Coagulation Flashcards
Platelet aggregometry
Basic principles
Molecular targets
More light passes through when aggregated
Ristocetin - reliant on GP1b + vWF
All others (ADP, collagen, thromboxane A2, epinephrine (weakest) - GP 2b/3a
vWD Type 2B - platelet agg results
No agg with ristocetin
Rest normal
Glanzmann’s thrombasthenia
- Defect
- platelet agg results
- CBC
Glanzmann’s thrombasthenia
- Reduced GP 2b/3a
- No agg with ADP, collagen, TXA2, epinephrine. Reduced with ristocetin
- Normal platelets
Bernard Soulier
- Defect
- platelet agg results
- CBC
Bernard Soulier
- Reduced GP1b
- No agg with ristocetin
- Thrombocytopenia, Large platelet with pseudonucleus
4 T’s of HIT - HIT Type 1
degree of Thrombocytopenia - > 100
Timing - within 2 days of starting
Thrombosis - no risk
(oTher causes)
4 T’s of HIT - HIT Type 2
degree of Thrombocytopenia - < 100 ()also schistocytes)
Timing - 4-10 days of starting
Thrombosis - yes
(oTher causes)
vWD - Inheritance
Autosomal dominant EXCEPT 2N and 3
Hemophilia - inheritance
A and B are X-linked recessive
C is autosomal w partial dominance
Factor with shortest half life?
Factor 7
Platelet alpha vs dense granules
Alpha granules = large proteins (PDGF, vWF, PF4, fibrinogen)
Dense granules = small molecules (ADP, Ca2+, serotonin, histamine)
UFH vs LMWH
- Targets
- Clearance
- Dosing
- Monitoring
- UFH-AT3 mostly target thrombin (F2) and 10a, vs LMWH-AT3 mostly 10a
- UFH hepatically cleared, LWMH renally cleared
- UFH given IV, LWMH given IM
- UFH monitored by PTT, LWMH not routinely monitored
Protein C and S targets
Factor 5 and 8
Antithrombin targets
Factor 2 (thrombin) and factor 10a
Thrombin time vs Reptilase time
- Assay
- What it measures
- Diseases
Thrombin time
- Exogenous thrombin + platelet poor plasma
- Measures common pathway + fibrinogen to fibrin
- Elevated with paraprotein, amyloid, heparin, dysfibrinogenemia
Reptilase time
- Venom + PPP
- Measures only fibrinogen to fibrin
- Elevated with dysfibrinogenemia
Platelet storage disorders
- Defect
- platelet agg results
- CBC
Platelet storage disorders
- Defic in dense or alpha granules
- No second wave of agg
- Normal morphology
Defect:
Gray platelet
Quebec
Wiskott-Aldrich
Chediak-Higashi
Hermansky-Pudlak
Gray platelet - no alpha granules (large gray plt)
Quebec - no alpha granules
Wiskott-Aldrich - no dense granules
Chediak-Hiashi - no dense grnaules
Hermansky-Pudlak - no dense granules (swiss cheese plt)
NSAIDs - platelet agg results
No second wave to ADP and epi
No response at all to collagen or arachidonic acid
Ristocetin vWF : vWF antigen - high vs low
High Rcof:vWF Ag - vWD 2A
Low Rcof:vWF Ag - vWD 2M
vWD 2M
Defective GP1b binding, but no loss in large multimers
Factor 12 defic -symptoms, labs
Factor 12 defic
- No bleeding but increased risk of thrombosis
- Increased PTT, low prekallikrein, low HMWF
Factor 13 defic - symptoms, labs
Factor 13 defic
- Initially clot well but then delayed bleeding when clot breaks down
- Normal PT, PTT. Clot stability test - 5M urea
Vitamin K factors
2, 7, 9 10, C and S
TTP vs HUS
- Clinical
- Labs
- Treatment
- Clinical:
TTP = more neuro, microthrombi in other organs - Labs:
TTP = big vWF multimers, cant cleave
HUS = normal vWF cleavage - Treatment:
TTP = FFP + steroids + IVIG + splenectomy
HUS = supportive + antibiotics
Activated Protein C Resistance Assay
Add protein C to specimen
- No APCR ten increase PTT > 2:1
- APCR then increase PTT < 2:1
