A child with prolonged aPTT underwent laparotomy and still did not develop any bleeding complications. Which of the following clotting factors is most likely to be deficient?
Factor VII
Factor Xll
Factor X
Factor XIII
Ref: Nelson Textbook of Pediatrics, 18th editionExplanation:The dual mechanisms of activating clotting areA. Intrinsic - Surface activation -Measured by aPTTB. Extrinsic - Tissue factor mediated - Measured by PT* Deficiency of contact factors like Factor XII. prekallikrein & HMW Kininogen causes prolonged aPTT but no bleeding symptoms. (See the following table) Coagulation profile in common hematological conditionsDiseaseProthrombintime(PT)Partialthromboplastin lime (aPTT)BleedingtimePlateletcountBernard-Soulier syndromeUraffectedUnaffectedProlongedDecreased or unaffectedDisseminated intravascular coagulationProlongedProlongedProlongedDecreasedFactor XII deficiencyUnaffectedProlongedUnaffectedUnaffectedFactor V deficiencyProlongedProlongedUnaffectedUnaffectedFactor X deficiencyProlongedProlongedUnaffectedUnaffectedGlanzmann'sthrombastheniaUnaffectedUnaffectedProlongedUnaffectedHemophiliaUnaffectedProlongedUnaffectedUnaffectedLiver failure, earlyProlongedUnaffectedUnaffectedUnaffectedLiver failure end-stageProlongedProlongedProlongedDecreasedThrombocytopeniaUnaffectedUnaffectedProlongedDecreasedUremiaUnaffectedUnaffectedProlongedUnaffectedVitamin K deficiency or warfarin TherapyProlongedNormal or mildly prolongedUnaffectedUnaffectedVon Willebrand diseaseUnaffectedProlongedProlongedDecreased
Hemorrhagic and Thrombotic Diseases