Von Willebrand Disease (vWF) is the Most Likely Diagnosis
Given the family history affecting both mother and brother (indicating autosomal inheritance pattern), post-circumcision bleeding, and the fact that vWF is the most common inherited bleeding disorder affecting both sexes equally, von Willebrand disease (Answer B) is the correct diagnosis. 1
Key Diagnostic Reasoning
Family History Pattern Rules Out Hemophilia A
- Hemophilia A follows X-linked recessive inheritance, affecting primarily males 2
- The mother being affected essentially excludes hemophilia A, as female carriers rarely manifest bleeding symptoms unless they have extremely skewed X-inactivation 2
- An affected mother and brother indicates autosomal inheritance, which is characteristic of von Willebrand disease 1
Post-Circumcision Bleeding is Classic for vWF
- Significant bleeding after circumcision is a classic presentation of von Willebrand disease 3, 1
- The American Academy of Pediatrics specifically identifies post-circumcision bleeding as a key historical feature suggesting a bleeding disorder 3
- vWF commonly presents with mucocutaneous bleeding, which includes prolonged bleeding from surgical sites 1
Why Other Options Are Less Likely
Hemophilia A (Option A):
- Would not affect the mother given X-linked inheritance pattern 2
- While post-circumcision bleeding occurs in 23% of hemophilia patients, the maternal involvement excludes this diagnosis 4
Platelet Function Disorder (Option C):
- Less common than vWF overall 1
- Family history pattern could fit, but vWF is significantly more prevalent (1 in 1,000 people) 1
- Without additional features suggesting platelet dysfunction, vWF remains more likely
DIC (Option D):
- Would present with systemic illness, multiorgan involvement, and acute deterioration 5
- A 12-hour delay with minor bleeding and stable vital signs is inconsistent with DIC
- Family history would not be relevant in DIC 5
Critical Diagnostic Pitfall
Standard coagulation screening (PT/aPTT) does NOT reliably detect von Willebrand disease 5, 1. The American Academy of Pediatrics emphasizes that normal PT/aPTT cannot rule out vWF, and specific von Willebrand factor assays are required for diagnosis 1.
Recommended Diagnostic Workup
- Specific vWF testing is mandatory: vWF antigen, vWF activity (ristocetin cofactor), and factor VIII levels 1
- Initial screening with CBC, PT, aPTT, and peripheral smear should still be performed 5
- Von Willebrand factor is an acute phase reactant and can be falsely elevated during stress or illness, requiring repeated testing for reliable results 1
- Consultation with pediatric hematology is warranted due to diagnostic complexity 1