Vitamin K deficiency bleeding of the newborn

Question 1

summary

Answer 1

Refers to spontaneous bleeding in a newborn caused by a deficiency of vitamin K dependent-coagulation factors.
As vitamin K does not cross the placental barrier, is not present in breast milk, and is not synthesized in the sterile gut of a newborn, vitamin K levels are low in all neonates.
VKDB is categorized as early-onset (within 24 hours after birth), classic (within 4 weeks), or late-onset (between 2–8 months). Bleeding is usually intracranial, subgaleal, gastrointestinal, or nasal. Treatment is focused on managing the bleeding with, e.g., transfusions and restoring bleeding homeostasis by administering vitamin K.

Question 2

Etiology

Answer 2

Exclusive breastfeeding: low vitamin K levels in breast milk (most important in late-onset VKDB)
Poor placental passage of vitamin K
Vitamin K deficiency in the mother (e.g., because of anticonvulsant therapy; most important in early-onset VKDB; maternal malnutrition)
Underdeveloped intestinal flora (which produces vitamin K)
Long-term antibiotic treatment in newborns

Question 3

Clinical features

Answer 3

Early onset: within 24 hours after birth; intracranial bleeding common
Classic: within 4 weeks after birth; intracranial bleeding rare
Late onset: between 2–8 months after birth; intracranial bleeding common

Question 4

Diagnostics

Answer 4

↑ Prothrombin time (PT)
Normal or ↑ activated partial thromboplastin time (PTT)
Normal bleeding time

Question 5

Treatment

Prevention

Answer 5

Treatment
Administration of vitamin K

Prevention
In the US, all newborns receive intramuscular vitamin K (0.5–1 mg) at birth.