Vitamine K deficiency

1. Big picture

Vitamin K deficiency in pediatrics is mainly an early-life bleeding disorder. The exam topic is usually vitamin K deficiency bleeding of the newborn, formerly called hemorrhagic disease of the newborn or morbus haemorrhagicus neonatorum.

The key clinical idea:

Newborn/young infant
+ no vitamin K prophylaxis or exclusive breastfeeding
+ mucosal/GI/umbilical/needle-site bleeding
± intracranial hemorrhage
+ prolonged prothrombin time
= vitamin K deficiency bleeding

This is high-yield because it is preventable, potentially fatal, and can present suddenly with intracranial bleeding in a previously healthy breastfed infant.