Pediatric Splenomegaly

Updated: Dec 30, 2020
  • Author: Trisha Simone Natanya Tavares, MD; Chief Editor: Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP  more...
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Overview

Practice Essentials

The diagnostic criteria for splenomegaly are not clearly defined. Not only is there is no consensus on the upper limit of normal size, but splenic size varies with age, geographic origin, and body size. [1]

The ability to palpate a child’s spleen is not always an abnormal finding. Approximately 10% of normal, healthy children have a palpable spleen, with this percentage being even higher in newborns without respect to gender or gestational age. [2]

Splenomegaly decreases in frequency with age because the ratio of the splenic volume to the abdominal volume reduces over time. [3]

A normal-sized spleen may also become palpable if pulmonary pathology results in hyperinflation of the lungs or if the spleen undergoes displacement due to intra-abdominal pathology; this condition is called pseudo-splenomegaly. [4]

In a child whose spleen is palpable without underlying disease, the organ will be elastic, soft, porous, homogenous, nontender, and less than 2 cm inferior to the left costal margin. There will be no palpable projections in a palpable but otherwise normal spleen. [5]

However, any abnormal splenic characteristic that can be palpated on physical examination should prompt further evaluation. A detailed history and physical examination should be performed; this should include a detailed family history and a comprehensive past medical history, with a review of all systems. Abnormal splenic enlargement is frequently accompanied by signs or symptoms that indicate the underlying etiology. 

History in pediatric splenomegaly

Identify any family history of splenectomy, blood transfusion, cholecystectomy, jaundice, known hematologic disorders, or known heritable disorders. Ancestry and ethnic origin should also be determined.

Patient history should include all known medical conditions (including those that are intermittent, resolved, or mild), such as cardiac, neurologic, gastrointestinal, infectious, metabolic, oncologic, and developmental.

The following should also be determined:

  • Perinatal complications and maternal pregnancy complications
  • Medication history, including use of over-the-counter and supplemental/alternative/naturopathic medications
  • History of abdominal and other trauma
  • Surgical history
  • History of anemia, jaundice, pallor, and transfusions
  • Exposure history, including sexual history, travel history, substance use, dietary history, and medication history

Signs and symptoms of pediatric splenomegaly

Complaints and examination findings will depend entirely on the underlying etiology. Determine the chronicity of symptoms. Some patients may present with the following:

  • Failure to thrive, weight loss, malaise, lethargy, night sweats
  • Feeding difficulties
  • Developmental or neurologic abnormalities
  • Infections
  • Abnormal stooling patterns, early satiety, nausea, vomiting, abdominal pain, or other gastrointestinal changes
  • Musculoskeletal abnormalities, including pain, limited range of motion, arthritis, arthralgia, or abnormal bone development
  • Pruritus, pallor, icterus, exanthem, or enanthem
  • Abnormal vital signs
  • Ophthalmologic abnormalities (uveitis, iritis, vascular occlusion, opacification)
  • Abnormal heart sounds
  • Dyspnea, abnormal breath sounds
  • Hepatomegaly, abdominal masses or tenderness

Workup in pediatric splenomegaly

Splenomegaly is usually the result of a systemic disorder rather than primary splenic disease. Therefore, diagnostic studies are not directed solely towards the spleen. Instead, the goal of testing should be to evaluate any abnormal findings detected during the history or physical examination. 

The most useful initial laboratory test is the complete blood count (CBC) with manual differential and peripheral blood smear. This test should be performed on all patients with an enlarged spleen.

Assessment of transaminase levels and other examinations of hepatobiliary function may be indicated. Additional diagnostic studies will depend on the patient presentation and should be tailored to each individual.

Imaging is not required for all children who are being evaluated for splenomegaly. If imaging is performed, ultrasonography is recommended; this modality can be used to measure splenic dimensions and show splenic architecture. Ultrasonography will also rule out the presence of space-occupying lesions and will provide information about other intra-abdominal organs. 

Computed tomography (CT) scanning and magnetic resonance imaging (MRI) of the left upper quadrant can help in further evaluating splenic parenchymal architecture, and can be used in defining splenic size and shape. [6, 7] These imaging modalities are, however, rarely indicated. Ultrasonography alone is the most appropriate means of imaging the spleen in pediatric patients, since it is noninvasive and does not employ ionizing radiation; moreover, it lacks radiographic magnification, and patients are not subject to the osmotic side effects of iodinated contrast. In addition to being safe, ultrasonography displays real-time images and is easily repeated, with no anesthesia required. [1]

CT scanning or MRI should be used only if there is a clear need for additional imaging detail that cannot be provided by ultrasonography. Emitting gamma radiation, technetium-99m (99mTc) sulfur colloid can be used to examine the reticuloendothelial system via scintillation scanning; moreover, it is the only test that provides functional information about the spleen. It is not indicated in routine evaluation of splenomegaly. [8]

Management

Because splenomegaly is usually the result of a systemic disease, the primary goal is treatment of the underlying process.  

Splenectomy

If the patient meets the appropriate criteria, splenectomy may be offered. Careful evaluation and planning are required prior to surgical removal of a child’s spleen. 

Hemolytic conditions and space-occupying lesions are the most common diagnoses behind splenectomy in children.

Splenectomy for hemolytic conditions

Some hemolytic conditions with severe manifestations will require splenectomy. Appropriate evaluation of the patient’s history and laboratory findings is key.

In general, patients should be offered splenectomy only if there is severe transfusion-dependent anemia  or symptomatic splenomegaly. Consult a hematologist to determine disease-specific guidelines for splenectomy. Stomatocytosis is a definitive contraindication for splenectomy due to the risk of thromboembolic complications. [9]

Sickle hemoglobinopathies may result in splenectomy if the patient meets specific criteria such as repeated or severe sequestration episodes. Conservative management is sometimes effective, however, so the decision to remove the spleen should be based on the individual child’s risk. Some children with hematologic conditions that are being treated with splenectomy should also undergo cholecystectomy at the same time as spleen removal. [10, 11]

Splenectomy for splenic lesions

Because the definition and grading of splenomegaly in children is not standardized, surgical management is not standardized either. Accurate evaluation of the spleen size and configuration is key to planning the surgical procedure. Furthermore, the benefit-to-risk ratio must be carefully determined if splenectomy is considered. Partial spleen removal may be an option. [12, 13, 14, 15] Minimally invasive techniques are preferred in splenectomy in children but require pediatric-specific instruments and protocols. [3, 16]

Splenic lesions such as cysts, abscesses, and hematomas are a common indication for splenectomy. [17]

Postsurgical complications of splenectomy

Splenectomy has been found to result in increased risk for several conditions, including stroke, pulmonary hypertension, arrhythmia, and myocardial infarction. [18, 19]

The most closely correlated adverse effect of pediatric splenectomy is infection, with all persons without normal splenic function being at increased risk for infections and children being at higher risk than adults. Infection risk is greatest during the first few years after spleen removal. [20, 21]

The risk of infection from the gram-negative organisms Capnocytophagacanimorsus and Bordetellaholmesii is particularly increased. Asplenic patients also have greater susceptibility to infection from intra-erythrocytic parasites and encapsulated bacteria. 

Overwhelming post-splenectomy infection (OPSI) syndrome is rare but may be fatal. A syndrome of fulminant sepsis occurring in asplenic or hyposplenic individuals, the condition is associated with high mortality and morbidity. Poorly opsonized bacteria such as encapsulated bacteria are the most common infectious organisms causing OPSI. Early signs of OPSI may be mild and nonspecific.

Because patients without functional spleens are immunocompromised, appropriately timed vaccination must be performed to reduce the risk of post-splenectomy infection.

Asplenic patients must also undergo urgent clinical evaluation whenever they have any signs or symptoms that are suggestive of infection. The nature and duration of any antimicrobial prophylaxis should be individually determined for each post-splenectomy patient based on diagnosis, age, exposures, and other factors that modify risk. [22, 20]

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Pathophysiology

Anatomy

The spleen is the largest lymphoid organ in the body. Although these data are controversial, Rosenberg et al proposed that normal splenic lengths should be no greater than the following [23] :

  • 6.0 cm at age 3 months
  • 6.5 cm at age 6 months
  • 7.0 cm at age 12 months
  • 8.0 cm at age 2 years
  • 9.0 at age 4 years
  • 9.5 cm at age 6 years
  • 10.0 cm at age 8 years
  • 11.0 cm at age 10 years
  • 11.5 cm at age 12 years
  • 12.0 cm at age 15 years or older (females);13.0 cm at age 15 years or older (males)

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. The MPS delivers antigens to the immune system; originally called the reticuloendothelial system, the MPS 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. [24]

The splenic tissue consists of red and white pulp contained in a capsule. Blood enters the spleen through the splenic artery, a branch of the celiac artery, and then travels into the smaller arterioles, approaching 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 hemo-concentrated 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 the spleen 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, with this delay providing 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. This is clinically significant in patients with portal hypertension.

Function

One of the primary functions of the spleen is the filtration of defective blood cells. Erythrocytes slowly pass through the hypoxic and acidotic environment of the splenic cords and squeeze through narrow slits into the sinusoids. Although normal erythrocytes readily accomplish this passage, aged or abnormal red cells, such as spherocytes and sickle cells, remain in the spleen to be ingested by the macrophages lining the cords. [25]

In addition, Fc receptors on splenic macrophages bind to immunoglobulin G (IgG) antibody–coated erythrocytes or IgG antibody–coated platelets, which are subsequently 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 if the bone marrow is unable to meet demands. The production of blood cells by the spleen is referred to as extramedullary hematopoiesis. [26]

In addition, the spleen is critical for removing circulating bacteria. The amorphous polysaccharide coat of encapsulated bacteria greatly impairs their clearance in the absence of antibody, and only the spleen's phagocytic cords can effectively clear encapsulated organisms.

The splenic white pulp processes intravenous antigens and produces antibody that, during subsequent exposures, permits efficient bacterial clearance by the rest of the MPS. [26]

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Epidemiology

Frequency

United States

A 1- to 2-cm splenic tip is palpable in approximately 30% of full-term neonates and in as many as 10% of healthy children overall. [3] A 1967 study found that approximately 3% of healthy college freshmen had palpable spleens, with initial and follow-up research confirming that the students within this subgroup were not at increased risk for subsequent serious disease. [27, 28]

International

Due to the varying incidence of infections that cause splenomegaly, the prevalence of the condition in children differs by geographical region.

Malaria, schistosomiasis, and other infections in endemic areas are frequent causes of splenomegaly. [29, 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%. [30] Such hyperendemic areas may have a prevalence of massive splenomegaly (hyper-reactive malarial splenomegaly) of 1-2% in children. [31]

Mortality/Morbidity

Splenic rupture

Splenic rupture may occur in acute splenomegaly associated with infectious mononucleosis. The incidence is approximately 1:1000, and it usually occurs in the first 3 weeks of illness. [32] The American Academy of Pediatrics Council on Sports Medicine and Fitness has recommended that children with acute splenomegaly restrict their participation in sports. [33] Disorders associated with chronic splenomegaly do not result in the same level of splenic friability and risk of rupture as disorders that cause acute splenomegaly. [34, 35] Spleens are also prone to rupture if they contain infected tissue, malignant cells, hematomas, or other space-occupying lesions. [36, 37]

Hypersplenism

Hypersplenism is the occurrence of (most commonly) thrombocytopenia, and occasionally leukopenia and anemia, in the context of significant splenomegaly. The thrombocytopenia is usually mild but is variable. In liver cirrhosis, the underlying mechanism may involve mechanical pooling and cytokine effects changes.

A clinical syndrome resulting from excess splenic function, hypersplenism occurs as the spleen’s MPS tissues hypertrophy. The reduction of circulating blood elements has been attributed to several possible mechanisms: excessive splenic phagocytic activity, splenic antibody formation that causes hematopoietic cell destruction, increased activity of normal splenic function, and sequestration of blood cells.

Venous obstruction is the most common cause of hypersplenism. Any increase in portal pressure is reflected in the splenic venous sinuses. This impairs blood flow out of the cords and results in the sequestration of blood cells and hypersplenism. Hypersplenism in children is most often the result of portal hypertension. Extrahepatic venous obstruction from portal vein thrombosis is the most frequently identified cause of increased portal pressures. Hepatic function will be normal in extrahepatic venous obstruction. Intrahepatic obstruction is typically due to cirrhosis. In addition to splenomegaly on examination, patients with portal hypertension may have caput medusae (dilated veins surrounding the umbilicus), edema, and/or gynecomastia. [38, 39, 40, 9]

Cytopenias in hypersplenism contribute to overall morbidity. The cytopenias are usually mild but may be severe and symptomatic. Thrombocytopenia is the most common abnormality. In hepatic cirrhosis, the underlying mechanism may include mechanical pooling and cytokine effect.

Race

There is an indirect relationship between splenomegaly and ethnic origin. Specific causes of splenomegaly have differing frequency in various racial groups. Examples include splenic sequestration as a complication of sickle cell disease in patients of African, West Asian, Southeast Asian, or Mediterranean ancestry and non-cirrhotic portal fibrosis in patients of Iranian, South Asian, or Japanese ancestry. [41] Pyruvate kinase deficiency is seen with increased frequency in some Amish communities and in several European regions. [42]  

Age

The etiology of splenomegaly varies with age due to auxologic factors and as a result of differing infection rates in relation to age group.

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Prognosis

The prognosis of splenic enlargement depends on the etiology and severity and the risks of side effects from therapy.

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Patient Education

For non-pathologic enlargement of the spleen, reassurance of the family is sufficient. However, disease-specific education should be provided to patients who have pathologic splenomegaly. Some patients must be advised to avoid splenic trauma. Selected individuals will need to undergo self-examination (or parental examination) of the spleen to monitor for changes in size that may suggest sequestration or other complications. All patients with an absent spleen or with reduced splenic function should be carefully educated about the risks of infection and the need for vaccination. They must also understand the indications for clinical evaluation and must be prepared to obtain urgent medical attention when there are concerning signs or symptoms.

Risks of traumatic rupture of a large and/or fragile spleen must also be discussed. Other education depends on the specific etiology of the splenomegaly and the potential side effects of the prescribed treatment.

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