Question

The nurse is caring for a client admitted with bleeding tendencies. The physician suspects hemophilia. Which laboratory value supports the diagnosis? A. Prolonged aPTT B. Increased protime C. Abnormal fibrinogen level D. Increased platelet count

Short answer

Answer: Prolonged aPTT (activated partial thromboplastin time)

Step-by-step solution

Understand Hemophilia

Hemophilia is a rare genetic bleeding disorder that affects the blood's ability to clot, causing excessive bleeding even from minor injuries. The two main types of hemophilia are hemophilia A and hemophilia B, both resulting from deficiencies in clotting factors VIII and IX, respectively.

Analyze the Laboratory Values

Now, let's analyze the different lab values given in the options: A. Prolonged aPTT (activated partial thromboplastin time): aPTT is a test that measures the time it takes for blood to clot in a sample. A prolonged aPTT indicates a deficiency or dysfunction in the intrinsic and common clotting pathways, including factors VIII and IX. B. Increased protime (prothrombin time): Prothrombin time measures the clotting ability of the extrinsic and common pathways. An increase in protime suggests issues with clotting factors involved in these pathways (factors II, V, VII, and X). C. Abnormal fibrinogen level: Fibrinogen is a protein involved in the final stages of the clotting process, and an abnormal fibrinogen level suggests an issue with the production or function of fibrinogen itself. D. Increased platelet count: Platelets are small cells in the blood that help form clots to stop bleeding. An increased platelet count suggests that the number of platelets is not the cause of a bleeding disorder.

Choose the Correct Laboratory Value

Based on our analysis of the given options, the laboratory value that best supports the diagnosis of hemophilia is prolonged aPTT (Option A). This is because a prolonged aPTT signals issues with the intrinsic and common clotting pathways that involve clotting factors VIII and IX, which are precisely deficient in hemophilia A and hemophilia B.

Key concepts

Hemophilia

Hemophilia is an inherited bleeding disorder where the blood doesn't clot normally due to a lack of sufficient blood-clotting proteins, specifically clotting factors. This condition can result in prolonged bleeding after an injury or surgery. Hemophilia A and B are the most common types, caused by deficiencies in clotting factor VIII and IX, respectively.
The disorder is genetic and primarily affects males, as it is linked to the X chromosome. Females can be carriers and might show mild symptoms.
People with hemophilia often experience joint bleeding, which can lead to joint damage over time if not treated properly. Routine treatment involves replacing the missing clotting factors to prevent bleeding episodes.

Laboratory Values in Nursing

Laboratory values are essential in nursing to understand and monitor a patient's health status. They help in diagnosing diseases, including bleeding disorders like hemophilia. For hemophilia, specific tests like the activated partial thromboplastin time (aPTT) are critical.

• Prolonged aPTT: An extended aPTT indicates possible deficiencies in clotting factors VIII and IX, a hallmark of hemophilia.
• Prothrombin Time (PT): This measures time to form a clot via the extrinsic pathway, influenced by other factors not primarily affected by hemophilia.
• Fibrinogen Levels: Although related to clotting, deviations here are not typically linked to hemophilia.
• Platelet Count: High or low counts affect bleeding but do not directly relate to hemophilia's specific clotting factor issues.

Understanding these lab values allows nurses to provide targeted care and anticipate potential complications.

Clotting Factors

Clotting factors are proteins in blood plasma that work with platelets to stop bleeding by forming a clot. The process involves a cascade of events where each factor activates the next, a process divided into intrinsic, extrinsic, and common pathways.

• Intrinsic Pathway: Involves factors VIII and IX; deficiencies here are linked to hemophilia A and B.
• Extrinsic Pathway: Mainly involves factor VII; more related to other disorders, but not typically hemophilia.
• Common Pathway: Conversion of prothrombin to thrombin, leading to fibrin creation; essential for the final clot structure.

Recognizing how these pathways interact helps diagnose specific bleeding disorders. In hemophilia, the absence or dysfunction in factors VIII or IX disrupts the intrinsic pathway, leading to prolonged bleeding.