What labs should be run for an 11-year-old with frequent epistaxis (nose bleeds)?

Laboratory Evaluation for Frequent Nosebleeds in an 11-Year-Old Child

For an 11-year-old with frequent epistaxis, a targeted laboratory evaluation should include a complete blood count (CBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), and von Willebrand factor testing as the initial screening tests. 1

Initial Assessment Before Laboratory Testing

Before ordering laboratory tests, consider:

• Frequency and severity of bleeding

  • Duration >30 minutes suggests severe epistaxis 1
  • ≥3 recent episodes may indicate need for evaluation 1

• Bleeding pattern

  • Unilateral vs. bilateral bleeding
  • Presence of other bleeding symptoms (gums, easy bruising, etc.)

• Risk factors 1

  • Family history of bleeding disorders
  • Personal history of excessive bleeding after procedures
  • Medication use (anticoagulants, intranasal medications)

Recommended Laboratory Tests

First-line Tests:

1. Complete Blood Count (CBC)

   • Evaluates for thrombocytopenia and anemia
   • Assesses platelet count and morphology

2. Coagulation Studies

   • Prothrombin Time (PT)/INR - evaluates extrinsic pathway
   • Activated Partial Thromboplastin Time (aPTT) - evaluates intrinsic pathway

3. Von Willebrand Disease Testing 1, 2

   • Von Willebrand Factor (vWF) antigen
   • vWF activity (ristocetin cofactor activity)
   • Factor VIII activity

Second-line Tests (if indicated by history or first-line results):

• Platelet Function Analysis (PFA-100) 1
• Factor XIII assay (if other tests normal but bleeding persists) 3
• Specialized platelet aggregation studies (for suspected platelet function disorders) 3

When to Expand Laboratory Evaluation

Expand laboratory evaluation when:

• Recurrent bilateral nosebleeds with family history of bleeding disorders 1, 2
• Presence of telangiectasias on nasal or oral mucosa (suggests hereditary hemorrhagic telangiectasia) 1
• Nosebleeds accompanied by other bleeding symptoms (gum bleeding, easy bruising, prolonged bleeding from minor cuts) 1
• Severe or difficult-to-control epistaxis despite appropriate first-line measures 2

Special Considerations

• In children with recurrent epistaxis but no other bleeding symptoms and normal physical examination, laboratory testing may not be necessary initially 2
• Most pediatric nosebleeds (>90%) originate from Kiesselbach's plexus in the anterior nasal septum and are benign 2
• Consider nasal endoscopy before extensive laboratory testing if unilateral recurrent bleeding is present, especially in adolescent males (to rule out juvenile nasopharyngeal angiofibroma) 1, 2

Common Pitfalls to Avoid

• Overinvestigation: Not all children with recurrent epistaxis require extensive laboratory evaluation, especially with isolated anterior nasal bleeding and no other symptoms 2
• Underinvestigation: Failing to test for von Willebrand disease, which is the most common inherited bleeding disorder 1
• Missing nasal pathology: Ensure anterior rhinoscopy is performed to identify local causes before attributing to systemic disorders 1
• Ignoring medication effects: Some medications can affect test results (particularly platelet function tests) 1

By following this targeted approach to laboratory evaluation, you can efficiently identify or rule out underlying bleeding disorders in an 11-year-old with frequent epistaxis while avoiding unnecessary testing.