Osseous Changes in Erythroblastosis Fetalis

Abstract

To the roentgenologist, erythroblastosis fetalis represents a disease entity chiefly of obstetrical importance, in which his role as diagnostic consultant is quite limited. He realizes that, since the discovery of the Rh factor by Levine in 1941, a voluminous literature has accumulated concerning the clinical and laboratory aspects of the disease. Nevertheless, papers of radiological interest have been few and inconclusive. Admittedly, erythroblastosis does not consistently cause characteristic osseous changes comparable with other blood dyscrasias, such as Cooley's anemia or sickle-cell anemia, but the likelihood of encountering erythroblastosis is considerably greater, and roentgen manifestations undoubtedly occur. To clarify our present knowledge and to stimulate further investigation of this condition, we have selected for emphasis those findings of importance to the roentgenologist. In addition, we are presenting our analysis of x-ray studies of the largest collection of proved cases yet reported. Etiology Fifteen per cent (15 per cent) of white mothers lack the so-called Rh agglutinogen and are, therefore, termed Rh-negative. Sensitization of these mothers by the Rh-positive red blood cells of the fetus causes the formation of an anti-Rh agglutinin. Erythroblastosis develops because of the presence of this abnormal agglutinin in the serum of mothers of affected infants. Passage of this diffusible substance into the fetal circulation results in destruction of erythrocytes and the production of a typical clinicopathological syndrome. Clinical and Laboratory Aspects The physical findings in erythroblastosis fetalis are dependent upon excessive hemolysis with increased hematopoiesis. These basic changes result in jaundice, the most common sign; hepatic and splenic enlargement; petechiae, ecchymoses, and mucosal bleeding. Pigmentation of certain cerebral nuclei (kernicterus) may occur if the jaundice is intense. Universal edema or fetal hydrops is usually found only in those infants dying before or shortly after delivery. Laboratory findings include a macrocytic anemia, an increase in the number of nucleated red blood cells, leukocytosis, thrombocytopenia, and elevated icterus index. Review of the Literature of Roentgenological Interest Roentgen methods were utilized in the diagnosis of erythroblastosis for the first time by Hellman and Irving in antepartum studies (5). These authors described thickening and increased density of the fetal soft parts and a corona-like shadow surrounding the skull in maternal abdominal films. Such findings were present in three cases of the hydrops variety and were attributed to marked edema of the soft tissues. Particularly striking was the contrast afforded by the swelling of the scalp. Later, Javert re-emphasized the halo effect around the skull (6). He also pointed out a Buddha-like habitus of the fetus; this bizarre position was produced by extension of the lower extremities due to soft-tissue edema.