In a healthy 23‑year‑old female with recurrent epistaxis twice daily, intermittent gingival bleeding, mild anemia (hemoglobin ~11.7 g/dL), normal iron studies, normal platelet count, normal von Willebrand factor (VWF) antigen and activity, normal factor VIII activity, and a mildly prolonged activated partial thromboplastin time (aPTT), do these laboratory results explain her symptoms?

Her labs do NOT fully explain her symptoms and suggest further evaluation is warranted, particularly for hereditary hemorrhagic telangiectasia (HHT) or a mild bleeding disorder.

Key Laboratory Findings Analysis

The mildly prolonged aPTT (38 seconds) is the only abnormal coagulation parameter, but her von Willebrand factor studies are borderline-low normal and do not meet diagnostic criteria for von Willebrand disease 1:

• VWF antigen: 67 IU/dL (normal 50-200)
• VWF activity: 69 IU/dL (normal 50-200)
• Factor VIII: 65% (normal range)
• VWF:RCo/VWF:Ag ratio: >0.5 (normal, excludes Type 2 VWD variants)

The cutoff for definitive VWD diagnosis is <30 IU/dL for VWF levels 1. Her values of 65-69 IU/dL fall in the "gray zone" (30-50 IU/dL is considered borderline), but are technically within normal limits. This does NOT exclude a bleeding disorder, as some patients with values of 30-50 IU/dL may still have clinically significant bleeding if there is supporting clinical and family evidence 1.

Critical Clinical Red Flags Not Explained by Labs

Her clinical presentation is highly concerning and disproportionate to her laboratory findings:

• Recurrent epistaxis twice daily during episodes - this frequency and pattern is abnormal
• Bilateral nasal involvement
• Gingival bleeding with tooth brushing
• Cyclic pattern (15-20 day intervals between episodes)
• Mild anemia (hemoglobin 10.7-11.7 g/dL) with normal iron studies suggests chronic blood loss

Most Likely Diagnosis: Hereditary Hemorrhagic Telangiectasia (HHT)

The pattern of recurrent bilateral epistaxis with gingival bleeding in a young woman strongly suggests HHT 2. HHT occurs in 1 in 5,000-18,000 individuals and is frequently underdiagnosed 2.

Curaçao Criteria for HHT Diagnosis 2:

1. ✓ Recurrent spontaneous epistaxis - PRESENT
2. Telangiectasias (lips, oral cavity, fingers, nose) - needs examination
3. Visceral involvement (GI, pulmonary, hepatic, cerebral AVMs) - needs screening
4. Family history - she reports no family history, but HHT has variable penetrance

Diagnosis requires 3 of 4 criteria for definite HHT, 2 of 4 for possible HHT 2.

Why HHT Labs Appear Normal:

HHT is a vascular disorder, not a coagulation defect. Standard coagulation tests (PT, aPTT, platelets, VWF) are typically normal in HHT patients 2. The bleeding occurs from fragile telangiectatic vessels with thin walls that rupture easily, not from defective hemostasis.

The Mildly Prolonged aPTT

The isolated aPTT prolongation (38 seconds, mildly elevated) with normal PT, normal platelets, and borderline-normal VWF studies is non-diagnostic but warrants attention:

• Could represent mild Factor VIII, IX, or XI deficiency not severe enough to cause her symptoms 1, 3
• Could be a lupus anticoagulant (though she lacks other systemic symptoms) 4
• Could be laboratory variation - aPTT has high coefficients of variation 1
• Does not explain the severity or pattern of her bleeding

Recommended Next Steps

1. Physical Examination for HHT (Priority)

• Examine for telangiectasias on:
  • Lips, tongue, oral mucosa, hard palate 2
  • Nasal mucosa (endoscopic examination by ENT)
  • Fingertips, nail beds
  • Conjunctiva

2. Family History Reassessment

• Specifically ask about epistaxis, GI bleeding, telangiectasias in first-degree relatives
• HHT is autosomal dominant with variable penetrance 2

3. If HHT Suspected

• Refer to ENT or HHT Center of Excellence 2
• Screen for visceral AVMs (chest CT, brain MRI, abdominal imaging)
• Consider genetic testing for ENG, ACVRL1, SMAD4 mutations

4. If HHT Excluded

• Repeat VWF testing during an active bleeding episode (VWF levels can vary) 1
• Consider platelet function testing (light transmission aggregometry) - not yet performed 5, 6
• Evaluate for mild factor deficiencies beyond Factor VIII (factors IX, XI, XIII) 6
• Consider bleeding assessment tool (BAT) to objectively quantify bleeding severity 5

Common Pitfalls to Avoid

1. Do not dismiss normal coagulation studies - HHT and some platelet function disorders have normal routine labs 2, 6
2. Do not attribute all bleeding to "local causes" - this delays diagnosis of systemic disorders 7
3. Do not wait for severe anemia - chronic mucosal bleeding causes iron deficiency even with normal iron studies initially 5, 6
4. Do not overlook the bleeding pattern - twice-daily epistaxis is NOT normal and demands investigation 2, 8

Bottom Line

Her labs show borderline-low VWF levels and mild aPTT prolongation that do NOT adequately explain the severity and pattern of her bleeding symptoms. The clinical presentation—recurrent bilateral epistaxis, gingival bleeding, and cyclic pattern—is most consistent with hereditary hemorrhagic telangiectasia (HHT), which requires clinical diagnosis based on the Curaçao criteria, not laboratory testing 2. Immediate referral to ENT for mucosal examination and HHT evaluation is warranted 2. If HHT is excluded, repeat VWF testing and comprehensive platelet function studies should be pursued 5, 6.