Labs
What is the first lab finding in quantitive platelet disorders?
Thrombocytopenia
Classic presentation of someone with HUS? (think age and CC)
A kid with bloody diarrhea
What is the average age of onset for TTP?
40 years old
What are the receptors used primary hemostasis? Which one is affected in ITP
1. GPIb and GPIIb/IIIa
2. autoantibodies against GPIIb/IIIa
This person started drinking coffee at 3 years old
What is the precursor to platelets?
Megakaryocytes
Schistocytes
Microthrombi form and destroy RBCs as they pass over
What is the enzyme that is deficient in TTP? What is the normal function?
ADAMTS13
Usually cleaves von Willebrand factor. VWF is normally large and this protease cleaves the multimers into smaller sizes so appropriate amount of platelets bind
How does ITP differ from TTP?
Both can be autoantibody related. TTP is autoantibodies against ADAMTS13 while ITP is autoantibodies against GPIIB.
This person does anki on the stairclimber at level 10
Mikayla!
Normal Hemoglobin and WBC
Thrombocytopenia
Peripheral blood smear: normal RBCs, few large platelets, no schistocytes
What is the diagnosis?
Immune Thrombocytopenia
What is the triad of symptoms of HUS?
1. Thrombocytopenia
2. AKI
3. Microaniopathic Hemolytic Anemia
What causes the enzyme deficiency? (Bonus name the treatment)
1) Acquired TTP: autoantibodies against ADAMTS13
2) Congenital TTP: gene mutations resulting in deficiency of ADAMTS13
What would be seen on a blood smear for ITP?
Megathrombocytes (enlarged and immature platelets)
This person would be seen zooming around campus on an electric scooter
Joey
Normal platelets and RBCs
Platelet aggregation shows absent aggregation response to ADP, epinephrine, collagen, and thrombin, but normal aggregation response when exposed to Ristocetin.
What is the diagnosis? Bonus what is the Ristocetin test?
Glanzmann Thrombastenia (GPIIb/GPIIa receptor complex)
What bacterial toxin is associated with HUS?
What is the classic pentad of clinical findings for TTP?
1. Fever
2. Anemia (MAHA)
3. Thrombocytopenia
4. Renal Symptoms
5. Neuro Symptoms
What is first line treatment for ITP? What is second line?
First Line: corticosteroids + IVIG
Second Line: Splenectomy
This person had an achilles tendon injury
Patrick
60 year old man develops severe thrombocytopenia and thrombosis despite being on an anticoagulant. Platelet count drops from 250,000/uL to 45,000/uL.
Whats going on?
Heparin Induced Thrombocytopenia (HIT)
HUS does not affect the coagulation cascade. PT, PTT, and D-dimer are all normal. DIC is the pathologic activation of the coagulation cascade which consumes clotting factors, platelets, and triggers secondary fibrinolysis.
Describe the steps of primary hemostasis
1. endothelial damage exposes subendothelial collagen
2. vWF binds collagen
3. platelets bind vWF via Gp1b
4. conformational change exposes GpIIa/GpIIb allowing for aggregation of platelets
How is ITP different from Glanzmann Thrombasthenia?
ITP --> autoantibodies (IgG) against GPIIb/IIIa
Glanzmann --> genetic mutation leading to deficiency or dysfunction of the GPIIb/IIIa receptor
These two people competed in the STL Honors Division Science Fair in 2019
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