Coagulation Disorders Flashcards
What is the normal platelet count range?
150,000–450,000/μL.
What is the primary regulator of platelet production?
Thrombopoietin (TPO).
What are the three main processes that can cause thrombocytopenia?
Decreased bone marrow production, sequestration (e.g., in the spleen), and increased platelet destruction.
What is immune thrombocytopenic purpura (ITP)?
An acquired thrombocytopenia caused by autoantibodies against platelet antigens.
What are the two major diagnostic concerns in ITP?
Distinguishing ITP from other causes of thrombocytopenia and Determining if it is primary or secondary.
What is primary ITP?
ITP due to autoimmune mechanisms without an apparent associated condition.
What is secondary ITP?
ITP associated with another condition, such as autoimmune diseases, infections, or medications.
What is the annual incidence of ITP in adults?
Approximately 1 to 6 per 100,000 adults.
What is the prevalence of ITP in adults?
Approximately 12 per 100,000.
What are the common clinical manifestations of ITP?
Petechiae, purpura, epistaxis, and severe bleeding (e.g., intracranial hemorrhage).
What is the typical platelet count in severe ITP?
Below 20,000/μL.
What is the primary mechanism of platelet destruction in ITP?
Autoantibodies (typically IgG) against platelet membrane glycoproteins (e.g., GPIIb/IIIa).
What is the role of autoreactive cytotoxic T cells in ITP?
They contribute to platelet destruction and impaired platelet production.
What is the first-line treatment for ITP?
Corticosteroids (e.g., prednisone, dexamethasone) and IVIG.
What is the second-line treatment for ITP?
Splenectomy, rituximab, or thrombopoietin (TPO) agonists (e.g., romiplostim, eltrombopag).
What is the prognosis of ITP in adults?
Most adults reach a stable platelet count, but many require ongoing therapy. Spontaneous remission occurs in 10-20% of cases.
What is the most common inherited coagulation disorder?
Hemophilia A (factor VIII deficiency).
What is the inheritance pattern of hemophilia A and B?
X-linked recessive.
What is the incidence of hemophilia A worldwide?
1 in 10,000 males.
What is the most common bleeding manifestation in severe hemophilia?
Hemarthrosis (bleeding into joints).
What is the classification of hemophilia based on factor activity?
Severe (<1%), moderate (1-5%), and mild (6-30%).
What is the primary treatment for hemophilia?
Factor replacement therapy (e.g., FVIII for hemophilia A, FIX for hemophilia B).
What is the goal of primary prophylaxis in hemophilia?
To maintain clotting factor levels at ≥1% to prevent bleeding episodes.
What is the most serious complication of hemophilia?
Intracranial hemorrhage or bleeding into critical areas (e.g., oropharyngeal spaces).
What is the most common inhibitor complication in hemophilia?
Development of neutralizing antibodies against factor VIII or IX.
What is the most common infectious complication in hemophilia?
Hepatitis C virus (HCV) and HIV due to contaminated blood products.
What is the most common cause of acquired coagulopathy?
Disseminated intravascular coagulation (DIC).
What is the most common vitamin deficiency causing coagulopathy?
Vitamin K deficiency.
What is the most common liver disease-related coagulopathy?
Impaired synthesis of clotting factors due to liver failure.
What is the most common inherited factor deficiency after hemophilia A and B?
Factor XI deficiency (hemophilia C).
What is the most common cause of an isolated prolonged PT?
Factor VII deficiency.
What is the most common cause of an isolated prolonged aPTT?
Hemophilia A or B, or factor XI deficiency.
What is the next step if both PT and aPTT are prolonged?
Perform a mixing study to determine if there is a factor deficiency or inhibitor.
What is the most common bleeding site in hemophilia?
Joints (hemarthrosis), especially knees, elbows, and ankles.
What is the most common life-threatening bleeding in hemophilia?
Intracranial hemorrhage or bleeding into the retroperitoneum.
What is the most common cause of thrombocytopenia in ITP?
Autoimmune destruction of platelets by antiplatelet antibodies.
What is the role of bone marrow examination in ITP?
Reserved for patients with atypical features or those who do not respond to initial therapy.
What is the most common laboratory finding in ITP?
Isolated thrombocytopenia with large platelets on peripheral smear.
What is the most common cause of secondary ITP?
Autoimmune diseases (e.g., SLE), infections (e.g., HIV, HCV), or medications.
What is the most common bleeding symptom in ITP?
Mucocutaneous bleeding (e.g., petechiae, purpura, epistaxis).
What is the most common treatment for severe ITP bleeding?
High-dose corticosteroids and IVIG.
What is the most common complication of splenectomy in ITP?
Increased risk of infections (e.g., encapsulated bacteria).
What is the most common cause of acquired hemophilia?
Development of autoantibodies against factor VIII.
What is the most common cause of vitamin K deficiency?
Malabsorption, liver disease, or use of warfarin.
What is the most common cause of DIC?
Sepsis, trauma, or malignancy.
What is the most common inherited platelet function disorder?
Von Willebrand disease (vWD).
What is the most common type of von Willebrand disease?
Type 1 vWD (partial quantitative deficiency of von Willebrand factor).
What is the most common treatment for von Willebrand disease?
Desmopressin (DDAVP) or von Willebrand factor concentrates.
What is the most common cause of acquired von Willebrand syndrome?
Underlying conditions such as myeloproliferative disorders or autoimmune diseases.
What is the most common cause of thrombocytopenia in hospitalized patients?
“Drug-induced thrombocytopenia (e.g., heparin-induced thrombocytopenia)
