M103 T2 L6 Flashcards
What are the causes of bleeding?
Vascular disorders
Platelet disorders
Defective coagulation
What are the patterns of bleeding for vascular and coagulation disorders?
vascular - bleeding into mucous membranes and skin
coagulation - bleeding into joints and soft tissues
What types of vascular bleeding is there?
Inherited (rare) - haemophilia a & b
Acquired (common)
coagulation cascade defect
What is the normal range of platelets? In what range is thrombocytopenia?
150-400 x 10^9/L
thrombo - less than the lower range
What are the symptoms of thrombocytopenia?
Epistaxis
GI bleeds
menorrhagia
bruising
At what platelet level will symptomatic bleeding occur?
when the platelet level falls below 10 x 10^9/L
What are the common aquired causes of thrombocytopenia?
ITP
drug-related
DIC
How is immune thrombocytopenia treated?
steroids and/or intravenous immunoglobulins
thromboietin agonists
immunosuppression
splenectomy
What are the symptoms of immune thrombocytopenia and what are they caused by?
affected individuals can develop red or purple spots on the skin caused by bleeding just under the skin’s surface
What are the acquired causes of disorders of platelet function?
iatrogenic illness
drs prescribing aspirin, NSAIDs that are very effective anti-platelet agents
What is prothrombinase made up of?
factor 10
factor 5
calcium
pplpds (surface of the platelets)
Where does the coagulation happen?
at the surface of the membrane of the platelet - very convoluted
What are the clinical features of Haemophilia A & B?
Spontaneous bleeding into joints and muscle
Unexpected post-operative bleeding
Chronic debilitating joint disease
Family history in majority of cases
What are consequent conditions due to haemophilia?
major haematoma
haemarthrosis
chronic joint deformity
intra-cranial bleed
Describe the genetics of a haemophiliac family
mother carrier - sons will have haemophilia, daughters will be carriers
positive father - sons will be normal, daughters will be carriers
What are the tests of coagulation?
APTT
PT
TT
Fibrinogen level
Clotting factor assays (normal level 100%)
D-dimers - breakdown products of fibrin clot
Which tests are done to diagnose haemophilia?
Prolonged APTT
Normal PT
Low factor VIII or IX levels
<1% = severe; 1-5% = moderate; >5% = mild haemophilia
When measuring factor VIII or IX levels, what are the percentages for the three levels of severity of haemophilia?
<1% = severe 1-5% = moderate >5% = mild haemophilia
Why were high proportions of haemophiliac patients getting AIDS?
the treatments of these patients with infected with the clotting factors of infected blood products