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Question 361
Physiology → Haematology
Classification
Question
SSBAQuestion Header
A patient with an inherited coagulation disorder has normal initial haemostasis but subsequently develops persistent oozing when vascular spasm wears off.
Question Stem
Which combination best identifies the disorder and its treatment?
Options
A
Autosomal dominant factor VII deficiency treated with vitamin K
B
X-linked recessive factor IX deficiency treated with platelet transfusion
C
X-linked recessive factor VIII deficiency treated by supplying factor VIII
D
Autosomal recessive factor V deficiency treated with factor VII
E
X-linked dominant platelet disorder treated with factor XIII
Explanation
Haemophilia A is associated with a recessive abnormality of the X chromosome and deficiency of factor VIII, affecting the intrinsic pathway. Initial haemostasis due to vascular closure is preserved, so bleeding time is normal, but failure of clotting becomes apparent as persistent oozing after vascular spasm wears off. Treatment is replacement of the missing factor VIII.
Option Validity
A) Haemophilia A is associated with an X-linked recessive abnormality and factor VIII deficiency, not an autosomal dominant factor VII disorder.
B) The described Haemophilia A defect is factor VIII deficiency; platelet transfusion does not replace the missing coagulation factor.
D) Factor V deficiency does not correspond to the described X-linked factor VIII disorder or its treatment.
E) Haemophilia A is a coagulation-factor deficiency rather than an X-linked dominant platelet disorder, and treatment is replacement of factor VIII.
Further Reading
Saxena. Textbook for MRCOG-1. Physiology - Haematology - Haemophilia A, p.72.