Vitamin K Deficiency Bleeding (VKDB)

Pathophysiology & Classification

• Deficiency in Vitamin K-dependent coagulation factors: II, VII, IX, and X. Neonates have sterile guts (unable to synthesize phylloquinone/menaquinone) and poor placental transfer.
• Early VKDB (0-24 hours): Associated strictly with maternal medications inhibiting Vitamin K (Anti-epileptics like Phenytoin/Phenobarbital, or Warfarin, Isoniazid). Severe bleeding, often intracranial.
• Classic VKDB (1-7 days): Due to physiological deficiency and delayed feeding. Presents with GI bleeding, mucosal bleeds, profound umbilical stump oozing, or post-circumcision hemorrhage.
• Late VKDB (2-12 weeks): Almost exclusively in exclusively breastfed infants (breast milk is very poor in Vit K) who did not receive IM prophylaxis, or infants with unrecognized cholestasis (biliary atresia causing fat-malabsorption). Extreme risk (50%) of catastrophic Intracranial Hemorrhage (ICH).

Diagnostic Profile

• Profoundly prolonged PT (Prothrombin Time) and INR (International Normalized Ratio).
• Variable prolongation of aPTT (Activated Partial Thromboplastin Time).
• CRITICAL DELINEATION: Platelet count and Fibrinogen levels are explicitly NORMAL (differentiates VKDB from DIC).
• Head Ultrasound required immediately if any neurologic signs (bulging fontanelle, seizures, extreme lethargy) or unexplained severe anemia to rule out ICH.

Prophylaxis & Acute Management

• Universal Prophylaxis: Exactly 1.0 mg Vitamin K1 (Phytonadione) administered Intramuscularly (IM) within 1 hour of birth. (0.5 mg for birth weights < 1500g).
• Oral prophylaxis is explicitly NOT recommended by the AAP due to high failure rates in preventing Late VKDB (poor absorption and compliance).
• Acute Treatment for active bleeding: Intravenous (IV) or Subcutaneous (SQ) Vitamin K1 (1 to 2 mg). Corrects PT within 4-6 hours.
• Severe Life-Threatening Hemorrhage (e.g., ICH): Do not wait for Vitamin K to act. Immediately transfuse Fresh Frozen Plasma (FFP) 10-15 mL/kg, or administer Prothrombin Complex Concentrate (PCC) for instant factor replacement.

Diagnostic & Management Algorithm

• VKDB Bleeding Protocol: [START] Unexplained bleeding in neonate -> [EVALUATE] Check PT/PTT -> [DECISION] Prolonged PT with NORMAL platelets? -> [YES] Vitamin K1 1-2 mg IV/SQ -> [DECISION] Life-threatening bleed (ICH)? -> [YES] Transfuse FFP or PCC

References

1. Mihatsch WA, Braegger C, Bronsky J, et al. Prevention of Vitamin K Deficiency Bleeding in Healthy Term Neonates. J Pediatr Gastroenterol Nutr.
2. AAP Committee on Fetus and Newborn. Vitamin K and the Newborn Infant. Pediatrics.