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Zorluk: OrtaMonitoring and Treatment Evaluation

A 52-year-old man is hospitalized for a proximal right lower extremity deep vein thrombosis. He is initially managed with a continuous intravenous unfractionated heparin infusion. On admission, his laboratory evaluation was unremarkable, including a platelet count of 240,000/mm³. On day 5 of hospitalization, routine morning laboratory testing reveals a platelet count of 110,000/mm³. He reports feeling well and is hemodynamically stable. Physical examination shows no new signs of bleeding, petechiae, or expanding edema. Which of the following is the most appropriate next step in the management of this patient?

  1. Discontinue unfractionated heparin and initiate a direct thrombin inhibitorCevap
  2. B
    Continue unfractionated heparin and order a serotonin release assay
  3. C
    Discontinue unfractionated heparin and initiate warfarin therapy
  4. D
    Continue unfractionated heparin and monitor the platelet count every 12 hours
  5. E
    Discontinue unfractionated heparin and transfuse one unit of apheresed platelets

Cevap

Discontinue unfractionated heparin and initiate a direct thrombin inhibitor
The clinical scenario presents a classic presentation of Heparin-Induced Thrombocytopenia (HIT) Type 2, which is characterized by an otherwise unexplained >50% drop in platelet count occurring 5 to 10 days after exposure to heparin products. The fundamental treatment evaluation step when HIT is suspected is the immediate discontinuation of all heparin products (including flushes) and the prompt initiation of an alternative, non-heparin anticoagulant. Direct thrombin inhibitors (such as argatroban or bivalirudin) or fondaparinux are the standard of care to prevent catastrophic arterial or venous thromboses.

Adım Adım Çözüm

1
Calculate the percentage drop in the patient's platelet count.
The platelet count decreased from 240,000/mm³ to 110,000/mm³, which is a >50% drop.
A >50% decrease in platelet count is a hallmark laboratory finding of Heparin-Induced Thrombocytopenia (HIT).
2
Analyze the timing of the thrombocytopenia relative to the medication exposure.
The drop occurred precisely on day 5 of unfractionated heparin therapy.
HIT type 2 typically develops 5 to 10 days after the initiation of heparin, as it takes time for the body to form IgG antibodies against the heparin-platelet factor 4 (PF4) complex.
3
Determine the necessary clinical intervention based on the suspected diagnosis.
The immediate required action is stopping all heparin products and starting a non-heparin anticoagulant.
Because HIT is a highly prothrombotic state, stopping heparin alone is insufficient; an alternative anticoagulant (such as argatroban or bivalirudin) must be given to prevent new thromboses while avoiding the complications of warfarin.

Anahtar Kavram

Monitoring for and managing Heparin-Induced Thrombocytopenia (HIT)
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Konular

Monitoring and Treatment Evaluation

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