Hello! Thank you for the query. Enlarged mesenteric lymph nodes is the most common finding of the small intestine disease in abdominal ultrasound. Lymph nodes gets enlarged due to inflammatory process. It can be intestines infection, appendicitis, inflammatory bowels disease, Yersinia infection and many more. So without knowing other symptoms like abdominal pain localization, diarrhea presence, fever presence it is very hard to determine which exactly condition is causing it. I suggest you to visit gastroenterologist and have some diagnostics. Stool tests, blood work, CRP, urine analysis should be done at first. If the pain is located in the right lower abdomen, and doctors are not sure if it is appendicitis or not, abdomial CT should be done. Hope this will help. Regards.