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- 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.
Depends on the underlying process that causes lymph node enlargement
Palpable nodes are present in up to 50% of neonates (cervical, axillary, inguinal), infants, and older children (all areas except epitrochlear, supraclavicular, and popliteal).
- 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.
- 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.