Sickle-cell anemia, which is inherited as a dominant mendelian characteristic, is found almost exclusively in Negroes, and is the most common primary blood dyscrasia in Negro hospital patients. The sickle-cell trait, or the constitutional tendency of the bone marrow to produce elongated, semilunar erythrocytes, is found in 7.5 per cent of the Negro race. This trait becomes of significance, however, only when the number of abnormal erythrocytes is great enough to cause clinical symptoms. It has been estimated that the ratio of sickle-cell anemia to sickle-cell trait is 1 to 40. Pathology The fundamental pathology of sickle-cell anemia is blood stasis, with congestion and thromboses. It is presumed that the elongation of the erythrocytes makes their passage through capillaries difficult, thus causing stagnation of blood. Widespread and severe blood stasis may occur, these episodes being reflected in the clinical course as crises. The elongated erythrocytes are treated as abnormal cells and destroyed by the body, resulting in the production of an hemolytic anemia of varying severity. The general pathology of sickle-cell anemia is well illustrated by the changes which occur in the spleen. In the early stages, changes are referable to organic congestion with elongated red cells and the lysis of these cells by the reticulo-endothelial system. During acute exacerbations the spleen is enlarged and purplish-red in color. The trabeculae and malpighian follicles are not prominent, but the parenchyma is dark red and velvety. Perivascular hemorrhages are common. Later there is progressive organization of these hemorrhages and of the multiple areas of infarction. With contraction of the newly formed fibrous tissue, the spleen becomes smaller and harder and quite nodular. Eventually it shrinks to an atrophic nodule weighing only a few grams. The changes in the bone are just as remarkable as those in the spleen. Congestion of the bone marrow occurs early, and areas of hemorrhage are common. As the anemia progresses, the bone marrow becomes very hyperplastic. This hyperplastic marrow is not confined to the medullary cavity but extends into the haversian canals as well, giving the bone a honeycombed appearance. Later, as the result of congestion and thrombosis, necrosis, hyalinization, fibrosis, abnormal calcification, and new bone formation occur. The bones with their hyperplastic marrow have considerably less structural strength than normally, with the result that compression deformities appear, such as biconcave deformity of the vertebrae and coxa plana. Any of the organs of the body may be involved in sickle-cell anemia, the changes being congestion, thrombosis, and replacement fibrosis. Symptomatology The basis for this report is a series of 49 cases of active sickle-cell anemia in which radiographic studies were made in the University of Tennessee Department of Radiology. Of the 49 patients, 31 were male and 18 female; all were Negroes.
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Open Access
Nov 1, 1956
Bryan Mcfarland 
