L41-bleeding Disorders Flashcards
How can abnormalities of hemostasis occur
Resulting from deficiency of platelets or coagulation factors which will cause bleeding tendency
or because of over activity of coagulation cascade which will cause thrombosis
How can excessive bleeding occur
Can result from deficiency of any one of many coagulation factors or platelets they can either be congenital acquired
What are the congenital bleeding disorders
Hemophilia a
Von Willebrand factor deficiency
What are the acquired bleeding disorders
Vitamin K deficiency
Liver disease
What are the platelet defects
Thrombocytopenia
Idiopathic thrombocytopenia
Describe hemophilia a
Bleeding disease Occurs mostly in males 85%Caused by an abnormality or deficiency of factor VIII 15% caused by deficiency in factor IX Transmitted by female chromosome Female may be carrier
Clinical picture of hemophilia a and treatment
▪️Bleeding usually does not occur except after trauma but in some patients degree of trauma required to cause severe and prolonged bleeding may be so mild that it’s hardly noticeable
for instance:bleeding can last for days after extraction of a tooth
▪️Treatment:the disease can be treated with a factor VIII rich preparations made from plasma or factor VIII produced by recombinant DNA techniques
Describe von Willebrand factor deficiency
Bleeding disorder by reducing platelet adhesion and by lowering factor VIII
Can be congenital or acquired
Describe vitamin K deficiency
Most common cause is liver failure to secrete bile in to GIT
Lack of bile causes inadequate fat digestion and absorption which represses Vit k absorption as well(fat soluble vitamin)
Formation of clotting factors (II,VII,IX,X) is greatly impaired and causes bleeding tendency
Describe liver disease
Almost all clotting factors are formed by liver
Diseases of liver such as hep or cirrhosis can depress clotting system causing inc tendency to bleed
Describe thrombocytopenia
Means very low number of platelets in blood
Tend to bleed from small venules and capillaries
Small punctuate hemorrhages occur through body tissues
Skin displays many small purplish blotches
Bleeding will occur when number falls below 50,000/ul
Describe idiopathic thrombocytopenia
Thrombocytopenia of unknown cause
Specific antibodies form and react against the platelets themselves to destroy them
Relief from bleeding 1 to 4 days can often be affected in a patient with thrombocytopenia by giving fresh whole blood transfusions that contain large number of platelets
Also splenectomy can be helpful since it removes large number of platelets from blood
When can thrombosis occur
Sluggish blood flow
What intima is damaged by atherosclerotic plates
congenital absence of protein C
Resistance to activated protein C
Mutations in protein S and anti thrombin III
How can sluggish blood flow create thrombosis
Because the slow flow permits activated clothing factors to accumulate instead of being washed away
Why does the absence of congenital protein C cause thrombosis
Leads to uncontrolled intravascular coagulation and in general death in infancy if this condition is diagnosis and treatment is instituted the coagulation defect disappears
