What are the causes of mesenteric adenitis?

Causes of Mesenteric Adenitis

Upper respiratory tract infections are the most common cause of mesenteric adenitis, reported in 22-53% of cases. 1

Infectious Causes

• Viral pathogens are the predominant infectious cause:

  • Epstein-Barr virus, Cytomegalovirus, Coxsackievirus, and Rubella are common viral triggers 1
  • Adenovirus type 7 has been specifically linked to mesenteric adenitis in controlled studies 2
  • Influenza B virus and Coxsackie B virus have established relationships with mesenteric adenitis 2

• Bacterial causes include:

  • Yersinia pseudotuberculosis - can cause significant mesenteric lymph node enlargement that may present as an abdominal mass 3
  • Salmonella enterica serovar Enteritidis - unlike Yersinia which is more common in Western countries, S. Enteritidis carries potential risk for serious systemic complications 4
  • Campylobacter jejuni - particularly common in Asia 1
  • Nontuberculous mycobacteria (NTM) - though these more commonly affect cervical lymph nodes 1

Non-Infectious Causes

• Inflammatory conditions:

  • Inflammatory bowel disease, particularly ulcerative colitis 1
  • Adult-onset Still's disease can present with abdominal pain and mesenteric lymphadenopathy 1

• Malignancy:

  • Lymphoma and leukemia should be considered in the differential diagnosis, particularly in adults with persistent mesenteric lymphadenopathy 1

Classification of Mesenteric Adenitis

• Primary Mesenteric Adenitis - self-limited condition without identifiable underlying cause 5
• Secondary Mesenteric Adenitis - occurs due to an identifiable primary condition 5
• Complicated Primary Mesenteric Adenitis - primary mesenteric adenitis with complications 5

Clinical and Diagnostic Features

• Mesenteric adenitis frequently mimics appendicitis, accounting for 19.8% of discharge diagnoses in patients initially admitted for suspected appendicitis 6

• CT findings typically show:

  • Three or more lymph nodes measuring at least 5mm in shortest axis clustered in the right lower quadrant
  • Normal appendix
  • Possible associated ileal or ileocecal wall thickening 6

• Ultrasound is the initial imaging modality of choice, with CT recommended when ultrasound is inconclusive 1

Special Considerations

• In immunocompromised patients, cytomegalovirus colitis can present with mesenteric lymphadenitis and carries a high mortality rate if misdiagnosed 1
• Patients with HIV may develop mesenteric lymphadenitis as part of immune reconstitution inflammatory syndrome 1
• Mesenteric adenitis is typically self-limited in immunocompetent patients, but certain pathogens like Salmonella Enteritidis may require specific treatment due to risk of systemic complications 4