Hypersplenism

Causes

Hypersplenism may be idiopathic (primary) or secondary to an extrasplenic disorder, such as chronic malaria, polycythemia vera, and rheumatoid arthritis. In hypersplenism, the spleen's normal filtering and phagocytic functions accelerate indiscriminately, automatically removing antibody-coated, aging, and abnormal cells, even though some cells may be functionally normal.

The spleen may also temporarily sequester normal platelets and red blood cells (RBCs), withholding them from circulation. In this manner, the enlarged spleen may trap as much as 90% of the body's platelets and up to 45% of its RBC mass.

Signs and symptoms

Most patients with hypersplenism develop anemia, leukopenia, or thrombocytopenia, often with splenomegaly. They may contract frequent bacterial infections, bruise easily, hemorrhage spontaneously from the mucous membranes and GI or genitourinary tract, and suffer ulcerations of the mouth, legs, and feet. They commonly develop fever, weakness, and palpitations.

Patients with secondary hypersplenism may have other clinical abnormalities, depending on the underlying disease.

Diagnosis

Splenomegaly and evidence of abnormal splenic destruction or sequestration of RBCs or platelets are necessary to diagnose hypersplenism.

• The most definitive test measures the accumulation of erythrocytes in the spleen and liver after LV. infusion of chromium-labeled RBCs or platelets. A high spleen-to-Iiver ratio of radioactivity indicates splenic destruction or sequestration.
• Complete blood count shows a decreased hemoglobin level (as low as 4 g/ dl), white blood cell count « 4,000/u1), platelet count « 125,000/u1), and reticulocyte count.
• Splenic biopsy, scan, and angiography may be useful; a biopsy is hazardous, however, and should be avoided if possible.

Treatment

Splenectomy is indicated only in transfusion-dependent patients who are refractory to medical therapy. Splenectomy seldom cures the patient but does correct the effects of cytopenia.

Postoperative complications include infection and thromboembolic disease. Occasionally, splenectomy may result in accelerated blood cell destruction in he bone marrow and liver. Secondary hypersplenism necessitates treatment of the underlying disease.

Prevention

Some of the underlying causes of hypersplenism or enlarged spleen can be prevented, such as certain forms of anemia and cirrhosis of the liver due to alcohol. In other cases, the hypersplenism may not be preventable, as it is a complication to an underlying disorder.