An exclusively breastfed term neonate presents on day 3 of life with bleeding from the umbilical stump. Coagulation studies show prolonged PT and aPTT with normal fibrinogen and platelet count. The underlying defect is:

• A Disseminated intravascular coagulation with consumption of all clotting factors
• B Deficiency of factor VIII caused by hepatic immaturity of glycoprotein synthesis
• C Deficiency of factors II, VII, IX and X secondary to inadequate vitamin K-dependent carboxylation ✓
• D Congenital afibrinogenemia unmasked by the stress of delivery

Explanation

Classic neonatal vitamin K deficiency bleeding results from poor placental transfer of vitamin K, negligible stores at birth, a sterile gut lacking synthesizing bacteria, and low vitamin K in breast milk. Factors II, VII, IX and X require gamma-carboxylation of glutamate residues by vitamin K, so their deficiency prolongs both PT and aPTT. Normal fibrinogen and platelets exclude disseminated intravascular coagulation, and isolated factor VIII deficiency would not prolong the PT.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.