//fpnotebook.com/
Factor IX Deficiency
Aka: Factor IX Deficiency, Factor 9 Deficiency, Christmas Disease, Hemophilia B, Plasma Thromboplastin Component Deficiency
- Epidemiology
- Accounts for 15% of Hemophilia cases (remainder are Hemophilia A which is a Factor VIII Deficiency)
- Pathophysiology
- Inherited sex linked trait
- Factor IX Deficiency
- Clinically indistinguishable from Hemophilia A (which is the much more common Factor VIII Deficiency)
- Symptoms
- Chronic history of Bleeding Diathesis since childhood
- Spontaneous bleeding
- Excessive Hemorrhage follows:
- Dental procedures
- Surgery
- Signs
- Joint deformities
- Muscle contractures
- Labs
- Partial Thromboplastin Time (PTT) prolonged
- Corrects with Factor IX supplementation
- Corrects with Normal serum
- Management: Recombinant Factor IX replacement
- Consult Hematology
- Indications
- Acute Bleeding
- Preoperative prophylaxis
- Dosing basic regimen
- Background
- Active Factor IX rises 1% for every Factor IX unit/kg given
- Example: 100% replacement = 100 units/kg
- Initial dose
- Factor IX 100 units/kg every 8-12 hours OR
- Factor IX (desired concentration - current concentration) * wtKg every 8-12 hours
- Factor IX Infusion
- Load: 100 units/kg
- Infusion: 4-5 units/hour (directed by Factor IX levels)
- Modifiers
- Subtract patient's weekly maintenance dose already given (last few days) from the acutely required units
- Additional factor dose is needed to overcome inhibitors (if present)
- Dosing in major bleeding (directed by involved region and target Factor IX levels)
- Major injury with active bleeding or preoperative and perioperative prophylaxis and management
- Target: 100% initially, then 80-100% until wound healed, then 30% of normal Factor IX Level until Suture removal
- Recombinant Factor IX 100 units/kg initially and then 50 units/kg daily (adjusted for healing)
- Joint bleeding (hemarthrosis)
- Target: 80% in acute period, then 40% every other day of normal Factor IX Level
- Recombinant Factor IX 80 units/kg initially, then 40 units/kg every other day (or every third day) until healed
- Gastrointestinal Bleeding
- Target: 100% initially, then 50% of normal Factor IX Level until healed
- Recombinant Factor IX 100 units/kg initially, then 30-40 units/kg daily
- Genitourinary bleeding
- Target: 100% initially, then 30% of normal Factor IX Level until healed
- Recombinant Factor IX 100 units/kg initially, then 30-40 units/kg daily
- CNS Bleeding
- Target: 80-100% initially, then 50-100% of normal Factor IX Level for 14 days
- Recombinant Factor IX 100 units/kg initially, then 50 units/kg daily
- Oral Bleeding
- Target: 100% of normal Factor IX Level
- Recombinant Factor IX 100 units/kg
- Consider topical Fibrinolytic agents
- Epistaxis
- Target: 80-100% initially, then 30% of normal Factor IX Level until healed
- Recombinant Factor IX 80-100 units/kg then 35-40 units/kg daily
- Muscle bleeding
- Target: 50% of normal Factor IX Level
- Recombinant Factor IX 40-60 units/kg daily then 20-30 units/kg every other day until healed
- Alternative agents when Factor IX is not available
- Fresh Frozen Plasma (FFP) 4 units
- Increases Factor IX to only 5%
- Prothrombin Complex Concentrate (PCC) 100 units
- Risk of thrombosis (reserve only for very serious bleeding such as CNS Hemorrhage)
- Adjunctive Agents to Consider
- Consult Intervention Radiology and surgery for localized Hemorrhage source control
- Aminocaproic Acid (Amicar)
- Tranexamic Acid (TXA)
- Desmopressin (DDAVP)
- References
- Deloughery and Orman in Majoewsky (2013) EM:Rap 13(9): 1-4
- Guest and Herbert in Swadron (2022) EM:Rap 22(4): 9
- DiMichele (1996) Pediatr Clin North Am 43(3): 709-36 [PubMed]