Editing Spleen (section)

=== Enlarged spleen ===
{{Main|Splenomegaly}}

Enlargement of the spleen is known as [[splenomegaly]]. It may be caused by [[sickle cell anemia]], [[sarcoidosis]], [[malaria]], [[bacterial endocarditis]], [[leukemia]], [[polycythemia vera]], [[pernicious anemia]], [[Gaucher's disease]], [[leishmaniasis]], [[Hodgkin's disease]], [[Banti's syndrome|Banti's disease]], [[hereditary spherocytosis]], [[cyst]]s, glandular fever (including [[Infectious mononucleosis|mononucleosis]] or 'Mono' caused by the [[Epstein–Barr virus]] and infection from [[Human betaherpesvirus 5|cytomegalovirus]]), and [[tumour]]s. Primary tumors of the spleen include [[hemangioma]]s and [[hemangiosarcoma]]s. Marked splenomegaly may result in the spleen occupying a large portion of the left side of the abdomen.

The spleen is the largest collection of [[lymphoid tissue]] in the body. It is normally palpable in preterm infants, in 30% of normal, full-term [[neonates]], and in 5% to 10% of infants and toddlers. A spleen easily palpable below the [[costal margin]] in any child over the age of three to four years should be considered abnormal until proven otherwise.

Splenomegaly can result from antigenic stimulation (e.g., infection), obstruction of blood flow (e.g., portal vein obstruction), underlying functional abnormality (e.g., [[hemolytic anemia]]), or infiltration (e.g., [[leukemia]] or storage disease, such as [[Gaucher's disease]]). The most common cause of acute splenomegaly in children is viral infection, which is transient and usually moderate. Basic work-up for acute splenomegaly includes a [[complete blood count]] with differential, platelet count, and [[reticulocyte]] and atypical lymphocyte counts to exclude hemolytic anemia and leukemia. Assessment of [[IgM]] antibodies to viral capsid antigen (a rising [[titer]]) is indicated to confirm Epstein–Barr virus or [[Human betaherpesvirus 5|cytomegalovirus]]. Other infections should be excluded if these tests are negative.

Calculators have been developed for measurements of spleen size based on [[CT scan|CT]], [[Ultrasound|US]], and [[Magnetic resonance imaging|MRI]] findings.