- inflammation of the mesenteric lymph nodes
- Considered present if a cluster of three or more lymph nodes, each measuring 5 mm or greater, is detected in the right lower quadrant mesentery.
- Can be acute or chronic
- often difficult to differentiate from acute appendicitis
- Microbial agents are thought to gain access to the lymph nodes via the intestinal lymphatics
- Cause inflammation and, occasionally, suppuration.
- A theory that swallowed pathogen-laden sputum may be the primary source of infection.
- Fecal-oral transmission occurs in Y enterocoliticainfection and may present as a common source outbreak.
- Beta-hemolytic streptococcus, Staphylococcus species, Escherichia coli, Streptococcus viridans, Yersinia species (responsible for most cases currently), Mycobacterium tuberculosis, Giardia lamblia, and non– Salmonella typhoid.
- Viruses, such as coxsackieviruses (A and B), rubeola virus, and adenovirus serotypes 1, 2, 3, 5, and 7, have also been implicated, Epstein-Barr virus (EBV), acute human immunodeficiency virus (HIV) infection, and cat scratch disease (CSD).
Gender & Age
- males and females equally
- Yersinia infection is more common in boys than in girls.
- can occur in adults but is more common in children and adolescents younger than 15 years
- Abdominal pain – Often right lower quadrant (RLQ) but may be more diffuse
- Concomitant or antecedent upper respiratory tract infection
- Nausea and vomiting (which generally precedes abdominal pain, as compared to the sequence in appendicitis)
- History of ingestion of raw pork may be obtained in areas with endemic Yersinia (e.g., Belgium).
- Fever (38-38.5°C)
- Flushed appearance
- Right lower quadrant (RLQ) tenderness – Mild, with or without rebound tenderness
- Voluntary guarding rather than abdominal rigidity
- Rectal tenderness
- Hyperemic pharynx
- Toxic appearance
- Associated peripheral lymphadenopathy (usually cervical) in 20% of cases
Classification (by imaging)
Primary mesenteric adenitis is described as right-sided mesenteric lymphadenopathy that does not have an identifiable acute inflammatory process or demonstrates only mild (<5 mm) wall thickening of the terminal ileum.  The etiology may be an underlying infectious terminal ileitis.
Secondary mesenteric adenitis on imaging studies demonstrates lymphadenopathy that is associated with a specific, identifiable intraabdominal inflammatory process.  In the presence of clearly detectable terminal ileal thickening (e.g., Crohn disease, infectious ileitis), the mesenteric adenitis is considered secondary.
- Meckel diverticulitis
- Intestinal duplication
- Regional enteritis
- Intestinal lymphoma
- Other causes of acute abdomen (e.g., porphyria, sickle cell vaso-occlusive crises, cecal tumor, familial Mediterranean fever)
- Acute Pyelonephritis
- Benign Neoplasm of the Small Intestine
- Chronic Mesenteric Ischemia
- Urinary Tract Infection (UTI) and Cystitis (Bladder Infection) in Females
- Ectopic Pregnancy
- Inflammatory Bowel Disease
- Pelvic Inflammatory Disease
- Urinary Tract Infection (UTI) in Males
- FBC, TWC>10 in at least 50% of cases.
- RP for severe vomit
- Serology can be supportive in diagnosis of etiologic agents such as Y enterocolitica.
- UFEME to exclude UTI
- Stool culture
- Blood culture, septicemia
- Computed tomography scanning
- Enlarged mesenteric lymph nodes, with or without associated ileal or ileocecal wall thickening, and a normal appearing appendix.
- Magnetic resonance imaging
- Complete recovery can be expected without specific treatment. Death is rare.
- But sepsis may have a fatal outcome.
- Volume depletion and electrolyte imbalance in patients with severe diarrhea, nausea, and vomiting
- Abscess formation
- Peritonitis (rare)
- risk of recurrence
Given the predominance of Y enterocolitica, initial antibiotic selection from
- trimethoprim-sulfamethoxazole (TMP-SMX)
- third-generation cephalosporin
These agents provide broad coverage for enteric pathogens.