Bleeding Patient Review excel Flashcards
How big are platelets?
2-3 uM in diameter
How long to platelets live?
9-10 in circulation
T or F: Newly formed platelets are smaller than normal platelets?
False. Larger (megathrombocytes)
T or F: Platelets have mitochondria?
TRUE
What are the platelet granules and what do they contain?
Dense - ATP, ADP, serotonin, calcium. Alpha - vWF, fibrinogen, Factor V, factors for platelet activation. Lysosomal - acid hydrolases.
Which platelet receptor interacts directly with the exposed subendothelium.
GpVI
T or F: A hemophiliac with normal platelet count and function will have a normal bleeding time?
True. Bleeding time is the platelet plug formation (primary hemostasis).
Which disorders will have decreased bleeding time?
Disorders of low platelet count or abnormal platelet function.
What is used more commonly instead of bleeding time now?
PFA-100 test (platelet function analyzer)
T or F: vWF disease will cause increased bleeding time?
True. A disorder of primary and secondary hemostasis
What type of vWF disease does DDAVP (arginine vasopressin treat)?
Type 1 only.
How do you test for Bernard-Soulier syndrome?
Ristocetin test. According to pathoma, platelets will also be very large (Big Suckers)
What is afibrogenemia?
Defects in fibrinogen. A primary and secondary hemostasis disorder due to lack of GpIIb/IIIa interaction and fibrin clot formation
What does Clopidogrel (Plavix) do?
ADP receptor inhibitor
What are the treatments for ITP?
corticosteroids, rituximab, IVIG, splenectomy, TPO agonist
What is the differential for thrombocytopenia?
Bone marrow disorder - aplastic anemia, primary myelofibrosis, myeldysplatic syndrome, leukemia; Metastasic cancer; TB; Toxins; B12/folate deficiency; ITP - auto or alloimmunity; TTP; HUS; DIC
What are the characteristics of TTP?
fever, renal insufficiency, microangiopathic hemolytic anemia with schistocytes, metal status changes, thrombocytopenia, release of large vWF multimers
What causes TTP?
Deficiency in ADAMTS13, which cleaves vWF multimers
What are the characteristics of HUS?
Similar to TTP but usually more renal failure
What type of bleeding is associated with a primary hemostasis disorder?
Mucocutaneous bleeding
What type of bleeding is associated with a secondary hemostasis disorder?
soft tissue/joint/deep bleeding
How can you test for fibrinogen defects?
Thrombin clotting time (TCT)
What is the main growth factor for megakaryocytes?
TPO (thrombopoetin)
What are the 4 events in the formation of a platelet plug?
adhesion, activation, aggregation, fibrin formation
Which platelet receptor binds to collagen?
Gp1a/2a
What are the 4 major ways platelet count can be decreased quantitatively?
Decreased production, abnormal distribution, increased destruction, dilution
What are the 2 major ways platelet count can be decreased qualitatively?
Inherited disorder, acquired disorder (medications, renal failure, cardiopulmonary bypass)
What is a normal platelet count?
150-400, 000/ uL
What is pseudothrombocytopenia?
appearance of platelet aggregation in a smear due to processing (typically caused by EDTA). Solution - run second smear using sodium citrate.
What is the differential for impaired/decreased platelet production?
Bone marrow failure, nutrition, ETOH, malignancies, drug-induced, radiation, viral infection
What is the differential for platelet disorders of dilution or distribution?
Hypersplenism, ETOH, hematologic disorders, storage diseases, consumption due to active bleeding or clotting, massive transfusion
What are major risks of long-term TPO agonist use?
myelofibrosis, thrombosis
What is the differential for disorders of increased destruction of platelets?
ITP, autoimmune (Lupus, RA), drugs, DIC, sepsis, TTP, post-transfusion purpura
What is the inheritance pattern of von Willebrand Disease?
Autosomal dominant
What does brisk bleeding from obvious trauma suggest about a bleeding disorder?
Local vascular defect
What does prolonged/recurrent bleeding suggest about a bleeding disorder?
generalized hemostatic disorder
What does sudden resumption of bleeding suggest about a bleeding disorder?
excessive fibrinolysis or abnormal crosslinking of fibrin
What does multiple site bleeding suggest about a bleeding disorder?
More severe, generalized hemostatic disorder
What other disorder may cause abnormal results in PFA-100 test?
anemia
T or F: Medications can cause abnormal PFA-100 tests.
True, aspirin and NSAIDs.
T or F: PFA-100 test can distinguish clotting disorder from low platelet count?
FALSE
