Mesenteric lymph nodes are the 100 to 150 lymph nodes that lie within the mesentery, a double-layered section of peritoneum, the membrane that lines the abdominal cavity. Peritoneum consists of connective tissue and mesothelium, a specialized membrane that produces a lubricating fluid. This fluid allows organs to move easily within the abdominal cavity. Mesothelium is best known as a part of the lungs, where it can be affected by a particular form of cancer called mesothelioma. Mesentery membranes not only help protect the internal organs but also play a key role in ensuring sufficient oxygen and nutrients are delivered.
Located in the lower abdomen, the mesenteric lymph nodes lie throughout the various intestinal loops and close to the superior mesenteric artery, one of the major blood vessels that supplies the intestines and lower abdominal organs with blood and oxygen. Part of the lymphatic system, these lymph nodes are a vital part of the immune system that helps the body fight disease. The lymphatic system itself spreads throughout the entire body, carrying specialized cells that trigger immune system responses when necessary.
Under certain circumstances, the mesenteric lymph nodes can become inflamed. This condition is referred to as mesenteric lymphadenitis, and it can stem from several causes. One common cause is a general infection of the large intestine or other parts of the intestinal system from bacterial, viral or parasitic causes. When infection sets in, the lymph nodes often respond by becoming enlarged as they work to fight off the infection. Abscesses in the lower abdomen or peritonitis, which is an infection of the peritoneum, can also cause the mesenteric lymph nodes to swell.
Symptoms of mesenteric lymphadenitis are similar to those of appendicitis, including abdominal pain and fever. Unlike appendicitis, this type of inflammation of the mesenteric lymph nodes usually will resolve on its own without invasive treatment or surgery. Rarely serious, this problem is seen most often in children in conjunction with an intestinal infection.
Another less common and much more serious cause of inflammation of the mesenteric lymph nodes is cancer. Several kinds of cancer can lead to mesenteric lymphadenitis, including cancer that is centered in the gastrointestinal tract and more widespread cancers that affect all of the lymph nodes, such as lymphoma. Enlarged mesenteric lymph nodes are often discovered during abdominal CAT scans. If the cause of the inflammation is not immediately apparent, a biopsy might be necessary to diagnose or rule out cancer.