Splenomegaly

Splenomegaly is almost always secondary to other diseases, of which there are many, as well as possible ways to classify them.

Myeloproliferative and lymphoproliferative diseases, storage diseases (eg, Gaucher disease), and connective tissue diseases are the most common causes of splenomegaly in temperate climates, whereas infectious diseases (eg, malaria, kala-azar) predominate in the tropics.

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Causes of splenomegaly

The following diseases are usually the cause of pronounced splenomegaly ( the spleen is palpated 8 cm below the costal arch): chronic lymphocytic leukemia, non-Hodgkin's lymphoma, chronic myelogenous leukemia, true polycythemia, myelofibrosis with myeloid metaplasia, and hairy cell leukemia.

Splenomegaly may lead to cytopenias.

Congestive splenomegaly (Banti disease)

• Cirrhosis.
• External compression or thrombosis of the portal or splenic vein.
• Certain disorders of vascular development

Infectious or inflammatory diseases

• Acute infections (eg, infectious mononucleosis, infectious hepatitis, subacute bacterial endocarditis, psittacosis).
• Chronic infections (eg, miliary tuberculosis, malaria, brucellosis, Indian visceral leishmaniasis, syphilis).
• Sarcoidosis.
• Amyloidosis.
• Connective tissue diseases (eg, SLE, Felty's syndrome)

Myeloproliferative and lymphoproliferative diseases

• Myelofibrosis with myeloid metaplasia.
• Lymphomas (eg, Hodgkin's lymphoma).
• Leukemias, especially chronic lymphocytic leukemia and chronic myelogenous leukemia.
• Polycythemia vera.
• Essential thrombocythemia

Chronic, usually congenital, hemolytic anemias

• Red blood cell shape abnormalities (eg, congenital spherocytosis, congenital elliptocytosis), hemoglobinopathies including thalassemias, sickle cell variant hemoglobin (eg, hemoglobin SC disease), congenital hemolytic anemias of Heinz bodies.
• Red blood cell enzymopathies (eg, pyruvate kinase deficiency)

Storage diseases

• Lipid (for example, Gaucher, Niemann-Pick, Hand-Schüller-Kristscher diseases).
• Non-lipid (eg, Letterer-Siwe disease).
• Amyloidosis

Spleen cyst

• Usually caused by resolution of a previous hematoma

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Symptoms of Splenomegaly

Splenomegaly is a hallmark of hypersplenism; spleen size correlates with the degree of anemia. An increase in spleen size of approximately 2 cm below the costal margin can be expected for every 1 g decrease in hemoglobin. Other clinical features usually depend on the manifestations of the underlying disease; splenic pain is sometimes present. Unless other mechanisms worsen the manifestations of hypersplenism, anemia and other cytopenias are mild and asymptomatic (eg, platelet count 50,000 to 100,000/μL, white blood cell count 2,500 to 4,000/μL with normal leukocyte differentiation). Red blood cell morphology is usually normal, except for rare spherocytosis. Reticulocytosis is common.

Hypersplenism is suspected in patients with splenomegaly, anemia, or cytopenia; diagnosis is similar to that for splenomegaly.

Examination for splenomegaly

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Anamnesis

Most of the symptoms that are detected are due to the underlying disease. However, splenomegaly itself may cause a feeling of rapid satiety due to the effect of the enlarged spleen on the stomach. Feelings of heaviness and pain in the left upper quadrant of the abdomen are possible. Severe pain in the left side suggests the presence of splenic infarction. Recurrent infections, symptoms of anemia, or bleeding manifest the presence of cytopenia and possible hypersplenism.

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Inspection

The sensitivity of palpation and percussion in detecting splenic enlargement is 60-70% and 60-80%, respectively, in cases of ultrasound-documented splenomegaly. Normally, up to 3% of people have a palpable spleen. In addition, a palpable mass in the left upper quadrant may be due to a cause other than an enlarged spleen.

Other additional symptoms include splenic friction rub, suggesting splenic infarction, and epigastric and splenic sounds, which indicate congestive splenomegaly. Generalized adenopathy may suggest myeloproliferative, lymphoproliferative, infectious, or autoimmune disease.

Diagnosis of splenomegaly

When confirmation of splenomegaly is needed in cases of questionable results after a preliminary examination, ultrasound is the method of choice due to its high accuracy and low cost. CT and MRI can provide a more detailed image of the organ. MRI is especially effective in identifying portal thrombosis or splenic vein thrombosis. Radioisotope examination is a highly accurate diagnostic method that can identify additional details of the splenic tissue, but the method is very expensive and difficult to perform.

Specific causes of splenomegaly identified on examination should be confirmed by appropriate investigations. In the absence of an obvious cause for splenomegaly, infection must be ruled out first, since it requires early treatment, unlike other causes of splenomegaly. The investigation should be more comprehensive in areas of high geographic prevalence of infection when the patient has clinical evidence of infection. A complete blood count, blood cultures, and bone marrow examination should be obtained. If the patient is asymptomatic, has no symptoms other than those due to splenomegaly, and has not been at risk for infection, there is no need for extensive investigations other than a complete blood count, peripheral blood smear, liver function tests, abdominal CT, and spleen ultrasound. If lymphoma is suspected, peripheral blood flow cytometry is indicated.

Specific abnormalities in peripheral blood tests may suggest the cause of the lesion (eg, lymphocytosis suggests chronic lymphocytic leukemia, leukocytosis with immature forms suggests other leukemias). Elevated basophils, eosinophils, nucleated red blood cells, or teardrop red blood cells suggest a myeloproliferative disorder. Cytopenia suggests hypersplenism. Spherocytosis suggests hypersplenism or hereditary spherocytosis. Liver function tests will be abnormal in congestive splenomegaly with cirrhosis; isolated elevation of serum alkaline phosphatase suggests possible liver infiltration from a myeloproliferative disorder, lymphoproliferative disorder, or miliary tuberculosis.

Several other studies may be useful even in asymptomatic patients. Serum protein electrophoresis identifies monoclonal gammopathy or decreased immunoglobulins, possible with lymphoproliferative disorders or amyloidosis; diffuse hypergammaglobulinemia suggests chronic infection (eg, malaria, Indian visceral leishmaniasis, brucellosis, tuberculosis), cirrhosis with congestive splenomegaly, or connective tissue disease. Elevated serum uric acid suggests a myeloproliferative or lymphoproliferative disorder. Elevated leukocyte alkaline phosphatase suggests a myeloproliferative disorder, whereas decreased levels suggest chronic myelogenous leukemia.

If the examination does not reveal any abnormalities other than splenomegaly, the patient should be examined again in an interval of 6 to 12 months or if new symptoms appear.

Splenomegaly increases splenic mechanical filtration and destruction of red blood cells, and often white blood cells and platelets. Compensatory bone marrow hyperplasia of those cell lines whose levels are reduced in circulation is evident.

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Treatment of splenomegaly

Treatment of splenomegaly is directed at the underlying disorder. An enlarged spleen does not require treatment unless severe hypersplenism develops. Patients with a palpable or very large spleen should probably avoid contact sports to avoid the risk of rupture.