PERIPHERAL BLOOD AND BILIRUBIN VALUES IN NORMAL FULL-TERM PRIMAQUINE-SENSITIVE NEGRO INFANTS: EFFECT OF VITAMIN K

Abstract

Serial determinations of hematocrit, reticulocyte, and bilirubin values were carried out during the first 8 days of life in 30 fullterm primaquine-sensitive Negro infants placed on three different schedules of vitamin K prophylaxis: 10 did not receive vitamin K, 10 were given 2.5 to 7.5 mg of the tetrasodium diphosphate salt of menadione (Synkavite) intramuscularly, and 10 received 1.0 to 18.75 mg of vitamin K1 (Konakion) intramuscularly during the first 24 hours of life. Similar observations were made on 60 full-term Negro infants who had normal or only slightly decreased levels of erythrocyte glucose-6-phosphate dehydrogenase activity. Although none of the infants manifested bilirubin levels greater than 14.5 mg/100 ml, the values in the primaquine-sensitive infants not given vitamin K were significantly higher than those observed in the other babies on the fifth and eighth days of life. The bilirubin values in all the infants were similar during the first day of life; maximal levels, however, occurred later in 5 of the 10 primaquine-sensitive infants who did not receive vitamin K. Reticulocyte counts were elevated in many of the primaquine-sensitive infants, regardless of their vitamin K grouping. The primaquine-sensitive infants could not be differentiated from normal babies on the basis of hematocrit values, the occurrence of Heinz bodies, and the morphology of the erythrocytes. The suggestion is made that primaquine-sensitive Negro newborn infants have a shortened survival time of the erythrocyte, predisposing them to the development of hyperbilirubinemia. Furthermore it is suggested that the capacity of some primaquine-sensitive infants to maintain normal bilirubin levels in the face of increased bilirubin formation is affected by the administration of vitamin K1. Reasons are given for using vitamin K1 rather than the water-soluble analogues of vitamin K, in the prophylaxis of hemorrhagic disease of the newborn. A dose of 18.75 mg of vitamin K1 was given safely to four primaquine-sensitive full-term Negro newborn infants. Until there is conclusive evidence that these large doses are necessarily beneficial, then no more than 2.0 mg of vitamin K1 should be given to these infants.