Secondary (Clotting Factors) Hemostatic Disorders Flashcards
What are common symptoms of secondary hemostatic (coagulation factor) disorders?
- hemarthrosis
- traumatic ecchymosis/hematoma
- prolonged bleeding from laceration (ie. surgery)
- GI/urinary tract bleeding
- petechiae typically not seen
What is the most common inherited coagulation disorder?
von Willebrand disease
How does vitamin K related to hemostasis?
Vitamin K is required for production of factors II, VII, IX, X and proteins C and S
How does liver failure relate to hemostasis?
Many of the coagulation factors are made in the liver and may be deficient in severe liver failure
-liver is also responsible for activating vitamin K, meaning no vitamin K-dependent coagulation factors
How is the effect of liver failure on coagulation followed?
PT, shows changes earlier from liver failure than other measures
What is hemophilia A?
- deficiency in factor VIII (hemophilia “A-ight/8”)
- X-linked recessive
What lab findings would be expected in hemophilia A?
- elevated PTT (FVIII is in the intrinsic pathway)
- normal PT
- normal platelets
- normal bleeding time
What is the classical presentation of hemophilia A?
-male
*symptoms vary with severity of disease*
-hemarthrosis (very indicative of hemophilia)
-muslce hemorrhages (very indicative of hemophilia)
-petechiae absent
- traumatic ecchymosis/hematoma
- prolonged bleeding from laceration (ie. surgery)
- GI/urinary tract bleeding
What is the treatment for hemophilia A?
recombinant FVIII
What test confirms hemophilia A?
Performance of PTT with patients plasma and with plasma lacking factor VIII identifies if it is factor VIII and not a different intrinsic pathway factor that is deficient.
PTT does not correct in hemophilia A,
What is hemophilia B?
-hemostatic disorder caused by a deficiency in factor IX
-X-linked recessive
What lab findings would be expected in hemophilia B?
- elevated PTT (FIX is in the intrinsic pathway)
- normal PT
- normal platelets
- normal bleeding time
- indisthinguishable from hemophilia A without assay of coagulation factor levels
What is the classical presentation of hemophilia B?
- male
- clinically indistinguishable from hemophilia A
*symptoms vary with severity of disease*
- hemarthrosis (very indicative of hemophilia)
- muslce hemorrhages (very indicative of hemophilia)
- petechiae absent
- traumatic ecchymosis/hematoma
- prolonged bleeding from laceration (ie. surgery)
- GI/urinary tract bleeding
What is the treatment for hemophilia B?
recombinant FIX
What is acquired hemophilia?
- coagulation disorder caused autoimmune Abs against coagulation factors
- FVIII is the most common
- they mimic deficiency in cooresponding coagulation factor
How is hemophilia destinguished from acquired hemophilia?
Mixing study
- patients serum is mixed with serum containing all coagulation factors, PT/PPT is performed again
- if PT/PTT corrects it is hemophilia (Ab blocks coagulation factor in added serum)
What is von Willebrand disease?
-inherited hemostatic disorder caused by a deficiency von Willebrand factor
What lab findings would be expected in von Willebrand disease?
- increased bleeding time (platelet adhesion affected)
- elevated PTT (decreased half-life of FVIII due to lack of vWF)
- normal PT
- normal platelets
What is the mechanism of von Willebrand disease?
- vWB binds exposed subendothelial collagen
- platelet GPIb binds vWB during adhesion
- decreased vWF -> impaired platelet adhesion
- vWF also stabilizes FVIII
- decreased vWF -> decreased FVIII
What is the classical presentation of von Willebrand disease?
- mucosal and skin bleeding similiar to in platelet dysfuctions (*unusual since platelets are normal)
- no hemarthrosis (*despite elevated PTT/impacted FVIII)
What is the Ristocetin test?
-normally, ristocetin causes vWF to bind platelet GFIb -> agglutination of platelets
-if vWF is lacking, when ristocetin is added to blood agglutination will not occur
What is the treatment for von Willebrand disease?
-desmopression (increased vWB release from Weibel-Palade bodies of endothelium)
What is disseminated intravascular coagulation (DIC)?
What occurs with DIC?
- pathologic activation of coagulation cascade and fibrinolysis
- almost always secondary to some other disease processes
- consumes coagulation factors and platelets
- microthrombi -> ischemia/infarct and microagniopathic hemolysis
- bleeding from mucosal surfaces
What lab findings would be expected in DIC?
- decreased platelet count (used up)
- increased PT/PTT (coagulation factors used up)
- decreased fibriongen
- microangiopathic hemolytic anemia
- **elevated D-dimer (product of split cross-linked fibrin) (best screening test)
What are possible causes of DIC?
- tissue thromboplastin in amniotic fluid (pregnant women)
- sepsis (E. coli and N. meningitidis endotoxin)
- adenocarinoma (mucin)
- acute promyelocytic leukemia (excessive primary granules)
- rattlesnake venmon
What is the most common cause of DIC?
-pregnancy complicaitons
