If the polyp is not returned in time, it may become incarcerated and fall off with bleeding. Due to the small amount of bleeding, children rarely have significant anemia.

　　The etiology of juvenile polyps is unknown, and the pathogenesis is not yet clear, therefore, there is currently no precise preventive measure. Early detection and diagnosis are the key to the prevention and treatment of the disease. High-risk populations should undergo regular screening and be treated promptly upon detection.

　　Routine examinations are generally normal, and a few blood routine examinations may show decreased hemoglobin, and stool routine examinations may show occult blood positivity. During rectal examination, a single negative rectal examination cannot exclude the diagnosis of polyps. It can be re-examined after defecation or enema. High rectal polyps can be examined by sigmoidoscopy or colonoscopy, or by the method of double-contrast contrast after barium enema and air injection.

　　1. X-ray examination:X-ray is also very valuable for diagnosing high rectal polyps. The method of using barium enema and double-contrast contrast after barium excretion is to observe the shadow of filling defect in the intestinal cavity during the barium injection process. After barium excretion, the shadow of the filling defect with a circular barium ring can be seen when injecting air. However, it should be noted that it should be distinguished from intestinal bubbles and fecal masses. The method of distinction is: bubbles can move with the change of body position, with a larger range of movement, and fecal masses are flat and irregularly shaped filling defect shadows. When pressed with the hand, they often break apart. If the fecal mass is hard, it is difficult to distinguish from the polyp in terms of shape, but the fecal mass can change shape and position, or even disappear during re-examination.

　　2. Endoscopic examination:Gastrointestinal endoscopy can directly observe the location, size, shape, surface characteristics, number, color, and can perform histological examination to determine the nature and perform histological classification of gastrointestinal polyps, which is the most accurate and ideal method for diagnosing gastrointestinal polyps, and can also remove polyps.

　　Patients generally have no special dietary requirements, and it is recommended to eat light foods as the main diet, ensuring a reasonable dietary structure and nutrition, eating more fresh fruits and vegetables, and paying attention to dietary regularity.

　　For those who can feel low rectal polyps during rectal examination, they are generally removed by manual removal in the outpatient department. That is, the base of the polyp is compressed in the rectum with the finger, causing it to break off at the junction of the pedicle and the polyp, usually with little bleeding. If the polyp is large and the pedicle is long, the polyp can be pulled out of the anus with the finger, tied with a silk thread at the pedicle, and then returned to the rectum, waiting for it to fall off naturally. After the polyp is removed, the patient should rest for 1 hour, and if there is no bleeding during defecation or rectal examination, the child can return home. High rectal polyps can be removed under sigmoidoscopy or colonoscopy. If the above methods cannot remove the polyps, it is necessary to consider laparotomy and intestinal resection to remove the polyps, but this is rarely needed.