Development of hepatic central lobular necrosis secondary to acetaminophen overdose can be prevented effectively by which of the following if given within a few hours after ingestion :
**Core Concept**
Hepatic central lobular necrosis is a form of acute liver failure caused by acetaminophen (paracetamol) overdose, leading to severe coagulopathy, encephalopathy, and potentially death. The pathophysiology involves the formation of a toxic metabolite, N-acetyl-p-benzoquinone imine (NAPQI), which depletes glutathione stores and causes mitochondrial damage.
**Why the Correct Answer is Right**
N-acetylcysteine (NAC) is the antidote for acetaminophen overdose. It works by replenishing glutathione stores, which are depleted by NAPQI, thereby preventing liver damage. NAC also has antioxidant properties that help neutralize NAPQI. Administering NAC within a few hours after ingestion is crucial, as it can effectively prevent the development of hepatic central lobular necrosis.
**Why Each Wrong Option is Incorrect**
**Option A:** Activated charcoal may be used to prevent absorption of acetaminophen in cases of recent ingestion, but it is not effective in preventing liver damage once the toxic metabolite has formed.
**Option B:** Fomepizole is used to treat methanol or ethylene glycol poisoning, not acetaminophen overdose.
**Option C:** Penicillin is an antibiotic used to treat bacterial infections and has no role in the management of acetaminophen overdose.
**Clinical Pearl / High-Yield Fact**
NAC should be administered within 8-10 hours of acetaminophen ingestion for optimal effectiveness. The treatment window can be extended up to 24 hours in patients with elevated liver enzymes or coagulopathy.
**Correct Answer:** C. N-acetylcysteine