Benign Hematology: Understanding Prolonged PTT Causes and Workup

Framework for Prolonged PTT

• 💡 A structured framework is essential when encountering an abnormal Prolonged PTT (aPTT).
• 📌 The infographic categorizes causes into non-bleeding and bleeding scenarios.

Causes in Non-Bleeding Patients

• ⚠️ The primary consideration for non-bleeding patients with a prolonged PTT is Antiphospholipid Antibody Syndrome (APS), often associated with clotting.
• ❓ Symptoms like recurrent pregnancy losses can be a key indicator for APS, specifically Lupus Anticoagulant.
• 🏥 Other considerations include Hemophilia C and the less commonly remembered contact pathway disorders.
• ⚠️ A crucial, easily missed cause is Heparin or heparin derivatives, which can falsely elevate PTT.

Causes in Bleeding Patients

• 🩸 In patients experiencing bleeding with an elevated PTT, consider hemophilias (Factor VIII, IX, XI deficiencies).
• 🧩 Factor VIII inhibitors, potentially linked to CLL or postpartum states, can also cause bleeding.
• ⚠️ Von Willebrand disease is a significant cause of bleeding with an elevated PTT, as Von Willebrand factor protects Factor VIII.
• 💊 Medications like Heparin can also manifest with bleeding alongside PTT elevation.

Workup for Von Willebrand Disease

• 📈 Von Willebrand disease is the most common inheritable bleeding disorder and warrants consideration, especially in cases of heavy menstrual bleeding.
• 🔬 Diagnosis involves checking Von Willebrand factor antigen, activity assays (like ristocetin cofactor activity), Factor VIII activity, and potentially multimer analysis.
• 🤝 Referral to hematology is a reasonable approach for complex workups, depending on practice patterns.