Pre-5: Quantitative Disorders Flashcards
Normal platelet count
150-400 x 10^9/L
Thrombocytopenia
50-100 x 10^9/L
Thrombocytopenia results from three distinct mechanisms:
- Deficient Platelet Production
- Abnormal Distribution of Platelets
- Increased Platelet Destruction
Deficient platelet production
- Myelophthisis
- Aplasia
- Ineffective erythropoiesis
- Congenital Disorders
Abnormal platelet distribution
Hypersplenism
Hemangiomas
Increased platelet destruction
Immune origin - primary
Immune origin - secondary
Microangiopathic thrombocytoepnia
Pregnancy-associated thrombocytopenia
Caused by an auto-Ab to the patient’s plts
Idiopathic Thrombocytopenic Purpura (ITP)
Most common disorder causing severe isolated thrombocytopenia
Idiopathic Thrombocytopenic Purpura (ITP)
In chronic ITP, the target for the autoantiplatelet antibodies is platelet membranes which are
GP IIb/IIIa
GP Ib/IX
GP Ia/IIa
GP VI
Treatment for Idiopathic Thrombocytopenic Purpura (ITP)
Splenectomy
Corticosteroid (Prednisone)
IVIG
Caused by an alloantibody to HPA-1a (Human Platelet Antibody-1a)
Post-Transfusion Purpura (PTP)
The recipient’s plasma is found to contain alloantibodies to antigens on the platelets or platelet membrane of the transfused blood product, directed against antigen the recipient does not have
Post-Transfusion Purpura (PTP)
Treatment for Post-Transfusion Purpura (PTP)
Plasmapheresis
Rare hemolytic disease of newborn
Isoimmune Neonatal Thrombocytopenia
Fetal-maternal incompatibility of platelet antigens, and destruction of fetal platelets by a transplacental transfer of maternal antibody
Isoimmune Neonatal Thrombocytopenia
recognized as the most common cause of Drug-Induced Immune Thrombocytopenia (DIIT)
Quinine
develops secondary to antibody produced to Platelet factor 4 - Heparin complex
Heparin-Induced Thrombocytopenia and Thrombosis (HITT)
Heparin-Induced Thrombocytopenia and Thrombosis (HITT)
- Appears 4-7 days after treatment
- As low as 20x10^9/L
- Severe thrombocytopenia and thrombotic episodes
TYPE 2
Heparin-Induced Thrombocytopenia and Thrombosis (HITT)
- Appears early in treatment
- Rarely falls below 100x10^9 /L
- NO resultant bleeding or thrombotic complications
TYPE 1
directly related to the accumulation of ultra large von Willebrand factor (ULVWF) multimers in the plasma due to deficiency of the von Willebrand factor cleaving protease known as a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13)
Thrombotic Thrombocytopenic Purpura (TTP)
Mutations in ADAMTS-13 gene
Congenital/Familial TTP
Antibodies anti-ADAMTS13
Idiopathic TTP
Classic PENTAD of TTP
FAT RN
- Fever
- Anemia
- Thrombocytopenia
- Renal failure
- Neurologic findings
Shiga-toxin-producing organisms
Hemolytic Uremic Syndrome (HUS)
Bacteria responsible for HUS
Escherichia coli 0157:H7
Types of HUS:
- usually involves diarrhea
- primarily affects infants, small children
- associated with shiga toxin
- often resolves with supportive care, with recovery of renal function
Typical HUS (90%)
Types of HUS:
- may or may not involve diarrhea
- can affect children or adults
- may be familiar or sporadic
- requires immediate attention to avoid fatality and optimize outcomes
Atypical HUS (10%)
TRIAD for HUS
RAT:
- Renal injury
- Anemia
- Thrombocytopenia
A complication or intermediary phase of many diseases such as liver disease, renal disease, and lymphoproliferative disorders
Disseminated Intravascular Coagulation (DIC)
Positive for D-Dimer assay (most specific test)
Disseminated Intravascular Coagulation (DIC)
● Thrombocytopenia
● The PT, PTT, and thrombin time are prolonged
● The fibrinogen level is reduced to less than 100 mg/dL
● Fibrin degradation products, inducing D-dimers, are significantly increased
Acute, uncompensated DIC
● Normal or Elevated
● The only elevated result may be the D-dimer assay
Chronic, compensated DIC
HELLP syndrome;
Hemolysis
Elevated Liver enzymes
Low Platelet count
Defined as platelet count above normal range
THRombocytosis
<1,000 x 10^9/L
Normal platelet function
Secondary Thrombocytosis
(REACTIVE)
> 1,000 x 10^9/L
Defective platelet function
Primary Thrombocytosis
(AUTONOMOUS)
