Lymphadenopathy and Lymphadenitis

PATHOGENS

• Lists below are by no means comprehensive but list commonly considered pathogens causing lymphadenopathy, as well as some non-infectious considerations.
• Acute generalized LN (presenting in two or more regional groups): HIV, syphilis, EBV, CMV, Toxoplasma, Bartonella and Brucella
  • Occasionally, lymphoma and hypersensitivity reactions.
  • HAART-associated immune reconstitution syndrome in HIV+ pts (IRIS).
• Acute localized:
  
  • Cervical: group A streptococci, EBV, TB, cat-scratch disease (Bartonella), lymphoma, temporal arteritis, chronic fatigue syndrome,
  • Pre-auricular: adenovirus, conjunctivitis, tularemia, Bartonella (Parinauds syndrome).
  • Epitrochlear: hand infection (medial 3 fingers), syphilis.
  • Inguinal: syphilis, herpes, chancroid, LGV, chancroid, HIV, tularemia, plague.
  • Mesenteric: Yersinia
    • It may mimic appendicitis, especially right-sided.
  • Chronic generalized: syphilis, TB, histoplasmosis, cryptococcosis, cat scratch disease (Bartonella), Stills disease, inflammatory bowel disease, Whipple’s disease, chronic granulomatous disease (CGD), lymphoma, HIV, sarcoid, hyperthyroidism, posttransplant lymphoproliferative disorder
• Chronic localized: TB, cryptococcus, histoplasmosis, cat scratch disease (Bartonella), lymphoma, metastatic cancer, Kikuchi-Fujimoto disease, Rosai-Dorman disease, Castleman’s disease (some HHV-8).
• Non-infectious: many conditions, but consider sarcoidosis, Kikuchi-Fujimoto disease (usually cervical LN), lymphoma, SLE, metastatic malignancy, Rosai-Dorman disease, Castleman’s disease (some HHV-8), reactive lymphoid hyperplasia (RLH), hemophagocytic lymphohistiocytosis HLH, dermatopathic lymphadenitis (DLN), Kimura disease, chronic granulomatous disease (CGD) and lymphadenopathy-associated with autoimmune and metabolic/storage disease.
  • Other nodal entities could include lymph node infarction, foreign body reactions, drug reactions, and extramedullary hematopoiesis.