Lymphadenopathy

Lymphadenopathy is a topic covered in the Select 5-Minute Pediatrics Topics.

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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 5–25% of newborns (cervical, axillary, inguinal) and in >50% of 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

Commonly Associated Conditions

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

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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 5–25% of newborns (cervical, axillary, inguinal) and in >50% of 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

Commonly Associated Conditions

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

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