Updated: Sep 4, 2008
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
Anatomy
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.2
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.
Function
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.3
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.4,5,1
Malaria, schistosomiasis, and other infections in endemic areas are frequent causes of splenomegaly.6
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%.7 Such hyperendemic areas have a prevalence of massive splenomegaly (hyperreactive malarial splenomegaly) of 1-2% in children.8
Splenic rupture may occur in acute splenomegaly associated with infectious mononucleosis. The incidence is 1:1000, and it usually occurs in the first 3 weeks of illness.9
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.10,11
Hypersplenism is the occurrence of thrombocytopenia, and occasionally leukopenia and anemia, in the context of significant splenomegaly.12 The cytopenias are usually mild but may contribute to overall morbidity.13
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.14
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.
Despite the extensive differential diagnoses of splenomegaly, careful history taking and physical examination, along with a CBC count and liver function tests, often help in narrowing the list of possible causes. The history should include attention to the following important areas, as listed below.15
The patient should be examined in the supine or right lateral decubitus position. The spleen is best palpated with the clinician kneeling on the patient's right side and by palpating the left upper quadrant of the abdomen with the right hand.
Palpation should start just above the pubis and move toward the left upper quadrant to find the medial border of the spleen. The examiner usually palpates the spleen by feeling its inferolateral margins. If the enlarged tip of the spleen is below the examiner's hands, he or she often misses it. Likewise, light pressure should be used with small children, because the spleen can easily be pushed out of the way without the clinician feeling its edge. At times, the superior medial edge of the spleen is more readily palpated than the inferior margin.
Percussion over the left lateral areas of the lower ribs may reveal splenomegaly that is not evident upon palpation.16,17,18 This procedure is particularly helpful in a crying child in whom splenic palpation is difficult. It is similarly helpful in children and adolescents who are obese. A normal-sized liver and spleen may also become palpable if pulmonary pathology is causing hyperinflation of the lungs (pseudosplenomegaly). The spleen is occasionally confused with the left lobe of the liver or with a tumor in the left upper quadrant (eg, Wilms tumor, neuroblastoma). The characteristic downward movement of the spleen with inspiration and its relatively flat surface and shape can help in differentiating it from other masses of the left upper quadrant. Important features on physical examination are as follows:15
Despite the numerous causes of splenomegaly (see Differentials), the spleen is rarely the primary site of disease.
| Acute Lymphoblastic Leukemia | Juvenile Rheumatoid Arthritis |
| Acute Myelocytic Leukemia | Malaria |
| Chronic Granulomatous Disease | Myelofibrosis |
| Coccidioidomycosis | Neuroblastoma |
| Cytomegalovirus Infection | Pneumonia |
| Endocarditis, Bacterial | Salmonella Infection |
| Gaucher Disease | Sarcoidosis |
| Heart Failure, Congestive | Serum Sickness |
| Hepatitis B | Sickle Cell Anemia |
| Hepatitis C | Syphilis |
| Histiocytosis | Systemic Lupus Erythematosus |
| Histoplasmosis | Toxoplasmosis |
| Hodgkin Disease | Tropical Splenomegaly Syndrome |
| Human Immunodeficiency Virus Infection | Tuberculosis |
Hepatitic cirrhosis
Portal hypertension
Cavernous transformation of the portal vein
Chronic myelocytic leukemia
Hereditary spherocytosis
Autoimmune hemolytic anemia
Chediak-Higashi syndrome
Immunodeficiency disorders
Niemann-Pick disease
Lipid storage diseases
Langerhans cell histiocytosis
Hematomas
Pseudocysts
Because splenomegaly is usually the result of a systemic disease, the primary goal is treatment of the underlying process. In certain circumstances, splenectomy may be the therapy of choice for symptoms or complications caused by the enlarged organ. However, because of the risk of overwhelming sepsis in children who are asplenic, the risks and benefits must be carefully weighed when splenectomy is being considered.10,11
Splenic trauma is the most common indication for splenectomy, although attempts at splenic preservation are increasingly important. Nonsurgical management for splenic trauma has success rates of 52-98%, with failure usually occurring in the first 96 hours. Splenic cysts, tumors, and vascular lesions may also require surgical removal. Whenever possible, splenic tissue is preserved to decrease the risk of septicemia, but total splenectomy is occasionally necessary.24,25
A pediatric hematologist and/or oncologist is the usual consultant when the cause of splenomegaly is not obvious or when a primary hematologic or oncologic disorder is suspected.
The choice of therapy depends on the specific etiology of the splenomegaly.
Active immunization increases resistance to infection. Vaccines consist of microorganisms or cellular components, which act as antigens. Administration of the vaccine stimulates the production of antibodies with specific protective properties.
With the increased problem of penicillin resistance in S pneumoniae, prevention by using the conjugated pneumococcal vaccine in children or by using the unconjugated 23-valent pneumococcal vaccine in adults is mandatory. Likewise, immunizations with the conjugated H influenzae type B and meningococcal A and C vaccines are essential. Vaccines are administered at least 10 days before splenectomy.
Sterile solution of saccharides of capsular antigens of S pneumoniae serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F individually conjugated to diphtheria CRM197 protein. These 7 serotypes responsible for >80% of invasive pneumococcal disease in children <6 y in the United States and account for 74% of penicillin-nonsusceptible S pneumoniae (PNSP) and 100% of pneumococci with high-level penicillin resistance.
Customary age for first dose is 2 mo, but can be administered as young as 6 wk. Preferred sites for IM injection are anterolateral aspect of thigh in infants or deltoid muscle of upper arm in toddlers and young children. Do not inject in gluteal area or areas with a major nerve trunk or blood vessel.
Number of 0.5-mL doses is 3 for infants aged 7-11 mo (4 wk apart; third dose after first birthday), 2 for those aged 12-23 mo (2 mo apart), and 1 for those aged 2-5 y.
Minor illnesses (eg, mild upper respiratory tract infection with or without low-grade fever) are not generally contraindications.
Not established
0.5 mL IM; 3 doses q2mo; fourth dose of 0.5 mL at 12-15 mo of age, or at 2 mo or later after third dose; recommended dosing interval is 4-8 wk
Immunosuppressive agents (immunosuppressive doses of corticosteroids, antimetabolites, alkylating agents, cytotoxic agents) may decrease effects; may increase effects of anticoagulant therapy; globulin preparations may interfere with immune response and reduce efficacy (do not administer within 3 mo of vaccination)
Documented hypersensitivity to any component or diphtheria toxoid; severe or moderate febrile illness; thrombocytopenia or coagulation disorder contraindicating IM injection (unless benefits outweigh risks)
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
For IM use only, do not administer IV under any circumstances; take special care to prevent injection into or near blood vessel or nerve; caution in patients with possible history of latex sensitivity (packaging contains dry natural rubber); does not replace 23-valent pneumococcal polysaccharide vaccination in children >24 mo of age with sickle cell disease, asplenia, HIV infection, chronic illness, or those who are immunocompromised; caution in coagulation disorders
Polyvalent vaccine used for prophylaxis against infection from S pneumoniae. Used in populations at increased risk of pneumococcal pneumonia (ie, >55 y, chronic infection, asplenia, immunocompromise).
0.5 mL IM/SC once
<2 years: Contraindicated (antibody response poor in this age group)
>2 years: 0.5 mL IM/SC; repeat dose after 3-5 y in high-risk children (eg, those with functional or anatomic asplenia or conditions associated with rapid antibody decline after initial vaccination)
Immunosuppressive agents (eg, large amounts of corticosteroids, antimetabolites, alkylating agents, cytotoxic agents) may reduce effectiveness; therapy with immunoglobulin preparations likely to block active immunity induced; withhold for 3 mo after discontinuation of immunoglobulin therapy
Documented hypersensitivity to any component or thimerosal; severe or even moderate febrile illness; age <2 y; thrombocytopenia or any coagulation disorder that contraindicates IM injection unless potential benefit clearly outweighs risk
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Arthralgia, fever, urticaria, and Guillain-Barré syndrome (rare)
Capsular polysaccharide antigens (groups A, C, Y, and W-135) of Neisseria meningitidis. For active immunization against invasive meningococcal disease caused by inclusive serogroups. May be used to prevent and control outbreaks of serogroup C meningococcal disease according to Centers for Disease Control and Prevention (CDC) guidelines.
Routine vaccination recommended for high-risk groups (eg, patients with deficiencies in late complement components [C3, C5-C-9], functional or actual asplenia, or laboratory or industrial exposure to N meningitidis aerosols; travelers or residents of hyperendemic areas).
Vaccine induces antibody response for serogroup A in individuals as young as 3 mo, but poorly immunogenic for serogroup C in recipients <18-24 mo.
0.5 mL SC
<2 years: Not established
>2 years: Administer as in adults
Coadministration with whole-cell pertussis or whole-cell typhoid vaccines may increase endotoxin content; immunosuppressive drugs may interfere with immune response
Documented hypersensitivity; acute illness (avoid); IV/IM/ID administration
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Asplenic patients with lymphoid tumors who receive chemotherapy or irradiation respond poorly; for information concerning geographic areas where vaccination is recommended, see the Meningococcal Conjugate Vaccine: ACIP Recommendation page from the CDC Advisory Committee on Immunization Practices (ACIP); spontaneous reports of Guillain-Barré syndrome recently (2005) reported with Menactra
For routine immunization of children against invasive diseases caused by H influenzae type B by decreasing nasopharyngeal colonization. The CDC ACIP recommends that all children receive one of the conjugate vaccines licensed for use in infants beginning routinely at age 2 mo.
Not indicated
Regimens vary depending on product.
Example:
HibTITER:
2-6 months: 0.5 mL IM q2mo for 3 doses
7-11 months: 0.5 mL IM q2mo for 2 doses in previously unvaccinated children
12-14 months: 0.5 mL IM once in previously unvaccinated children
15-71 months: 0.5 mL IM once in previously unvaccinated children
Booster dose: 0.5 mL at age 15 mo or at least 2 mo after last dose of immunization series; booster dose unnecessary in children vaccinated for the first time at age 15-71 mo
Immunoglobulins given within 1 mo or concurrently with immunosuppressants may inhibit full immunologic response
Documented hypersensitivity
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Delay immunization if febrile illness evident; may cause erythema, swelling, or tenderness; cause-and-effect relationship with Guillain-Barré syndrome after vaccination not established
Daily antibiotic prophylaxis with penicillin is recommended to prevent pneumococcal septicemia.
Inhibits biosynthesis of cell-wall mucopeptide. Bactericidal against sensitive organisms when adequate concentrations reached. Most effective during stage of active multiplication. Low concentrations produce bacteriostatic effects.
<5 years: 125 mg PO bid
>5 years: 250 mg PO bid
Probenecid may increase effectiveness by decreasing clearance; tetracyclines are bacteriostatic, decreasing in effectiveness of penicillins when administered concurrently
Documented hypersensitivity
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Caution in renal impairment
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splenomegaly, splenic enlargement, enlarged spleen, palpable spleen, hypersplenism, splenic enlargement, splenectomy, mononuclear-phagocyte system, MPS, malaria, schistosomiasis, hyperreactive malarial splenomegaly, splenic rupture, noncirrhotic portal fibrosis, sickle cell disease, hepatitis, portal hypertension, abdominal trauma, splenic hematoma, diarrhea, salmonellosis, leukemia, Hodgkin disease, jaundice, sepsis, hypotension, umbilical catheter thrombosis, anemia, leishmaniasis, trypanosomiasis, splenic pseudocyst, cytomegalovirus, human immunodeficiency virus, HIV, hemolytic anemia–associated gallstones, hemolytic anemia, thalassemia, glucose-6-phosphate dehydrogenase deficiency, G6PD deficiency, hereditary pyropoikilocytosis, pyruvate kinase deficiency, hereditary spherocytosis
Mundeep K Kainth, DO, Resident Physician, Department of Pediatrics, The Children's Hospital at Albany Medical Center
Mundeep K Kainth, DO is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.
Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP, Associate Professor of Pediatric Hematology-Oncology, Department of Pediatrics, Albany Medical Center; Faculty, Alden March Bioethics Institute
Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP is a member of the following medical societies: American Academy of Pediatrics, American Society of Pediatric Hematology/Oncology, Children's Oncology Group, and Royal College of Physicians of the United Kingdom
Disclosure: Nothing to disclose.
Richard H Sills, MD, Professor of Pediatrics, Upstate Medical University
Richard H Sills, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Society of Hematology, and American Society of Pediatric Hematology/Oncology
Disclosure: Nothing to disclose.
J Martin Johnston, MD, Associate Professor of Pediatrics, Mercer University School of Medicine; Director of Pediatric Hematology/Oncology, Backus Children's Hospital; Consulting Oncologist/Hematologist, St Damien's Pediatric Hospital
J Martin Johnston, MD is a member of the following medical societies: American Society of Pediatric Hematology/Oncology and Idaho Medical Association
Disclosure: Nothing to disclose.
Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation
James L Harper, MD, Associate Professor, Department of Pediatrics, Division of Hematology/Oncology and Bone Marrow Transplantation, Associate Chairman for Education, Department of Pediatrics, University of Nebraska Medical Center; Assistant Clinical Professor, Department of Pediatrics, Creighton University; Director, Continuing Medical Education, Children's Memorial Hospital; Pediatric Director, Nebraska Regional Hemophilia Treatment Center
James L Harper, MD is a member of the following medical societies: American Academy of Pediatrics, American Association for Cancer Research, American Federation for Clinical Research, American Society of Hematology, American Society of Pediatric Hematology/Oncology, Council on Medical Student Education in Pediatrics, and Hemophilia and Thrombosis Research Society
Disclosure: Nothing to disclose.
Helen SL Chan, MBBS, FRCP(C), FAAP, Senior Scientist, Research Institute; Professor, Division of Hematology/Oncology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Canada
Helen SL Chan, MBBS, FRCP(C), FAAP is a member of the following medical societies: American Academy of Pediatrics, American Association for Cancer Research, American Society of Hematology, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.
Robert J Arceci, MD, PhD, King Fahd Professor of Pediatric Oncology, Department of Oncology, Division of Pediatric Oncology, Johns Hopkins University School of Medicine
Robert J Arceci, MD, PhD is a member of the following medical societies: American Association for Cancer Research, American Association for the Advancement of Science, American Pediatric Society, American Society of Hematology, and American Society of Pediatric Hematology/Oncology
Disclosure: Nothing to disclose.