Liver & Gall Bladder
Which of the following histologic changes is most likely to be seen in a biopsy specimen taken from liver of a pt who died from an overdose of acetaminophen ? (LQ)
|B||Focal scattered necrosis|
a. The type and distribution of necrotic hepatocytes is often a clue as to the cause of the hepatic injury.
b. Focal scattered necrosisis characteristic of viral hepatitis, but may also be seen with bacterial infections or other toxic insults.
c. In focal necrosis, there is necrosis of single hepatocytes, or small clusters of hepatocytes, that is randomly located in some, but not all, of the liver lobules.
d. In contrast, zonal necrosis refers to the finding of hepatocellular necrosis in identical areas in all of the liver lobules.
e. There are basically three types of zonal necrosis. Centrilobular (acinar zone 3) necrosis is characteristic of ischemic injury (heart failure or shock), toxic effects (acetaminophen toxicity), carbon tetra chloride exposure, or chloroform ingestion.
f. Drugs such as acetaminophen may be metabolized in zone 1 to toxic compounds that cause necrosis of zone 3 hepatocytes because they receive the blood from zone 1.
g. Midzonal (zone 2) necrosis is quite rare, but may be seen in yellow fever, while pen- portal (zone 1) necrosis is seen in phosphorus poisoning or eclampsia.
h. Submassive necrosis refers to liver cell necrosis that crosses the normal lobular boundaries.
i. Classically the necrosis goes from portal areas to central veins (or vice versa) and is called bridging necrosis.
j. If the hepatocellular necrosis is severe, it is called massive necrosis.