Splenomegaly

Basics

Description

  • A palpable spleen is found in most premature infants and in 30% of term infants. A spleen tip is still palpable in 10% of infants at 1 year of age and in 1% of children at 10 years of age.
  • Normal spleens are not greater than 6 cm at 3 months, 7 cm at 12 months, 9.5 cm at 6 years, 11.5 cm at 12 years, and not greater than 13 cm for adolescents.
  • Splenomegaly can also be a spleen width >4 cm or diameter >7 cm.
  • Normal spleen size varies but is typically less than 250 g.
  • The clinical significance of splenomegaly found on radiologic study, but not palpable on physical exam, is unclear in the absence of other laboratory or clinical data.
  • Normal spleens are soft at the midclavicular line, nontender, and often palpable only on deep inspiration.
  • Dullness on percussion beyond the 11th intercostal space suggests splenomegaly.
  • A spleen edge palpated >2 cm below the costal margin is always an abnormal finding.
  • Splenic tenderness is always abnormal.

Pathophysiology

  • The spleen is a hematopoietic organ with 2 main parts:
    • White pulp is the lymphoid tissue.
    • Red pulp is the red cell mass.
  • Splenic sinusoids are lined with macrophages that destroy abnormal red cells.
  • The spleen also serves as a reservoir for platelets. A normal-sized spleen can hold 1/3 of the circulating platelets; an enlarged spleen can hold up to 90% of the circulating platelet mass.
  • Normal splenic volume by CT scan is 214.6 cm3 (range, 107.2 cm3–314.5 cm3).
  • Splenic size does correlate with height.

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