111 - Disorders of Platelet & Vessel Wall Flashcards
Platelets are activated by attaching to __ and __ found in the sub-__ which has been exposed due to injury or shear force. The activated platelets activate the production of __
vWV
collagen
epithelium
fibrin
Platelets are released from __ in response to stimulation by __ which is produced in the __
megakaryocytes
TPO
liver
What are the main reasons or thrombocytopenia?
decreased production (do BM biopsy) splenic aggregation increase in destruction (HUS/vasculitis/TTP/DIC/ITP) pseudothrombocytopenia
Why and how should we approach to a 60 years old patient with thrombocytopenia?
Looking for MDS, performing BM biopsy
What is the most common non-iatrogenic factor leading to thrombocytopenia?
infection:
DIC in G(-) systemic infection
ITP in viral infection and HIV
HIT= __
heparin induced thrombocytopenia
HIT does not increase the risk for __ as much as it does for __
bleeding
thrombosis
HIT is caused as antibodies against the __/__ complex are produced. It can also happen due to treatment with __, but is much more common when treating with __.
PF4/heparin
LMWH
UFH
What are the 5T for HIT?
thrombocytopenia Timing Thrombosis oTher Type of heparin
How do you treat HIT?
early diagnosing
stop heparin->switch to different anti coagulant (e.g. coumadin)
perform imaging to rule out thrombosis (lower limbs doppler)
Why coumadin should be administrated to patients with HIT only after platelets are back to normal level?
It decrease the level of protein C&S which may lead to skin necrosis
ITP= ___. It is an __ disorder, leading to immune mediated destruction of platelets.
Immune Thrombocytopenic Purpura
acquired
ITP tends to be __ in children, and secondary after: 4
acute SLE HIV HCV HP
When considering ITP, what may suggest a life threatening bleeding?
Wet purpura and retinal bleeding, together with low platelets and otherwise normal CBC
What is the typical clinical presentation of ITP? 3
cutaneous bleeding (ecchymoses / petechia)
membranous bleeding- wet purpura
other (retinal, GI, menorrhagia, CNS)
What are the 4 tools in diagnosing ITP?
- serology for HIV/HCV/SLE
- serum protein electrophoresis + immunoglobulin levels (hypogammaglobulinemia + IgA deficiency )
- coombs (looking for hemolysis- EVANS syndrome)
- BM examination
What is Evans syndrome?
autoimmune hemolysis + ITP
What is the goal of treating ITP?
reduce platelets destruction and reduce antibodies production