📌 Platelet vs Coagulation Disorders
Platelet: superficial bleeding (petechiae, ecchymosis, mucosal). Coagulation: deep bleeding (haemarthrosis, muscle haematoma, delayed bleeding).
🧪 Initial Labs
CBC, PT, aPTT, INR, fibrinogen, D-dimer, peripheral smear. Mixing studies: corrects with normal plasma = factor deficiency; no correction = inhibitor.
💊 Platelet Transfusion Thresholds
<10k (asymptomatic), <20k (fever/sepsis), <50k (invasive procedure), <100k (ECMO/neurosurgery). Transfuse 5-10 mL/kg.
🩸 DIC Management
Treat underlying cause. Transfuse if bleeding: platelets (<50k), FFP (10-15 mL/kg), cryoprecipitate (fibrinogen <100).
⚠️ HIT (Heparin-Induced Thrombocytopenia)
Platelet drop >50% 5-10 days after heparin. Stop all heparin. Use direct thrombin inhibitor (argatroban, lepirudin).
🧬 Haemophilia A/B & vWD
Haemophilia A (factor VIII deficiency): isolated prolonged aPTT. vWD: prolonged bleeding time, normal PT/aPTT (may have low factor VIII).