Thrombelastography as screening test for the diagnosis of Scott syndrome
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Tipo de produção
conferenceObject
Data de publicação
2012
Título da Revista
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Título do Volume
Editora
WILEY-BLACKWELL
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Citação
HAEMOPHILIA, v.18, suppl.3, Special Issue, p.105-105, 2012
Resumo
Background: Scott syndrome (SS) is a rare bleeding disorder, characterized by impaired platelet procoagulant activity (PCA). The laboratory tests for its diagnosis are available in specialized laboratories, and sometimes only for research purposes. Case Report: A 35 year-old male patient was referred to our centre for diagnosis of hemostasis disorder. He had a history of bruises and hematomas since childhood. Blood transfusion was required after postectomy and crural hernioplasty. His family history for bleeding was negative. Laboratory investigation showed normal measurement of all coagulation factors, including VWF antigen/activity, normal evaluation of fibrinolytic system (alpha2-antiplasmin, plasminogen, and euglobulin lysis time), as well as plateletaggregometry (ADP, ADR, arachidonic acid, collagen, and ristocetin). Thrombelastography (TEG) was hypocoagulant (prolonged R and K; reduced angle MA, G, TG, MRTG, and TMRTG), which led us to consider abnormality of PCA. Then a series of TEGs was performed, mixing total blood (patient and control) with platelet-poor plasma (PPP) and platelet-rich plasma (PRP) of the patient and control. When PRP (control) was added to patient’s total blood, TEG was normalized, suggesting PCA dysfunction, and the hypothesis of SS was made. A PCA test was performed using washed platelet and activated prothrombinic complex, resulting in reduced PCA. After that, we performed the phosphatidylserin expression by flow cytometry, using annexin V and a thrombin generation assay (TGA) with control PRP, confirming the diagnosis of SS. Conclusion: SS is a rare disease, and usually confirmatory tests are not part of the routine, even in specialized laboratories. TEG using mixtures of total blood and PRP of patient and control can be a simple and less expensive alternative method for screening impaired PCA in patients with bleeding disorders. In this case, such an approach helped in elucidating the diagnosis when sophisticated tests such as annexin V and thrombin generation were not promptly available.