HEMOPHILIA Flashcards
What is the most common type of hemophilia?
A) Hemophilia A
B) Hemophilia B
C) Hemophilia C
D) Von Willebrand disease
Answer: A) Hemophilia A
Rationale: Hemophilia A accounts for 80% of all hemophilia cases.
Which of the following statements is TRUE about the inheritance of hemophilia?
A) It is an autosomal recessive disorder.
B) It is an X-linked recessive disorder.
C) It is an autosomal dominant disorder.
D) It is a Y-linked disorder.
Answer: B) It is an X-linked recessive disorder.
Rationale: Hemophilia is an X-linked recessive disorder primarily affecting males, while females are generally carriers.
What is the most common genetic mutation causing severe hemophilia A?
A) Point mutation in the F9 gene
B) Inversion of intron 22 in the F8 gene
C) Large deletion in the F9 gene
D) Frameshift mutation in the F8 gene
Answer: B) Inversion of intron 22 in the F8 gene
Rationale: Inversion of intron 22 is found in 40% of cases of severe hemophilia A.
Hemophilia is classified as severe when FVIII or FIX activity is:
A) >25%
B) 6–30%
C) 1–5%
D) <1%
Answer: D) <1%
Rationale: Severe hemophilia is defined by FVIII or FIX activity levels of less than 1%.
What is the hallmark feature of chronic hemarthroses in hemophilia?
A) Acute joint swelling and erythema
B) Synovial thickening and synovitis
C) Increased joint mobility
D) Hematuria
Answer: B) Synovial thickening and synovitis
Rationale: Chronic hemarthroses lead to synovial thickening and synovitis, resulting in progressive joint deformity.
Which laboratory test abnormality is most commonly associated with hemophilia?
A) Prolonged prothrombin time (PT)
B) Prolonged activated partial thromboplastin time (aPTT)
C) Low platelet count
D) Increased bleeding time
Answer: B) Prolonged activated partial thromboplastin time (aPTT)
Rationale: Hemophilia is associated with isolated prolongation of aPTT due to deficient FVIII or FIX activity.
In patients with hemophilia and prolonged aPTT, which condition must be ruled out before confirming the diagnosis?
A) Von Willebrand disease
B) Disseminated intravascular coagulation (DIC)
C) Thrombocytopenia
D) Leukemia
Answer: A) Von Willebrand disease
Rationale: Von Willebrand disease needs to be excluded in cases with prolonged aPTT and low FVIII activity, as it can mimic hemophilia.
What factor extends the circulating half-life of FVIII to approximately 12 hours?
A) Platelets
B) Von Willebrand factor (VWF)
C) Fibrinogen
D) Factor IX
Answer: B) Von Willebrand factor (VWF)
Rationale: FVIII’s half-life is extended when it is complexed with von Willebrand factor.
What is the primary goal of primary prophylaxis in hemophilia management?
A) Prevent spontaneous bleeding episodes
B) Prevent joint abnormalities
C) Maintain clotting factor levels ~1% or higher
D) All of the above
Answer: D) All of the above
Rationale: Primary prophylaxis aims to maintain clotting factor levels ~1% or higher to prevent spontaneous bleeding and joint abnormalities.
Which of the following is true regarding cryoprecipitate in hemophilia treatment?
A) It is enriched with FVIII protein bound to VWF.
B) Each bag contains approximately 80 IU of FVIII.
C) It is primarily used in emergencies when factor concentrates are unavailable.
D) All of the above
Answer: D) All of the above
Rationale: Cryoprecipitate is enriched with FVIII bound to VWF, contains ~80 IU of FVIII per bag, and is reserved for emergency use due to the risk of bloodborne diseases.
What is the half-life of factor IX (FIX)?
A) 8–12 hours
B) 24 hours
C) 48 hours
D) 72 hours
Answer: B) 24 hours
Rationale: FIX has a longer half-life (~24 hours) compared to FVIII (8–12 hours).
Serious bleeds involving the CNS or retroperitoneum require factor levels of:
A) 30–50% for 2–3 days
B) 50–100% for 7–10 days
C) 100% for 1–2 days
D) None of the above
Answer: B) 50–100% for 7–10 days
Rationale: Serious bleeds require sustained factor levels of 50–100% for 7–10 days to ensure proper control and prevent complications.
What is the recommended factor level for prophylaxis in major surgery for hemophilia patients?
A) 30–50% for 2–3 days
B) 50–100% for 1–2 days
C) 100% for 7–10 days
D) 80% for 1–3 days
Answer: C) 100% for 7–10 days
Rationale: Prophylactic replacement for major surgery aims to achieve normal factor levels (100%) for 7–10 days, tapering thereafter based on the surgical wounds.
What is the primary mechanism of action of DDAVP in hemophilia A patients?
A) It directly increases FVIII synthesis.
B) It releases FVIII and VWF from endothelial stores.
C) It increases FIX levels by stimulating the liver.
D) It enhances platelet aggregation.
Answer: B) It releases FVIII and VWF from endothelial stores.
Rationale: DDAVP causes a transient rise in FVIII and VWF by releasing these factors from vascular endothelial stores.
Why is DDAVP not effective in patients with severe hemophilia A?
A) They have no endothelial stores of FVIII to release.
B) DDAVP only affects FIX levels in severe cases.
C) DDAVP is rapidly degraded in these patients.
D) Severe hemophilia A patients are resistant to DDAVP.
Answer: A) They have no endothelial stores of FVIII to release.
Rationale: Severe hemophilia A patients lack sufficient FVIII stores, making DDAVP ineffective.
When using DDAVP, the expected peak increase in FVIII levels occurs:
A) 10–20 minutes after infusion
B) 30–60 minutes after infusion
C) 2–3 hours after infusion
D) Immediately after infusion
Answer: B) 30–60 minutes after infusion
Rationale: FVIII levels typically peak 30–60 minutes after DDAVP administration.
Which of the following is NOT an indication for antifibrinolytic drugs in hemophilia?
A) Bleeding in the gums
B) Gastrointestinal bleeding
C) Oral surgery
D) Hematuria
Answer: D) Hematuria
Rationale: Antifibrinolytic drugs are not recommended for hematuria due to the risk of forming an occlusive clot in the genitourinary tract.
