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Zorluk: ZorHemodynamic and Coagulation Processes

A 74-year-old man is evaluated in the emergency department for a 1-week history of progressively enlarging, spontaneous bruises on his trunk and arms. Today, he developed severe right thigh pain and swelling, rendering him unable to walk. He has no prior personal or family history of abnormal bleeding. His medical history is significant for rheumatoid arthritis and hypertension. Current medications include methotrexate, low-dose prednisone, and amlodipine. His temperature is 37.1°C (98.8°F), blood pressure is 105/65 mm Hg, and pulse is 112/min. Physical examination reveals a large, tense, and highly tender hematoma over the right anterior thigh, along with multiple extensive ecchymoses across his chest and abdomen. Laboratory studies are as follows:

TestResultReference Range
Hemoglobin8.8 g/dL13.5–17.5 g/dL
Platelet count245,000/mm³150,000–400,000/mm³
Prothrombin time (PT)11.5 sec11–14 sec
Activated partial thromboplastin time (aPTT)82 sec25–40 sec

A 1:1 mixing study with normal pooled plasma is performed, and the patient's aPTT remains prolonged at 76 seconds.

Which of the following is the most appropriate next step in management to achieve acute hemostasis?

  1. Administration of recombinant factor VIIaCevap
  2. B
    Administration of factor VIII concentrate
  3. C
    Administration of fresh frozen plasma
  4. D
    Intravenous infusion of desmopressin
  5. E
    Administration of high-dose intravenous immunoglobulin

Cevap

Administration of recombinant factor VIIa
The correct response is the administration of recombinant factor VIIa. This patient's clinical presentation—sudden onset of severe, spontaneous soft-tissue bleeding in an older adult with an underlying autoimmune disorder—is classic for acquired hemophilia A. This condition is caused by the spontaneous development of neutralizing autoantibodies (inhibitors) directed against factor VIII. Laboratory hallmarks include an isolated prolonged aPTT and a normal PT. The critical diagnostic step is the 1:1 mixing study: failure of the aPTT to correct when mixed with normal pooled plasma confirms the presence of an inhibitor rather than a factor deficiency. Because the high-titer autoantibodies will rapidly neutralize any administered factor VIII, traditional replacement therapies (e.g., factor VIII concentrate, fresh frozen plasma) are ineffective for acute bleeding. Instead, hemostasis must be achieved using 'bypassing agents' such as recombinant factor VIIa or activated prothrombin complex concentrate (aPCC). Recombinant factor VIIa directly activates factor X on the surface of activated platelets, bypassing the requirement for the factor VIII/IXa complex and effectively generating a thrombin burst to halt the hemorrhage.

Adım Adım Çözüm

1
Interpret the coagulation panel and mixing study results.
The patient has an isolated, severely prolonged aPTT that fails to correct following a 1:1 mixing study with normal plasma.
Failure to correct on a mixing study distinguishes a factor inhibitor (neutralizing autoantibody) from a simple factor deficiency.
2
Integrate laboratory findings with the clinical presentation.
The presentation of severe spontaneous bleeding (muscle hematoma) in an elderly patient with an autoimmune disease (rheumatoid arthritis) and a factor inhibitor points to acquired hemophilia A (factor VIII inhibitor).
Acquired hemophilia A typically presents in older adults or post-partum women, often associated with autoimmune conditions or malignancies, and causes life-threatening soft tissue bleeding.
3
Determine the optimal pharmacotherapy to rapidly reverse the coagulopathy and achieve hemostasis.
A bypassing agent, such as recombinant factor VIIa or activated prothrombin complex concentrate (aPCC), must be administered.
Standard factor VIII replacement strategies are rendered ineffective by the circulating autoantibodies. Bypassing agents initiate the coagulation cascade downstream or independently of factor VIII to stop the bleeding.

Anahtar Kavram

Acquired Hemophilia A Management
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Konular

Hemodynamic and Coagulation Processes

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