My German shepherd recently seems lethargic and to have lost his appetite. He also appears weak and listless. My veterinarian examined him and scheduled some tests. The doctor told me my dog had splenomegaly. What is this? What could be wrong with my dog?
Splenomegaly is enlargement of the spleen. It is not a disease; rather it is a clinical sign associated with an underlying disease process or disorder. There are many underlying problems that may cause splenomegaly.
The spleen has a number of functions. These include removing old or damaged red blood cells and cell fragments from the bloodstream; providing a reservoir for phagocytes that remove bacteria from the blood; acting as a storehouse for blood; supporting antibody synthesis; and producing red blood cells when the bone marrow fails to produce a sufficient amount. Diseases and disorders that directly or indirectly affect any of these functions may contribute to splenomegaly.
There are many causes of splenomegaly. Systemic bacterial, fungal, and parasitic infections affecting other organs and tissues may affect the spleen as well and cause splenic enlargement. Diseases that cause destruction of red or white blood cells or platelets and the resulting anemia, leukopenia, and thrombocytopenia, respectively, may, by a variety of pathophysiologic mechanisms, cause splenomegaly. Processes that cause portal hypertension (high blood pressure in the venous system of the liver) and congestive heart failure may lead to splenic congestion and enlargement. Bleeding and hematoma formation (bruising) in the spleen can enlarge it. Tumors such as hemangioma and hemangiosarcoma, a common malignancy, can lead to splenomegaly. Some primary problems of the spleen, such as splenic torsion, may cause it as well.
Diagnosis of the underlying problem will require a physical examination, bloodwork (complete blood count, microscopic analysis of a sample of blood cells, urinalysis, and blood chemistry), and possibly radiographs (x-rays), and ultrasonography. In some cases a fine-needle aspirate cytoanalysis (microscopic cell study) or surgical biopsy of the spleen will be necessary.
Treatment is directed at the underlying disease process. Splenectomy (surgical removal of the spleen) may be performed if the benefit of doing so outweighs the disadvantages. Animals without spleens may have more infections and a more difficult time fighting them off. However, an animal with splenic hemangiosarcoma, a malignant cancer, would obviously benefit from having a splenectomy. Splenectomy is routinely performed when cancer is suspected to minimize complications and to limit the entry of tumor cells into the circulation.
You need to communicate closely with your veterinarian about your dog's ultimate diagnosis and treatment.
10/23/00
