I. Pathological analysis of pediatric mesenteric lymphadenitis Mesenteric lymphadenitis was first reported by Brennemann in 1921, so it is also known as Brennemann syndrome. Because the etiology of this disease has not been elucidated, it is also referred to as acute nonspecific mesenteric lymphadenitis. It is also believed that the closure of the ileocecal valve, which allows intestinal toxins or bacterial metabolites to remain in the ileum for a longer period of time and be easily absorbed, is another important reason why mesenteric lymphadenitis is more likely to occur in the ileocecal region. The cause of pediatric mesenteric lymphadenitis (enlarged abdominal lymph nodes) is pediatric mesenteric lymphadenitis is a common pediatric lesion, generally thought to follow upper respiratory tract infection, bloodstream infection with streptococci or viruses (i.e., after a cold or flu), and also thought to be related to intestinal inflammation and parasitic diseases. It is mostly seen at the end of the ileum (clinical manifestations such as right lower abdomen and periumbilical pain). The lymph nodes show multiple congestion and enlargement. There may be a small amount of inflammatory exudate in the abdominal cavity. Microscopically, the lymph sinuses are dilated and neutrophils enter the lymph sinuses by small vessels and phagocytose bacteria. Acute mesenteric lymphadenitis is often associated with upper respiratory tract infections. Children are growing, their immune system is active, their immune function is strong, and their lymphatic follicle production centers are obvious; on the other hand, because the child’s organism is not yet well developed, various intestinal bacteria, viruses, and toxins may pass through the intestinal mucosa and cause mesenteric lymphadenitis. The clinical diagnosis of pediatric mesenteric lymphadenopathy (clinical diagnosis of pediatric mesenteric lymphadenopathy) is relatively difficult to diagnose because pediatric mesenteric lymphadenopathy usually occurs at the end of the ileum, and is easily misdiagnosed. At present, the diagnosis of this disease mainly relies on medical history, clinical manifestations and routine blood tests. The application of ultrasound has opened up a new way of examination for the diagnosis of this disease. Acute mesenteric lymphadenitis is characterized by an increase in the number of mesenteric lymph nodes in the ileo- and colonic regions, an increase in diameter, an oval shape, a target-like structure or a uniform hypoechoic structure without fusion, and a qualitative diagnosis can be made based on these features. In the process of diagnosing pediatric mesenteric lymphadenitis, it is necessary to differentiate from the following lesions occurring in the ileo- and colonic regions. 1. Differentiation from acute mesenteric lymphatic tuberculosis: Acute mesenteric lymphatic tuberculosis appears ultrasonographically as round or oval enlargement of mesenteric lymph nodes, with incomplete envelope, fusion, and uneven internal echogenicity; in advanced stages, scattered liquefied areas and intense light clusters or dots with acoustic shadowing may appear, which may be combined with large amounts of ascites and intestinal adhesions. 2. Differentiation from malignant lymphoma: Mesenteric malignant lymphoma tends to be rounded on ultrasound, with aspect ratio <2, involving long segments, and may have fusion, central necrosis, and punctate calcification, which are distinctly different from this disease. 3. Differentiation from acute appendicitis: In acute appendicitis, the right lower abdominal lymph nodes are enlarged on ultrasound, which is similar to the ultrasound performance of acute mesenteric lymphadenitis, but the number of enlarged lymph nodes is small, generally ≤3, and the ultrasound performance of acute appendicitis is also present, so it is easy to differentiate from this disease. Criteria for lymph node enlargement Combining domestic and international criteria for determining lymph node enlargement, the criteria for determining lymph node enlargement are: more than 2 lymph nodes in the same area of mesentery, with a long-axis diameter >25px or short-axis diameter >12.5px are considered enlarged. Normal mesenteric lymph nodes are mostly located around the umbilicus, and one or several of them can be seen in the shape of kidney or bean, with clear borders and smooth surface, and no blood flow signal or only punctiform blood flow signal can be detected in the lymph nodes. The enlarged lymph nodes are mostly located in the right lower abdomen or periumbilical region, or both the right lower abdomen and periumbilical region are enlarged. Most of the enlarged lymph nodes around the umbilicus are multiple and clustered, and most of the enlarged lymph nodes in the right lower abdomen are isolated. The enlarged lymph nodes were also kidney-shaped, with a smooth and intact surface and clear demarcation of the dermal medulla. In some patients, a small amount of liquid dark area was seen in the right iliac fossa triangle. Pediatric mesenteric lymphadenitis (enlarged abdominal lymph nodes) Clinical manifestations, symptoms Fever, abdominal pain, vomiting, or diarrhea or constipation may occur. The abdominal pain sometimes resembles colic in the right lower abdomen, but can also be in other areas. Lymphatic tuberculosis has low-grade fever and changes in stool symptoms. Lymphatic tuberculosis is usually caused by tuberculosis from other sites. Treatment of pediatric mesenteric lymphadenopathy (treatment of pediatric mesenteric lymphadenopathy) The disease is mostly a viral or bacterial infection, and most have a good prognosis. The lymph nodes do not degenerate under normal circumstances and no problems remain! It will improve and heal with anti-inflammatory and antispasmodic treatment (commonly known as anti-inflammatory and pain relief, which needs to be treated under the diagnosis and guidance of a doctor)! Enlarged lymph nodes are caused by inflammation and should be treated by applying antibiotics in sufficient quantity as soon as possible so that the enlarged inflamed lymph nodes can be completely cured. However, recurrent attacks or incomplete treatment can turn into chronic mesenteric lymphadenitis, where the child often has abdominal pain from time to time, and the location is not fixed, and medication takes a long time to treat. In addition to this, chronic mesenteric lymphadenitis can be caused by tuberculosis, with intestinal tuberculosis or tuberculous peritonitis and a history of exposure to tuberculosis. Clinical manifestations include chronic tuberculosis toxicity, low fever, night sweats, lethargy, poor appetite, abdominal pain, and enlarged lymph nodes with significant pressure pain in the right lower or left upper abdomen. Anti-tuberculosis treatment is generally effective. It should be noted that it should also be differentiated from lymphoma, which may also manifest as enlarged mesenteric lymph nodes and be identified by biopsy. Pediatric mesenteric lymphadenitis (enlarged abdominal lymph nodes) predisposes to this disease in children and young adults, but it can also occur in young children, middle-aged and elderly people. The clinical treatment of pediatric mesenteric lymphadenitis 1, children’s lymphatic system is not well developed, when the body is infected with viruses and bacteria, causing lymph node inflammation or mesenteric lymph node enlargement, the problem is not big, to 7-8 years old will develop well, the key to enhance the child’s physical fitness, less colds and fevers, it is recommended not to use random drugs on their own. 2, if the child does not have a fever, generally do not deal with; if the child has a slight fever, poor appetite, abdominal pain is more intense, then you can appropriate infusion treatment. 3, we now often encounter pediatric patients with abdominal pain, and can not find out what the cause, ultrasound examination found that children with enlarged abdominal lymph nodes, if abdominal pain and other symptoms are obvious or timely treatment, but to distinguish from chronic gastritis, duodenal bulb ulcer, erosion and HP (Helicobacter pylori) infection 4, the main treatment is a regular diet, it is recommended not to eat puffed fried and other junk snacks, drink less milk, not to eat rice cakes, dumplings and so on. Do not eat rice cakes, dumplings and other foods that do not digest.