Coagulation Disorders

Question 1

What is the normal platelet count range?

Answer 1

150,000–450,000/μL.

Question 2

What is the primary regulator of platelet production?

Answer 2

Thrombopoietin (TPO).

Question 3

What are the three main processes that can cause thrombocytopenia?

Answer 3

Decreased bone marrow production, sequestration (e.g., in the spleen), and increased platelet destruction.

Question 4

What is immune thrombocytopenic purpura (ITP)?

Answer 4

An acquired thrombocytopenia caused by autoantibodies against platelet antigens.

Question 5

What are the two major diagnostic concerns in ITP?

Answer 5

Distinguishing ITP from other causes of thrombocytopenia and Determining if it is primary or secondary.

Question 6

What is primary ITP?

Answer 6

ITP due to autoimmune mechanisms without an apparent associated condition.

Question 7

What is secondary ITP?

Answer 7

ITP associated with another condition, such as autoimmune diseases, infections, or medications.

Question 8

What is the annual incidence of ITP in adults?

Answer 8

Approximately 1 to 6 per 100,000 adults.

Question 9

What is the prevalence of ITP in adults?

Answer 9

Approximately 12 per 100,000.

Question 10

What are the common clinical manifestations of ITP?

Answer 10

Petechiae, purpura, epistaxis, and severe bleeding (e.g., intracranial hemorrhage).

Question 11

What is the typical platelet count in severe ITP?

Answer 11

Below 20,000/μL.

Question 12

What is the primary mechanism of platelet destruction in ITP?

Answer 12

Autoantibodies (typically IgG) against platelet membrane glycoproteins (e.g., GPIIb/IIIa).

Question 13

What is the role of autoreactive cytotoxic T cells in ITP?

Answer 13

They contribute to platelet destruction and impaired platelet production.

Question 14

What is the first-line treatment for ITP?

Answer 14

Corticosteroids (e.g., prednisone, dexamethasone) and IVIG.

Question 15

What is the second-line treatment for ITP?

Answer 15

Splenectomy, rituximab, or thrombopoietin (TPO) agonists (e.g., romiplostim, eltrombopag).

Question 16

What is the prognosis of ITP in adults?

Answer 16

Most adults reach a stable platelet count, but many require ongoing therapy. Spontaneous remission occurs in 10-20% of cases.

Question 17

What is the most common inherited coagulation disorder?

Answer 17

Hemophilia A (factor VIII deficiency).

Question 18

What is the inheritance pattern of hemophilia A and B?

Answer 18

X-linked recessive.

Question 19

What is the incidence of hemophilia A worldwide?

Answer 19

1 in 10,000 males.

Question 20

What is the most common bleeding manifestation in severe hemophilia?

Answer 20

Hemarthrosis (bleeding into joints).

Question 21

What is the classification of hemophilia based on factor activity?

Answer 21

Severe (<1%), moderate (1-5%), and mild (6-30%).

Question 22

What is the primary treatment for hemophilia?

Answer 22

Factor replacement therapy (e.g., FVIII for hemophilia A, FIX for hemophilia B).

Question 23

What is the goal of primary prophylaxis in hemophilia?

Answer 23

To maintain clotting factor levels at ≥1% to prevent bleeding episodes.

Question 24

What is the most serious complication of hemophilia?

Answer 24

Intracranial hemorrhage or bleeding into critical areas (e.g., oropharyngeal spaces).

Question 25

What is the most common inhibitor complication in hemophilia?

Answer 25

Development of neutralizing antibodies against factor VIII or IX.

Question 26

What is the most common infectious complication in hemophilia?

Answer 26

Hepatitis C virus (HCV) and HIV due to contaminated blood products.

Question 27

What is the most common cause of acquired coagulopathy?

Answer 27

Disseminated intravascular coagulation (DIC).

Question 28

What is the most common vitamin deficiency causing coagulopathy?

Answer 28

Vitamin K deficiency.

Question 29

What is the most common liver disease-related coagulopathy?

Answer 29

Impaired synthesis of clotting factors due to liver failure.

Question 30

What is the most common inherited factor deficiency after hemophilia A and B?

Answer 30

Factor XI deficiency (hemophilia C).

Question 31

What is the most common cause of an isolated prolonged PT?

Answer 31

Factor VII deficiency.

Question 32

What is the most common cause of an isolated prolonged aPTT?

Answer 32

Hemophilia A or B, or factor XI deficiency.

Question 33

What is the next step if both PT and aPTT are prolonged?

Answer 33

Perform a mixing study to determine if there is a factor deficiency or inhibitor.

Question 34

What is the most common bleeding site in hemophilia?

Answer 34

Joints (hemarthrosis), especially knees, elbows, and ankles.

Question 35

What is the most common life-threatening bleeding in hemophilia?

Answer 35

Intracranial hemorrhage or bleeding into the retroperitoneum.

Question 36

What is the most common cause of thrombocytopenia in ITP?

Answer 36

Autoimmune destruction of platelets by antiplatelet antibodies.

Question 37

What is the role of bone marrow examination in ITP?

Answer 37

Reserved for patients with atypical features or those who do not respond to initial therapy.

Question 38

What is the most common laboratory finding in ITP?

Answer 38

Isolated thrombocytopenia with large platelets on peripheral smear.

Question 39

What is the most common cause of secondary ITP?

Answer 39

Autoimmune diseases (e.g., SLE), infections (e.g., HIV, HCV), or medications.

Question 40

What is the most common bleeding symptom in ITP?

Answer 40

Mucocutaneous bleeding (e.g., petechiae, purpura, epistaxis).

Question 41

What is the most common treatment for severe ITP bleeding?

Answer 41

High-dose corticosteroids and IVIG.

Question 42

What is the most common complication of splenectomy in ITP?

Answer 42

Increased risk of infections (e.g., encapsulated bacteria).

Question 43

What is the most common cause of acquired hemophilia?

Answer 43

Development of autoantibodies against factor VIII.

Question 44

What is the most common cause of vitamin K deficiency?

Answer 44

Malabsorption, liver disease, or use of warfarin.

Question 45

What is the most common cause of DIC?

Answer 45

Sepsis, trauma, or malignancy.

Question 46

What is the most common inherited platelet function disorder?

Answer 46

Von Willebrand disease (vWD).

Question 47

What is the most common type of von Willebrand disease?

Answer 47

Type 1 vWD (partial quantitative deficiency of von Willebrand factor).

Question 48

What is the most common treatment for von Willebrand disease?

Answer 48

Desmopressin (DDAVP) or von Willebrand factor concentrates.

Question 49

What is the most common cause of acquired von Willebrand syndrome?

Answer 49

Underlying conditions such as myeloproliferative disorders or autoimmune diseases.

Question 50

What is the most common cause of thrombocytopenia in hospitalized patients?

Answer 50

"Drug-induced thrombocytopenia (e.g., heparin-induced thrombocytopenia)