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': 'Centrizonal necrosis of liver occurs with -a) Carbon tetrachloride (CC14) toxicityb) Heart failure (CHF)c) Smoking (chronic)d) Chronic alcoholism \nSelect and explain. \nA. ac, B. ab, C. ad, D. bc', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hepatocellular necrosis: -\n\nLiver necrosis is a common manifestation of many liver diseases and it can present in various ways.\nIf severe it can cause liver failure.\nIn some cases however the necrosis is subclinical, revealed only by elevations of liver enzymes in serum.\nVarious diseases can cause different patterns of necrosis. These are —\n\nFocal Necrosis -\nRandomly occurring necrosis of single cells or small clusters of cells.\nIt can involve any area of the lobule\nAll lobules are not involved.\n\nCharacteristic features on biopsy are -\n\nCouncilman bodies\nAreas of lysed liver cells surrounded by collection of kupffer cells and inflammatory cells.\n\nCauses of Focal necrosis -\nViral hepatitis, Bacterial infections, Toxic damage\nZonal necrosis -\nThe characteristic of zonal necrosis is that identical regions of liver lobules are involved.\nAll liver lobules are involved.\nThe necrosis is divided according to the zone involved\n(Note: In focal necrosis any area of lobule and some lobules are involved.)\n\nTypes of zonal necrosis\n(a) Centrizonal necrosis (centrilobular) → Necrosis in the cells surrounding central hepatic vein, seen in -\n\nCardiac failure or shock \xa0 \xa0\xa0\nCarbon tetrachloride toxicity (CC14) \nChloroform toxicity\nViral hepatities\n\n(b) Peripheral zonal necrosis (periportal) → Necrosis is seen in areas around the portal tracts, Seen in\n(i)\xa0Eclampsia \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\n(ii)\xa0Phosphorus poisoning\n(c) Midzonal necrosis →\xa0Rare, seen in yellow fever\n\nAlso know —\n\nSubmassive necrosis → Occurrence of liver cell necrosis that is not limited by lobular boundaries i.e., the necrosis extends beyond lobular boundaries.\nMassive liver necrosis →\xa0In this large areas of liver cell undergo necrosis. Only small areas are left intact.\nMassive and submassive liver necrosis are clinically manifested as.\n\tAcute liver failure of variable severity\xa0\xa0\n\tSerum enzyme levels are very high', 'role': 'assistant'}]