Vitamin K Deficiency (Answer: C)
The most likely diagnosis is Vitamin K deficiency, given the combination of delayed umbilical cord separation, bleeding from the umbilical site, prolonged PT and PTT, normal platelet count, and delayed clot time in a newborn. 1, 2
Diagnostic Reasoning
Why Vitamin K Deficiency is Most Likely
Umbilical stump bleeding with prolonged coagulation times is the classic presentation of Vitamin K Deficiency Bleeding (VKDB) in newborns and should be excluded first before considering inherited bleeding disorders 1, 2
Vitamin K deficiency affects multiple coagulation factors simultaneously (factors II, VII, IX, and X) because all are vitamin K-dependent, producing prolonged PT and PTT together 1, 2
The laboratory pattern of prolonged PT and PTT with normal platelet count is almost diagnostic of VKDB in a bleeding infant 1
The absence of vitamin K prophylaxis at birth is a significant risk factor, and not all institutions mandate its administration 1, 2
Why Other Options Are Excluded
Hemophilia A (Option A):
- Hemophilia A would prolong only the PTT, not the PT, since factor VIII is part of the intrinsic pathway only 2, 3
- While hemophilia can present with umbilical stump bleeding, the prolonged PT excludes this diagnosis 3
Von Willebrand Disease (Option B):
- Von Willebrand disease typically presents with prolonged bleeding time due to impaired platelet adhesion, and would not cause both prolonged PT and PTT 1, 3
- Von Willebrand disease is not reliably detected by PT/PTT screening and typically does not cause severe umbilical stump bleeding in newborns 3
Thrombocytopenia (Option D):
- Normal platelet count explicitly excludes thrombocytopenia, which by definition requires low platelet count 1, 2, 3
Immediate Management
Administer 1 mg vitamin K intramuscularly or intravenously immediately while awaiting confirmatory laboratory correction 1, 2, 4
Expect PT/PTT correction within 2-4 hours if VKDB is the diagnosis - this rapid response confirms the diagnosis retrospectively 1, 2, 4
Verify whether vitamin K prophylaxis was given at birth, as breast-feeding without vitamin K prophylaxis is the primary risk factor for VKDB 1, 2
If life-threatening bleeding is present, consider Fresh Frozen Plasma (FFP) 10-20 mL/kg for immediate factor replacement while awaiting vitamin K effect 1, 4
Critical Pitfall
If coagulopathy does not correct with vitamin K within 2-4 hours, then pursue specific factor assays (Factor VIII and IX levels) to evaluate for inherited hemophilia, as vitamin K deficiency must be ruled out first regardless of the initial laboratory pattern 2