This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': "Virchow's triad includes all of the following, EXCEPT- \nSelect and explain. \nA. Venous stasis, B. Injury to veins, C. Blood hypercoagulability, D. Venous thrombosis", 'role': 'user'}, {'content': "Answer: D \nExplanation: Virchow's triad refers to three primary influences that predispose to thrombus formation.\n\n\nEndothelial injury (or vascular injury)\nStasis or turbulence of blood flow\nBlood hypercoagulability\n\n\nVirchow's triad should be the cornerstone for assessment of risk factors for deep venous thrombosis.\nStasis can occur with venous insufficiency, severe heart failure, or prolonged bed rest or immobility of an extremity following coma, pelvic or limb fracture, paralysis, extended aeroplane travel, or a lengthy operation.\nEndothelial injury can result from direct trauma (severed vein, venous cannulation, or transvenous pacing) or local irritation secondary to the infusion of chemotherapy, previous DVT, or phlebitis.\n\nDamaged endothelium leads to platelet aggregation, degranulation and formation of thrombosis as well as vasoconstriction ad activation of the coagulation cascade.\nThe hypercoagulable state can be inherited or acquired.\nThese are\n\ndef. of antithrombin III, protein C or S\nincreased homocysteine\nfactor V Leiden mutation\nprothrombin gene mutation\nantiphospholipid syndrome\nparoxysmal nocturnal hemoglobinuria\nmalignancy (lung cancer - most commonly pancreas, prostate, breast, ovary etc...)\nnephrotic syndrome\npregnancy, high dose estrogen therapy or OCPs.\n\nSome important questions on deep vein thrombosis\n\nHoman's sign → Calf tenderness on forced ankle dorsiflexion.\nPhlegmasia alba dolens → Painful white leg\nPhlegmasia cerulea dolens → Painful blue leg\nMoses Sign → Calf tenderness on direct pressure on the calf\nPratt's Sign → Calf tenderness on squeezing the calf from the sides. Duplex ultrasound is the diagnostic modality of choice in deep vein thrombosis.", 'role': 'assistant'}]