The Presentation of a Fussy Infant With Bruising: Late-Onset Vitamin K Deficiency Bleeding.

Vitamin K plays an integral role in the clotting cascade. Deficiency, specifically in vulnerable neonates with insufficient stores, can lead to spontaneous bleeding and devastating effects. In this case, we report a young infant with late-onset vitamin K deficiency bleeding who did not receive vitamin K prophylaxis after birth. Initially presenting with bruising and fussiness, the patient was later found to have intracerebral hemorrhage with midline shift and uncal herniation. The infant was not a surgical candidate and died shortly thereafter. Laboratory studies confirmed the diagnosis of late-onset vitamin K deficiency bleeding as the cause of hemorrhage and death.