Coagulation Flashcards
How does aspirin work?
Irriversibly inhibits cyclooxygenase thereby inhibiting TXA2 synthesis.
How does clopidogrel work?
Inhibits ADP induced expression of Gp2b/3a.
Function of vWF?
Helps in primary haemostasis, binds to exposed collagen, platelets bind vWF via Gp1b receptor at the site of injury. Platelets undergo conformational change.
CARRIES AND PROTECTS FACTOR 8!
How do you measure the effect of heparin?
PTT
Coagulation factors involved in intrinsic pathway and how is it measured?
12, 11, 9, 8
THE NEXT FACTOR STARTS WITH THE LAST LETTER OF THE PREVIOUS FACTOR!
PTT
More letters than PT so more factors.
Activated by surface activation, sub-endothelial collagen SEC, more letters than TT
Coagulation factors in the extrinsic pathway and how is it measured?
7
PT
Tissue activation, tissue thromboplastin PT, less letters than SEC.
How is warfarin therapy monitored?
Prothrombin time PT, INR
What measures the common pathway?
TT
Starts with activated factor 5
What does PTT measure?
Intrinsic pathway and common pathway.
12, 11, 9, 8, 10, 5, 2 and 1
Heparin therapy
What does PT measure?
Extrinsic pathway and common pathway.
7, 5, 10, 2 and 1
Warfarin therapy (INR)
Features of platelet disorders?
Superficial bleeding into skin, mucosal membranes.
Bleeding immediately after injury.
Features of coagulation disorders?
Bleeding into deep tissues, muscles, joints
Delayed but severe bleeding after injury
Bleeding often prolonged.
Normal platelet count?
150-400x10^9g/l
PT/PTT of platelet disorders?
Normal
Who does acute ITP commonly affect?
Children
Who does chronic ITP usually affect?
Adults- usually women of childbearing age.
What causes ITP?
Destruction of platelets in spleen, splenic macrophages phagocytose platelets, leading to THROMBOCYTOPENIA.
Features of Acute ITP and treatment?
Predominantly affects children.
Preceding infection.
SELF LIMITING, treatment with steroids and IVIG if platelet count really low or major bleeding.
Features of chronic ITP?
Adults, usually women of childbearing age.
No trigger
LONG TERM RELAPSE-REMITTING
Treatment with IVIG (short lived effect), STEROIDS, SPLENECTOMY
Deficiency in haemophilia A and inheritance?
Factor 8 deficiency (Ayyy for A sounds like eight)
X linked recessive
Features and management of Haemophilia A?
Spontaneous, deep bleeding, haemarthrosis
Normal platelet count, normal bleeding time, RAISED APTT, normal PT
More common than haemophilia B
Management: FACTOR 8 CONCENTRATE
Deficiency in haemophilia B and inheritance?
Factor 9 deficiency
X linked recessive.
Key features of haemophilia B and management?
Spontaneous deep bleeding, haemarthrosis
Normal platelet count, normal bleeding time, raised APTT, normal PT.
Management: Factor 9 concentrate
Features of von willebrand disease and treatment?
Autosomal dominant
Presents with mild mucosal bleeding and skin bleeding. Deep tissue and joint bleeding not usually seen.
Increased PTT, increased bleeding time, decreased Factor 8, normal INR.
Treatment is DESMOPRESSIN (ADH analog), increasees vWF release from weibel-palade bodies of endothelial cells.
Which factors do you require vitamin K for synthesis?
2, 7, 9 and 10 and protein C/S (which is why warfarin can be procoagulative at first)
Buses that go down high street ken, 27, 9, 10
Management of vitamin K deficiency?
IV vitamin K replacement, FFP, PCC (prothrombin complex concentrate)
Coagulation test results for Vitamin K deficiency?
INR: increased APTT: increased Thrombin time: normal Platelet count: normal Bleeding time: normal
Differential for vitamin k deficiency?
Liver disease (would have a decreased platelet count unlike vitamin k deficiency) Scurvy (corkscrew hair)
Coagulation test results for liver disease?
INR: increased APTT: increased Thrombin time: normal or increased Platelet count: normal or decreased Bleeding time: normal or increased
Increased AST
Coagulation test results for DIC?
INR: increased APTT: increased Thrombin time: increased Platelet count: decreased Bleeding time: increased
D DIMER INCREASED
DECREASED FIBRINOGEN
SCHISTOCYTES
Best screening for DIC?
Elevated d-dimer
