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Splenomegaly is almost always secondary to other disorders. Its causes are myriad, as are the many possible ways of classifying them (see Table: Common Causes of Splenomegaly*). In temperate climates, the most common causes are
In the tropics, the most common causes are
If splenomegaly is massive (spleen palpable 8 cm below the costal margin), the cause is usually chronic lymphocytic leukemia, non-Hodgkin lymphoma, chronic myelocytic leukemia, polycythemia vera, myelofibrosis with myeloid metaplasia, or hairy cell leukemia.
Splenomegaly can lead to cytopenia (see Hypersplenism).
Most of the presenting symptoms result from the underlying disorder. However, splenomegaly itself may cause early satiety by encroachment of the enlarged spleen on the stomach. Fullness and left upper quadrant abdominal pain are also possible. Severe pain suggests splenic infarction. Recurrent infections, symptoms of anemia, or bleeding manifestations suggest cytopenia and possible hypersplenism.
The sensitivity for detection of ultrasound-documented splenic enlargement is 60 to 70% for palpation and 60 to 80% for percussion. Up to 3% of normal, thin, people have a palpable spleen. Also, a palpable left upper quadrant mass may indicate a problem other than an enlarged spleen.
Other helpful signs include a splenic friction rub that suggests splenic infarction and epigastric and splenic bruits that suggest congestive splenomegaly. Generalized adenopathy may suggest a myeloproliferative, lymphoproliferative, infectious, or autoimmune disorder.
Common Causes of Splenomegaly*
If confirmation of splenomegaly is necessary because the examination is equivocal, ultrasonography is the test of choice because of its accuracy and low cost. CT and MRI may provide more detail of the organ’s consistency. MRI is especially useful in detecting portal or splenic vein thromboses. Nuclear scanning is accurate and can identify accessory splenic tissue but is expensive and cumbersome.
Specific causes suggested clinically should be confirmed by appropriate testing (see elsewhere in The Manual). If no cause is suggested, the highest priority is exclusion of occult infection, because early treatment affects the outcome of infection more than it does most other causes of splenomegaly. Testing should be thorough in areas of high geographic prevalence of infection or if the patient appears to be ill. CBC, blood cultures, and bone marrow examination and culture should be considered. If the patient is not ill, has no symptoms besides those due to splenomegaly, and has no risk factors for infection, the extent of testing is controversial but probably includes CBC, peripheral blood smear, liver function tests, and abdominal CT. Flow cytometry of peripheral blood is indicated if lymphoma is suspected.
Specific peripheral blood findings may suggest underlying disorders (eg, small-cell lymphocytosis in chronic lymphocytic leukemia and large granular lymphocytosis in T-cell granular lymphocyte [TGL] hyperplasia or TGL leukemia; leukocytosis and immature forms in other leukemias). Excessive basophils, eosinophils, or nucleated or teardrop RBCs suggest myeloproliferative disorders. Cytopenias suggest hypersplenism. Spherocytosis suggests hypersplenism or hereditary spherocytosis. Liver function test results are diffusely abnormal in congestive splenomegaly with cirrhosis; an isolated elevation of serum alkaline phosphatase suggests hepatic infiltration, as in myeloproliferative and lymphoproliferative disorders and miliary TB.
Some other tests may be useful, even in asymptomatic patients. Serum protein electrophoresis identifying a monoclonal gammopathy or decreased immunoglobulins suggest lymphoproliferative disorders or amyloidosis; diffuse hypergammaglobulinemia suggests chronic infection (eg, malaria, kala-azar, brucellosis, TB) or cirrhosis with congestive splenomegaly, sarcoidosis, or connective tissue disorders. Elevation of serum uric acid suggests a myeloproliferative or lymphoproliferative disorder. Elevation of WBC alkaline phosphatase suggests a myeloproliferative disorder, whereas decreased levels suggest chronic myelocytic leukemia.
If testing reveals no abnormalities other than splenomegaly, the patient should be reevaluated at intervals of 6 to 12 mo or when new symptoms develop.
Hypersplenism is cytopenia caused by splenomegaly.
Hypersplenism is a secondary process that can arise from splenomegaly of almost any cause (see Table: Common Causes of Splenomegaly*). Splenomegaly increases the spleen’s mechanical filtering and destruction of RBCs and often of WBCs and platelets. Compensatory bone marrow hyperplasia occurs in those cell lines that are reduced in the circulation.
Hypersplenism is suspected in patients with splenomegaly and anemia or cytopenias. Evaluation is similar to that of splenomegaly (see Splenomegaly).
Unless other mechanisms coexist to compound their severity, anemia and other cytopenias are modest and asymptomatic (eg, platelet counts, 50,000 to 100,000/μL; WBC counts, 2500 to 4000/μL with normal WBC differential count). RBC morphology is generally normal except for occasional spherocytosis. Reticulocytosis is usual.
Treatment is directed at the underlying disorder. However, if hypersplenism is the only serious manifestation of the disorder (eg, Gaucher disease), splenic ablation by splenectomy or radiation therapy may be indicated (see Table: Indications for Splenectomy or Radiation Therapy in Hypersplenism). Because the intact spleen protects against serious infections with encapsulated bacteria, splenectomy should be avoided whenever possible, and patients undergoing splenectomy require vaccination against infections caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. After splenectomy, patients are particularly susceptible to severe sepsis and are often given daily prophylactic antibiotics such as penicillin or erythromycin. Patients who develop fever should receive empiric antibiotics.
Indications for Splenectomy or Radiation Therapy in Hypersplenism
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