Signs and symptoms of mesenteric lymphadenitis may include:

• Abdominal pain, often centered on the lower, right side, but the pain can sometimes be more widespread
• General abdominal tenderness
• Fever

Depending on what's causing the ailment, other signs and symptoms may include:

• Diarrhea
• Nausea and vomiting
• General feeling of being unwell (malaise)

The most common cause of swollen mesenteric lymphadenitis is a viral infection, such as gastroenteritis — often called stomach flu. This infection causes the lymph nodes in the mesentery — the thin tissue that attaches your intestine to the back of your abdominal wall — to become inflamed.

Your lymph nodes play a vital role in your body's ability to fight off illness. They're scattered throughout your body to trap and destroy viruses, bacteria and other harmful organisms. In the process, the nodes closest to the infection can become sore and swollen — for instance, the lymph nodes in your neck may swell when you have a sore throat. Other nodes that commonly swell are located under your chin and in your armpits and groin.

Some children develop an upper respiratory infection before or during a bout of mesenteric lymphadenitis. Experts think there may be a link between the two.

If swollen lymph nodes are caused by a serious bacterial infection that isn't treated, the bacteria could spread to your bloodstream, causing a potentially life-threatening infection (sepsis).