Acetaminophen poisoning causes which of the following changes in the liver?
**Core Concept**
Acetaminophen (APAP) poisoning leads to hepatocellular injury through the formation of a toxic metabolite that depletes glutathione levels in the liver, leading to mitochondrial damage and cell death. This process is mediated by the cytochrome P450 enzyme system, specifically CYP2E1.
**Why the Correct Answer is Right**
The toxic metabolite of APAP, N-acetyl-p-benzoquinone imine (NAPQI), is produced through the cytochrome P450 system. Normally, NAPQI is detoxified by glutathione, but in the setting of APAP overdose, glutathione stores are depleted, allowing NAPQI to accumulate and cause mitochondrial damage and DNA fragmentation. This ultimately leads to hepatocyte apoptosis and necrosis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because APAP poisoning does not primarily cause cholestasis, which is a decrease or stoppage of bile flow. APAP-induced liver injury is characterized by hepatocellular damage rather than bile duct obstruction.
**Option B:** This option is incorrect because APAP poisoning does not primarily cause fatty liver disease. While some patients with APAP overdose may develop fatty liver changes, this is not the primary mechanism of liver injury.
**Option C:** This option is incorrect because APAP poisoning does not primarily cause autoimmune hepatitis. APAP-induced liver injury is a direct toxic effect of the drug rather than an autoimmune response.
**Clinical Pearl / High-Yield Fact**
Remember the "APAP-ALPS" acronym to help remember the key points of acetaminophen toxicity: **A**cetaminophen-induced hepatotoxicity, **P**roduction of NAPQI, **A**ccumulation of NAPQI in the liver, **P**roduction of mitochondrial damage, and **Q**ualitative depletion of glutathione stores.
**Correct Answer: C. Hepatocellular injury**