Vitamin K deficiency in newborns: a case report in alpha-1-antitrypsin deficiency and a review of factors predisposing to hemorrhage.

A 4-week-old, breast-fed female infant appeared healthy until signs and symptoms of CNS deterioration suddenly occurred. At presentation the infant was found to have a left-sided parietal intracerebral hematoma, markedly prolonged prothrombin time, and partial thromboplastin time, normal platelet count, and jaundice with a total and direct serum bilirubin level of 5.4 mg/dL and 2.6 mg/dL, respectively. Vitamin K1 and fresh frozen plasma returned the prothrombin time and partial thromboplastin time to normal values within 18 hours, suggesting that the infant had severe vitamin K deficiency complicated by intracerebral hemorrhage. Evaluation of the infant's direct hyperbilirubinemia led to the diagnosis of homozygous (pi-type ZZ [PiZZ] ) alpha-1-antitrypsin deficiency. The clinical circumstances predisposing to vitamin K deficiency in newborns and infants are discussed. Based on our observations in this case, we suggest that cholestatic liver disease should be suspected when unexplained vitamin K deficiency occurs in early infancy. The role of vitamin K in hemostasis and the laboratory diagnosis of vitamin K deficiency are discussed as they apply to the evaluation of hemorrhage in newborns and infants.