Hemostasis and Related Disorders Flashcards
What are the two important molecules inside WEIBEL-PALADE bodies responsible for endothelial function?
W: vWF (role in hemostasis)
P: P-selectin (role in inflammation)
What are the two sources of vWF?
- WEIBEL-PALADE bodies of ENDOTHELIAL cells
2. alpha granules of PLATELETS
Do quantitative platelet disorders (thrombocytopenia) or qualitative platelet disorders show PETECHIAE?
QUANTITATIVE PLATELET - i.e. THROMBOCYTOPENIA
What is the most common cause of THROMBOCYTOPENIA in children and adults? What is the pathophysiology?
IMMUNE THROMBOCYTOPENIC PURPURA (ITP) -
Spleen plasma B cells produce IgG AutoAbs -> IgG Ab bind GPIIb/IIIa receptors on PLT -> Ab-bound PLTS are then CONSUMED by splenic macrophages
**Spleen = makes + consumes plasma cell IgG
Which age population is CHRONIC IMMUNE THROMBOCYTOPENIC PURPURA most prevalent in? Which disease state is a SECONDARY cause of chronic ITP?
Women of child-bearing age
SLE (Lupus) is an important secondary cause of ITP
What are the three treatment plans in order of severity for IMMUNE THROMBOCYTOPENIC PURPURA?
- Corticosteroids - Effective moreso in the acute form classically seen in children
- IVIG - To overrun the splenic macrophages system to consume the IVIGs rather than IgG-bound to platelets (EFFECT IS SHORT-LIVED: Mainly to fend off a fatal complication of intracranial hemorrhage)
- SPLENECTOMY - Remove primary source of IgG + site of destruction (ONLY in refractory cases)
Helmet, sheared RBC on blood smear
SCHISTOCYTE
What are the two etiologies of microangiopathic hemolytic uremia?
TTP: Thrombotic thrombocytopenic purpura
HUS: hemolytic uremic syndrome
What enzyme is deficient in TTP? What does it do?
ADAMTS13 - Enzyme that breaks down vWF multimers into smaller monomers for eventual degradation
Who is the most common population affected by thrombotic thrombocytopenic purpura? What is the most common means of acquiring TTP?
ADULT FEMALES with an autoimmune disease who acquired autoAb against ADAMTS13
Who is the most common population affected by hemolytic uremic syndrome? What is the most common means of acquiring HUS?
CHILDREN
After exposure to uncooked meat -> Acquiring E.coli O157:H7 infection and e.coli VEROTOXIN -> Damages endothelial cells -> PLT microthrombi -> RBC get sheared while passing through -> SCHISTOCYTES
Which infection causes hemolytic uremic syndrome? What is the toxin?
E.Coli O157:H7
E.Coli VEROTOXIN
Which system is predominantly affected by HEMOLYTIC UREMIC SYNDROME?
Renal insufficiency
Which system is predominantly affected by THROMBOTIC THROMBOCYTOPENIC PURPURA?
CNS Abnormalities
How do IMMUNE THROMBOCYTOPENIC PURPURA and MICROANGIOPATHIC HEMOLYTIC ANEMIA differ in terms of lab findings?
SAME except for the presence of schistocytes and anemia in MICROANGIOPATHIC HEMOLYTIC ANEMIA
SAME FINDINGS: Thrombocytopenia, Increased bleeding time, Normal PT/PTT, Megakaryocyte hyperplasia on bone marrow
What is the treatment plan for MICROANGIOPATHIC HEMOLYTIC ANEMIA, particularly due to THROMBOTIC THROMBOCYTOPENIA PURPURA?
- PLASMAPHERESIS: Removes proteins from blood and thus removes autoAb against ADAMTS13
- CORTICOSTEROIDS - Decrease overall Ab protein prdn
Which qualitative platelet disorder impairs PLATELET ADHESION ONLY (specifically GP1b deficiency)?
BERNARD SOULIER SYNDROME
Which qualitative platelet disorder impairs PLATELET AGGREGATION by affecting degranulation process (specifically lowers TXA2 levels)?
ASPIRIN TOXICITY
Which qualitative platelet disorder impairs PLATELET AGGREGATION ONLY (specifically GPIIb/IIIa deficiency)?
GLANZMANN THROMBASTHENIA
Which qualitative platelet disorder impairs BOTH PLATELET AGGREGATION and ADHESION?
UREMIA -Poor kidney function -> Buildup of nitrogenous waste
What is the major difference in sites of bleeding between disorders of primary hemostasis versus those of secondary hemostasis?
PRIMARY HEMOSTASIS DISORDERS - Mucosal (particularly epistaxis) + Skin bleeding
SECONDARY HEMOSTASIS DISORDERS - Deep tissue and joint bleeding, re-bleeding after surgical procedures
INTRINSIC PATHWAY
PTT (More letters than PT, More coagulation factors involved), SEC (subendothelial collagen), HEP (3 letter pattern, more accurate measurement of effect of heparin than coumadin)
EXTRINSIC PATHWAY
PT, TT (Tissue thromboplastin factor), Coumadin
What is the inheritance pattern of HEMOPHILIA A? What factor is deficient in this d/o?
X-linked recessive
Generally mother is asymptomatic with the grandfather having a tendency to bleed (hemophilia)
HEMOPHILIA AAAEIGHT = DEFICIENCY OF factor EIGHT
What are the lab findings of HEMOPHILIA A?
INCREASED PTT, Normal PT
DECREASED Factor VIII
Normal platelet count (150-400K), Normal bleeding time (5-7min)
What is the Tx of HEMOPHILIA A
Recombinant FVIII