Mesenteric adenitis is a condition characterized by inflammation of the mesenteric lymph nodes. It classically presents with lymphadenopathy and right lower quadrant abdominal pain, sometimes associated with fever, malaise, anorexia, diarrhea, abdominal pain, and a systemic inflammatory response. It is often mistaken for appendicitis.

Most commonly, mesenteric adenitis is diagnosed in pediatric patients and is associated with bacterial or viral infections (eg, Yersinia spp, Escherichia coli, Salmonella spp, Group A streptococcal pharyngitis) as well as inflammatory bowel disease and lymphoma. Immunocompromised patients are at increased risk for both gastrointestinal tract infections and mesenteric adenitis.

The disease course can range from mild symptoms that are self-limited to severe symptoms and systemic infection requiring hospitalization, intravenous fluid resuscitation, and broad-spectrum antibiotic therapy. Presentation can be either acute or chronic. Disease course can be complicated by abscess formation or end-organ damage from sepsis.