Description

• Term used to describe ≥1 enlarged lymph nodes >10 mm in diameter (for inguinal nodes, >15 mm; for epitrochlear nodes, >5 mm)
• Any palpable supraclavicular and popliteal lymph node is considered abnormal.

Epidemiology

Pathophysiology

• Lymph nodes are often palpable in normal, healthy children.
  • Normal lymph nodes: generally <10 mm
  • They are present from birth, peak in size between 8 and 12 years of age, and then regress during adolescence.
• Lymph nodes drain contiguous areas.
  • Cervical nodes drain head and neck area (up to 15% of biopsied nodes are malignant).
  • Axillary nodes drain arm, thorax, and breast.
  • Epitrochlear nodes drain forearm and hand.
  • Inguinal nodes drain leg and groin.
  • Supraclavicular nodes drain thorax and abdomen.
• Lymphatic flow from adjacent nodes or inoculation site brings microorganisms to lymph nodes.
• Lymph node enlargement may occur via any of the following mechanisms:
  • Nodal cells may replicate in response to antigenic stimulation (e.g., Kawasaki disease) or malignant transformation (e.g., lymphoma).
  • Lymphocyte proliferation due to immune defect (e.g. primary immunodeficiency disease [PIDD])
  • Large number of reactive cells from outside node (e.g., neutrophils or metastatic cells) may enter node.
  • Foreign material may be deposited into node by lipid-laden histiocytes (e.g., lipid storage diseases).
  • Vascular engorgement and edema may occur secondary to local cytokine release.
  • Suppuration secondary to tissue necrosis (e.g., Mycobacterium tuberculosis)
• Many systemic infections (e.g., HIV) cause hepatic or splenic enlargement in addition to generalized lymphadenopathy.

Etiology

Usually determined by performing a thorough history and physical exam

Commonly Associated Conditions

Many systemic infections, malignancy, and lymphoproliferative disorders cause hepatic or splenic enlargement in addition to generalized lymphadenopathy.