Hematology Oncology · Year 2 · from Hematology Oncology

Case 2: Hemophilia A with Hemarthrosis

Patient Presentation

Demographics: 12-year-old male

Chief Complaint: Acute right knee swelling and pain for 8 hours

History of Present Illness: The patient was playing soccer when he felt sudden pain in his right knee. The knee became progressively swollen over several hours. He has known severe hemophilia A diagnosed in infancy and has had previous hemarthrosis episodes affecting his left elbow and ankles. He is on prophylactic factor VIII replacement but missed his last two scheduled doses. His maternal uncle also has hemophilia.

Physical Examination:

  • Vital signs: BP 108/65, HR 92, RR 18, Temp 37.0C, weight 40 kg
  • General: Boy in moderate distress due to pain
  • Right knee: Markedly swollen, warm, tender; held in flexion; unable to fully extend
  • Left elbow: Chronic changes with limited range of motion from prior hemarthrosis
  • Skin: No petechiae or purpura
  • Abdomen: No hepatosplenomegaly

Workup and Results

Complete Blood Count:

  • WBC: 8,400/uL
  • Hemoglobin: 11.8 g/dL
  • Platelets: 285,000/uL

Coagulation Studies:

  • PT/INR: 12.8 sec / 1.0 (normal)
  • aPTT: 72 sec (prolonged; normal 25-35 sec)
  • Fibrinogen: 310 mg/dL (normal)

Factor Assays:

  • Factor VIII activity: <1% (severe deficiency)
  • Factor IX activity: 95% (normal)
  • von Willebrand factor antigen: 105% (normal)

Mixing Study:

  • aPTT corrects with 1:1 mix with normal plasma

Clinical Image

Clinical photograph and radiograph demonstrating acute hemarthrosis with joint swelling and effusion, alongside chronic hemophilic arthropathy changes from recurrent bleeding episodes.

Diagnosis

Severe Hemophilia A with Acute Hemarthrosis

Key features:

  • X-linked recessive inheritance (family history)
  • Severe disease: Factor VIII <1%
  • Prolonged aPTT with normal PT (intrinsic pathway defect)
  • aPTT corrects with mixing study (factor deficiency, not inhibitor)
  • Characteristic deep tissue bleeding pattern

Treatment Plan

  1. Acute hemarthrosis treatment:
  • Recombinant factor VIII replacement
  • Target factor level: 40-60% initially
  • Dose calculation: Weight (kg) x desired % rise x 0.5 = units
  • For this patient: 40 kg x 50 x 0.5 = 1,000 units
  • Repeat in 24 hours, continue until bleeding resolved
  1. Joint management:
  • Rest, ice, compression, elevation (RICE)
  • Immobilization initially, then early mobilization
  • Physical therapy after acute phase resolves
  1. Long-term management:
  • Resume prophylactic factor VIII (25-40 IU/kg 3x weekly)
  • Consider emicizumab for prophylaxis
  • Education about adherence
  • Monitor for inhibitor development
  1. Avoid:
  • Aspirin and NSAIDs (use acetaminophen for pain)
  • Intramuscular injections
  • High-risk contact sports

Teaching Points

  1. Hemophilia A (factor VIII deficiency) is X-linked recessive, affecting males with carrier females
  2. Severity classification: severe <1%, moderate 1-5%, mild 5-40% factor activity
  3. The characteristic bleeding pattern is deep tissue: hemarthrosis, muscle hematomas, delayed post-surgical bleeding
  4. aPTT is prolonged while PT remains normal (factor VIII is in intrinsic pathway only)
  5. Mixing studies correct in deficiency but not in presence of inhibitors
  6. Prophylaxis prevents joint damage and is now standard of care for severe hemophilia
  7. Emicizumab (bispecific antibody mimicking factor VIII) has transformed prophylaxis

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