PLATELET DISORDERS Flashcards
disorder of platelet adhesion - deficiency of glycoprotein Ib/Ix
bernard-soulier syndrome
disorders of platelet aggregation - deficiency of glycoprotein IIb/IIIa
Glanzmann-Thrombasthenia
alpha or dense granules deficiency
disorders of platelet secretion
platelets fail to promote activation of the blood clotting proteins
disorders of platelet procoagulant activity
drugs like aspirin, non-steroidal anti-inflammatory drugs like indomethacin, ibuprofen
acquired platelet function disorders
Defect in adherence - The glycoprotein (Ib) receptor for VIII:Vwf is absent on platelet membrane and the Rx: platelets transfusion
Bernard-Soulier Syndrome
Defect in aggregation - the platelets lack surface glycoprotein receptor (IIb, IIIa) necessary for binding fibrinogen (fibrinogen receptor) and bleeding is prolonged
Glanzmann Thrombasthenia
congenital abnormalities of platelets can be divided into ________ and those of _______
disorders of platelet production ; platelet function
congenital abnormalities all are very ____
rare
congenital abnormal in general, cause moderate to severe _______
severe problems
autosomal recessive preleukemic condition which often presents as thrombocytopenia with skeletal or genitourinary abnormalities
Fanconi’s Anemia
congenital abnormalities laboratory features
- abnormal chromosomal fragility
- the condition can be cured with bone marrow transplantation (BMT)
thrombocytopenia clinical symptoms typically not seen until ______
<100 x 10^9/L
thrombocytopenia more often _____
<50 x 10^9/L
thrombocytopenia spontaneous bleeding occurs ____
<20 x 10^9 / L
thrombocytopenia life-threatening _______
<10 x 10^9/L
thrombocytopenia clinical manifestation
- petechiae
- menorrhagia
- spontaneous bruising
- fatal bleeding into the CNS may occur
- spontaneous bleeding in GI-tract, GU-tract and nose
- prolonged BT but normal coagulation tests
thrombocytopenia is due to
- deficient platelet production
- abnormal platelet distribution (splenic sequestration)
- increased destruction
- secondary to an underlying disease
- most common cause of excess or abnormal bleeding
thrombocytopenia
thrombocytopenia platelet count
< 100,000 cu mm
platelet count <50, 000
variable risk
platelet count <20,000
transfusion appropriate
platelet count <10,000
spontaneous hemorrhage
platelet dysfunction
mucus membrane bleeding
mucus membrane bleeding
epistaxis
gingival
vaginal bleeding
petechiae, purpura
von willebrand disease : qualitative alterations in the vWF structure and function
Type 2
von willebrand disease : least common and most severe
type 3
- complete absence of vWF in plasma or storage organelle
- autosomal recessive
type 3 - vWD
list of acquired vWD
- lymphoproliferative disease
- tumors
- autoimmune disease
- cardiac/vascular disease
- medications (valproic acid)
- hypothyroidism
thrombocytopenia lab error: can have platelet clumping due to _____ tube this may cause platelet count to appear false low - peripheral smear examination can confirm normal platelet count. BLood can be collected in ____ tube and re-run to confirm normal count.
EDTA ; NA citrate
for TTP this rare disorder of the ______ system will cause patient to require _____ to remove inhibitors of ____ factor.
anticoagulation ; plasmapheresis ; VW
give pt ______ to replace normal VW factor
FFP (fresh frozen plasma)
this is a rare but serious disease that requires care under hematologist
TTP
Giant Platelets (abnormalities)
- May-Hegglin Anomaly (giant platelets and Dohle Bodies in the neutrophils)
- Bernard Soulier syndrome
- Alport syndrome
- Storage pool syndrome
- normal total platelet mass
- normal platelet number in circulation
pseudothrombocytopenia
pseudothrombocytopenia causes
- inadequate anticoagulated blood sample
- EDTA-induced platelet clumping
- Giant platelet
- Platelet satellitism
associated with decreased or ineffective magakaryopoiesis and thrombopoiesis
decreased platelet production
decreased platelet production marrow damage
- aplastic anemia
- fanconi’s anemia (defect in DNA repair genes)
- malignancy (w/ or w/o myelopthisis)
decreased platelet production is also associated with
- congenital defect (Congenital thrombocytopenias)
- PNH
decreased platelet production viral infections
rubella, CMV, EBV, HIV, Hep-C
decreased platelet production ineffective production
Nutritional Deficiencies: B12, Folate, Severe Fe deficiency
decreased platelet production drugs
thiazides, estrogen, chemotherapy, linezolid
decreased platelet production toxins
alcohol, cocaine
decreased platelet production marrow failure (pancytopenia)
aplastic anemia, chemotherapy, toxins
decreased platelet production is also associated with
B12, folate or iron deficiency
viral infection
decreased platelet production : drugs that can selectively reduce platelet production
- alcohol
- estrogens
- thiazides
- chlorpropamide
- interferon
decreased platelet production : amegakaryocytic thrombocytopenia
- myelodysplasia (pre-leukemia)
- immune (related to aplastic anemia)
decreased platelet production is also related to the ___ thrombocytopenia and ____ thrombocytopenia
cyclic thrombocytopenia (rare)
inherited thrombocytopenia
TTP is characterized _______ anemia and profound _____
microangiopathic hemolytic anemia ; profound intravascular platelet clumping
disease was first reported in 1923 at beth israel in nyc
TTP
the 16 year old girl who presented with
anemia, petechiae, coma and death
in first TTP, terminal arterioles and cappilaries were occluded by ______ mostly composed of platelets
hyaline thrombi
treatment of platelet disorders - congenital disorders
- platelet transfusions (leucodepleted, HLA compatible and irradiated)
- DDAVP
- Tranexamic acid
- Recombinant factor VIIa
- Bone marrow transplantation
