20.500.12556/DiRROS-29180 Venom-induced recurrent thrombocytopenia a model of intervention-driven platelet modulation We present the case of a Vipera ammodytes ammodytes (Vaa, nose-horned viper)-bitten patient with recurrent thrombocytopenia. A 53-year-old patient envenomated by Vaa experienced three episodes of venom-dependent thrombocytopenia (4, 57 and 11 × 109/L), all of which we managed with antivenom Fab fragments. Despite these three severe episodes of thrombocytopenia within 24 h, platelet function remained intact, as demonstrated by normal thromboelastometry and aggregometry (96, 126, and 150 U) results after antivenom was administered and the platelet count normalized. Furthermore, flow cytometry showed only 0.3–1.7% expression of P-selectin on platelets, indicating that platelets did not activate but remained functional during and after thrombocytopenia. We assessed platelet function using rotational thromboelastometry, which evaluates the overall kinetics of hemostasis, including clot formation and stability. We performed aggregometry, which also reflects platelet function, only when the platelet count was within the normal range. Flow cytometry quantified P-selectin expression as a key marker of platelet activation. This case demonstrates that a component of Vaa venom can repeatedly induce venom-dependent thrombocytopenia, which is reversible by intervention, while platelet function remains intact. Vipera ammodytes ammodytes venom thrombocytopenia functional platelets snaclec strup trombocitopenija funkcionalni trombociti true false true Angleški jezik Slovenski jezik Neznano 2026-04-23 10:08:34 2026-04-23 10:08:34 2026-04-24 04:05:28 0000-00-00 00:00:00 2025 0 0 Nasl. z nasl. zaslona; Opis vira z dne 24. 12. 2025; str. 1-7 iss. 12, [Article no.] 605 Vol. 17 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 615.9 2072-6651 10.3390/toxins17120605 262844931 RAZ_Dobaja_Mojca_2025.pdf RAZ_Dobaja_Mojca_2025.pdf 1 6743AA541B42BFEAC2C9E2B3FDFE3EFD 720cf1caa598a016a553c90c2c68aa091f6ef461abcf2f3c2ceb127ee0fa97a3 c1dfbc21-3eeb-11f1-b867-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=43623 https://www.mdpi.com/2072-6651/17/12/605 1 a212698c-3eeb-11f1-b867-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=43622 Univerzitetni klinični center Ljubljana 0 0 0