Description

• Characterized by benign inflammation of the mesenteric lymph nodes; can be acute or chronic, primary or secondary
• May clinically mimic acute appendicitis

Epidemiology

• Commonly misdiagnosed, making definitive incidence difficult to determine
• Most common cause of appendicitis-like pain in children (1)
  • 20% in patients presenting for appendectomy (1)
  • More common than acute appendicitis <10 years (2)
• More common in children <15 years old than in adults
  • Primary adenitis is more common in children.
  • Secondary adenitis is more common in adults.
    • Rule out diverticulitis, appendicitis, Crohn disease, or systemic infectious/inflammatory disease (e.g., HIV, SLE, sarcoidosis).

Prevalence
Affects males and females equally

• Adenitis secondary to Yersinia infection is more prevalent in boys than girls.
  • Yersinia enterocolitica is most common in North America, Eastern Europe, and Australia.

Etiology and Pathophysiology

• Primary: underlying inflammatory process not present; presumed due to acute infectious gastroenteritis (specifically, terminal ileitis)
• Secondary: underlying inflammatory process present
• In infectious cases, pathogens are ingested, translocate through the intestinal epithelium via Peyer patches, and gain access to mesenteric lymph nodes where an inflammatory reaction causes symptoms and clinical disease:
  • Y. enterocolitica
  • Campylobacter jejuni
  • Salmonella typhi
  • β-Hemolytic Streptococcus spp.
  • Staphylococcus spp.
  • Streptococcus viridans
  • Escherichia coli
  • Mycobacterium tuberculosis
  • Giardia lamblia
  • Epstein-Barr virus (EBV) (mononucleosis)
  • Acute HIV infection
  • Rubeola virus
  • Bartonella henselae (cat-scratch disease)
  • Adenovirus species
  • Toxoplasma gondii

Genetics
No known genetic susceptibility

Risk Factors

• Typically preceded by URI or pharyngitis
• History of ingesting undercooked pork particularly in areas where Yersinia is endemic (parts of Europe)

General Prevention

Minimize risk by fully cooking foods, especially meat.

Commonly Associated Conditions

• Appendicitis
• Diverticulitis
• Crohn disease
• Celiac disease
• Other systemic inflammatory/autoimmune disease