Osseous Changes in Rubella Embryopathy

RUBELLA infection during the first trimester of pregnancy may result in a variety of abnormalities in the fetus. These include cardiac anomalies, cataracts, chorioretinitis, deafness, and intrauterine growth retardation (1). This paper describes roentgen alterations in the bones observed in 7 newborn infants with intrauterine rubella infection. The osseous changes in two of these infants (Figs. 1 and 2) have been described in a previous publication (2). By the use of recently developed technics of propagating the rubella virus in tissue culture (3, 4), it has been confirmed that an individual may contract rubella without clinical evidence of the disease (5). By these methods it has also been demonstrated that a fetus, infected as a result of maternal rubella during the first trimester of pregnancy, harbors the virus for prolonged periods of intrauterine life and may continue to excrete the virus for a variable period after birth (6). In the current group of cases, 4 of the 7 mothers suffered an illness compatible with rubella during the first trimester of pregnancy. Dr. Louis Z. Cooper of the rubella study group at the New York University School of Medicine found 6 infants harboring an interfering agent in tissue culture compatible with rubella virus. In the seventh case, the mother had characteristic rubella during the first trimester and the infant showed bone changes and other congenital anomalies consistent with rubella embryopathy ; no culture was obtained in this instance. Cardiac abnormalities were observed in 6 of the infants ; in 5 heart enlargement was demonstrated on routine chest films. Roentgenographic Findings The roentgenographic findings in the bones in all cases were similar in appearance and location, but varied somewhat in intensity. Although all the long bones may be involved, there was a predilection for the distal portions of the femora. The changes primarily involved the metaphyseal areas. The zones of provisional calcification were absent and the ends of the metaphyses were irregular. The metaph-yses showed disorganized structure with longitudinal or ovoid lucencies alternating with coarse bony trabeculae (Figs. 1–6). The entire metaphyseal region occasionally appeared to be demineralized, but the disorganization and irregularity of the bony trabeculae were diagnostically more consistent. The normally smooth and sharp border of the metaphyseal-epiphyseal junction was interrupted by areas of rarefaction, and a frayed or dentate appearance resulted. No evidence of metaphys eal cupping, however, was encountered. In 3 cases in which the epiphyses of the knee were ossified at birth, the distance between the ends of the metaphyses and the epiphyses was normal, as were the out-lines of the epiphyses. In one child the epiphyseal ossification centers of the knee were irregular with a frayed margin (Fig. 6). Ossification centers at the knee were absent in 3 of 7 infants whose birth weights were lower than anticipated.