Lymphadenopathy

Basics

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

Incidence

Depends on the underlying process that causes lymph node enlargement

Prevalence

Palpable nodes are present in up to 50% of neonates (cervical, axillary, inguinal), infants, and older children (all areas except epitrochlear, supraclavicular, and popliteal).

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
  • Infectious etiology more likely in a child <5 years old (i.e., Staphylococcus aureus, Streptococcus pyogenes).

Commonly Associated Conditions

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

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