A 4 year old boy presents with intermittent epistaxis for 2 years, with approximately 3 to 4 episodes per month, each lasting for between 20 to 30 minutes. His mother relates that he has experienced mild bruising following vaccination in the past, and that she has occasionally observed bruises in his extremities, which she attributed to his being an active child. His surgical history is significant for prolonged postoperative bleeding following a tonsillectomy. He has never been transfused with blood or blood products. His family history is negative for bleeding disorders, and he has a healthy sister who is 10 years old. His birth and developmental histories are unremarkable. A liver profile, renal profile, serum electrolyte assay, and erythrocyte sedimentation rate are found to be within normal parameters.
WBC: 5,900/mm3 (3,500-10,500) Hb: 12.1 g/dL (11-18) RBC: 4.5x10^6/mm3 (3.9-5.0x10^6) RDW: 14 (11.6-14.6) Platelets: 176,000/mm3 (150,000-450,000) Reticulocyte count: 1.1% (0.5-2.3) The peripheral smear reveals normocytic normochromic red blood cells. Leukocyte and platelet counts, sizes, and morphology are all normal.
aPTT : 29s (control: 30s) PT: 16s (control: 17s) INR: 1.0 (0.9-1.1) Bleeding time: >10 min (1-9) Screening tests for Von Willebrand disease: negative.
The platelet aggregation test shows normal agglutination with ristocetin but no aggregation with ADP, collagen, adrenaline or sodium arachidonate.
Flow cytometry: - Levels of glycoprotein IIb and IIIa are 5.7% of normal. Platelet Associated Immunoglobulin (PAIg) : - Increased levels of platelet-associated immunoglobulin-G are present - Plasma IgG2 concentration: 16g/L (1.1-6.6)