Match each clinical vignette describing a patient with a hypercoagulable or thrombotic disorder to the underlying pathophysiologic mechanism responsible for their presentation.
- A -year-old man presents with a left lower extremity deep venous thrombosis. He has no prior medical history but has a strong family history of venous thromboembolism. Laboratory evaluation reveals that his activated partial thromboplastin time (aPTT) does not prolong appropriately when exogenous activated protein C is added to his plasma sample.An inherited missense mutation resulting in a modified coagulation factor that resists proteolytic cleavage by a natural anticoagulant.
- A -year-old woman with a history of three consecutive early pregnancy losses presents with a swollen, painful right calf. Her aPTT is significantly prolonged. A mixing study with normal pooled plasma fails to correct the aPTT, but the aPTT normalizes completely upon the addition of excess exogenous phospholipids.Presence of circulating autoantibodies that bind to protein-phospholipid complexes, interfering with in vitro clotting assays but promoting in vivo thrombosis.
- A -year-old man presents with severe abdominal pain and is found to have a portal vein thrombosis. He reports frequent headaches and severe generalized pruritus after taking hot showers. Complete blood count shows a hematocrit of , leukocyte count of , and platelet count of . Serum erythropoietin is markedly decreased.An acquired somatic mutation in a cytoplasmic tyrosine kinase (JAK2), leading to constitutive downstream signaling independent of growth factors.
- A -year-old woman being treated for a pulmonary embolism develops exquisitely painful, demarcated purpuric lesions that rapidly progress to full-thickness skin necrosis on her thighs and abdomen. These lesions appeared on day of starting a new oral anticoagulant therapy.A transient hypercoagulable state caused by the rapid drug-induced depletion of a vitamin K-dependent natural anticoagulant with a very short half-life.
Cevap
Factor V Leiden matches to the inherited mutation resisting natural anticoagulants; Antiphospholipid syndrome matches to autoantibodies affecting phospholipid assays; Polycythemia vera matches to the acquired JAK2 mutation; Warfarin-induced skin necrosis matches to the rapid depletion of a short half-life protein.
Each clinical scenario uniquely maps to a distinct mechanism of hypercoagulability. The presentation of APC resistance is exclusive to Factor V Leiden. The inhibitor pattern on mixing study that corrects with phospholipids is the defining laboratory feature of Lupus Anticoagulant. Pancytosis with low EPO and an atypical venous thrombosis points unequivocally to the JAK2 mutation in Polycythemia Vera. Finally, skin necrosis upon warfarin initiation is the classic presentation of a rapid, drug-induced decline in Protein C.
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Anahtar Kavram
Pathophysiology and diagnostic hallmarks of acquired and inherited hypercoagulable states (Factor V Leiden, Antiphospholipid Syndrome, Polycythemia Vera, and Protein C deficiency/Warfarin necrosis).
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