Why do children always cry out for abdominal pain? Is it a trick to avoid going to school? Is it a parasite, but the child has already taken worming medicine and it has not improved; is it enteritis, but the child’s appetite and bowel movements are normal? Is mesenteric lymphadenitis that difficult to treat? The child’s stomach pain and sometimes the enlarged lymph nodes on ultrasound seem to be consistent with mesenteric lymphadenitis, and this diagnosis is consistent with the child’s family’s psychology, but this diagnosis is often incomplete. What are enlarged lymph nodes? Normal mesenteric lymph nodes are mostly smaller than 7 mm. ultrasound diagnoses enlarged lymph nodes according to different criteria, for example, CT generally considers a diameter greater than 1 cm as the threshold value for enlargement. Ultrasound, on the other hand, considers the presence of more than 2 lymph nodes in the same area of the mesentery, with a long-axis diameter greater than 10 mm, a short-axis diameter greater than 5 mm, and an aspect ratio greater than or equal to 2 as enlargement. What strongly suggests clinical significance lies more in the structure of the lymph nodes, for example, a normal one would have parallel growth, smooth envelope, clear corticomedullary demarcation, visible lymphatic portals, and an aspect ratio less than 1. Do enlarged mesenteric lymph nodes mean inflammation? The most common cause of enlarged mesenteric lymph nodes in children is mostly reactive enlargement, which is commonly caused by intestinal and extraintestinal diseases or infections, as well as external stimuli such as food allergies and food intolerances. After the primary disease is controlled and the external stimuli are eliminated, this reactive enlargement and swelling of the mesenteric lymph nodes will return to normal, which means that the enlargement is not always inflammatory. Inflammation is often characterized by “redness, swelling, heat, and pain,” so lymphadenitis is unlikely in a child with no fever, no history of antecedent infection of the whistle tract, non-persistent pain that resolves on its own, and good general condition. Asking about the characteristics of the abdominal pain helps to identify it, because the swollen lymph nodes are not necessarily inflammatory, so antibiotics are not always needed. Abdominal pain is not necessarily caused by this swollen lymph node? Yes, it should be said that abdominal pain can have many causes, including medical and surgical diseases, and can be pathological or functional, but abdominal pain in children, which is generally good, is mostly likely to be due to functional causes of intestinal cramps. The enlarged lymph nodes are related to the growth and development characteristics of children: children are in the growth and development period, the body’s immune system is active, the immune function is strong, and the lymphatic follicle production center is obvious; on the other hand, because the development of the child’s body is not yet perfect, various stimulating factors may stimulate the enlarged lymph nodes. However, this enlarged lymph node is not necessarily the cause of abdominal pain. Some people say that abdominal pain is also a “growing pain”? Yes, there is such a term. It is not a disease, but rather a growth phenomenon, mostly seen in children during the growth period. The mechanism of this condition is that the rapid growth and development in childhood causes a temporary shortage of blood supply to the body, and the intestines become temporarily ischemic. In this case, spasmodic contractions of the intestines can occur and cause abdominal pain. In addition, abdominal pain can also be caused by the uncoordinated action of gastrointestinal nerve inhibition due to the disorder of plant nerve function. Therefore, for children with abdominal pain and enlarged mesenteric lymph nodes suggested by ultrasound, clinical attention should be paid to analyze the causes of enlarged mesenteric lymph nodes, including intestinal and extraintestinal diseases. In addition, if the enlarged mesenteric lymph nodes do not retract or even increase in size after standard treatment, the original diagnosis needs to be reviewed to avoid missed diagnosis or misdiagnosis.