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: Pathology
[{'content': 'True about Thrombocytopenic purpura is- \nSelect and explain. \nA. Haemolysis is extravascular, B. Normal renal function test, C. Thrombosis in cerebral blood vessels, D. Immediate cure following plasmapheresis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Thrombotic thrombocytopenic purpura (TTP)\n\nTTP is included among a group of diseases called thrombotic microangiopathic which are characterised by widespread thrombosis in microcirculation.\nThe other disorder which is included in this group includes hemolytic uremic syndrome (HUS).\nSmall vessels like terminal arterioles and capillaries are involved.\xa0\n\nPathogenesis of TTP\n\nPatients with TTP are deficient in an enzyme called ADAMTS13 also known as vWF metalloprotease that degrades very high molecular weight multimers of vWF.\nIn the absence of this enzyme, these multimers of vWF accumulate in plasma and promote platelet macroaggregate\xa0formation throughout the microcirculation leading to symptoms of TTP.\n\nClinical features\n\nTTP is characterized by a\xa0pentad\xa0of : -\n\n\nMicroangiopathic hemolytic anemia\xa0\xa0→\xa0Because red cells are forced to squeeze through abnormally narrowed small vessels because of thrombi.\nThrombocytopenia\xa0\xa0→\xa0 Due to consumption of platelets in the formation of platelet thrombi.\nNeurological symptoms \xa0→\xa0\xa0 Due to the presence of thrombi in CNS microcirculation.\nRenal dysfunction\xa0\xa0\xa0→\xa0 Due to the presence of thrombi in renal microcirculation.\nFever', 'role': 'assistant'}]