Hemophilia A is caused due to deficiency of which clotting factor?

Appeared in: MNS 2024

Explanation

Hemophilia A, or classic hemophilia, is the most common hereditary coagulation disorder, caused by a deficiency of clotting Factor VIII.
It is an X-linked recessive disorder, which means it predominantly affects males, while females are usually carriers.
Factor VIII is a crucial cofactor in the intrinsic pathway of the coagulation cascade, and its absence impairs the ability to form a stable fibrin clot, leading to prolonged bleeding.
The severity of bleeding in Hemophilia A correlates with the level of Factor VIII activity; levels below 1% are considered severe.

Option A: A deficiency in Factor IX causes Hemophilia B, not Hemophilia A.
Option B: Factor X deficiency is a rare, autosomal recessive bleeding disorder known as Stuart-Prower factor deficiency. It affects the common pathway of coagulation.
Option D: Factor VII deficiency is another rare, autosomal recessive bleeding disorder. It affects the extrinsic pathway of coagulation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of Hemophilia A as background academic context rather than a clinical decision trigger.
Nurses must be vigilant in preventing injury in patients with hemophilia. This includes patient education about avoiding contact sports and using protective gear.
A key nursing intervention is to avoid intramuscular (IM) injections and use the subcutaneous route whenever possible to prevent deep muscle hematomas.
During a bleeding episode (hemarthrosis), the nurse should apply the RICE principle (Rest, Ice, Compression, Elevation) and administer the prescribed factor concentrate promptly.

How to Approach the Question

First, identify the core concept of the question, which is the specific clotting factor deficiency associated with 'Hemophilia A'.
This is a factual recall question. Access your knowledge base regarding bleeding disorders.
Differentiate between the common types of hemophilia: Hemophilia A (Factor VIII), Hemophilia B (Factor IX), and Hemophilia C (Factor XI).
Eliminate the options that are associated with other types of hemophilia or different coagulation disorders.
Select the option that correctly links Hemophilia A with its corresponding deficient factor.

Concept Tested & Keywords

QRKzoK76lPf7qxUQ9UFWDr

E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 134-136

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 671-673

E6 Medicine Davidson Principles Practice 24e p. 991-993

Practise the full MNS 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.