Pericardial effusion mistaken for cardiac enlargement in severe anemia.

Anemia is sometimes the sole cause of enlargement of the so-called cardiac silhouette. Successful treatment of the anemia may then restore the silhouette to normal. The enlargement has been attributed to cardiac dilatation. Because of the recognized difficulty in distinguishing l)ericarlial effusion from cardiac dilatation, direct puncture was attempted in two instances of anemnia with the silhouette enlarged presumably due to dilatation. In each instance, the enlargeenieiit wsas de(monstrated to be due almost exclusively to pericardial effusion.