Splenomegaly

Background

The spleen plays an important role in cellular and immune response to infection and inflammation.  It also has a phagocytic role and acts as a filter for circulating microorganisms, old and deformed red cells, and other antigens.  The enlargement of the spleen is usually accompanied by hepatomegaly and other signs and symptoms of systemic illnesses.  On some occasions, it may be the only finding.

The spleen is felt in 30% of normal newborns and up to 10% of one year olds.  It may also be felt in 1% of normal older children and adolescents.  An enlarged spleen may not be palpable until it is 2-3 times its normal size.  Reasons for feeling a normal spleen include an unusual position and being pushed down by hyperexpanded lungs.  During the examination of the spleen, the child should be in the supine position or on their right side.  It is important to start low in the abdomen to prevent missing a massively enlarged organ.  Asking the e patient to take a deep breath may be helpful.  The presence of an enlarged spleen may be confirmed by ultrasound, computerized tomography, or radionucleotide studies.  symptoms of splenic enlargement may include pain secondary to capsule stretching or shock because of atraumatic rupture of a tense capsule.

General mechanisms of splenic enlargement

  1. Proliferation of lymphoid tissue
  2. infiltration by neoplastic cells or lipid-laden macrophages
  3. extramedullary hempatopoiesis
  4. Increase of phagocytic cells
  5. Obstruction of vascular drainage leading to congestion

Specific etiologies

  1. Infection
    1. Viral- EBV. CMV, Parvovirus 19, HIV
    2. Bacterial- Typhoid fever, SBE, Septicemia, Cat Scratch, TB
    3. Protozoal- Malaria
    4. Fungal- Histoplasmosis, Coccidiodmycosis
  2. Hematological Disorders
    1. Hemolytic disorders- autoimmune, red cell membrane defects including spherocytosis, elliptocytosis. G6PD, pyruvate kinase deficiency
    2. Hemoglobinopathies- Sickle cell syndromes, thalessemia syndromes
    3. Extramedullary hematopoiesis- Thalassemia and osteopetrosis
  3. Splenic infiltration
    1. Gaucher's and Niemann-Pick
    2. Leukemic infiltration,
    3. Hodgkin's disease
  4. Lupus, JRA, Sarcoidosis
  5. Trauma
  6. Splenic cysts, hemangiomas,
  7. Disorders of Splenic blood flow- evaluation should include liver function tests and evaluation for esophageal varices.  If there is no liver disease found, splenoportal venography should be performed.
    1. Cavernous transformation of the portal vein
    2. Hepatic cirrhosis
    3. Portal and/or splenic vein thrombosis

References

  1. Wolf, Ann D., and Joel E. Lavine. Hepatomegaly in neonates and children. Pediatrics in Review 21.9 (2000): 303-310.
  2. Barkun, Alan N., et al. The bedside assessment of splenic enlargement. The American journal of medicine 91.5 (1991): 512-518.
  3. Pozo, Anna L., Edmund M. Godfrey, and Kristian M. Bowles. Splenomegaly: Investigation, diagnosis and management. Blood reviews 23.3 (2009): 105-111.

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