Midzonal necrosis in liver may occur in-
**Core Concept**
Liver cell necrosis can occur in different zones of the liver lobule, depending on the underlying cause. Midzonal necrosis is a specific pattern of liver cell death that is characteristic of certain types of liver injury.
**Why the Correct Answer is Right**
Midzonal necrosis typically occurs due to a combination of hypoxia and hypoperfusion in the midzonal area of the liver lobule. This type of injury often results from conditions that lead to a decrease in blood flow to the liver, such as **ischemia** or **congestive heart failure**. The midzonal area is particularly susceptible to injury because it is relatively far from the hepatic artery and portal vein, which supply oxygen and nutrients to the liver cells.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the pathophysiology of midzonal necrosis. While **cirrhosis** can lead to various types of liver cell injury, it is not specifically associated with midzonal necrosis.
* **Option B:** **Hepatitis B virus** infection can cause liver cell injury, but it is not typically characterized by midzonal necrosis. The pattern of liver cell injury in viral hepatitis is more variable and can include different zones of the liver lobule.
* **Option C:** **Carbon tetrachloride** toxicity can cause liver cell necrosis, but it is not specifically associated with midzonal necrosis. The pattern of liver cell injury in carbon tetrachloride toxicity is more diffuse and can involve multiple zones of the liver lobule.
**Clinical Pearl / High-Yield Fact**
Midzonal necrosis is often associated with conditions that lead to a decrease in blood flow to the liver, such as congestive heart failure or **shock**. This type of liver injury can be a marker of severe underlying disease and may require aggressive treatment.
**Correct Answer: B. Hepatitis B virus**