Acquired Bleeding Disorders Flashcards
Name 6 acquired bleeding disorders
Vit K deficiency Massive transfusion syndrome DIC Iatrogenic Acquired inhibitors
How do you determine if a bleeding disorder is due to an inhibitor or a deficiency?
If APTT is prolonged, repeat with 50:50 mix patient to normal plasma. Deficiency= significant correction, inhibitor=no correction
In which aquired bleeding disorder is the TT the longest?
DIC
Why does liver disease result in clotting disorders?
Clotting factors are synthesised in the liver
Why does massive transfusion result in bleeding disorders?
Dilution of clotting factors
In which bleeding disorders is the thrombin time increased?
DIC and heparin overuse
In which bleeding disorders is the platelet concentration decreased?
Liver disease
DIC
Massive transfusion
What are the vitamin K dependent clotting factors?
2,7,9,10
How does vit. K usually work?
Acts as a cofactor in a modification step after the synthesis of the clotting factors- vit K reductase works to reduce vit k epoxidase back to its active form- vit k (red)
How does warfarin work?
Inhibits the recycling of vitamin K i.e. blocks the synthesis of vit k reductase
4 causes of vitamin K deficiency
Obstructive jaundice (bile salts can’t reach the gut, fat and subsequently vit. k can’t be absorbed)
Prolonged nutritional deficiency
Broad spectrum antibiotics
Neonates (1-7 days) ‘haemorrhagic disease of the newborn
What is the cause of haemorrhagic disease of the newborn?
Vit K deficiency at birth
What is the monitoring blood test for warfarin and what is the normal range?
International normalised ratio INR (PT)
How does heparin work?
Activates antithrombin III which results in an increased rate of inactivation of thrombin and factor Xa
How does fondaparinux work?
Acts against factor Xa
