- Author: Alexander Gozman, MD; Chief Editor: Robert J Arceci, MD, PhD more...
Splenomegaly in childhood is generally first suspected upon physical examination. One third of newborns and 10% of children may normally have a palpable spleen. The tip of the normal, palpable spleen is soft, smooth, nontender and less than 1-2 cm below the left costal margin. A pathologically enlarged spleen is often firm, may have an abnormal surface, and is frequently associated with signs and symptoms of the underlying disease. When any of these features are noted, or if the tip of the spleen is enlarged more than 1-2 cm below the costal margin, further evaluation should be considered.[1, 2]
The spleen is the largest lymphoid organ in the body. The spleen and the lymph nodes are the major components of the mononuclear-phagocyte system (MPS). They serve as filters that remove damaged cells, microorganisms, and particulate matter and deliver antigens to the immune system. The MPS, originally called the reticuloendothelial system, consists of fixed phagocytic cells in different organs. These phagocytes locally interact with lymphocytes and play an essential role in the recognition of antigens and their interaction with immunocompetent cells.
The splenic tissue consists of red and white pulp lying in a capsule. Blood enters the spleen through the splenic artery, a branch of the celiac artery. It then travels into the smaller arterioles and approaches the white pulp. The white pulp, rich in T and B lymphocytes, receives plasma for antigen processing. Splenic macrophages efficiently ingest these antigens and deliver them to the immunocompetent cells of the spleen for antibody production and stimulation of T-lymphocyte immune responses. The remaining hemoconcentrated blood continues into the contiguous red pulp, the sinuses and cords of which are also lined with macrophages.
The red pulp forms most of the splenic tissue and consists of splenic cords, the circulation of which is designated as open because no well-defined endothelial lining is present. To exit the cords, blood must pass through 1-µm to 5-µm slits in this fenestrated basement membrane to reach the venous sinusoids. The circulation through the cords is slow and congested. This delay provides prolonged exposure of blood cells, bacteria, and particulate matter to the dense mononuclear-phagocyte elements in the red pulp.
After reaching the sinuses, blood from the red pulp empties into the splenic vein, which joins the superior mesenteric vein to form the hepatic portal vein. Because no valves are present in the splenic venous system, the pressure in the splenic vein reflects the pressure in the portal vein.
One of the primary functions of the spleen is the filtration of defective cells. Erythrocytes slowly pass through the hypoxic and acidotic environment of the splenic cords and then squeeze through narrow slits into the sinusoids. Although healthy erythrocytes readily accomplish this passage, aged and abnormal red cells, such as spherocytes and sickle cells, remain behind to be ingested by the macrophages lining the cords. Fc receptors on splenic macrophages also bind to IgG antibody-coated erythrocytes or platelets, which are mainly cleared by the spleen.
The spleen is also critical for clearing circulating, particularly encapsulated, bacteria. The amorphous polysaccharide coat of encapsulated bacteria greatly impairs their clearance in the absence of antibody, and only the spleen's highly efficient phagocytic cords can effectively clear them. The splenic white pulp processes these intravenous antigens and produces antibody that, during subsequent exposures, allows for efficient clearance by the rest of the MPS.
The splenic cords are uniquely capable of removing erythrocytic inclusions, such as nuclear remnants (ie, Howell-Jolly bodies) or precipitated globin (ie, Heinz bodies), without destroying the cell. The spleen also serves as a reservoir for platelets and produces blood components (extramedullary hematopoiesis) if the bone marrow is unable to meet demands.
A 1-cm to 2-cm splenic tip is palpable in 30% of full-term neonates and in as many as 10% of healthy children. Approximately 3% of healthy college freshmen have palpable spleens. Initial and follow-up studies confirm that these college freshmen are not at high risk for subsequent serious disease.[5, 6, 1]
In malaria-endemic areas, the prevalence of splenomegaly (ie, spleen rate) is a measure of malaria exposure. In hyperendemic areas (eg, Papua New Guinea), the spleen rate in children exceeds 50%. Such hyperendemic areas have a prevalence of massive splenomegaly (hyperreactive malarial splenomegaly) of 1-2% in children.
Splenectomy is uncommonly performed in children with splenomegaly. Nevertheless, should it be clinically indicated, the overall risk of postsplenectomy sepsis is approximately 2%, with increased incidence and mortality in young children.[11, 12]
Hypersplenism is the occurrence of thrombocytopenia, and occasionally leukopenia and anemia, in the context of significant splenomegaly. The cytopenias are usually mild but may contribute to overall morbidity.
Specific causes of splenomegaly are most common in certain racial groups. Examples include splenic sequestration as a complication of sickle cell disease in patients of African or Mediterranean ancestry and noncirrhotic portal fibrosis in patients of Iranian, South Asian, or Japanese ancestry.
The etiology of splenomegaly varies with age. For example, splenic sequestration in sickle cell disease occurs early in life, before the splenic involution that ultimately occurs in most patients with sickle cell disease.
Arkles LB, Gill GD, Molan MP. A palpable spleen is not necessarily enlarged or pathological. Med J Aust. 1986 Jul 7. 145(1):15-7. [Medline].
Brown NF, Marks DJ, Smith PJ, Bloom SL. Splenomegaly. Br J Hosp Med (Lond). 2011 Nov. 72(11):M166-9. [Medline].
Sills RH. Splenic function: physiology and splenic hypofunction. Crit Rev Oncol Hematol. 1987. 7(1):1-36. [Medline].
Mebius RE, Kraal G. Structure and function of the spleen. Nat Rev Immunol. 2005 Aug. 5(8):606-16. [Medline].
McIntyre OR, Ebaugh FG. Palpable spleens in college freshmen. Ann Intern Med. 1967 Feb. 66(2):301-6. [Medline].
Ebaugh FG, McIntyre OR. Palpable spleens: ten-year follow-up. Ann Intern Med. 1979 Jan. 90(1):130-1. [Medline].
Ancliff P, Hann I. Splenomegaly. Sills RH, ed. Practical Algorithms in Pediatric Hematology and Oncology. Basel, Switzerland: Karger; 2003. 50-1.
Genton B, al-Yaman F, Beck HP, et al. The epidemiology of malaria in the Wosera area, East Sepik Province, Papua New Guinea, in preparation for vaccine trials. I. Malariometric indices and immunity. Ann Trop Med Parasitol. 1995 Aug. 89(4):359-76. [Medline].
Pitney WR. The tropical splenomegaly syndrome. Trans R Soc Trop Med Hyg. 1968. 62(5):717-28. [Medline].
Farley DR, Zietlow SP, Bannon MP, Farnell MB. Spontaneous rupture of the spleen due to infectious mononucleosis. Mayo Clin Proc. 1992 Sep. 67(9):846-53. [Medline].
Castagnola E, Fioredda F. Prevention of life-threatening infections due to encapsulated bacteria in children with hyposplenia or asplenia: a brief review of current recommendations for practical purposes. Eur J Haematol. 2003 Nov. 71(5):319-26. [Medline].
Price VE, Dutta S, Blanchette VS, Butchart S, Kirby M, Langer JC, et al. The prevention and treatment of bacterial infections in children with asplenia or hyposplenia: practice considerations at the Hospital for Sick Children, Toronto. Pediatr Blood Cancer. 2006 May 1. 46(5):597-603. [Medline].
Wilson DB. Acquired platelet defects. Nathan DG, Orkin SH, Ginsburg D, Look AT. Nathan and Oski's hematology of infancy and childhood. 6th ed. Philadelphia, PA: WB Saunders; 2003. Vol 2: 1599.
Peck-Radosavljevic M. Hypersplenism. Eur J Gastroenterol Hepatol. 2001 Apr. 13(4):317-23. [Medline].
Sarin SK, Kapoor D. Non-cirrhotic portal fibrosis: current concepts and management. J Gastroenterol Hepatol. 2002 May. 17(5):526-34. [Medline].
Tunnessen WW Jr. Splenomegaly. Roberts K, Tunnessen W, eds. Signs and Symptoms in Pediatrics. 3rd ed. Philadelphia, PA: Lippincott Williams and Wilkins; 1999. 475-83.
Baris HN, Cohen IJ, Mistry PK. Gaucher disease: the metabolic defect, pathophysiology, phenotypes and natural history. Pediatr Endocrinol Rev. 2014 Sep. 12 Suppl 1:72-81. [Medline].
Nixon RK Jr. The detection of splenomegaly by percussion. N Engl J Med. 1954 Jan 28. 250(4):166-7. [Medline].
Castell DO. The spleen percussion sign. A useful diagnostic technique. Ann Intern Med. 1967 Dec. 67(6):1265-7. [Medline].
Grover SA, Barkun AN, Sackett DL. The rational clinical examination. Does this patient have splenomegaly?. JAMA. 1993 Nov 10. 270(18):2218-21. [Medline].
Pochedly C, Sills RH, Schwartz AD, eds. Disorders of the Spleen: Pathophysiology and Management. New York, NY: Marcel Dekker; 1989.
Kinney TR, Ware RE, Schultz WH, Filston HC. Long-term management of splenic sequestration in children with sickle cell disease. J Pediatr. 1990 Aug. 117(2 Pt 1):194-9. [Medline].
Robertson F, Leander P, Ekberg O. Radiology of the spleen. Eur Radiol. 2001. 11(1):80-95. [Medline].
Schlesinger AE, Hildebolt CF, Siegel MJ, Pilgrim TK. Splenic volume in children: simplified estimation at CT. Radiology. 1994 Nov. 193(2):578-80. [Medline].
Ginzel AW, Kransdorf MJ, Peterson JJ, Garner HW, Murphey MD. Mass-like extramedullary hematopoiesis: imaging features. Skeletal Radiol. 2011 Nov 20. [Medline].
AAP. Immunocompromised children. Pickering LK, ed. Red Book: 2003 Report of the Committee on Infectious Diseases. 26th ed. Elk Grove, IL: American Academy of Pediatrics; 2003. 69-81.
Lane PA. The spleen in children. Curr Opin Pediatr. 1995 Feb. 7(1):36-41. [Medline].
Rice HE, Oldham KT, Hillery CA, Skinner MA, O'Hara SM, Ware RE. Clinical and hematologic benefits of partial splenectomy for congenital hemolytic anemias in children. Ann Surg. 2003 Feb. 237(2):281-8. [Medline].
Ahad S, Gonczy C, Advani V, Markwell S, Hassan I. True benefit or selection bias: an analysis of laparoscopic versus open splenectomy from the ACS-NSQIP. Surg Endosc. 2013 Jan 26. [Medline].
Hassan ME, Al Ali K. Massive splenomegaly in children: laparoscopic versus open splenectomy. JSLS. 2014 Jul-Sep. 18 (3):[Medline].
Li S, Li M, Xu W, Sun C, Liu L. Single-Incision Laparoscopic Splenectomy Using the Suture Suspension Technique for Splenomegaly in Children with Hereditary Spherocytosis. J Laparoendosc Adv Surg Tech A. 2015 Sep. 25 (9):770-4. [Medline].
Eichner ER. Sports medicine pearls and pitfalls--defending the spleen: return to play after infectious mononucleosis. Curr Sports Med Rep. 2007 Apr. 6(2):68-9. [Medline].
Rice SG; American Academy of Pediatrics Council on Sports Medicine and Fitness. Medical conditions affecting sports participation. Pediatrics. 2008 Apr. 121(4):841-8. [Medline].
Goddard SL, Chesney AE, Reis MD, et al. Pathological splenic rupture: a rare complication of chronic myelomonocytic leukemia. Am J Hematol. 2007 May. 82(5):405-8. [Medline].
Jandl JH, Aster RH. Increased splenic pooling and the pathogenesis of hypersplenism. Am J Med Sci. 1967 Apr. 253(4):383-98. [Medline].
Goodman J, Newman MI, Chapman WC. Disorders of the spleen. Greer JP, Foerster J, Lukens J, et al, eds. Wintrobe's Clinical Hematology. 11th ed. Philadelphia, Pa: Lippincott Williams and Wilkins; 2004. 1893-909.
Shurin SB. Splenomegaly. Kliegman R, Nieder M, Super D, et al, eds. Practical Strategies in Pediatric Diagnosis and Therapy. Philadelphia, PA: WB Saunders; 1996. 352-9.