[Late manifestation of vitamin K deficiency in breast fed infants].

Two breast fed infants had late manifestations of Vitamin K deficiency. No underlying disease was found in the first case. The second patient was found to have alpha 1-Antitrypsin deficiency (Pi type ZZ). The latter patient initially responded well to a single dose of vitamin K administered orally (3 mg). However, three weeks later, he was admitted to our hospital with severe intracranial hemorrhage due to severe vitamin K deficiency. Vitamin K requirements in infants and clinical characteristics of vitamin K deficiency in infants older than 1 week are discussed.